California red scale is a citrus pest found throughout California, except in Coachella Valley, where an eradication program is in place. These insects may be tiny, but California red scale is a serious pest of citrus trees. And their range is expanding. Like other armored scale insects, California red scale (Aonidiella aurantii) have piercing, filamentous mouthparts that are inserted into stems, fruit, and leaves, and suck life-giving sap from your tree. These particular scale insects prefer lemons, limes, Valencia and Navel oranges.
California red scale and yellow scale are almost indistinguishable to the untrained eye. Yellow scale (Aonidiella citrina) is less of a problem than red scale and is rarely found on mature wood, whereas red scale can be found anywhere on the tree. The two pests behave in very similar ways, with the California red scale being a far more problematic pest. Red scale lifecycle You will probably never see a tiny, flying male red scale. They live for about 6 hours and have only one purpose. The females, however, attach themselves to your citrus trees, where they feed on your tree and give birth to 100 to 150 crawlers. Two or three crawlers are born every day to each female. These crawlers leave to find their own feeding site. They can also be blown to nearby trees by the wind, or move from place to place by catching a ride on a bird in a practice known as phoresy - though I don’t know if they do it on purpose. Once they settle on a new location, both males and females begin to grow a waxy dome over themselves. Male covers are more elongated, while female covers are more rounded. Females molt two more times, while males molt under their first dome four times before taking to the air. Damage caused by California red scale Chlorosis, twig and branch dieback, fruit loss, and, in severe cases, tree death can all result from California red scale infestations. This damage most commonly occurs at the end of summer, when trees are water stressed and scale populations are at their peak. How to control California red scale Scale insects are naturally protected from pesticides. And California red scale has developed a resistance to many insecticides, so, unless you are a commercial farmer or city government, you do not have access to chemicals powerful enough to kill off California red scale. [And would you really want to spray that stuff on your food?] Keeping your trees healthy with regular, deep summer irrigation will reduce water stress. And avoiding the use of broad spectrum insecticides will allow natural predators to do their thing against scale populations. Parasitic wasps and several varieties of lady beetles can provide significant control of scale insects. Because ants, dust, and poor air flow all make it more difficult for these beneficial predators to find and catch their prey, be sure to prune for good air flow, wrap tree trunks with sticky barriers to block ants, and give your trees an occasional rinse with the hose during the dustier parts of summer. In winter, apply dormant oils. The next time you go water your citrus trees, take a closer look to see if California red scale has made an appearance. With a name like insidious flower bugs, I had to write about them. These predatory insects are a type of minute pirate bug. They eat many small garden pests and their eggs. And they bite. Insidious flower bug bites Yes, insidious flower bugs (Orius insidiosus) bite. We don’t know why. And it hurts. A lot. Some people react to these bites with welts, swelling, or redness, while others have no reaction [other than the pain]. Since these insects are not quick to fly away after biting, you may get some satisfaction out of ending them, but that wouldn’t be in your garden’s best interest. And insidious flower bug bites cannot actually harm you. In fact, they are so tiny that robber flies eat them. [Thanks to Jim Elve for permission to use this amazing photograph!] Beneficial biter
Despite their bite, insidious flower bugs really are beneficial. They feed heavily on thrips [their favorite food], corn earworm eggs, mites, spider mites, small caterpillars, bollworms, whiteflies, scale insects, European corn borers, armyworms, potato leafhoppers, and a slew of aphid varieties, including spotted tobacco aphids, corn leaf aphids, and potato aphids. Insidious flower bugs are so beneficial, that they are raised commercially as a biological control against thrips, European red mites, twospotted spider mites, and most aphid varieties in eggplant, strawberry, cucumber, and sweet peppers crops. Research conducted in Florida found that insidious flower bugs were more effective at controlling thrips on sweet peppers than insecticides. Other research has demonstrated similar results with twospotted spider mites on bean plants, and soybean aphids on soybeans. Insidious flower bug description These mixed blessings are small, only 1/5 of an inch long. They tend to be flattened, with an oval to triangular shape. They are black with white markings. Nymphs are yellowish-orange to brown, wingless, and teardrop shaped. If you look at an insidious flower bug under a microscope, you can see that they have piercing mouthparts, called beaks, which they use to repeatedly stab and suck the juices from their prey. Orius insidiosus lifecycle Insidious flower bugs seem to come out of the woodwork in late summer, though they have been around since they hatched, starting in spring. Eggs are laid in plant tissue, then hatch into nymphs, going through five instars before reaching adulthood. This takes approximately 20 days, and there can be several generations a year. Most of their diet consists of insects and insects eggs, but they occasionally eat plants and pollen when prey is scarce. Attracting insidious flower bugs Despite the bite potential, these predators are good to have around. You can attract them to your garden by growing alfalfa, buckwheat, soybeans, cotton, grapes, and most deciduous fruits. You can reduce the chances of getting bit by wearing dark clothing on hot days in late summer. For the most part, insect repellants do not work against these garden visitors. If you love your trees (or your blueberries), be on the lookout for Asian longhorned beetles.
The U.S. Customs Department is working hard to halt the importation of these pests. Eradication in the U.S. is still possible, but it’s an uphill battle. And they need our help. Asian longhorned beetle identification Asian longhorned beetles (ALBs), also known as starry sky or sky beetles, are easy to identify. Approximately one inch wide and and an inch-and-a-half long, they are shiny black with 20 white spots on each wing cover, and they feature an impressive set of black and white banded antennae. They have long, whitish-blue feet and large mandibles. Larvae are large and cream colored. ALB lifecycle Adult female beetles chew pits into wood and then deposit their eggs into those pits, one at a time. She can lay up to 90 eggs in just a few weeks. When the eggs hatch, larvae tunnel deep into the tree (where they are safe from predators and pesticides), leaving behind a trail of frass. Deep within the tree, the larvae go through several instars before entering a pupal stage. As adults, they tunnel out of the tree, leaving 3/8-inch exit holes along trunks and branches. Piles of frass can be seen at the base of infected trees and in branch crotches. Branch dieback and leaf wilting are early signs of infestation. The egg sites and larval feeding make the trees susceptible to many other pests and diseases, as well as more vulnerable to damage from heavy winds. Sap is often seen oozing from wounds. This larval tunneling causes extensive damage and girdling, making the wood unusable and eventually killing the tree. Infested trees must be removed and destroyed by trained professionals. Do not attempt this yourself. Trees susceptible to ALB
Many popular hardwood trees are vulnerable to ALB infestation. These trees include alder, ash, beech, birch, boxelder, elm, hackberry, hornbeam, horse chestnut, mimosa, planes, poplar, sycamore, and willow. And blueberries! And members of the Prunus family, which includes apricots, peaches, nectarines, cherries, and almonds! We do not yet know what the impact will be on California’s native hardwood trees. Experts predict that this pest could cause more damage than gypsy moths, Dutch elm disease, and chestnut blight combined, destroyed millions of acres of trees across the country, in parks, along streets, in backyards, and in agriculture. Dead and dying trees are more likely to cause fires and they are unable to support the biodiversity that keeps a region healthy. If you consider all the wood-based products we use every day, ALB could cause many prices to increase significantly. All because of an insect. If you see it, catch it! Report it! If you see an Asian longhorned beetle, catch it. Period. Just do it. They don't bite or sting. While they can fly, they don’t do it very well and only for short distances. You can do this. Your efforts could save millions of trees and billions of dollars. Seriously. Put your captive in a glass jar [they chew through trees, remember?] and place it in the freezer. Be sure to label the jar with where you found it (GPS position, if possible), the date you found it, and your contact information. These reports are critical if we are to protect our trees. Using this information, experts can create quarantine zones and implement eradication programs most effectively. If you live in California, call the CDFA hotline at 1-800-491-1899. In fact, put the number in your phone now, so you’ll have it if you ever need it. I did. If you live outside of California, report it to your state’s Department of Agriculture. Together, we can save millions of trees. Ladies bugs, or lady beetles, are always welcome in the garden, except when they’re not. Because, if it’s a Mexican bean beetle, it’s the last thing you want to see in your garden! Mexican bean beetles are found throughout Mexico and much of the eastern U.S., and in areas west of the Rockies that receive a lot of rain or irrigation. These pests have been found in and eradicated from California once. Let’s find out why Mexican bean beetles are so bad.
Mexican bean beetle identification Mexican bean beetles look like ladybugs, sort of. They have the same oval, domed shaped, and they have spots. To be exact, Mexican bean beetles have eight black spots on each side. These evil cousins to ladybugs can range in color from golden yellow to a rusty brown. Larva look like spiny oval pills and the eggs are yellow. Pupae are found hanging from the underside of leaves. Mexican bean beetle lifecycle In late spring, adults emerge and begin feeding and breeding. Each female will lay hundreds of eggs in clusters on bean leaves. When these eggs hatch, the real damage begins. Heavy infestations can defoliate an entire field of legumes. After a few weeks of feeding, the larvae enter a pupal stage. Newly emerged adults often travel long distances in their search for food. Host plants Mexican bean beetles (Epilachna varivestis) are a type of lady beetle that eats plants, rather than other insects. In particular, these pests feed on legumes. That means your cowpeas, mung beans, soybeans, green beans, wax beans, lima beans, peas, and fava beans are at risk. It also means you need to monitor any alfalfa, peanuts, wisteria, lupins, tamarind, carob, and lentils for signs of Mexican bean beetle feeding. Mexican bean beetle damage and control Adult beetles feed on the undersides of leaves, leaving them skeletonized. Beetles may also feed on fruit and flowers. The larvae eat even more than the adults! Luckily, parasitic wasps can do a lot to reduce bean beetle populations, so avoid using broad spectrum pesticides and insecticides. You can also use row covers when you know that Mexican bean beetles are present or likely to appear. As always, take the time to quarantine new plants. If you live in California and suspect seeing a Mexican bean beetle, please try to capture it and report it to the California Pest Hotline at 1 (800) 491-1899, or contact your local Department of Agriculture. Moles are creatures of darkness. They almost never leave their tunnels. Often falsely blamed for plant damage, moles are primarily insect eaters. Mole description Moles are rather funny looking. They have stubby, hairless tails, cylindrical bodies (usually 5 to 7 inches long), pointed snouts, and short, webbed hands and feet. They don’t see very well because their eyes are covered with skin, and you can’t see their ears. Mole fur, however, is quite thick and velvety, and moleskin is the stuff of hiking blister legends. There are 42 mole species worldwide, 7 of which live in North America, and 4 species found in California:
Moles like their privacy. Unless it’s the breeding season, you will only find one mole per tunnel system. Moles have one litter each year, usually with 3 or 4 young, in spring. Differences between moles and pocket gophers Many people assume that moles and voles (also known as pocket gophers) are related. They are not. Voles are plant eating rodents, while moles are primarily insect-eating members of the Scapanus species, more closely related to shrews. Crescent-shaped mounds with closed holes indicate the presence of pocket gophers. Pocket gopher populations can lead to girdled trees, slope erosion, and dead plants. Moles, on the other hand, have round mounds which may have open or closed holes, and long surface ridges from their shallow tunnels are often visible. Moles normally feed on worms, grubs, insects, and other invertebrates. Moles will occasionally eat mice, shrews, and nuts. Your average mole will eat 40 pounds of insects each year. Mole tunnels
Moles create an extensive system of both deep and shallow tunnels. The deeper tunnels are their permanent housing, with separate rooms for food storage, sleeping, and rearing young. Tunnels are usually 2 inches in diameter and found 8 to 12 inches below the soil surface. The shallow tunnels are for hunting out grubs, worms, centipedes, and other soil dwelling creatures. It is the shallow tunnels that cause most of the problems associated with moles. As they burrow under the surface of the soil, looking for their supper, moles often dislodge smaller plants and expose root systems to the air, drying them out. If you want a lawn that looks like a putting green, moles are not your friends. Mole management If you cannot tolerate moles in your garden or landscape, trapping will be necessary. While there are dozens of repellants, scaring devices, home remedies, and plants that claim to offend moles, research has not shown that any of these methods actually work. The only exception is castor oil solutions, which have been shown effective on eastern moles. Flooding tunnels wastes water and does not rid an area of moles. [They’ve dealt with floods for far longer than we have been gardening.] Trapping always works. Underground harpoon traps and scissor-jaw traps are the most effective methods. Of course, this means dealing with a dead mole and a messy trap. Some new mole baits are showing limited effectiveness, but then you have to worry about children, pets, and local wildlife also suffering a horrible death. Plus, if your landscape was appealing to a mole before, it probably will be again, to a different mole. If you have valuable plants that need protection against moles, you can install a hardware cloth barrier 2-feet into the ground, with a 6-inch lip bent at a 90° angle away from the plant to thwart mole digging. Mole trivia Moles are fascinating creatures. Some of the more interesting mole facts include:
If you can tolerate moles, they actually provide many benefits to the garden and landscape. Did you know that mole saliva contains toxins that paralyze earthworms? Researchers have found underground storage spaces filled with thousands of paralyzed earthworms, for later eating. Now you know. Kuno scale is a pest of plum and other stone fruits.
Like other soft scale, kuno scale (Eulecanium kunoensis) is a sap-sucking insect that hides under a dome-shaped protective barrier. Unlike armored scales, which can be separated from their dome, kuno and other soft scales are attached to their dome. Kuno scale description Kuno scale females are 1/6 of an inch in diameter and a dark, shiny brown. They actually look like tiny beads on tree stems, during summer. Just before egg production, they turn yellow or orange, with black markings. During winter, they are more flattened and less shiny. If you remove a kuno scale from its host, you will see a visible lip on her body, which is used as a point of attachment. Nymphs are flattened, and either brown or yellow. Male cocoons are 1/12 of an inch long and translucent. Kuno scale lifecycle Eggs hatch under their mother in spring. These first instar nymphs are called ‘crawlers’ because they crawl away from her and find a place to feed on leaves throughout the summer, going through multiple instars as they feed. In fall, mature nymphs find a hiding place on twigs just before leaf fall. These nymphs overwinter on twigs and reach adulthood in spring, just in time to lay more eggs. Kuno scale damage As a sap-sucking insect, Kuno scale sucks phloem sap from twigs and leaves. While it prefers plum trees, Kuno scale can also be found on peach, cherry, nectarine, apricot, and almond, as well as rose, walnut, and pyracantha. These pests can populate an area so quickly, that it can seem as though they appeared overnight. Plants may appear water stressed. Heavy infestations can lead to twig dieback and premature leaf drop. Also, Kuno scale produces a lot of honeydew (sugary poop). Honeydew is the perfect growth medium for sooty mold. It also attracts ants, which will protect and farm Kuno scale. If you see ant trails on your plum tree, make a point of finding out where they are going in your tree. Kuno scale control Since ants protect Kuno scale from natural predators, blocking ants from getting up in your trees is the easiest control measure. To do this, simply wrap the tree trunk with a sticky barrier. You can also apply horticultural oil to twigs and the ends of branches just as buds are swelling, in spring. You can also try drenching the undersides of leaves in early summer, but this is tricky, because it’s not a good idea to spray dormant plum or walnut trees with oil, especially during periods of drought. And, let’s face it, spraying the underside of leaves is a royal pain. Stinging insects can really take the fun out gardening. Knowing what to watch for can reduce your chances of getting stung. Some insects will bite you, while others have a chemical arsenal at their disposal that they can inject through a stinger which may or may not be barbed. While bug bites may suck, today we are talking about those insects with stingers. Those insects are bees, wasps, and one type of ant. Stingers A stinger is a pointed organ, often attached to a venom gland. The venom causes pain and paralysis of specific organs within the victim. Normally found at the tail end of an insect, stingers are used as weapons against real and perceived threats. Most stingers are relatively smooth and can be used repeatedly. Honey bees and a handful of other species have barbed stingers that are torn from the insect’s body, causing it to die with minutes. These barbed stingers, once embedded in flesh, continue to saw their way deeper, injecting even more venom. This is why it is so important to remove the stinger as soon as possible after being stung. [Barbed stingers are able to sting other insects repeatedly without harming the attacker.] Bees Buzzing bees are usually a welcome sound in the garden. As highly efficient pollinators, they are the reason many of our crops produce food for us. There are over 20,000 species of bees around the world, but the honey bee is the most well known. If a honey bee stings you, it is because she feels that she, or her hive, are threatened. Moving deliberately and calmly around bees is often all it takes to avoid getting stung. There are four major types of bees found in North America: bumble bees, carpenter bees, honey bees, and sweat bees: Bumble bees Bumble bees (or bumblebees) are important pollinators. Fat, furry, and hard working, it is best to leave these garden helpers alone. Their stings are about as painful as a honey bee sting, but they only sting when provoked. California varieties include the American bumble bee, western bumble bee, golden northern bumble bee, tricolored bumble bee, and the yellow-faced bumble bee. Small colonies often build nests under patios and attic soffits. Carpenter bees Solitary carpenter bees build circular holes and tunnels in wood. While they may damage your fence, they are powerful pollinators. Male carpenter bees look like golden teddy bears and they cannot sting you. Female carpenter bees are a metallic black and rather noisy. Generally, they will not sting if you leave them alone.
Sweat bees Tiny sweat bees are often mistaken for flies. Sweat bees are attracted to the salt in human sweat. They do sting, but it is considered only mildly painful. Varieties found in California include the agapostemon and bicolored agapostemon sweat bees. Wasps Wasps are aggressive. They will come after you, and sting multiple times. While wasps do not pollinate flowers, they are garden predators. Wasps will also parasitize many garden pests by laying their eggs on or in other insects. Unlike most bees, which are covered with tiny hairs, wasps are smooth-bodied and are usually marked bands of black and yellow. Wasps have remained relatively unchanged over the past 34 million years. There are over 75,000 species of wasps around the world. Many different types of wasps found in California including blue-winged, braconids, common thread-waisted, black and yellow mud dauber, cuckoo, four-toothed mason, ichneumon, short-tailed ichneumon, and giant ichneumon, great black, great golden digger, horntail, leucospid, multillid, potter, spider wasps, and weevil wasps. Not all of these species attack humans. Hornets and yellow jackets are both types of wasps that do attack. Hornets (Provespa and Vespa genera) There are 22 species of Vespa and 3 species of Provespa. Provespa are unique in that they are nocturnal. Hornets are aggressive social insects. They feed on sugary plants and fruit, as well as other insects, including honey bees. Hornet stings are more dangerous to humans that other insect stings because they contain higher concentrations of acetylcholine. Hornet stingers are not barbed and can be reused many times. Also, when one hornet stings you, it releases chemicals that tell other hornets to sting you, as well. These same chemicals are also released when you kill a hornet, so be forewarned. Hornets build ‘paper’ nests in trees and under the eaves of houses. Bald-faced hornets and European hornets are commonly found in California. Yellow jackets Most yellow jackets are black and yellow, though some are black and white. Yellow jackets have a distinct side-to-side flying pattern and all female yellow jackets have barbed stingers that can reused several times. They do not carry pollen on their legs. Yellow jackets prey on pest insects., and they feed on nectar, fruit, and tree sap. Yellow jackets build paper nests in trees, burrows, and under house eaves. Only the inseminated queen lives through the winter. All the other members of a yellow jacket colony die the year they are born. Yellow jackets are responsible for the greatest number of allergic reactions among stinging insects. They are often found around trash cans and picnics. Ants There are many different ant species found in California, but only the red imported fire ant (RIFA) has a stinger. While other ants can inflict a painful bite, fire ant stings burn furiously for quite a while. There is no mistaking that sensation! Red imported fire ants (RIFA) came to North America in 1985, from South America. By 1998, they had spread throughout the southeastern states, from their point of entry in Alabama. By 2007, fire ants had found their way to the west coast and everywhere in between. Fire ants eat meat, grain, sugar, and grease. They are a highly organized social species that will work together to kill young livestock and wildlife. They can really dampen a picnic, too. Be on the look-out for mounds in the soil. Allergies
If you are allergic to wasps, you will also be allergic to hornets. If you are allergic to stinging insects, you should always carry antihistamines or an EpiPen with you. Signs of an allergic reaction include shortness of breath, swelling of the face, lips, or throat, severe itching, weak or racing pulse, nausea, wheezing or gasping. If any of these symptoms occur, get medical help immediately. Call 911, grab a family member, or a neighbor right away. These symptoms can quickly escalate into a life-threatening situation. Otherwise, follow these steps to ease your temporary pain. If you get stung If you are unlucky enough to get stung, inspect the area to see if a stinger is visible. If it is, scrape it out with your fingernail. Then, clean the area with soap and water, take an antihistamine, and apply an ice pack. You can also take aspirin or acetaminophen to ease the pain, just be cautious about mixing medications, as that can cause yet another medical problem. Generally speaking, you are going to feel really miserable for 30 to 45 minutes, moderately uncomfortable for the rest of the afternoon, and you may experience discomfort for a week or so. You may also want to apply hydrocortisone or calamine lotion to the area. Pastes made of baking soda or colloidal oatmeal can also sooth the area. If you haven’t had a tetanus shot in the past 10 years, it can be a good idea, as well. To avoid gettin stung, take the time to look before reaching into an area, and wear protective clothing when outside. Cottony cushion scale inspires a certain measure of fascination. One look at these intricate insects, and you’re sure to want to learn more. Cottony cushion scale (Icerya purchasi) are soft scale insects. Like other scale insects, their lifecycle touches on the bizarre. But before we get started, take a look at this photo and see if you can figure out what, exactly, is insect and what might be something else. Cottony cushion scale lifecycle Females can produce young with or without the help of a male. She will lay 600 to 800 eggs. Before she does, she will carry them around in a white, fluted sac that can be 2 or 3 times the length of her body. Most people mistake this egg sac for the insect’s body. Did you? The eggs hatch out into crawlers. First stage (instar) crawlers are red, with black legs and antennae. These newlings make their way to nearby leaf veins, where they will begin producing their telltale white, cottony secretion. As they grow, these tiny pests will shed their outgrown skins (molt) and grow a bigger protective coating. Second instar crawlers make their way to twigs and leaves. Third instars prefer branches. Adults are usually found on branches and tree trunks. Nearly every cottony cushion scale insect you see will be female, and they tend to form colonies. The males have red wings, but are really too small to see. The image below was taken after a female and her eggs were collected and placed in a container until they hatched. The coin next to them is a dime. Damage caused by cottony cushion scale
Scale insects feed by inserting tiny, straw-like structures into bark, leaves, or fruit. One attached, they will suck the sugary juices out of fruit, or mainline sap directly from the xylem. This high sugar diet results in the insects pooping out honeydew, an equally sweet, high nutrient discharge that ants and fungi just love. Heavy infestations can lead to overall stress and loss of vigor, branch dieback, and defoliation of affected areas. Very often, it is the presence of sooty mold and heavy ant traffic that will first cue you to the presence of scale insects. How to control cottony cushion scale Natural predators do a much better job of controlling these pests than we do. Specifically, the vedalia beetle (Rodolia cardinalis) and the parasitic fly (Cryptochaetum iceryae) feed only on this particular pest and nothing else. Normally, these two beneficial insects are all that is needed to control a cottony cushion scale infestation. Unfortunately, dust, ants, and insecticides can interrupt that assistance. 'Ants will actively protect and farm scale insects. You can remove that protection by attaching sticky barriers around the trunks of trees. Chemical controls are not generally effective against cottony cushion scale insects (regardless of what they say on the label). Take a look at your trees on a regular basis to see if cottony cushion or other scale insects have set up shop in your garden. Earworms. Those songs that get caught in our mind and play over and over and over… These are not those earworms, but they can be just as annoying. You don’t grow corn, you say? Don’t think that your garden plants are off the hook, just yet. The larval form of the corn earworm (Helicoverpa zea) goes by several names, such as cotton bollworm and tomato fruitworm. Tomato?!!? Yes, this is the dreaded tomato fruitworm. And these innocuous-looking moths can migrate as far as 400 km (or nearly 250 miles) to get at many favorite garden plants, including melon, beans, spinach, soybeans, peas, okra, squash, and sweet potato. Corn earworm description Adult moths are a little more than an inch across, and pale tan to light brown. The front wings can have various markings, and the hind wings are dirty white with a dark gray band at the tip. These moths are often found early in the worming, crawling in the lawn, as they get warm enough to start moving. [If seen, stomp on them!] Eggs are spherical and slightly flattened, with ribbed lines running from end to end. They look a lot like cabbage looper eggs. Larva start out a creamy white color, with a dark head. They have distinct, sparse hairs (tubercles) with dark spots. As the larva feed, the color changes to greenish-yellow to nearly black, depending on the food supply. Fine white lines can be seen along the body. The hairs and the spots remain. On some individuals, stubby bristles or spines can be seen with a hand lens. Corn earworm lifecycle Tiny pale green eggs turn creamy white, and then yellowish or gray. They are laid singly on upper and lower surfaces of leaves, leaf hairs, and on corn silk. They develop a reddish-brown ring within 24 hours. Eggs darken in color just before hatching, usually less than 72 hours after being laid. Larvae go through 4 to 6 instars, or developmental stages, all the while feeding heavily. In fact, corn earworm larvae are a brutal bunch. In addition to attacking your tomatoes, they will also attack and feed on other insets, especially butterfly and moth larvae, including their own kind. After 12 to 16 days, the larvae enter a pupal stage. If the soil is moist enough and temperatures are warm enough, an adult moth will emerge to begin the cycle again. A single adult female corn earworm moth can lay up to 2,500 eggs in her lifetime. Corn earworm damage Adult moths feed on nectar and pollen, but they are not the problem. It is the larval stage that causes all the damage. Being polyphagous, corn earworm larva eat many different things. And you won’t even know they are there until it is too late, unless you look very closely. The larvae feed inside the fruit, so it’s not until you cut into it or take a bite that the pest is discovered. Yuck! Also, larvae may move from fruit to fruit, leaving behind a wake of squishy, watery digested insides filled with frass and shed skins. Damaged fruit tends to ripen prematurely and the feeding action makes plants susceptible to other problems, including fungal diseases and mold growth. Because the larvae are inside the fruit, control is difficult. Controlling corn earworms Protected within fruit, corn earworms are tough to get rid of. Making matters worse, these pests have developed a resistance to our chemical arsenal. This means that integrated pest management must be used instead. Integrated pest management (IPM) is an approach that uses many sustainable methods to provide the least amount of damage. IPM practices that reduce the damage caused by corn earworms include:
Monitoring plants regularly for signs of eggs of young larvae can help you protect your tomato, corn and other garden plants.
Did you know that plants use the saliva of their attackers to figure out which defense chemicals to produce? Whether you call them June beetles, Junebugs, or May beetles, these small, reddish-brown, clumsy flyers can be annoying. They get their name because of when they emerge. In some regions, these pests come out in June, while other places get them in May, hence the difference.
Junebug damage
Adult Junebugs feed on leaves. They fly in from weedy areas to feed at night. During the day, they tend to hunker down in a shady spot or burrow into the soil until dusk. The damage they cause is similar to Fuller rose beetles, earwigs, and snails. Grasshoppers and caterpillars may also cause similar damage. The only way to be sure is to catch them in the act. The more insidious damage occurs underground as Junebug grubs feed on the roots of your lawn, especially ryegrass and bluegrass. Symptoms of infestation include brown, dying patches. If things get really bad, you can actually roll up patches of turf because it is no longer attached to the ground! Large numbers of Junebugs can defoliate a young tree in a matter of days. This is especially true for avocado trees, which may need to be protected with netting. Controlling Junebugs Commercial growers use blacklight traps when Junebug infestations cause too much damage. This is not recommended for home growers because the trap may attract more Junebugs than it captures. Heavy infestations are treated with an application of entomopathogenic nematodes. For the most part, home gardeners can’t do anything besides hand pick them whenever they are seen. Junebugs really are clumsy flyers, so it’s not hard to catch them. They are attracted to lights at night and often bump into windows and screens. When I catch them, I feed them to my chickens, who are very happy to help with Junebug control. If you have children, you can always gift them a butterfly net and offer a bounty on every Junebug they catch! Neonicotinoids are a class of insecticides.
When neonicotinoids first came on the market in the 1980’s, they were touted as a cure-all for garden pests around the world. Since neonics affect certain receptors in an insect’s nervous system, humans and other mammals, birds, and fish would be perfectly safe, they said. That sort of marketing should have been a warning from the beginning. What quickly followed were massive bee die offs, and threats by the EU to regulate this class of chemicals, but it's not that simple. To understand the pros and cons of this insecticide, we need to know more about how it works. What are neonicotinoids? Neonicotinoids, or neonics, as they are more conveniently known, are a class of insecticides that are chemically similar to nicotine. This class of chemicals includes several ingredients you may see on a bottle of insecticide:
After the disaster of DDT, other chemical insecticides were tried. Organophosphates and carbamates were the most common, but these are far more toxic than the neonics. By 2013, according to YaleEnvironment360, 95% of the U.S. corn and canola crops, most of the cotton, sugar beet, and sorghum crops, and a “vast majority of fruit and vegetables, including apples, cherries, peaches, oranges, berries, leafy greens, tomatoes, and potatoes, to cereal grains, rice, nuts, and wine grapes” were sprayed with neonics. How do neonics work? Neonicotinoids work by interrupting an insect’s nervous system. Since insect nervous systems are so different from other living things, these chemicals are generally safe, as far as poisons go. Initially, plants and seeds were sprayed with neonicotinoids. Neonics are systemic, which means they can be sprayed on seeds or plants, or watered in. Sprayed seeds grow into plants that contain the insecticide. Sprayed plants absorb the chemical, which is then spread throughout the plant via the xylem. When an insect comes along and takes a bite, or grabs some nectar or pollen - WHAM! They’ve been poisoned. Problems associated with neonics The initial problems with neonics occurred when seeds were sprayed with the chemical and then put through a seed spreader that created clouds of neonicotinoids, killing tens of thousands of honey bees. Also, sprayed insecticides tend to go all over the place, causing overspray damage to nearby plants, waterways, and air. Of course, all this made the news and got everyone excited, but those particular problems have been resolved in most countries. Now, neonics are more commonly applied as a drench, which is poured into the soil, to be absorbed by the roots. This eliminates overspray. Treated seeds are now managed in ways that prevent the pneumatic seed dispersal issue. Currently acceptable application rates seem to only be causing minimal harm to honey bee colonies, but they are still devastating to native bee populations. Does your garden really need chemicals? Individuals impact the amount of chemicals found in the environment by thinking before buying:
As we have learned in the past, spraying chemicals all over the place ends up causing unexpected problems. These chemicals start building up in our ground water and soil. Also, insects evolve much faster than we do. It is common for insects to develop a resistance to the poisons we spray on them, while we remain vulnerable. Neonicotinoids may or may not be the next DDT. The truth is, we don’t know. What we do know is that there are better ways for home gardeners to care for their plants than to inundate the environment with chemicals. Crawlers with no legs, a species with no males, and broody females who keep thousands of eggs warm and safe - what are these garden pests? Citricola scale. Native to Japan and southern China, citricola scale is currently found in California, Arizona, and Maryland, and in several other countries. Also known as gray citrus scale, citricola scale (Coccus pseudomagnoliarum) can be found feeding on citrus and pomegranate twigs in spring and early summer, and immature scale insects can be found feeding on the underside of leaves in late summer and fall. In addition to feeding on pomegranate, lemon, lime, orange, and grapefruit, these sap-sucking pests also feed on elm, bay laurel, hackberry, and oleander. Citricola scale lifecycle There are only female citricola scale insects. They reproduce asexually (parthenogenesis). Each female can produce between 1,000 and 5,000 eggs during the summer. She will keep her eggs safe under her body until they hatch out in to crawlers, usually from June through August. That may sound like a crazy broody season, but citricola scale eggs hatch after only 2 or 3 days. The babies that come out of those eggs are called crawlers. The name crawlers sounds a little misleading because they don’t look as though they could do anything. But they do. These crawlers move to a good feeding site, attach themselves, becoming sessile (fixed), and feed until they molt into second instar nymphs, usually around November. These nymphs produce a lot of honeydew and are often protected and farmed by ants. Citricola scale description
Citricola scale start out as a yellow, oval egg. First instar crawlers are oval, flat, and nearly translucent. Sometimes they are yellowish-green to brown. Second instars are mottled brown. Citricola scale adults are one-quarter of an inch long, gray, oval, and flat. Well, slightly convex, but flat enough. They can be difficult to see because they start taking on the color of the twig to which they are attached. Citricola scale are often confused with brown soft scale (which was the only image I could get my hands on). Citricola scale or brown soft scale? Citricola scale tends to have only one or two generations each year, while brown soft scale can have multiple generations going at any one time. This means that citricola scale insects you see will nearly always be at the same life stage, while brown soft scale specimens may be at any life stage. Also, adult citricola insects are gray, while brown soft scale adults are brown or yellow. Damage caused by citricola scale Underneath those tiny domes of protection, citricola scale attach themselves to stems and leaves of citrus and pomegranate. They pierce the surface to reach the phloem, to siphon away valuable nutrients and sugary sap, weakening the tree. And they poop. This poop, called honeydew, contains a lot of sugar, and it creates the perfect growing medium for sooty mold fungus. Sooty mold blocks photosynthesis, further reducing your tree’s vigor. Citricola scale can reduce flowering and fruit production. During heavy infestations, twigs can be killed by citricola scale. How to control citricola scale Regularly monitoring citrus and pomegranate trees for these pests is your first line of defense. If you notice ant trails or sooty mold, take a closer look at twigs and leaves for signs of scale. Since ants protect these pests, you can eliminate that protection, making the citricola scale more vulnerable, by wrapping the tree’s trunk with a sticky barrier. Also, there are naturally occurring parasitic wasps that will control citricola scale insects (as long as you do not apply broad spectrum pesticides). Applying dormant oil in winter can also help reduce citricola scale populations. Research has shown that 40% of citricola scale in San Joaquin Valley are resistant to organophosphates. It is believed that there is also a cross-resistance to malathion and carbaryl. This looks to be yet another example of chemical pesticides actually making the pests stronger, as we add more poisons to the environment and our food chain. Bottom line, to control citricola scale on your pomegranate and citrus trees, inspect twigs very closely in April through June, and then look at the underside of leaves in late July. These pests can then be flicked off the leaf or stem with your fingernail. Relatively new to the United States, the European pepper moth is poised to cause significant damage to gardens and commercial agriculture. Each time an invasive plant or pest is brought into an area, there’s no telling what might happen. Resident predators or local diseases may make short work of the interloper. Then again, the insurgent may find a rich, predator-free environment perfectly suited to a population explosion. We don’t know, yet, which way things will go for the European pepper moth, but it’s probably a good idea to know what we’re up against, just in case. Plants damaged by European pepper moths It’s difficult to get excited about something that hasn’t directly caused damage in your garden, so here’s the list of just some of the plants harmed by the pepper moth: If that list doesn’t get your attention, I don’t know what will. Also on the list of favorite foods are roses, African daisies, azaleas, orchids, and many other flowers and ornamentals.
Damage caused by pepper moths The moths themselves don’t cause any harm to plants. Like other moths and butterflies, it is the larval stage, or caterpillar, that feeds voraciously on leaves, roots, buds, fruit, and flowers. Pepper moth caterpillars may girdle young seedlings, causing what looks like damping off disease. Later larval instars may burrow into stems unnoticed, until the the stem collapses. Leaf damage starts out looking crescent-shaped, similar to damage by the Fuller rose beetle, or round, but the entire leaf ends up being eaten. Feeding is normally seen in the lower leaves, then moving up the plant until it is completed defoliated. Feeding on the roots can interfere with a plant’s overall health and vigor and feeding on buds, flowers, and fruit, well, there goes your crop. So, what does the European pepper moth look like? Pepper moth identification and lifecycle Also known as the European marsh pyralid, adult pepper moths (Duponchelia fovealis) have a wingspan of approximately three-quarters of an inch wide and a body less than half an inch long. The forewings are grayish-brown with two distinct yellowish-white transverse lines. The outermost line has a “finger” that points backwards. At rest, the pepper moth holds its wings out to either side in a triangular shape. The head, body, and antennae are olive brown, and the abdomen features cream-colored rings. Legs are pale brown. Both sexes have long abdomens, but the male’s is unusually long, and he holds his curved upwards at rest. Pepper moth eggs are really tiny (1/50 of an inch). The eggs start out whitish green or pale yellow, which turn pink, then red, as they mature. Just before hatching, the egg turns brown. Eggs are laid singly or in batches on the underside of leaves, normally near the leaf veins. Eggs can also be found on stems, at the crown, in the soil, on the tops of leaves, and even on greenhouse walls and furnishings. Caterpillars start out salmon pink with a black head, and a line of gray and brown spots along each side. Some sections may feature a double row of dots. Using a hand lens, you can see a hair emerging from each spot. Just behind the head, you can also see a hard plate, which is the same color as the head. As they grow, the pink turns a dirty white color that can range from pure white to pale or even dark brown, depending on which of your garden plants they are eating. These caterpillars can grow to over an inch long. Just before pupating, they may lose their spots. Pepper moth caterpillars create a cocoon out of soil, frass, and webbing. The cocoon can be 1/2 to 3/4 of an inch long. A single female pepper moth can lay up to 200 eggs. Under optimal conditions (temperatures around 68°F), those eggs can hatch in 4 to 9 days. Over the next 3 or 4 weeks, the caterpillars feed ravenously. Then, pupation takes 1 or 2 weeks. Adult moths live to mate and procreate for a week or two and the whole process begins again. In greenhouse environments, 8 or 9 generations a year can occur. That ends up being a lot of pepper moths! In areas like California, where cold winters rarely occur, this pest could prove to be devastating. These moths have an unusual flight pattern - both males and females fly fast and low, with their abdomens curved upwards. You may see individual moths, or they may swarm. Pepper moth caterpillars are photophobic, which means they do not like light. If you shine a flashlight on a pepper moth caterpillar, it will become agitated, moving rapidly side to side. How the pepper moth got here Pepper moths have been present in Europe for a very long time. In 1984, it became a greenhouse pest in Europe and Canada for the cut flower, vegetable, and aquatic plant industries. It is believed to have been spread globally through infested plants from those products. [Yet another example of why it is so important to quarantine new plants!] By 1988, the pepper moth had developed a taste for strawberries. In 2004, the pepper moth was found on begonia plants in San Diego, CA. It was again detected in 2010. By 2011, the European pepper moth had been found in seventeen California counties, as well as in fourteen other states. Departments of Agriculture in each of these states is monitoring for this pest. If you think you see one, please try to capture it and report it to your local County Extension Office. Native to Europe, the pepper moth moth prefers fresh and saltwater marshes. You might think, since you don’t have a marsh in your garden, that your plants are safe. But most of us have a creek, reservoir, or some other body of water nearby, and a pepper moth can fly up to 62 miles. What to look for Now that you know what these pests can do, keep an eye out for the following signs of pepper moth infestation: feeding tunnels, webbing, leaf rolling, frass, leaf wilting, and stem collapse. Also, check the debris (detritus) that falls from container plants and around the base of the containers for signs of eggs or pupae. You can also lightly brush the soil around potentially infested plants for signs of pupae and cocoons. How to control European pepper moths At this point, the best biological controls are to spray Bacillus thuringiensis (Bt) or beneficial nematodes (Heterorhabditis bacteriophora and Steinernema spp.). Rove beetles seem to enjoy feeding on pepper moth eggs and caterpillars, and certain predatory mites and wasps also parasitize these pests, so avoid using broad-spectrum pesticides. Since pepper moths prefer moist, hidden areas, keeping your garden tidy and free of overly moist areas can reduce the chance of perpetuating the species in your neck of the woods. Again, because this is a relatively new pest, with the potential for significant long term damage, if you see one, please report it. If you live in California, you can call 1-800-491-1899. If you live elsewhere, contact your local Department of Agriculture for reporting instructions. Knowing where this pest is can help in its eradication, which is really good news for your tomatoes, basil, figs, and cucumbers! What's eating your trees? If you see orange frass and bark damage, it's probably the American plum borer. Like flathead borers, clearwing moths, and shothole borers, the American plum borer (Euzophera semifuneralis) feeds on the cambium layer of branch crotches, the lower trunk, and the root crown. This feeding weakens and damages branches, and can even kill a young tree. Host trees American plum borers feed on many popular fruit and nut trees, as well as several ornamentals. Here is a partial list of trees favored by plum borers: Plum borer lifecycle Each spring, adult plum borers emerge, mate, and eggs are laid in bark wounds. These wounds can be caused by branches rubbing together, a poorly aimed weedwacker, a careless pruning job, or any number of other insect pests. Also, branches that are growing too close together or at a tight angle, and heavily furrowed bark, can provide the necessary shelter. When the eggs hatch, larva enter the bark wound and begin feeding on the cambium, which contains the vascular tissue carrying water and nutrients throughout the plant. The larvae burrow shallow, irregularly-shaped tunnels between the wood and the bark. These larvae go though several stages, or instars, growing progressively larger, over the next 30 to 38 days. Finally, the larvae pupate in a loosely spun cocoon, inside the tree, where they overwinter. There can be up to four generations each year. Pupae that occur during the early part of the season can reach adulthood in as little as 10 days. Plum borer description Adult plum borer moths are dark gray with black and brown wing markings. The legs and body of the adult moth are a dusky gray with a reflective bronze. The wings have a white fringe. The larva can be white, green, or pink and are usually one inch long. If you use a hand lens, you should be able to see a circle of tiny hooks on the bottom of a plum borer’s fourth set of feet (B), called prolegs, as opposed to clearwing moth larvae (A), which have two rows of hooks. [Now you know how larva can climb up vertical surfaces!] More often, you will see the damage caused by the American plum borer, long before you actually see the insect. Damage caused by plum borers
As plum borers feed, they leave behind a trail of destruction. Reddish orange frass collects wherever they feed. Also webbing and extensive gumming can be seen. Gumming is a gooey discharge plants use to protect themselves. The gum hardens as it dries, but, unlike sap, it is relatively easy to wash off. Eventually, branches are weakened to the point of breaking and the tree’s overall health declines, reducing or eliminating any chance of harvesting those delicious plums. Controlling plum borers Plum borers are easier to prevent than control. Once they enter a tree, they are relatively safe from predators and pesticides. Use these tips to prevent a plum borer infestation:
If a bark injury is already present, or if your tree has bacterial galls or a fungal canker, and you know that plum borers are nearby, it may be worthwhile to hire a professional to apply a residual, contact insecticide. Over-the-counter products are not effective against the American plum borer. If you see tiny dark nubs on your citrus or olive twigs, your tree may be infested with black scale. Black scale (Saissetia oleae) build a soft, thin, way covering over themselves as protection. Unlike armored scale insects, this protective covering cannot be removed from soft scale insects. Black scale is a type of soft scale that produces a lot of honeydew. Honeydew is a nice way of saying sugary bug poop. Honeydew provides the perfect growing medium for sooty mold. It also attracts ants, which can carry diseases.
These crawlers go through several instars, or stages. In the second instar, they develop a ridge on their back. This ridge expands into an “H” shape. After they molt a second, time, they head for twigs, and begin growing in earnest. This is where their bodies become more circular and their protective cover turns a leathery mottled gray. As each of these offspring approaches reproductive age, the cover gets darker and harder, and the “H” often disappears.
How to control black scale Black scale insects tend to be a serious problem every 5 to 10 years. Normally, local parasitic wasps and other predators keep this pest under control. Dust and the use of broad spectrum pesticides can interfere with these natural controls. In years of heavy infestation, specific pesticides may be needed. Before using a pesticide against scale insects, be sure to look closely. If you see tiny holes in the scales, there is no need to spray. Those holes are from scale parasites which have already done their job. You can also reduce scale populations by hand. Simply grab a wet, soapy rag and start wiping them off. While you’re at it, you can help your tree increase photosynthesis by wiping off the sooty mold, too. This pest is an outlaw, of sorts, carrying death and disease in its wake. Glassy-winged sharpshooters may have a cool name (and they look pretty amazing), but they are a serious pest that carries several diseases to your garden and landscape plants. This pest first appeared in San Jose, California, in 2001 and efforts are being made to control its spread. Let's see how we can help control this pest. Glassy-winged sharpshooter description Sharpshooters are a type of leafhopper. They have narrow bodies and strong legs. Glassy-winged sharpshooters tend to be 1/2 inch long and dark, shiny brown above, and yellow underneath. The wings are clear with reddish veins and spines can be seen on the hind legs, if you look closely. Glassy-winged sharpshooter lifecycle Clusters of white eggs are laid on the underside of leaves and then covered with a white, powdery coating, called a brochosome. This coating and the nearby leaf tissue turn brown after the eggs hatch and the nymphs use their piercing mouth parts to suck sugary sap from the xylem. These nymphs will molt several times before reaching adulthood. While sharpshooter feeding is not a serious threat to healthy host plants, these insects carry many diseases, and their excrement forms a coating on leaves that looks like whitewash and falls on cars below. Heavy feeding on new, small plants can cause wilting. Sharpshooter host plants These pests are opportunists. Scientists estimate that there are over 700 different types of plants used by sharpshooters as food. These plants include grapes, citrus trees, and stone fruits. This means most of the fruit and nut trees in your garden or landscape are susceptible to these pests. What’s worse, as these pests feed, the bacteria they carry is injected into the plants! Diseases carried by glassy-winged sharpshooters The glassy-winged sharpshooter (Homalodisca vitripennis [formerly H. coagulata]), like other sharpshooters, are sap-sucking insects. As they feed on plants infected with the Xylella fastidiosa bacteria, the bacteria begin reproducing within the insects mouthparts. When the sharpshooter feeds on successive plants, the bacteria and the diseases they cause, are also transferred. These pests can bring several, currently incurable, diseases to your foodscape, including: How to control glassy-winged sharpshooters Insect predators, such as parasitic wasps, and naturally occurring pathogens are the most effective, long-term control measure, so avoid using broad-spectrum insecticides. In severe cases, insecticides may need to be used. Just be sure to use them sparingly and follow the directions exactly. Insecticidal soaps and oils have also proven effective. If you see a glassy-winged sharpshooter, please contact your local Sheriff or County Extension Office right away! [Yes, I’m kidding about the Sheriff. But I’m serious about the County Extension.]
The tiny Asian citrus psyllid is costing orange growers billions of dollars in losses, and it might be on your trees! The Asian citrus psyllid (Diaphorina citri) arrived in North America from Asia or India in 1998. The insect feeds on the sap found in leaves and stems of citrus trees. As they feed, they produce large amounts of honeydew (sugary bug poop). This honeydew is a popular food of ants and the sooty mold fungus. That wouldn’t be a serious problem, by itself. The situation is made far worse because the Asian citrus psyllid carries a bacteria that causes a devastating disease called huanglongbing (HLB). Also known as citrus greening, HLB is a vascular disease that kills trees and there is no cure. Trees infected with citrus greening must be destroyed.
Asian citrus psyllid identification This pest is about the size of a grain of rice. It is a mottled brown color with a light brown head. The wings have a dark brown band around the outer edge and look as though they are being held up and behind the insect when at rest. Most adults have a dusty appearance. Nymphs are yellowish orange with long, white waxy secretions, called tubules. Tiny, almond-shaped eggs start out pale, turn yellow, and then orange just before hatching. [I couldn't find a photo I could use, so Google it.] Asian citrus psyllid lifecycle Adult females lay between 300 and 800 eggs. These eggs are laid on new growth, on shoot tips and between unfurling leaves. Nymphs go through five instars. The entire lifecycle takes from 15 to 47 days, depending on conditions. There can be up to 10 generations a year. [I don’t know about you, but that’s some crazy math. If there are any mathematicians reading this post, I would love to read in the comments just how many offspring that can mean!] Host plants and signs of infestation You can tell by the name that these pests feed on oranges, lemons, limes, and grapefruit. They have also been found feeding on kumquat (Fortunella sp.), Indian wood apple (Limonia polyandra), jasmine, citron (Citrus medica), pummelo (Citrus x maxima), mock orange, Cape chestnut, Bengal quince (Aegle marmelos), and others. There are several signs of infestation that all citrus tree owners should watch for on a frequent basis:
Financial impact of Asian citrus psyllids Some pests are more costly than others. This one tops the list. Infection of citrus trees around the world is wiping out entire regions of citrus growers. Companies that sell citrus products are paying more for domestic citrus, and they must also buy citrus products from other countries, causing the loss of local jobs. Also, over $1 million a year is being spent on public education, to slow the spread of this problem. This means even higher prices. The reason for this educational investment is that there are more citrus trees in backyards than in commercial orchards. Uninformed homeowners are far more likely to allow this pest to expand its range even further. Halting the spread of citrus greening Learning what to look for is one of the best ways to help slow this threat to citrus. These tips will go a long way toward preventing the spread of this disease:
Please read my post on huanglongbing disease and find out if you are in or near a quarantine zone. It is up to citrus tree growers everywhere to help combat this devastating pest. If you suspect or see signs of the Asian citrus psyllid or huanglongbing disease, immediately contact the CALIFORNIA DEPARTMENT OF FOOD AND AGRICULTURE HOTLINE: 1‐800‐491‐1899, or your local Department of Agriculture. Western tussock moth caterpillars can defoliate a tree in record time and they are wreaking havoc in many regions. There are over 2,500 species of tussock moth (Lymantriinae) worldwide. The family name Lymantriinae comes to us from the Latin word for ‘defiler’. Cousin to the gypsy moth of East Coast nightmares. the western tussock moth is making itself felt west of the Rockies. Western tussock moth caterpillars feed on leaves and young fruit. What makes these pests so much of a threat is how much and how fast they eat. Western tussock moth larva, or caterpillars, will feed heavily on apple, apricot, cherry, citrus, pistachio, plum, and prune trees, as well as many ornamentals, such as oak, ceanothus, and willow. Western tussock moths (Orgyia vetusta, formally known as Hemerocampa vetusta) are normally present in this area, being native to the west coast of North America, but chilly winter weather and natural predators usually keep their numbers limited. Warmer winter weather allows these moths have a boom population, and 2018 is one of those years. Currently, local parks and walking trails are finding trees, sidewalks, and park equipment covered with these caterpillars. Caterpillars are falling out of trees onto cars and people, there are so many of them. Newly hatched caterpillars have a habit of using a silk thread to balloon themselves to a new location. Walking into a cloud of ballooning caterpillars isn’t something most people enjoy. Western tussock moth description These pests are easy to identify. A Western tussock moth caterpillar is 1-1/2 to 2 inches long and features white tufts (called pencils) that stick up along the back, with two black tufts on its head, and one on its read end. They also have paler tufts along their entire length and sides. You will also see bright red and orange spots. The adult female moth is unique in that she does not fly. She is short-winged (brachypterous) and stays with the cocoon. She is a pale gray color, but you probably won’t see her. The males find her because of chemical scents, called pheromones, that she releases. The male moth does have wings. He also has prominent, fringed antennae. He may be dark or light brown, depending on the local environment, with black and white markings. Larva go through several stages, called instars. Until they reach their full size, they are black, with black hair pencils on their first four abdominal segments. Western tussock moth lifecycle Adult moths do not feed. Each female moth lays hundreds of eggs. Eggs are laid directly on the cocoon. The female moth covers the eggs with a protective coating and then covers that with a camouflaging layer of hairs (setae) from her own body. The eggs overwinter in this protected state and then hatch in spring through mid-summera. These caterpillars feed intensely for 40 to 60 days before pupating. While the caterpillars of some tussock moth species spread an irritant on the setae (hairs) that cover their bodies, the western tussock moth does not fall in that group, but they can be a pain, nonetheless. Western tussock moth controls
Local governments use several methods to control heavy infestations of western tussock moth caterpillars:
Hopefully, your garden and landscape will be spared a visit from the western tussock moth. If you are not so lucky, you can spray Bacillus thuringiensis (Bt) to deter these pests. If a severe infestation does occur, you may have to prune out heavily affected limbs. Most of us grew up learning about how pollen sticks to bees as they go from flower to flower, collecting nectar and pollinating many common food crops. But that’s not how it works for your tomatoes and peppers. Instead, they use buzz pollination. Standard pollination
Most flowering plants (angiosperms) have male parts, called anthers, that have pollen on the outside, available to all takers. This pollen held in place by its extreme stickiness. [That stickiness is why you need to use soap and water to get pollen off your face and eyelashes, for those of you who are prone to allergies.] This pollen can be knocked loose by busy pollinators and then carried on the wind, or the pollinators find themselves covered with the sticky stuff, as they move from flower to flower, feeding on nectar and collecting pollen. Dry, dusty pollen Some flowers don’t have sticky pollen. Instead, they have pollen that is dry and dusty. If that pollen was exposed, it would all be gone with the first breeze, most of it never making it to another flower. Instead, these plants have evolved a specialized type of anther, known as a poricidal anther. Poricidal anthers are tubes with tiny openings at one end, but these openings are too small for bees to use. To make matters worse, these plants generally do not offer nectar, so how do they get pollinated? Pollination by vibration Approximately 8% of the world’s flowers are only pollinated when the correct sound wave frequency occurs nearby. When it does, the flower explodes a small dose of pollen into the air, coating whatever is at hand with genetic information and protein-rich food. This is called buzz pollination, or sonication. It gets those names because certain insects that have learned how to buzz at just the right frequency to trigger these plants to share their bounty. These flowers release pollen at frequencies between 40 to 1000 Hz, depending on the species [You can use a tuning fork or an electric toothbrush to try this for yourself.] Scientists believe this arrangement evolved as a means to ensure that each visiting pollinator carries away a smaller portion of pollen (which they are less likely to drop on their way to the next flower) and that those portions are spread out over a greater number of pollinators, and over a wider time frame, for better odds of procreation. How’s that for evolution? Not honey bees Honey bees do not use sonication to get at pollen, but several other bees do. Sweat bees, carpenter bees, and bumblebees all use buzz pollination to get at the pollen held in poricidal anthers. They do this by disconnecting their wings from their flight muscles [I have no idea how they do this!] and vibrating those muscles at just the right frequency. In most cases, this frequency is close to middle C. The force generated during sonication can reach 30 Gs, which is almost more than a human can tolerate! Which plants use sonication? You may be surprised to learn that many common garden plants use sonication. Members of the legume and nightshade plant families frequently use buzz pollination to generate the fruits and vegetables we love. In addition to tomatoes and peppers, other edible plants that use buzz pollination include eggplants, potatoes, peas, blueberries, tomatillos, and kiwifruit. How are your flowers being pollinated? Antlions are fierce predators of the garden. Cousin to lacewings and owlflies, and often mistaken for dragonflies or damselflies, these beneficial insects fly at dusk and at night. It is their larvae, however, that do the most damage to garden pests, such as ants and termites. Antlion lifecycle Adult antlions live for only 20 to 25 days, and most antlion species do not eat anything. Those that do only eat pollen and nectar. Instead of dining, they flutter around at dusk and during the night, attracted to lights and flames, in search of a mate. After mating, the female lays her eggs in sand or plant debris. Those eggs hatch into ferocious larvae that feed until they are ready to pupate into adults. This entire cycle make take 2 to 3 years to complete. Antlion description Adult antlions have two pairs of clear, thin wings, and a narrow abdomen. They can be differentiated from damselflies by their long, clubbed antennae. Also, adult antlions don’t appear to fly very well. Antlion larvae are often called doodlebugs because of the squiggly trails they leave behind. Antlion larvae are spindle-shaped, with a plump middle and three pairs of legs. [You may have seen a variation of an antlion in the ‘Ceti eels’ from Star Trek II: Wrath of Khan]. Antlions appear to have a mobile neck (prothorax) and the head is flattened with very large, heavily ‘toothed’ jaws. Those teeth are actually sharp, hollow tubes. Within these jaws of death, antlion larvae have a canal that carries venom to immobilize their prey and enzymes to liquify them, once they are paralyzed. If that weren’t terrifying enough, antlion larvae feature forward facing bristles that help them to stand stand ground against significantly larger prey. One weird thing about antlion larvae is that they do not have an anus. Instead of releasing waste, they store it for later use as a building material for their cocoon. Any unused waste material is then released at the end of its pupal stage. [I suppose that it’s no surprise that antlion cocoons look like rabbit droppings or bird poop…] Signs of antlion habitation
How would you know if antlions are in your garden? You might see adult antlions fluttering around your porch light. Or, you might see holes in the ground. While some antlions hide in wait for their prey under leaf litter, other species of antlion larvae trap their prey in pits. They build these traps by walking backwards in circles, flipping grains of dirt and sand out of the hole with its very large jaws. Ultimately, they end up with a very steep-sided hole that can be 3/4” to 1-1/2” deep. The soil or sand around the pit is loose. At the bottom of that pit, the antlion larvae waits quietly for its next meal. As an unsuspecting insect walks by, they may fall in. When they do, it’s all over for them! As soon as prey fall in, the antlion quickly flips more soil out of the hole, making it deeper and causing grains of soil to fall on the prey, knocking it deeper into the hole. Finally, the insect is grabbed by the antlion’s large jaws and the liquefaction of its insides begins. After everything has been sucked out, the husk it thrown out of the hole and everything is tidied up for the antlion's next guest. Antlion folklore There is a tale that says you can talk antlion larvae out of their holes. Simply bend down, close to the hole, and tell the antlion to tell you what you want to know. At the sound of your voice, the antlion emerges from their hole, but why? The tale says that the larvae want to hear what you have to say. What’s really happening, is the soil is disturbed by your movement and the sound vibrations of your voice, so the antlion thinks it either has lunch, or a housekeeping job to attend to. There are over 600 antlion species worldwide. Antlion larvae are often used as fishing bait, and some people keep them as curiosity pets. How many do you have in your garden? Under the bark of your fruit trees, there may be tiny bark beetles, chewing destructive tunnels. There are over 200 different types of bark beetles in California (600 nationwide). We currently host 20 invasive species of bark beetle, half of which were only discovered since 2002. The shot hole (or shothole) borer has been here long enough that it is considered naturalized. Bark beetle galleries
Bark beetles spend most of their lives in a system of tunnels, called a gallery. They chew these tunnels under the bark, in the sapwood or cambium layer. If you pull the bark away from an infested area, the gallery can clearly be seen. As the larvae feed on sapwood, expanding the gallery, these tunnels criss-cross each other, damaging the xylem and phloem, making it difficult for trees to transport water and nutrients. Parent tunnels tend to be 2 inches long and run parallel to the grain. They are normally clean. Larval tunnels, like a teenage boy’s room, radiate away from the parent tunnels, against the grain, are smaller, and tend to be filled with frass and sawdust. Shot hole borer host plants Shot hole borers, also called fruit tree bark beetles, prefer (you guessed it!) fruit trees, especially those in the stone fruit family. This means your almond, apricot, cherry, nectarine, and peach trees are susceptible, along with apple, pear, and avocado. Shot hole borers also feed on English laurel, mountain ash, hawthorn, and elm. Shot hole borer lifecycle and feeding Shot hole borers (Scolytus rugulosus) start out as white, round or oval eggs, laid in the gallery. These eggs hatch out into white, legless larvae that are 1/6 of an inch long and slightly larger just behind the head. These larvae overwinter in the gallery, creating more tunnels. As they feed, they poop. To make room for this material, the borers widen their tunnels and push the poop out, leaving signs of frass and sap to drip down the side of your tree. All this chewing causes further damage to the tree’s vascular bundles. After 6 to 8 weeks of tunneling and pooping in your fruit tree, the larvae are ready to enter a pupal stage. Pupae are white, with tiny hairs and large knobs (tubercles). Pupae are found at the end of tunnels. Finally, adult shot hole borers emerge to chew exit holes and the cycle starts all over again. Adult shot hole borers are only 1/10” long and brown or black. These new adults first emerge in spring or early summer and will feed on small twigs, buds, and leaf bases before chewing a new entry hole, where they will excavate more tunnels, further weakening your trees. Entry holes are often found near lenticels. Lenticels are lens-shaped openings in the bark used in gas exchange (sort of like a breathing hole, but not really). Female shot hole borers lay up to 50 eggs. There can be 2 or more generations each year. Symptoms of shot hole borer infestation As shot hole borers first start chewing galleries under the bark of your fruit trees, you are unlikely to see their entry holes (unless your vision is a lot better than mine). These holes are only 3/100 of an inch in diameter. What you may see, however, is oozing, gumming, or staining, as the tree tries to defend itself. You may also see crusty white exudates. [An exudate is something that seeps out.] This white crust is sugar from the tree’s sap. You may also see a sawdust-like frass. If you look very closely, you may be able to see a female’s abdomen sticking out from the hole. Twig dieback may also be seen. Much like the shotgun pattern seen on leaves infected with the shot hole disease fungus, shot hole borers leave behind a similar pattern on tree bark, hence the name. Shot hole borer controls Healthy trees are generally able to protect themselves against shot hole borers. This means regular irrigation to avoid water stress, proper fertilizing, depending on the age, size, and life stage of the tree, and pruning out dead and diseased wood. It also mean whitewashing trees in late winter to prevent sunburn damage to the bark. If infested wood is found, it should be removed and destroyed, to prevent the borers from spreading to healthy wood. Once shot hole borers are in the wood, there isn’t much else you can do. Insecticides are ineffective. You may be able to thwart some borers by applying sticky barriers around the trunks of your trees. Bottom line: keeping your trees healthy in the first place is a lot easier than pruning out branches and twigs infested with shot hole borers! Currants are a refreshing berry used to make jams, jellies, pies, and wine, but currant borers can really put a dent in your crop. In California, the invasive currant clearwing moth (Synanthedon tipuliformis) makes its appearance each April, laying eggs in bark crevices, at old pruning cuts, and in narrow branch crotches. While individual moths only live one week, overlapping generations can extend egg-laying through August. These pests bore into the canes of currants, and sometimes blackberries. Currant borer description Currant clearwing moths look more like wasps than moths. They have a long, narrow black body with yellow stripes. Males have four stripes; females have three. Wings are triangular and mostly clear, and the front and back wings are hooked together. Legs and antenna are long, and moths have a slightly paddle-shaped rear end. The wingspan is 1/2 to 3/4 of an inch wide. Larva are white to yellow, with brown head and legs, and a dark dorsal line may be visible. Larva look much like the American plum borer. Pupal cases are reddish brown and 3/4 of an inch long. Eggs are pale pink to red and very tiny. Currant borer damage
When the eggs hatch, larva chew entry holes in canes, burrowing into the cambial tissue and sapwood. Here, they will feed on sap and vascular tissue for the rest of the summer, and then overwinter within the canes. In March, they will resume feeding, going through several instars, before entering a pupal stage. All this boring and feeding can girdle branches, causing twig and branch dieback. It also restricts the growth of infested plants, resulting in fewer blooms (ergo, less fruit). You may be able to see sawdust-like frass mixed with sap oozing out of entry holes, and longitudinal scars on infested twigs and branches. Currant borer controls Once a branch is infested, it should be removed and destroyed, or thrown in the trash. Severely infested plants should be removed completely. Once borers are inside a plant, there isn’t much you can do. Some people try shoving wires into entry holes, trying to stab the larva, but this is only marginally effective. Woodpeckers enjoy catching adult moths on the wing and braconid wasps parasitize these pests. There are also some beneficial nematodes that are available commercially. I’m not sure which species of nematode will work against currant borers, but you basically inject the live nematodes into the borers’ holes and spray the branches with nematodes in solution. Nematodes are fiddly and I have not had good luck with them, but they may work for you. Rather than losing valuable plants, it is far easier to prevent borer infestations int the first place. Healthy plants are better able to protect themselves against infestation, and rapid growth tends to make stems susceptible. Caring for your currant plants in a way that keeps them healthy and growing at a steady pace, rather than overloading them with fertilizer for faster growth, is the best way to prevent infestations. Also, avoid water stress with regular irrigation, especially during the peak of summer. Whitewashing the trunks of mature tree-trained currants with a 50:50 mix of water and latex interior paint can help reduce sunburn damage, which is more susceptible to infestation. Pheromone traps can be used to monitor for this pest. Just remember that the down-side of using pheromone traps is that they end up attracting pests from a greater distance. According to the U.S. Dept. of Agriculture, insecticides should be applied 7 to 10 days after the first male moth is captured in a pheromone trap. If you decide to use an insecticide, please, Please, PLEASE, follow the directions on the label exactly. Insecticides are poisons. Finally, regularly inspecting your currants and blackberries for signs of infestation can give you a unique opportunity at borer control. Just before clearwing borers emerge, they have a habit of pushing themselves halfway out of their tunnel and just sitting that way for a bit - catching their breath, I assume. So, look for areas of damaged bark and frass. If you see a borer half-way out of a twig, cane, or branch, help it out the rest of the way and then feed it to your chickens or stomp on it. Endophytes are tiny heroes of the garden. You rarely see them with the naked eye, but most of these tiny organisms work hard to protect our plants. What are endophytes? The word ‘endophyte’ literally translates as ‘in the plant’ (‘endo’ = within; ‘phyte’ = plant). Endophytes are tiny organisms that live inside plants, for at least part of their life, without causing disease. In most cases, they provide a benefit to the host. The plant returns the favor by providing the endophytes with carbon [sugar]. Endophytes can be fungal, bacterial, or viral, or they can be other plants. Endophytes are everywhere and they can occur in any place within a plant. Some endophytes grow between plant cell walls, while others live inside plant cells, and they tend to grow at the same rate as their host. Researchers have learned that plants and their endophytes use chemical signals to communicate with each other. These communications determine which helpful chemicals and what quantities are needed by both sides of the arrangement. The science behind endophytes is relatively new. Because of this, the definitions are still being sorted out. Some scientists include parasitic and pathogenic organisms as endophytes, while others focus on the beneficial, or mutualistic forms. That’s where I stand, for now. There are several different ways that endophytes help their host plants. Nutrient acquisition Certain endophytes help plants get the food they need. The rhizobium bacteria that helps legumes fix atmospheric nitrogen is a type of endophyte. Other endophytes break down rock phosphate within the soil, making it absorbable to plant roots. Some scientists categorize mycorrhizae, or root fungi, as a type of endophyte, while others do not. [Isn't it exciting, being on the crest of new scientific research?]
Other benefits
Endophytes have been shown to enhance overall plant growth. They do this by improving a plant’s tolerance of abiotic stresses, such as drought, heat stress, water stress, salinity, and poor soil. When allowed to grow naturally, these mutually beneficial arrangements make both parties stronger. Unfortunately, the use of fungicides interferes with endophyte development. Also, the use of fertilizers reduces a plant’s reliance on its resident endophytes. This is, theoretically, fine, as long as the fungicides and fertilizers continue to be supplied. As soon as these artificial treatments are withdrawn, however, host plants are left with less food and protection. Commercial agriculture is slowly coming around to the long term benefits associated with these natural arrangements, but you can take advantage of it in your own garden right away by avoiding the use of chemical fertilizers and fungicides. Did you know that when you inoculate legumes, you are putting endophytes to work for you in the garden? Now you know! While these furry, clumsy, easy-going pollinators can sting you, repeatedly even, they generally choose to ignore us. [Unless they get caught in a certain young girl’s unruly long hair. Believe me. I speak from personal experience.] The name bumblebee, or bumble bee, comes from the characteristic buzz (bumble) of this gentle pollinator. Before it was called bumblebee, it was known as a ‘humblebee’ and before that a version of a ‘clumsily flying buzzing beetle’ or ‘dumbledor’ was used. [I’ll bet you weren’t expecting that one!] Charles Darwin had this to say about bumblebees in his book, On the Origin of Species (1859): "I have [...] reason to believe that humble-bees are indispensable to the fertilisation of the heartsease (Viola tricolor), for other bees do not visit this flower. From experiments which I have tried, I have found that the visits of bees, if not indispensable, are at least highly beneficial to the fertilisation of our clovers; but humble-bees alone visit the common red clover (Trifolium pratense), as other bees cannot reach the nectar." Bumbling bees Bumblebees really are clumsy fliers. They bump into stems, leaves, and branches quite frequently. Research conducted at the California Academy of Sciences and UC Davis explored how bumblebees are able to withstand the frequent collisions they experience each day. When I say frequent, I mean once a second, on average. Bumblebee evolution Cousin to honeybees (Apini), orchid bees (Euglossini), and stingless bees (Meliponini), bumblebees (Bombini Bombus) have pollen baskets on their legs, making them all corbiculate. Fossil evidence of the common ancestor to these beneficial insects dates back 100 million years. Bumblebees have been around for 25 to 40 million years, depending on who you ask. Bumblebees are more commonly found in higher latitudes and higher elevations than other bees. There are even two species found in the Arctic! This may be due to their fur coats, but scientists explain that bumblebees are able to regulate body temperature, using the sun’s radiation and ‘shivering’ to generate heat. Unlike other bees, bumblebee queens are known to incubate their eggs. Bumblebee description
Like other insects, bumblebees have a three part body made up of the head, thorax, and abdomen. The head features two compound eyes and three primitive eyes, mouthparts, and antennae. Female bumblebee antennae have 12 joints, while males have 13. The thorax is where the wings, legs, and wing muscles are found. The abdomen contains the digestive and reproductive organs and the stinger. Bumblebees have two pairs of wings, a fore wing and a rear wing. The wings connect to muscles that are attached to the inside of the plates that make up a bumblebee’s exoskeleton. A waxy substance is secreted from glands and discharged from between the plates. It looks a lot like dandruff. Bees groom the wax into clumps and use it to build honey pots, egg coverings, and as nesting material. Bumblebees do not have ears. We do not know if they can sense sound waves through the air. They do seem to be able to sense vibration through other materials, such as the ground. Unlike the oblong honey bee, or the shiny black female carpenter bee, your average bumblebee looks round and furry. This is because they are covered with very soft, finely branched bristles, called setae. Bumblebees can usually be differentiated from golden male carpenter bees by the presence of contrasting bands and other markings. This aposematic coloration serves as a warning to would-be predators. Some other insects, such as hoverflies, mimic and are protected by this coloration. This is called Batesian mimicry. Bumblebees come in a variety of sizes, ranging from 1/2 an inch, up to one-and-a-half inches long. [Don’t worry, that big one lives in Chile and is affectionately referred to as a ‘flying mouse’ - okay, maybe not affectionately.] Bumblebees store fat in their body. This fat is used up during hibernation. Bumblebees do not use the bee dances common to honey bees, but they do exhibit social learning. Youngster bumblebees are frequently bumped off of favored flowers by more mature bees. In a lab experiment, bumblebees were taught to move an object in exchange for a reward. Untrained bees who observed the task-reward process learned it more quickly than those bees who observed the same exchange performed by an inanimate object. In fact, observer bees consistently improve on the methods used initially, implying at least some level of cognition. Bumble bee-havior Most bumblebee species are social insects. They live in relatively small colonies, led by a queen. Honey bee colonies hold 10 to 60 thousand workers, during peak honey production, while a bumblebee colony may only contain 50 to 1,500 individuals. Bumblebee nests are first constructed by an over-wintered queen. After collecting pollen and nectar from flowers and finding a suitable nesting site, the young queen will build wax pots to store food, and wax cells to receive her eggs. As the eggs hatch into larvae, the cells are expanded into a lumpy mass of brood cells. Nesting sites can be in or on the ground, or in tussock grasses, depending on the species. Bumblebee nests are a food source for badgers and other insectivores. Bumblebees normally range only a mile or so from the nest. A queen bumblebee performs a mating flight before retiring to her nest. There, she will ‘decide’ whether or not to use the collected sperm to fertilize each egg she lays. Unfertilized eggs develop into males. Fertilized eggs grow up to be hormonally suppressed worker females or fertile queens. Mature males are forced out of the nest by the females. Males and new queens live independently from the colony, sleeping in flowers or holes in the ground. Bumblebee feeding Bumblebees feed on nectar, and pollen is collected for the young. Bumblebees lap up nectar with a long, hairy tongue, called a proboscis. The tip of the tongue may also be used as a straw. Because the tongue is so long, bumblebees are able to gather nectar from (and pollinate) deeper flowers than honey bees, which have shorter tongues. When bumblebees fly, the proboscis is often folded under the head. Some bumblebees feed on flowers from above, the way other bees and hummingbirds do, while other ‘rob’ the nectar by cutting a hole in the base of the flower. It is called ‘robbing’ because this behavior avoids pollen transfer. [The metabolic rate of bumblebees is 75% higher than a hummingbird’s.] Some species of bumblebee leave a scent marker behind on a flower, after it has fed. This marker deters other bumblebees from feeding on that flower, until the marker fades. Once a bumblebee has eaten its fill and collected all of the nectar it can carry, it returns to the nest and deposits its riches in brood cells, for the young, or in wax cells, for storage. Unlike honey bees, which process nectar into honey, bumblebees store it as-is. Bumblebees as pollinators Bumblebees are powerful pollinators. As they feed, moving from flower to flower, they collect and deposit pollen. Bumblebees are commonly used in greenhouse tomato production. They are fed sugar water so that they do not need to harvest nectar, and can focus exclusively on pollen. [Did you know that pollen is left behind at each flower because the act of flying causes the bee to build up a static charge? The plants, being rooted in the ground, are, well, grounded. The electrically charged pollen grains on the bee are attracted to the stigma, which happens to be the best grounded part of a flower, while the flower’s grounded pollen is attracted to the bee’s statically charged body. How bizarre and amazing is that?!!?] Bumblebees also pollinate plants by a method called buzz pollination, or sonication. They do this by disconnecting their wings from their flight muscles and vibrating their flight muscles at a frequency very close to middle C. [The frequency varies depending on plant species.] The force generated during sonication can reach 30 Gs, which is almost more than a human can tolerate! This vibration causes a flower’s pollen to burst forth. This method is particularly effective on blueberries and members of the nightshade family, such as tomatoes, tomatillos, and eggplant. Sweat bees, carpenter bees, and stingless bees sonicate, but honey bees do not. PBS has an amazing video of buzz pollination. Bumblebee species There are over 250 species of bumblebee worldwide and several of them are in trouble. This is especially unfortunate when you realize that native bumblebees are responsible for a lot of pollinating. Some of the more common bumblebees include:
These bumblebee species have not been seen in recent years:
Cuckoo bumblebees, or brood parasitic bees, do not live in colonies. Instead, cuckoo queens will invade a nearby bumblebee nest, kill the queen, and then start laying their own eggs, which end up being cared for by the murdered queen’s workers. [You can tell the difference between a cuckoo bumblebee and a social bumblebee by looking closely at the back leg: nesting female bumblebees have a pollen basket, which is bare and shiny, whereas a cuckoo bee hind leg is covered with hairs. They transport pollen by wedging it between the hairs.] Attracting bumblebees Like the European honey bee, bumblebee numbers are declining. This is largely due to habitat loss, pesticide use, and the mechanization of agriculture. You can counteract some of these effects by planting flowers that attract and provide for bumblebees. Bumblebees are attracted to flowers by both sight and smell. They seem to prefer flowers that grow on spikes, such as salvia and lavender. This may also be because these flowers tend to be blue, purple, or white, favorite colors of bumblebees. Bumblebees are also attracted to members of the sunflower family. The most important consideration when planting to attract bumblebees is that the stems are sturdy enough to support these heavy pollinators. Bumblebees can also see a flower’s temperature, as well as its electrical field. You may very well already have plants that attract bumblebees. If you allow your kale and other cabbage family members to bolt in early spring, bumblebees will take advantage of the blooms, and you will add these plants to your foodscape as seeds are dispersed later in the season. Other popular flowers that attract bumblebees include anise hyssop (Agastache foesniculum), guaras (Guara lindheimeri and other cultivars), bog sage (Salvia uliginosa), Mexican sage (S. mexicana) and many members of the mint family, including basil, thyme, sage, and rosemary. Native plants, such as manzanita, ceanothus, CA buckwheats, penstemons, currants, and gooseberries will also attract and provide for these hard working beneficial insects. Bumblebees are housing opportunists. They build nests in upturned planter pots, abandoned mouse burrows, and under boards. If you have a square foot of bare, undisturbed soil and the right flowers, you are pretty much guaranteed a visit. The U.S. Forest Service offers a nice poster of western bumblebees with dietary notes. You can also learn more about bumblebee conservation from the Xerces Society. Have your new seedlings been chewed off at ground level? It may be darkling beetles. Darkling beetle is the common name for all 20,000 species within the Tenebrionidae family. Some of the more famous California darklings include Blapstinus, Coelus., and Eleodes.. Darkling beetle identification Darkling beetles are dull black, blueish-black, or rusty brown, depending on the species. Unlike other beetles, the wings of darkling beetles are fused together. Some species have longitudinal ridges on their wing covers, but most are smooth, without markings of any kind. One exception is the wooly darkling beetle (Eleodes osculans), which is covered with tiny hairs. Darkling beetles can range from 1/8 to 1-1/2 of an inch long. The antennae are well developed and often have knobs at the ends (clubbed). Darkling beetles are frequently confused with predaceous ground beetles (Carabidae), but ground beetles are shiny and their antennae are more delicate. There are other differences, but you get the idea. Darkling beetle larva look like pale yellow or dark brown wireworms. They are less than 1/3 of an inch long and are often called false wireworms. You may know one particular branch of this family as mealworms (Tenebrio molitor). Did you know that mealworms can digest styrofoam? Stanford researcher Craig Criddle discovered that the bacteria found in a mealworm’s gut can transform polystyrene into “carbon dioxide and recyclable organic waste.” How cool is that?!!? (UCANR) Darkling beetle behavior
These pests tend to walk with their heads down and their abdomens somewhat lifted. Very often, they will stand completely still, in a headstand position, if frightened. While not dangerous, they can squirt you with a nasty smelling secretion from that rear end that does not wash off easily. This behavior is what gives some darkling beetles the name Skunk Beetle or Stink Beetle, not to be mistaken with stinkbugs. For the most part, these pests only come out at night, but you may catch one running across the patio or lawn during daylight hours. Normally, they hide under dirt clods, fallen tree bark, rocks, boards, wood chips, and in other dark places during the day. Often, the only way you know you have a darkling beetle problem is because of the damage they cause. Darkling beetle damage In addition to attacking seedlings at ground level, darkling beetles feed on the foliage of many garden plants, such as lettuce, chicory, cabbage, broccoli, and other brassicas, beans, melons, pumpkins, tomatoes, and squash. This feeding can be seen along leaf edges and on the underside of leaves. Darkling beetles also feed on the ‘netting’ (raised areas) of melons, the flowers of most cucurbits and pistachio, and on some fruit crops, such as figs. Some species of darkling beetle also act as vectors for plant diseases and poultry parasites. Some darklings can also cause structural damage to insulation and wooden buildings. They are also attracted to poultry feed, but my guess is that the chickens make short work of that arrangement, as long as the unavailable feed is stored properly, in a metal container. Darkling beetle control Commercial farmers use insecticides to kill these pests. They also use a shallow ditch, filled with water, to block these pests from coming out of the weeds and into the fields. If you are an organic grower, as I am, you will have to use cultural controls. You can minimize darkling beetle damage organically when you:
In 2015, a report published by The Coleopterists Bulletin warned that three non-native darkling beetles have been found in California and Nevada. Each of these species is somehow tied to ant or fire ant populations:
I was unable to find any freely available photos, so you will have to track them down on your own. If you see any of these invasive beetles, please capture them and contact your local County Extension Office. You may be surprised to learn that some people keep darkling beetles as pets. |
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