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The ashy gray lady beetle is both stylish and deadly. We’ve all seen the red-domed ladybugs of popular culture with their shiny black dots, but what about the black lady beetles with red dots?  Adult ashy gray lady beetle (Forest and Kim Starr, Starr Environmental, Bugwood.org) CC BY 3.0 US There are four black lady beetles with red spots: twicestabbed lady beetles (Chilocorus orbus), Axion plagiatum, Chilocorus kuwanae, and the ashy gray (Olla v-nigrum). Unlike other lady beetles, however, the ashy gray has two forms, dark and tan. And they can change at will!  Ashy gray lady beetle (Louis Tedders, USDA Agricultural Research Service, Bugwood.org) CC BY 3.0 US Ashy gray lady beetle description Ashy gray lady beetles are sometimes ashy gray or tan, with black spots. At other times, they are black with red dots. Before they reach their domed adulthood, ashy gray lady beetles look more like tiny alligators with yellow spots. And before that, as pupae, they look like little orangish-yellow nubs. As eggs, they look like clusters of white or yellow, usually found on the underside of leaves, close to prey.  Ashy gray lady beetle egg cluster (Lacy L. Hyche, Auburn University, Bugwood.org) CC BY 3.0 US  Ashy gray lady beetle larva (Louis Tedders, USDA Agricultural Research Service, Bugwood.org) CC BY 3.0 US Ashy gray lady beetle prey
While ashy gray lady beetles feed on the eggs of butterflies and moths, the lion’s share of their diet consists of aphids and psyllids. Since aphids and psyllids are disease-carrying, plant-sucking pests, we can use all the lady beetles in the garden as we can get. To attract ashy gray lady beetles and other beneficial insects to your yard, avoid using broad-spectrum pesticides, provide fresh, clean water, and install insectary plants, including dill, lavender, chives, mint, tansy, and yarrow. Rove beetles are a family of mostly elongated predators that protect your plants against a great many garden pests.  Myrmecosaurus ferrugineus rove beetle (Spongymesophyll) CC BY-SA 3.0 There are over 63,000 different species of rove beetles (Staphylinidae), making them the largest beetle family in the world. There are approximately 4,360 species in the United States. Rove beetles have been around for over 200 million years and it may take another 200 million years to sort out this particular family tree. Currently, there are over 30 subfamilies of rove beetle, and scientists are still trying to sort it out. However these tiny beetles end up being related, the majority of them pack a wallop when it comes to devouring many common garden pests.  Astenus cinctus rove beetle (Spongymesophyll) CC BY-SA 3.0 Also known as trash beetles, these beneficial insects are often found in leaf litter, mulch, under loose bark, and around fallen trees. They may also be found in bird nests and rodent burrows where they presumably feed on fly and flea larvae. This huge family is extremely diverse. Some have evolved to live within caves, while others prefer living in mushrooms. Rove beetle description As you might expect from a family of this size, rove beetles come in a variety of shapes and sizes. Most of them are very small, averaging only 0.08 to 0.30 inches long, but they can range from 0.03 to 1.5 inches in length. Most rove beetles have a narrow body that can squeeze into tiny crevices in search of prey and shelter. Rove beetles can be black to brown, yellow to red, and even an iridescent blue-green. They have thread-like antennae with 11 segments; some of them have little knobs at the ends. Most rove beetles have short wing covers (elytra), which means you can see several abdominal segments. Many rove beetles look like a multicolored earwig without its pincers, but certainly not all. #/media/File:Lithocharis_nigriceps_Kraatz,_1859_(37530171470).png) Staphylinidae rove beetle (Udo Schmidt) CC BY-SA 2.0 Rove beetle eggs are typically white, but can be spherical, pear-shaped or oval. Flattened larvae may have a distinct ‘neck’ or an armored head, though not all exhibit those characteristics. Pupae can be hard, dark colored cases, or naked white grubs, depending on the species. Adults tend to be long-lived. Many rove beetle species produce secretions. Some of these secretions help repel water, allowing clumsy insects to recover from falling into water, while other secretions can be particularly toxic. One of those toxic secretions, found in the Paederous group, is transferred from mother to offspring, at birth, providing protection against spiders. This secretion can cause skin irritation and it can damage your eyes. It is the most powerful animal toxin that we know of, but scientists are learning how to use it to heal lesions and treat cancer. Rove beetle diet Adult rove beetles eat mites and small insects, as well as root maggot eggs and larvae. Rove beetle larvae also parasitize root maggot larvae. The rove beetle diet is a Who’s Who of garden pests, including:
If eating all those pests weren’t reason enough to appreciate rove beetles, it ends up that adult rove beetles also pollinate cherimoya fruit.
You can help the rove beetles in your garden by avoiding the use of broad-spectrum pesticides and insecticides, and by maintaining permanent areas planted with bunch grasses or other low-growing perennials to provide year-round habitat for these tiny hunters. What types of rove beetles have you seen in your garden? Transpiration burn may sound like a bad deal, but it refers to the damage caused by mite feeding.
What is transpiration? Plants exhale water through tiny openings called stomas in a behavior known as transpiration. Stomas are generally found on the underside of leaves, but they also occur on stems and flowers. Stomas open and close to allow for gas exchanges necessary for photosynthesis [carbon dioxide in; oxygen out]. Transpiration also helps move plant nutrients, such as zinc, into and within a plant. The combined effects of plant transpiration and evaporation of water from the soil are called evapotranspiration. Maintaining the proper water levels within a plant is critical to its health. When mites start feeding, that balance changes. Types of mites There are over 42,000 different types of mites in the world. They can be black, yellow, green, brown, or red. They are tiny. Gall mites, spider mites, European red mites, and thread-footed mites are common garden pests. Some mites prefer buds, others raise blisters on plants, and others create rust patterns. All mites have piercing mouthparts used to suck suary fluids from your plants. Transpiration burn occurs when mite feeding reaches critical levels. Symptoms of transpiration burn Mite feeding often causes leaf stippling. The loss of water and nutrients from countless microscopic punctures threatens plant health, especially in areas with scorching summers prone to drought. As temperatures rise, mite feeding increases and bronzing occurs. The accumulated water loss from mite feeding reaches a point where entire areas of the leaves die, leaving spots of dead brown or black tissue. Less leaf area means less photosynthesis, reduced crops, and unhealthy trees. Transpiration burn is a common problem of pear trees. Preventing transpiration burn A large, well-hydrated tree can lose up to 100 gallons of water a day during the peak of summer. Proper irrigation, using irrigation rings or soaker hoses, can prevent water stress on fruit and nut trees, helping them counteract the damage caused by mites. Mite control is tricky. These pests quickly develop resistance to chemicals, so pesticides don’t work. You can use a strong stream of water from a garden hose to displace mites. You can also buy predatory mites that hunt and feed on the mites feeding on your plants. Insecticidal soaps and oils can also kill mites, but use them carefully. They can cause sunburn damage and other problems. Keep your plants healthy and monitor them regularly for webbing and stippling, so you can deal with mite populations before they get out of hand. If you have a walnut tree, you should know about walnut scale. Even if you don’t, this is still an interesting read.
Walnut scale insects (Quadraspidiotus juglansregiae) have a unique behavior that makes them particularly fascinating. Like other armored scale insects, females protect themselves under round, dome-shaped covers. But walnut scale takes this concept to a whole new level. Walnut scale lifecycle Female walnut scale insects lay eggs in spring. These eggs hatch in only 2 or 3 days. Female crawlers move around a little bit, searching for a good spot to set up household. Once a spot is selected, they begin feeding and start building their protective cover. Male crawlers wander around, looking for a female. When they find one, they huddle up next to her, tucking themselves under the edge of her ‘skirt’, where they excrete their own elongated scale coverings. This often creates a daisy-shaped cluster of scales. After these groups mate, those females lay the year’s second batch of eggs. These eggs hatch, usually mid- to late summer, and stay in the crawler stage over winter. In spring, females claim real estate and males emerge with wings, which they use to find a female. Walnut scale description Walnut scale coverings start out white. This is called the white cap stage. Then they darken to gray or brown within a week or so. If you lift the covering off the central, round female walnut scale, you would see a yellowish body with indented margins. Other scale insects do not share those characteristics. Damage caused by walnut scale Like other scale insects, walnut scales use piercing mouthparts to suck plant juices from the cambium layer of twigs and branches. This weakens the tree, leading to branch dieback, cracked bark, and reduced harvest. Walnut scale feeding also increases the likelihood of canker development and fungal diseases caused by Botryosphaeria. How to control walnut scale You can’t control them if you don’t know they are present. Make a point of inspecting your trees regularly for signs of infestation and infection. You can apply sticky barriers near walnut scale adults to capture crawlers, as they emerge. There are many beneficial predators that feed on scale insects. Parasitic wasps, twicestabbed lady beetles, and a tiny black beetle that goes by the name Cybocephalus californicus, in particular, love to feed on walnut scales. Commercial growers apply insecticides during dormancy or when crawlers emerge in spring. Narrow range oils can also be used, but walnut trees are very sensitive to horticultural oils. Do not use oils on walnut during dormancy, or between bud break and shoot elongation. Oil use at these times can harm your tree. Horticultural oil can be used with caution as buds begin to swell and the tree enters the delayed dormant period. If your walnut tree is water stressed or suffering other forms of stress, do not apply oil. Oils should also never be used when temperatures are above 90°F. Scale infestations are on the rise. This is believed to be the result of several different factors, including reduced numbers of beneficial insects. Keeping your trees healthy makes them less likely to be harmed by pests such as walnut scale. Now you know. After investing time and garden space to asparagus, one of the last things you want to see is something attacking your spears. Originally from Europe, this tiny fly is now found everywhere asparagus grows. While asparagus miners do not cause serious damage, they can carry a disease that will.  Adult asparagus miner (Morri362) CC BY 3.0 Asparagus miner description and lifecycle You won’t see the early life stages of asparagus miners. Whitish eggs are only 1/1000” in diameter and laid under the epidermis, at the base of asparagus stalks. Slightly larger larvae (15/1000”) are also white and tapered at both ends, with black mouth hooks. After feeding, they will grow to 1/5” in length before pupating. Pupae are dark brown and flattened and can be up to 17/100” long. These pests overwinter in the pupal stage, either in the soil or in stalks.  Asparagus miner pupa, late instar, early instar from left to right (Morri362) CC BY 3.0 Adult flies are small (1/10”), shiny black and somewhat humpbacked. They have clear, tapered wings. They appear most often in May and again near the end of the summer.
Damage caused by asparagus miners Damage is usually seen during the fern growth stage. As they feed, asparagus miners burrow a meandering pattern just below the surface. This feeding behavior can result in girdling, which causes chlorosis. More often, the damage is mostly cosmetic. The real problem associated with asparagus miners is that they are vectors for Fusarium root and crown rot. If you see bright yellow discoloration or wilting in your asparagus plants, it may be that asparagus miners have brought Fusarium root and crown rot to your asparagus bed. In that case, both the affected plant and the surrounding soil should be removed and thrown in the trash. Controlling asparagus miners Generally, parasitic wasps keep asparagus miners in check. If a heavy infestation occurs, remove the fern growth at the end of its season and throw it in the trash. Insecticides are not effective. Now you know. We’ve all heard about ladybugs, but what about twicestabbed lady beetles? Common ladybugs, or lady beetles, have the classic red half-domed shape, stubby antennae, and multiple black spots. This particular lady beetle has a black domed shape with two distinct red spots, hence the name. If you turn one over, their undersides are red or yellow.  Adult twicestabbed lady beetle (Judy Gallagher) CC BY 2.0 Twicestabbed lady beetle description
Twicestabbed lady beetles (Chilocorus orbus) are only one of four black lady beetles with red spots. The other three are Axion plagiatum, Chilocorus kuwanae, and ashy gray lady beetles. All four species are beneficial predators, so it isn’t critical to be able to tell them apart. [The ashy gray lady beetle has a unique ability to change its color from gray to red, but we will discuss that another day.] Twicestabbed lady beetle larva have the same bristled, elongated, alligator shape of other lady beetle larvae, but are more gray than black. Adults are 1/10 to 15 of an inch long. Twicestabbed lady beetle diet Twicestabbed lady beetles feed predominantly on adults and larvae of scale insects. Their diet includes armored scale on avocados, brown soft scale on citrus, European fruit lecanium on cherry, San Jose scale on pear, and more. You will rarely see twicestabbed lady beetle larvae because they spend most of their time hidden under scale insect domes, feeding. Eggs are even less likely to be seen, at 1/32” in length. Eggs may be laid singly or in clusters. Feeding is normally done by piercing the victim and sucking out their innards. Older lady beetles also bite and chew their food. As with other lady beetle species, it does no real good to buy them. If they don’t like what’s on the menu in your garden, they will simply fly away. If you make your garden appealing to lady beetles, they will find you. This means providing fresh, mosquito larvae-free water. [Use mosquito dunks in all standing water.] Lady bugs also eat pollen, so planting a variety of flower colors and shapes may attract them. Allowing dill, cilantro, and fennel to go to seed provides a ready food source for both you and lady beetles. Also, avoid the use of broad spectrum pesticides and insecticides. How many different species of lady beetles are in your garden? Brown soft scale (Coccus hesperidum) may be found on pomegranate and citrus trees, as well as bay laurel.
Brown soft scale lifecycle
Brown soft scale females give live birth, or lay eggs which hatch almost immediately. These young crawlers move around freely on leaves and twigs, feeding as they go. They continue moving around until they are about half grown, molting twice. Controlling brown soft scale Sticky barriers around the trunks of susceptible trees can cut off protection to brown soft scale pests by ants. Also, avoiding the use of broad spectrum pesticides allows natural predators to feed on these pests. If you see scale shells with holes in the top of them, you will know they have been parasitized by beneficial insects. Heavy infestations can be treated with dormant oil in winter, but this is rarely necessary. No, it's not a flying snake. Introducing another beneficial insect on the garden scene: the snakefly. #/media/File:Snakefly_-_Agulla_species,_Packer_Lake,_California_-_26063118522.jpg) Snakefly (Judy Gallagher) CC BY 2.0 I don’t know why they call it a snakefly. It doesn’t look like a fly or a snake. Apparently, snakeflies are native to the western half of North America, as well as Europe and Asia. Until yesterday, I had never heard of snakeflies. Let’s see what we can find out! The first thing I learned about snakeflies is that they are considered living fossils, having remained relatively unchanged for over 140 million years. Snakefly description Snakeflies (Agulla adnixa) have long, thin bodies with lifted torsos (prothorax), large eyes, extended mouthparts (mandibles), relatively long antennae, and a long, thin backend. Adults are reddish brown and can be 1/2 to 1” long. All four wings are transparent, and longer than the body, similar to lacewings (except that snakefly wings are covered with black veins). The long backend is not a stinger. Instead, it is an ovipositor, or egg-laying tube.  Snakefly (Judy Gallagher) CC BY 2.0 Larvae have squishy bodies, and the head and first segment are hardened (sclerotised), but they look like a cross between an earwig and a ladybug larvae. [Sorry, but I couldn't find any free-to-use photos.] Snakefly larvae have 3 pairs of true legs, and, you won’t believe this: Snakeflies have an adhesive strip on their abdomens that allows them to move up walls and trees!
Snakefly lifecycle Eggs are deposited in the soil, where they are able to absorb soil nutrients to help them grow and develop. When they hatch, larvae stay in the soil or move to the bark of nearby trees. There, they feed on soft-bodied pests, such as grubs and caterpillars, as well as the eggs and larvae of many garden pests. Snakefly larvae go through as many as 10 moltings before reaching adulthood. This process can take 2 to 6 years. Next, after temperatures reach 32°F, the larvae enter a pupal stage. Unlike other insects, the snakefly pupa is mobile, leaving its pupal cell for day trips or to relocate. The pupal stage is temperature dependent, lasts a few days to 3 weeks, upwards of 10 months. [This is one long lived insect!] Adults snakeflies are very territorial as they feed on insects, such as mites and aphids. [Yay!] It is also believed that they occasionally nibble on pollen. Snakeflies court one another with cleaning rituals. You may see them practicing their flirting skills by cleaning their legs and antennae when alone. Have you seen any snakeflies in your garden? To me, they look almost Edwardian. Calendula officinalis is an edible flower that can add color and attract honey bees to your garden. Believed to be native to Europe, Calendula officinalis has been grown by people for so long and in so many locations, it is hard to tell for sure.  ‘Calendula officinalis’ (Berdan) CC BY-SA 3.0
Pot marigold description Unlike the Tagetes genus of marigold, which have leaves that appear alternately along a stem, pot marigolds have slightly hairy leaves that are arranged in a spiral around the stem. They are short-lived perennials, typically grown as annuals, that grow 18 to 30” tall, with 2” flowers. Flowers are bright yellow or orangish-yellow, with ray florets and disk florets, common to sunflowers. Pot marigold’s curved seeds are actually dried fruits, called achenes.  Calendula seeds (H. Zell) CC BY-SA 3.0 Pot marigold as an attractant In addition to looking lovely as a border plant, or in a parterre, Calendula officinalis will attract important pollinators, such as honey bees to the garden. Unfortunately, they will also attract cabbageworm butterflies, large yellow underwings, an invasive moth of the cutworm variety, and setaceous Hebrew character moths, whose larvae feed on a number of popular garden plants. Pot marigolds as food Pot marigold flower petals have a tangy, peppery flavor. Traditionally added to German soups and stews, pot marigold is also added to herb butters and cheeses, or chopped and used to garnish deviled or scrambled eggs, fish dishes, or steamed vegetables. Pot marigold flower petals add color and tang to salads. If you add marigold flower petals to rice, while cooking, the rice will turn yellow. For this reason, it is also known as Poor Man’s Saffron. Farmers have fed marigolds to chickens for years to make the yolks a deeper yellow. One variety of pot marigold, ‘Mexican Mint’, has the flavor of tarragon. It is also known as Texas tarragon. Pot marigold petals also make a delightful tea.  Pot marigold at the beach (Public Domain) Pot marigolds as medicine Pot marigolds also have medical merit. Research has shown that tinctures of pot marigold are used today to treat skin irritations and burns, to speed healing, and to control bleeding. [I wonder how they would look growing next to some aloe vera - just to keep the medicinals together.] This is not my area of expertise, and I won’t make any personal claims, but it is interesting to see how, every once in a while, those old treatments hold true. That being said, some people are allergic to pot marigolds. How to grow pot marigolds Pot marigolds are easy to grow from seed and they tend to be drought tolerant. Start seeds in small pots, only lightly covered with soil. Keep the soil moist, but not soggy, until germination occurs. Then, move plants to a sunny location with good drainage. Calendula may need protection from scorching summer afternoon sun, and they can be grown in containers, or on windowsills. Marigolds readily self-seed. Calendula pests and diseases While these plants are relatively trouble-free, they may become infected with powdery mildew, root rot, and smut. They are also susceptible to Alternaria leaf spot, aster yellows, charcoal root rot, cottony rot, cucumber mosaic, gray mold, Pythium root rot, root knot nematodes, rust, southern blight, spotted wilt (from the tomato spotted wilt virus), stem rot, and Verticillium wilt. I couldn't find any pests that significantly bother pot marigolds. Many of these diseases can be prevented by providing good drainage and air flow, so top dress soil regularly with organic matter, space plants with mature sizes in mind, and avoid overhead watering. So, do you know if your marigolds are edible or not now? This poem may help:
Psyllids are jumping plant lice that suck plant juices. Most native psyllid species do not pose a threat to your garden. Local predators tend to keep those populations in check most of the time. Invasive psyllid species are something else altogether.  Asian citrus psyllid (USDA ARS) Psyllid identification Psyllids look like tiny cicadas or winged aphids with tubular mouthparts. They have powerful legs and short antennae. Psyllids can be 1/12 to 1/5” long. Adults hold their wings in a roofline position. Nymphs are flattened and look a lot like soft scale insects. Psyllid nymphs commonly produce waxy filaments or covers called lerps using wax and honeydew.  Potato psyllids look like flies (Whitney Cranshaw, Colorado State University, bugwood.org) CC BY 3.0 US Psyllid lifecycle
Regardless of the species, psyllids start as tiny eggs that hatch and go through five developmental stages or instars. Adult psyllids can fly, but most prefer to jump. If you think you see a psyllid run or fly, it is probably a psocid [SO-sid]. Psocids are beneficial insects that feed on fungi. They have a narrow “neck” and chewing mouthparts. Psyllid host plants As a species, psyllids have strong preferences for particular host plants. While some psyllids will prefer your sweet peppers and chilis, others will go after your peaches and nectarines, others will only feed on olive or pear trees, and other psyllid species will only feed on potato and tomato plants. The invasive Asian citrus psyllid carries huanglongbing,, a deadly citrus disease. Citrus trees infected with huanglongbing must be destroyed and removed by a professional arborist, which is both sad and expensive. These pests, when present, are most active in spring. Psyllid species most likely to threaten your garden include:
Dozens of psyllid species infest ornamental trees and shrubs, as well. These include the recent invasions of Ficus leaf-rolling psyllids and spotted gum psyllids. On the other hand, some psyllid species are beneficial. The Australian melaleuca psyllid, for example, has been purposefully introduced to Florida to help control paperbark trees, an invasive weed tree. Damage caused by psyllids One of the biggest problems associated with psyllids is their poop. After they have robbed your plants of valuable nutrients, they add insult to injury by excreting a large portion of the sap they ate and depositing it on leaves. Sap-sucker poo or honeydew is rich in sugar and other nutrients. Honeydew ends up being food for fungal sooty mold and disease-carrying ants. Psyllid feeding can also spread diseases, such as calico, and zebra chip, and disorders, such as galls, leaf and bud discoloration and deformation, and premature leaf drop. Leaf distortions often look similar to peach leaf curl. Pear psyllids inject fruit with toxins that blacken leaves and fruit skins. Psyllid feeding also creates points of entry for other pests and diseases. How to control psyllids in the garden Control psyllids with insecticidal soaps and yellow sticky sheets. Do not use dish soap. Parasitic wasps and pirate bugs feed on psyllids, so avoid using broad-spectrum insecticides. Severely infested plants should be removed and destroyed or thrown in the trash. Usually, simply monitoring plants can make controlling these and other pests much easier. To prevent invasive psyllids from finding your garden, only buy pest-free plants from reputable nurseries, and place new plants in quarantine.
Leafrollers are the larval forms of several tortricid moth species. Tortricid moth larvae feed on young buds, flower clusters, leaves, and fruit. Heavy infestations can kill strawberry, blueberry, blackberry and other cane fruit plants. Leafrollers are also found on almond, apple, apricot, avocado, cherry, citrus, grapes, pear, plum, prune, quince, and walnut, depending on the species. Leafrollers also occur on roses and several ornamental trees, including ash, birch, California buckeye, box elder, elm, locust, maple, poplar, and willow. The tubes are used to provide protection as larvae feed and pupate.
Leafroller species There are several leafroller species, here are some:
A quarantine is in place for the light brown apple moth. See if you live in an affected area by clicking on the CA Dept. of Food & Agriculture’s Boundary Index Map. If you live outside of California, you can contact your local Cooperative Extension Office for more information  Omnivorous leafroller larva (Barry Freeman) CC BY 3.0 Leafroller lifecycle
Leafrollers start out as clusters of flat, irregularly shaped eggs often found on twigs and leaves. These egg masses are coated with a dark gray or brown glue that later bleaches to white, giving them an appearance similar to fish scales. If you look closely at an egg mass in spring, you can see tiny pinholes where larvae have hatched. After hatching, larvae pull leaves into a cylinder for protection as they feed. Most larvae feed through summer and then overwinter as pupae, though some species continue feeding throughout the year, causing considerable damage. When disturbed, leafroller caterpillars tend to wriggle wildly and then rappel to the ground on a single silken thread. April is the time to start checking apple, apricot, avocado, cherry, peach, pear, plum and prune trees, and blueberries, for signs of the dreaded Pacific flathead borer.  Flathead borers Like other borers, these pests chew tunnels in wood, weakening a tree’s structure, and robbing it of important nutrients found in the inner cambium layer. Newly planted trees and trees weakened by drought, water-stress, scale insects, carpenterworms, or diseases, such as Phytophthora or Armillaria, are particularly susceptible. These weakened areas are then more likely to be attacked by other pests, such as shot hole borers. Pacific flathead borer feeding can also girdle a young tree, killing it. The only symptom you may see is a dark colored depression in the bark, or tiny cracks where you might see frass (bug poop), usually on the side receiving the most sunlight. Pacific flathead borer identification Pacific flathead borers (Chrysobothris mali) are flattened, wedge-shaped, dark bronze beetles that can be 0.5 to 0.75” long. You may see copper-colored spots on the wing covers. Eggs are very tiny, only 0.04” in diameter, flattened, oval, and white. Larvae grow to 0.75” in length and are white, with an amber colored head. Larvae are flattened, with a widened area just behind the head, tapering towards the rear end. Pupae are also whitish and flattened, getting darker as they mature. Pacific flathead borer lifecycle These pests overwinter in a prepupal stage. As temperatures begin to rise, they pupate. From April through July, adult beetles emerge, usually beginning around the same time apple trees are blooming. Then females mate and begin laying eggs in the bark, favoring areas weakened by sunburn or mechanical injury from tree supports, weedwackers, and out of control lawn mowers. When the eggs hatch, larvae burrow directly into the bark and begin feeding on the sugary cambium layer, robbing your trees of the nutrients they need to grow and produce fruit. As the larvae mature, they will either create a pupal chamber in the xylem, or burrow under the bark, where they will stay until the following spring.  Flathead borers are easy to miss Pacific flathead borer controls
Healthy trees are better able to resist and recover from Pacific flathead borer attack. This means selecting trees suitable to your microclimate, planting them at the proper depth, and feeding, irrigating, training, and pruning them properly. Since eggs are laid in weakened bark, protect trees from mechanical injury, and be sure to whitewash exposed bark before sun damage can occur. Birds, especially woodpeckers, will find and remove Pacific flathead borers, and carpenter ants eat both larvae and pupae. Insecticides are commonly used in commercial orchards to kill new larvae, but once the larvae are inside the tree, there is nothing you can do besides pruning out infested wood and burning it. Now you know. Tomato pinworms are the larval form of a moth that prefers feeding on members of the nightshade family. This means tomatoes, eggplants, and potatoes are at risk. It also means weeds and native plants in the same family can harbor these pests.  Tomato pinworm entry holes (UF/IFAS) Tomato pinworms (Keiferia lycopersicella) are predominantly found in areas with mild winters. They can also appear in greenhouses, so be sure to put new plants into quarantine until you are sure they are pest free. Tomato pinworm description Eggs are pale yellow, at first, but then they turn bright orange, just before hatching. Larvae appear dark with light bands. The moth is very small, and a mottled gray with long antennae.  Tomato pinworm moth (UF/IFAS)  Tomato pinworm larva (Alton N. Sparks, Jr., University of Georgia, bugwood.org) CC BY 3.0 US Tomato pinworm lifecycle Moths lay eggs singly or in groups on leaves. When the eggs hatch, larvae spin protective webs. Then they burrow into the leaf to begin feeding. As the larvae move through 4 developmental stages, or instars, they may also fold leaves, or pull multiple leaves together, for added protection from predators. Tomato pinworms also move into stems and fruit, where they can make your crop inedible.  Leaf mining damage caused by tomato pinworm (UF/IFAS) After eating their fill, larvae then drop to the ground and form a loose cluster of sand grains around themselves, in a form of pupa. Two to four weeks later, they emerge as adult moths. There can be 7 or 8 generations a year. Because there are so many generations each year, and because generations can overlap, serious infestations can decimate your tomato plants.  Tomato foliage showing field damage by tomato pinworm (UF/IFAS) How to control tomato pinworms In areas with mild winters, tomato pinworm eggs and larvae can overwinter in the soil, on tools, or in buckets or baskets. Closely monitoring plants for signs of infestation is your first line of defense. Pheromone traps can be used to monitor for the moth and mating disruptants can make it more difficult for adult males and females to find each other. Be sure to thoroughly compost or remove plant residue at the end of the growing season, and always put new plants into quarantine.  Larvae of tomato pinworm (UF/IFAS) Commercial growers use insecticides on the first and second instars, but later instars are protected by their spun tents and by being inside the plant. This is one pest that is hard to get rid of, once it becomes established. Moderate infestations can be slowed by not planting early and late season tomatoes the same year. To manage badly infested areas, the host crops must not be planted for a year or two, to break the tomato pinworm lifecycle.
Crop rotation is not effective, as the moths simply fly from one part of the garden to another. Sugar volcanoes are a tree’s response to boring, disease-carrying insects.
Now, when I say boring, I do not mean dull-witted conversationalists. These pests are invasive shot hole borers that chew holes through the bark to get at the sugary sap found in the cambium layer. Borers and disease Borer entry and exit holes, while very tiny (0.03” in diameter), compromise a tree’s outer layer of defense. As the beetles bore into the wood, they may carry three different species of fungal spores. These fungal spores enter the tree, bringing Fusarium dieback. Fusarium dieback is a fatal fungal disease in which fungi block a tree’s vascular system, halting the flow of water and nutrients. Avocados and exudates Fusarium dieback affects hundreds of tree species and grapevines, but sugar volcanos are specific to avocados and box elders. Exudates are secretions. When shot hole borers bring Fusarium dieback to an avocado tree, it responds by pushing a sugary exudate out of the borers’ entry and exit holes. This sugary secretion often includes frass and sawdust. As it dries, this sugary exudate forms a white, crusty ring or cone-shaped patch on the affected branch. And these crusty white patches, dear readers, are sugar volcanoes. Now you know. Gumming does not mean your tree has lost its dentures. Instead, it is responding to injury.  Canker-induced gummosis of Tibetan cherry (Rosser1954) Public Domain Unlike people and animals, plants do not have an active immune system. Instead, injured or infected areas are walled off to prevent further injury or the spread of infection or infestation. Gumming refers to how a specialized sap, or botanical gum, oozes out of an injury site or canker to provide protection.
Gumming is particularly common among stone fruits, such as nectarine and almond. It also occurs in mango and citrus. Causes of gumming Environmental stress, mechanical injury, insect attacks, and disease can all trigger a tree to start gumming. Gumming creates a protective barrier and may push any invaders out. You can use specific details surrounding gummosis to identify the problem. For example, gummosis caused by insect infestation or mechanical injury often exhibits bits of bark or sawdust mixed in with the gum. Look for other damage around the gumming site: Do leaves look sick or chewed upon? Has the bark’s integrity been breached? Do you see discoloration under the bark near the gumming?
How to manage gumming You can help your fruit and nut trees stay healthy by avoiding mechanical injuries, monitoring for pests and diseases, and regular feeding and irrigation. If you suspect disease has taken hold, scrape some of the bark from the area surrounding the gum. If you see discoloration or streaking, it is probably a disease that needs further attention. Removing affected branches can sometimes halt the progression of some diseases. Be sure to sanitize cutting tools between each cut with a household cleaner. If the gum emerges from circular holes and contains insect larvae, the tree has the problem in hand. All you need to do is monitor the situation. Before you swat that tiny wasp away, take a closer look. It may be one of the Good Guys.  'Exochus prosopius' (James Lindsey) CC BY-SA 2.5
Many sap-sucking pests are attracted to the color yellow, and you can use that to your plants’ advantage. Much the way sticky barriers prevent crawling insects from climbing up into fruit and nut trees, yellow sticky sheets attract and trap many flying insects that might carry death and disease to your garden plants.  Yellow sticky sheets capture pests without chemicals and help you monitor insect populations Unlike pesticides and other chemicals, insects cannot develop a resistance to stickiness - not any time soon, any way! Plus, sticky sheets do not cause harm to people or pets. The worst that can happen is they will stick to you temporarily. When an insect lands on the sticky surface, it means death. They cannot escape, reproduce, feed, or spread disease. They are done, and all you have to do is toss them in the trash. Yellow sticky sheets can capture a wide variety of pests, including:
 Yellow sticky sheet cut into flower shape to capture indoor pests Yellow sticky sheets are often used in tandem with pheromone traps. The pheromones lure the insects closer and then the yellow sticky sheet makes them unable to fly away.
Whether you use a pheromone trap in conjunction with yellow sticky sheets or not, you can use the sticky sheets to monitor for pest populations in and around specific plants or beds. Personally, I hang them in my citrus trees in early spring to significantly reduce leaf miner damage, and to help me know what else I happen to be up against at any given time. The best news about yellow sticky sheets? They’re cheap. And if you are having problems with indoors pests, you can always cut the sticky paper into a decorative shape and put it to work for your container plants! Every year, there are garden favorites that we plant religiously. Just as consistently, the same pests come, causing damage and carrying disease. What if there was a way to lure those pests away from your garden faves? There is. It’s called trap cropping.  Mature mustard plants lure flea beetles away from young broccoli plants (USU Extension) CC BY 3.0 Trap cropping refers to the purposeful planting of crops known to attract or repel specific pests within and around the crops you are trying to protect. This distraction reduces the damage done by pests. In some cases, the attractant trap crop can interfere with the pest’s lifecycle, or kill it outright. In other cases, as pests start feeding on the trap crop, you harvest it, breaking the lifecycle of specific pests.
Trap cropping is a form of companion planting (better known as intercropping). While mint, garlic, nasturtium, and fennel have often been touted as cure-alls for many pest problems, the science behind trap cropping is still relatively new and I was unable to find enough research geared specifically toward those plants. Fear not, however, as there is plenty of good information you can use to protect your garden plants! How trap cropping works Trap crops distract pests away from food crops. By providing a rich food source for these pests, they are less likely to damage your food crops. Also, heavy pest infestations attract beneficial predators, such as lacewings and lady beetles. Once an infestation occurs, the trap crop can be fed to your chickens, tilled under, or composted. In commercial fields, pests attracted to trap crops are killed off with pesticides or vacuumed off the plants and destroyed. Types of trap cropping There are several types of trap cropping:
Very often, trap cropping methods are used in combination, improving their effectiveness. These methods reduce the need for chemical pesticides, while increasing biodiversity. Which crops have the biggest pest problems in your garden? And how can you use trap cropping to protect them? Let us know in the Comments! In the short days of winter, many of your fruit trees look as though they aren’t doing much of anything. Other than collecting chill hours and working to stay alive, that would be mostly true. As the days begin to lengthen, leaf and flower buds start to swell. But, sometimes, those swellings are something else entirely. Also known as the almond and plum bud gall mite (Acalitus phloecoptes), this pest is native to Europe and the Middle East. As of January 2019, it made its way to California, threatening tens of thousands of plum, pluot, almond, apricot, and many other fruit and nut trees.  Plum stem exhibiting plum bud gall mite galls. Photo courtesy of Susan Casner-Kay. What are plum bud gall mites? Plum bud gall mites are a type of eriophyid mite. Eriophyid mites are a family of microscopic plant parasites. These pests enter stems and buds through lenticels and injury points, and then overwinter under the bark. Very little information is available about this new pest, but knowing what to look for can help you to stop it from spreading.  Microscopic image of eriophyid mite (Pixabay) Plum bud gall mite identification In late winter, galls begin to form around these tiny invaders. By spring, adults emerge from their protective galls. At 1/100th of an inch in length, these mites are too tiny to see with the naked eye. If you have a 20x hand lens, you may be able to see them, if you look very closely. They can be a translucent yellow, pink, white, or purple, with two pairs of legs up near the head. You are more likely to see galls on new shoots and fruit spurs that plants produce in response to these invaders. Galls are warty, bumpy growths that don’t look like normal tissue.  Dissected plum bud gall mite gall. Photo courtesy of Susan Casner-Kay. Controlling plum bud gall mites
Treating your trees with wettable sulfur in March or April, when plum bud gall mites first start to emerge from their protective galls, has been effective in controlling these pests in other regions. Treatments may need to be repeated, depending on the level of infestation. Note that apricot leaves are very sensitive to sulfur, so you can only treat apricot trees with sulfur before leaves emerge. Because these particular eriophyid mites are new to the region, we do not yet know what sort of an impact native predatory insects will have on controlling plum bud gall mite populations. If you happen to see this new pest on your trees, please contact your County Extension Office right away. “Go, Navy! Beat Army!” No, wait. Sorry, that’s not what I meant.
While it might be easier to list the plants not susceptible to beet armyworms, you need to know where to look for these pests. In addition to beets, the list of potential beet armyworm hosts includes beans, celery, cilantro, citrus, cole crops, cucurbits, lettuces, parsley, peppers, strawberries, and tomatoes. Beet armyworms also attack alfalfa and cotton. Beet armyworm lifecycle Female moths lay pale, pinkish or greenish striated eggs in clusters of more than 100 eggs, often on the upper sides of leaves. These clusters look fuzzy, due to hairlike scales left behind by the moth. After they hatch, larvae begin feeding on nearby leaves, slowly dispersing throughout the plant. As larvae get older, they also feed on fruit. After defoliating your plant, the mature larva drops to the ground, where it pupates in a shallow depression in the soil, or in a pocket excavated just below the soil surface. An adult moth emerges, and the whole process begins again. This cycle is completed in one month, so there can be multiple generations each year.  Beet armyworm moth (Dumi) CC BY-SA 3.0 Beet armyworm description
Larvae are smooth, pale green caterpillars, with several pale, wavy lines down the back and a broad stripe down either side. You may also see a dark spot above the second pair of legs. Other color variations can occur, depending on the food source and developmental stage. After 2 or 3 weeks of feeding, caterpillars will reach 1.25 inches in length. Adult moths are mottled brown and gray, with a 1-inch wingspan. Damage caused by beet armyworms Beet armyworms can destroy seedlings in only minutes. When feeding begins, the damage appears as clusters of circular or irregularly shaped holes in leaves. It can also cause flagging, a condition that slows or halts growth on one side of a plant. Larvae will feed on the crown of lettuce plants, killing them. As caterpillars get bigger, they can skeletonize all the leaves on a plant. Most fruit feeding occurs on or near the surface, and can be cut away, assuming other pathogens haven’t entered the fruit, causing disease or decay. Of course, you will want to wash the fruit thoroughly, to get rid of caterpillar feces. If beet armyworms feed on floral buds, the buds will abort. How to control beet armyworms In the home garden, natural predators are your plants’ best defense against beet armyworms. Predatory wasps will parasitize beet armyworm larvae, while big-eyed bugs, and minute pirate bugs will feed on the eggs. Spiders, damsel bugs, assassin bugs, tachinid flies, and lacewings will also feed on beet armyworms, so avoid using broad spectrum pesticides. In severe cases, you can apply spinosad or a specific type of Bacillus thuringiensis (ssp. aizawai). Prevent beet armyworm invasions by monitoring nearby weeds, especially lambsquarters, goosefoot, and pigweeds for signs of egg clusters. Harvesting your crops as soon as they are ready can also interrupt the lifecycle of these pests. Beet armyworms have been known to travel as far as 10 feet during a night, putting most of your garden plants at risk. Monitoring for signs of beet armyworm infestation can help you prevent the problem from spreading. Winter months are an excellent time to prune fruit and nut trees. Naked and dormant, it is easy to see each tree’s structure. This is also a good time to inspect for common pests, such as scale insects and European red mites. While you will certainly want to get rid of any San Jose scale, walnut scale, Italian pear scale, or frosted scale insects you see, you should leave the European red mites where they are. Why in the world would you want to leave pests on your trees?  European red mite being attacked by a predatory mite (CSIRO) CC BY 3.0 Like many other plant-sucking pests, European red mites overwinter as eggs, tucked tightly against the bark of twigs, stems and leaf and bud scars. When they hatch, they begin feeding. The thing is, these tiny pests have small populations, at first. They don’t cause significant damage until late summer. By that time, they will have attracted an army of hungry, beneficial predators. European red mite description and lifecycle If you look closely, you may be able to see the reddish-orange eggs of European red mites. If you use a hand lens, you might even be able to see that these eggs have a spike. While winter eggs are attached to bark and stems, summer eggs are generally found on leaves, near leaf veins, and on fruit. Around the same time that walnut trees start leafing out, these winter eggs will hatch and bright red, tiny mites will appear.  European red mite egg clusters can be found in the crooks of tree branches (University of Georgia Plant Pathology Archive, University of Georgia, bugwood.org) CC BY 3.0 These mites will go through 3 moltings, or instars. First instars have 3 pairs of legs, while older instars have 4 pairs of legs. Freshly molted mites may sometimes have a green tint. Adult females are reddish, with 4 rows of curved hairs emerging from white spots. Males are smaller than females and brown in color. Females measure in at 1/72 inch. Males are 1/80 inch, which means you could line up 4 of them on the edge of a dime.
Females can lay eggs without mating, but these offspring will all be male. [This is called arrhenotokous parthenogenesis. Most parthenogenetic offspring are female, as with aphids, so this is different.] If populations become especially high, European red mites will disperse themselves in a behavior called ballooning. Damage caused by European red mites While it is all well and good to let these pests have their day in early spring, as temperatures rise and populations increase, they can cause serious damage to apple, cherry, pear, plum, prune, and walnut. They may also be found on almond, chestnut, currants, gooseberries, grapes, peach, and raspberries, as well as roses, privet, lilac, elm, alder, and black locust. Young mites prefer feeding in the relative safety of the undersides of leaves. Older, more mature mites feed on both sides. Light feeding will cause leaf stippling. Heavy feeding can bronze leaves. Bronzing may be fine for baby shoes, but it makes photosynthesis impossible. Whereas other mites produce webbing and cause leaf drop, the European red mite produces little or no webbing and no leaf drop. Persistent, heavy mite feeding can also cause transpiration burn (dead spots), reduced fruit size and quality, shoot growth, trunk and limb growth, and root growth. If populations of European red mites become significant, you can apply delayed dormant horticultural oil, but that oil may cause sunburn damage. It’s a tough call. Since European red mites have demonstrated resistance to miticides (a type of pesticide geared toward mites), it is better to avoid chemical sprays. Spraying these pests with a hose does nothing. If your garden or landscape has a lot of biodiversity, odds are pretty good that there will be enough predators to control European red mite populations. Also, keeping plants dust-free makes the environment less hospitable to these pests. A break in the much appreciated rain and I found myself out in the garden. [Where else?] When I moved a large plant container, I saw something I had never seen before.  ‘Bipalium adventitium’ or yellow land flatworm found in Northern California (Sanjay Acharya) CC BY-SA 4.0 Curled up in a perfect spiral, under what had been the very center of my container, I saw a flat yellow worm with a dark stripe down the middle of its back. Of course, I had to collect it for identification. Unfortunately, this particular specimen escaped and is, I believe, lodged in my moisture meter. Land planarians, also known as land flatworms, or arrowhead flatworms, are a family of flatworms known as Geoplanidae. There are nearly 1,000 different species of flatworm worldwide, broken down into 4 subfamilies, but we know very little about them. What we do know is simply too strange not to share.  Valdivian Rainforest flatworm (José Grau de Puerto Montt) CC BY-SA 3.0 Invasive planarians Land planarians are native to Indo-China. Sometime around 1901, soil containing these flatworms was transported to the U.S. At first, land planarians were only found in greenhouses. Now they are found in several states including: Alabama, California, Mississippi, New Jersey, New York, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, and Texas. If you find one in a state not listed, I’m sure that your local County Extension Office would love to see it. At this point, land planarians are only found in places where nursery plants go. They withstand freezing temperatures by hiding in protected areas. They cannot, however, tolerate low humidity or drought. Land planarian description Land planarians are flat, slimy worms. Apparently, the slime helps them move and is the only way they can maintain internal moisture levels. That slime is said to taste terrible, though I don’t know how or who figured that out. That bad taste means they have few, if any, natural predators. Planarians can range from less than one inch to nearly a foot in length. Most planarian species tend to be brown or brownish-gray, but they can also be yellow, green, black, or even bluish-green. Most planarian species have dark longitudinal lines that start at the head. Heads tend to be triangular or crescent shaped. Planarians do not have a mouth, per se. Instead, they have a single opening on the underside of their body. If the outside of a planarian looks strange, the inside is even more bizarre. Planarians are a mass of squishy tissue and nerves, with a layer of locomotive hairs on the underside. They have no brain, circulatory system, respiratory system, or digestive system. So, how do they eat?  Black Brazilian flatworm (Piterkeo) CC BY-SA 3.0 Land planarian feeding Cousin to parasitic tapeworms, planarians are nocturnal predators that feed on slugs and snails, pillbugs, millipedes, spiders, and earthworms. They use chemical signals that are produced in folds of their skin to detect prey. Some land planarians use physical force to hold their prey, while others have a sticky mucous that entraps their victim. Now, when I said they feed, it isn’t feeding as we know it. When a land planarian feeds, it slimes over top of a potential food, attaches its “mouth” opening, and vomits digestive juices , liquifying its prey. Then, it sucks up the soupy nutrients. Land planarians do not have an anus, so waste products are released through the same opening used to bring it in. If that wasn’t weird enough, land planarian reproduction is even more odd.  Iberian flatworm (Eduard Solà) CC BY-SA 3.0 Flatworm reproduction Like many other flatworms, land planarians are able to reproduce either sexually or asexually. Sexual reproduction culminates in eggs being placed in cocoons that hatch in 3 weeks. A single planarian will, every couple of weeks or so, attach its tail to a rock or some other immoveable object and slime away, tearing its tail from its torso. A new tail grows from the wound, as we would expect of a flatworm. The tail segment left behind, however, does the same thing, growing a new torso and head within 10 days. [When food is scarce, it is not uncommon for land planarians to eat their own reproductive tissues.] Scientists love studying flatworms because of those reproductive habits. In one study, it was found that decapitated flatworms retained the memories of their parent worms. [I can’t make this stuff up.] As far as invasive pests go, planarians are not a significant problem, unless you have a greenhouse or practice vermiculture. [Vermiculture refers to raising worms.] In most outdoor gardens, fluctuations in humidity help keep land planarian populations in check. If you do have a greenhouse, or raise worms, flatworms can wipe out your entire worm population in short order. The next time you see slime trails, don't assume they were made by snails or slugs. It may be that those garden pests are on the run from something far more terrifying (to them).  Earthworm rescued from flatworm. Note the swollen area of the worm, 1/3 of the worm's length from its head - that was where the flatworm had started feeding. (Kate Russell) Galls are like warts or tumors in the plant world.  Oak apples are a type of gall (Maksim) CC BY-SA 3.0 Not really. Galls are neither warts nor tumors, but that’s how many of them appear. The word gall comes from the Latin galla, for oak-apple. Oak apples are not fruits. They are a plant’s reaction to the presence of a foreign substance.  Lime nail galls (Rosser1954) Public Domain The study of plant galls is called cecidology [see-SID-ology]. Most commonly associated with baseball-sized knobs seen on oak trees, galls come in all sizes and can occur on many different plants. Gall description Galls are swellings that occur in response to invasion. That invasion may be in the form of bacteria, fungi, insect larvae, eriophyid mites, nematodes, other pests, and even other plants. Mistletoe is one example of a gall-forming plant. Unlike fungal cankers, which involve plant tissue death, galls, fungal or otherwise, are cases of extra tissue growth. Galls are nearly always woody knobs that may occur anywhere on a plant. Galls may be simple, with a single chamber (unilocular), or highly complex, with multiple pockets (plurilocular). Galls can also look like a sphere, a saucer, pineapples, pinecones, pouches, pods, or fantastic, tiny red spikes. It just depends on the host plant and the cause of the gall.  Root galls found on roses Where they occur and how they look inside can tell you a lot about what caused them.
 Maple leaf galls (Jmeeter) CC BY-SA 3.0 If you cut a gall open, you will see distinctly arranged vascular tissues, depending on the cause of the gall, and an enlarged cambium layer. These distortions interfere with the flow of water and nutrients, leading to wilting and stunting. Or, you may see a large, open area, perfect for use as a larval nursery, with no noticeable impact on the host plant. Insect, mite, and nematode galls When insects invade a plant, they build galls. These galls can act as food or shelter for insects. They are not the same as the plant-produced domatia (tiny apartments) found in some thorns for beneficial insects. Insects inject chemicals (pseudo plant hormones) into host plants, triggering gall formation. Often, eggs are laid in these galls, providing developing larvae with food and protection. Gall wasps, sawflies, gall flies, scale insects, some aphid species, weevils, psyllids, and gall midges can all cause insect galls, but it is nearly always gall wasps or gall midges. Nematodes are microscopic round soil worms that can cause small galls on roots. Root knot nematodes are one such pest. These galls are made up entirely of plant tissue, unlike fungal and bacterial galls, which incorporate fungal or bacterial tissues, respectively. Insect galls may also house interlopers, technically called inquilines. Fungal galls When a fungus infects a plant, it grows alongside plant cells, creating swollen areas that can develop into galls. Several varieties of rust can cause galls to form. When these galls form on conifers, as in the case of cedar apple rust, they look like glutinous fingers called telial horns.  Dried cedar-apple rust gall Fungal galls on other types of leaves tend to look more spherical.  Eucalyptus leaf gall (fir0002) GFDL 1.2 Bacterial and viral galls Bacterial and viral galls develop because the bacteria or virus reprograms plant cells into producing more bacteria, viruses, or other supportive cells. Galls at or just below the soil level are nearly always crown gall. Crown gall is a bacterial disease that can occur on blackberries, sunflowers, grapes, and roses, along with almond, apple, apricot, cherry, and pear trees. Galls on roots may mean clubroot, a disease caused by parasites known as Phytomyxea. On the other hand, root galls may also indicate the presence of beneficial, nitrogen fixing Rhizobium bacteria. Galls have long been used in leather tanning, to make ink, and as astringents. Most galls contain high levels of tannic acid and resin. There are even a few edible galls, corn smut being the most notable. Sometimes, what looks like a gall is herbicide overspray. New and undifferentiated plant cells are most vulnerable to gall formation. Spring is a good time to monitor plants for signs of galls. Once gall development begins, the tissues have been reprogrammed and cannot return to normal. Gall management In a word, you can’t. Insect and mite galls rarely harm plants, and you can’t control these pests completely, anyway. Once they are inside the plant, there is nothing you can spray or apply that will reach them. Anyway, the gall is already in place. Fungal and bacterial galls may be prevented or reduced with fungicide treatments if you can time it perfectly. Or not.  Leaf galls on rhododendron (Xemenendura) CC BY-SA 3.0 If you are galled by galls, remove them with a sharp knife. Otherwise, recognize that galls are just another amazing aspect of playing with plants.
Damsel bugs have soft, slender bodies that may be brown, gray, yellowish, reddish brown, or tan. Adults are 3/8- to 1/2-inch long. They have long legs and long antennae, and may be confused with equally beneficial assassin bugs. Like assassin bugs, some damsel bugs can and will bite. They are, after all, predators. Medically speaking, as far as I know, damsel bug bites are harmless.
Damsel bug lifecycle Young damsel bugs, or nymphs, look a lot like adults, which means they go through an incomplete metamorphosis. They have 5 developmental stages, or instars, before reaching adulthood. This process takes approximately 50 days. Adult females hide eggs by laying them inside plant tissue. Damsel bugs are most active in the Bay Area mid-June through mid-August, but they overwinter in ground cover and winter crops, such as alfalfa and many legumes. Remember, just because you don’t see them doesn’t mean they aren’t there. Damsel bug prey Like lady beetles and praying mantis, damsel bugs are generalists. This means they will eat whatever they can hold onto long enough to eat. Very often, those meals are aphids, armyworms, small caterpillars and caterpillar eggs, fleahoppers, leafhoppers, lygus bugs, mites, proba bugs, spider mites, and thrips. (Hooray for damsel bugs!) Of course, they will also eat beneficial big-eyed bugs and minute pirate bugs, and occasionally they will even eat plants, but their net result to the garden is still very positive. In one study, it was estimated that a single adult damsel bug eats 42 moth larvae, 24 lygus bug nymphs, or 5 aphids every day. The same study estimated that a peak population of damsel bugs (283,000 bugs per acre) could consumer 12 million moth larvae, 6 million lygus bug nymphs, 1 million aphids, or some combination of those and other prey, every 24 hours. That’s some significant garden protection! If you keep a hand lens in your pocket, you may be able to see a damsel bug up close one day. What looks like a light dusting of snow may actually be life-threatening pests, called adelgids.  Hemlock Woolly adelgid (Connecticut Agricultural Research Station, bugwood.org) CC BY 3.0 Like their cousins, the aphids, adelgids pierce vascular bundles to suck out sugary fluids. While mature, healthy trees can withstand a mild adelgid infestation, saplings, young trees, and unhealthy trees can be killed by this tiny, soft-bodied pest. Adelgid species Scientists are still trying to nail down adelgid classification. There are 50 known species, all of which are native to the northern hemisphere, though several invasive species have made their way into the southern hemisphere. The most commonly found adelgids in California include the invasive balsam wooly adelgid (from Europe), the Cooley spruce gall adelgid (Adelges cooleyi Gillette), and pine adelgids. Adelgids are commonly found on stone pine and other conifer species, such as pine and spruce. Depending on the host plant, the pests are commonly known as “pine aphids” or “spruce aphids”, respectively, even though they are not actually aphids. [Thanks to my friend, Chuck, I now know that adelgids are also found on apple trees. Thanks, Chuck!] .jpg) Balsam woolly adelgid (Giles San Martin) CC BY-SA 2.0 Aphids vs. adelgids Aphids are significantly larger than adelgids, and they have two structures that adelgids do not: cornicles, and a tail-like cauda. Cornicles are tubes found sticking out of the 5th or 6th abdominal segments. These tubes are used to excrete a defensive chemical wax. Contrary to popular belief, cornicles are not used in honeydew distribution. Adelgids are covered with a dense wooly wax, so it is easy to mistake them for wooly aphids. This white fluff may be found on twigs, needles, bark, or cones.
Adelgid lifecycle Unlike aphids, which reproduce using both eggs and live birth, adelgids only lay eggs. Adelgids generally live for two years and each female can lay from one to several hundred eggs, depending on the species. Adelgid nymphs are called sistentes, which comes from a Latin that means ‘to stand’. When these sistentes overwinter, they are called neosistens. Some adelgid species require six generations to complete their lifecycle, moving between different tree species. Much like the Monarch butterfly, these insect pests do not live long enough to complete migration as individuals. Generally, it is only the immature stage that causes damage.  Twig tip dieback due to adelgid feeding (Dan Foster) CC BY-SA 3.0 Damage caused by adelgids Heavy infestations can cause yellowing, drooping, and dieback of twig tips. As they feed, adelgids release toxins that interfere with the tree’s ability to produce conductive sapwood. Eventually, the tree suffers severe water-stress and dies. These infestations can appear as swollen twigs, galls, or twig dieback. Adelgid galls look like tiny pineapples and can be green, red, or purple. The initial damage is usually seen on the underside of buds, before infestation and damage spread to the entire bud.  Adelgid galls (Dan Foster) CC BY-SA 3.0 Adelgid controls
These pests are easily dislodged with a stream of water from your garden hose, but that only works you see them, which means you have to go outside and look. Beneficial predators, such as lady beetles, green lacewings, and some fly larvae. Horticultural oils can slo be used, but they will discolor spruce tree needles. Infested twigs can be pruned out while they are still green (before adelgids have emerged) and thrown in the trash. Also avoid applying excess nitrogen, which can stimulate vulnerable new growth. The National Park Service estimates that adelgids are responsible for the death of 90% of the mature fir trees found in the Great Smokey Mountains National Park, since this pest’s arrival in 1962. If you have conifers on your property, it is a good idea to inspect them periodically for signs of adelgid infestation. |
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