Pollinators are animals that carry pollen from flower to flower. This pollen then fertilizes female flowers, allowing plants to produce fruit and seeds.
Without pollinators, we would be in a bad way. The U.S. Dept. of Agriculture tells us, “Of the 100 crop species which provide 90 percent of the world’s food, over 70 crops are pollinated by bees.”
Fruit set failure often means there are not enough pollinators. Insufficient pollination can also lead to blossom drop, crooking, and poor harvests. Today, we will find out who the pollinators are and how to attract more of them to the garden.
How does pollination occur?
Some plants have the ability to self-pollinate. If pollen grains can be moved from the male (anther) to the female (stigma) within the same flower, it is called autogamy. If pollen grains are carried from the anther of one flower to the stigma of another flower, while still on the same plant, it is called geitonogamy. When the pollen must be taken to the stigma of a different plant it is called cross-pollination, xenogamy, or allogamy. In some cases, self-pollination occurs before the flower even opens! This is called cleistogamy, but it has nothing to do with pollinators, so we will leave those flowers to themselves - which is what they seem to prefer anyway.
How do pollinators move pollen?
Even in the case of self-pollinating flowers, something is needed to break the pollen loose from the anther so that it can stick to the stigma. Note for those with allergies: pollen is very sticky. Rubbing or rinsing with water will not remove pollen. Soapy water is needed. So, as pollinators land on a flower, pollen sticks to them. Walking around on a flower knocks pollen loose to fall on the stigma and to stick to the body of the visitor. Next, that visitor flies, walks, or crawls away, carrying that pollen with them. When they visit the next flower, pollen is knocked loose from the anther and the pollinator’s body and the chance of fertilization starts going up. Some pollinators end up looking like Charles Schultz’ Pig-Pen, a walking cluster of pollen grains. Others have evolved with pockets on their legs! Honey bees and other apid bees have a pollen basket, or corbicula, on their legs that hold pollen wetted down with nectar. Other bees have a pollen basket called a scopa, on their abdomen. Whether they carry it on purpose or not, pollinators are drawn to flowers for several reasons.
How flowers attract pollinators
Plants have evolved with specific characteristics that attract the best pollinators for their needs. In some cases, the relationship is very specific. Figs are only pollinated by a fig wasp. No fig wasp - no figs. In most cases, plants go for the hard sell to attract as many pollinators as possible, using several different characteristics:
Installing a wide variety of plants is one of the best ways to attract pollinators.
Who are the pollinators?
There is far more to pollination than just the 1,000 different species of native, mostly non-stinging bees in California (4,000 nationwide; 20,000 worldwide). Bats, flies, moths and butterflies, beetles, birds, wasps, even lizards and monkeys can be pollinators. For that matter, so are we! As we walk through the garden, pollen attaches to our skin and clothing, to be deposited on the next plant we approach. We have also been known to hand-pollinate plants on purpose. More often, pollinators co-evolve in mutually beneficial relationships with their nectar and pollen food sources.
How to attract pollinators
First and foremost, get rid of the toxins that kill these beneficials. Broad spectrum insecticides, herbicides, and pesticides, even when they claim to be safe, should be avoided. They cause too much of an interruption in the normal, natural cycle of things. Yes, it means a few more pests in the garden, but it also means less toxins and more pollinators.
Second, pollinators need fresh water. While you do not want to create mosquito breeding grounds, bird baths, fountains, and other water features make lovely additions to the garden while providing water for pollinators.
Third, you need to provide adequate food and shelter for pollinators. Now, before you go out and buy one of those new fangled bug hotels, know that research does not show they are effective. In fact, these artificial clusters end up being breeding grounds for pests and diseases of pollinators! Most native bees are ground-dwelling, so they wouldn’t use them anyway.
You can certainly install a bat house, but most of the shelter you provide will be the same plants you install to provide pollinators with food. Use these strategies to provide shelter:
Plants that attract pollinators
Plants can be divided according to the pollinators they attract:
Butterflies also benefit from access to your compost pile and a patch of mud. They use the mud as a source of both water and minerals, and they enjoy eating rotten fruit.
Going native through the seasons
Since evolution is a really slow process, one of the best ways to attract a wide variety of pollinators to your garden is to install native plants. Native plants already provide for these beneficial insects and birds. You will also want to ensure that there are flowering plants available throughout the year. Not only will this help the pollinators, it will make your garden and landscape look better! Perennial natives, such as manzanita, make the job of attracting pollinators far easier. Here is a list of some California native plants that attract and provide for pollinators:
Video of male carpenter bee (Kate Russell)
Let it go to seed
All too often, we sabotage ourselves at the end of each growing season. Rather that pulling (never pull!) or cutting (better) spent plants, leave them in the ground (best) to go to seed. Not only will this provide for local pollinators, but it can also give you seeds for next year’s crops! I always let things go to seed. Now, as the seasons change, I find lettuce, escarole, cosmos, carrots, and more, growing where I never planted them, but where they can grow without any help from me.
Other causes of low pollination
Sometimes, pollinators are not the problem. Other causes of low pollination rates include:
For region specific planting advice, check out the Pollinator Partnership’s interactive tool. Simply type in your zip code and they provide valuable information about suitable plants that will attract pollinators.
Buffalo hopping from tree to tree? The image made me laugh, so I decided to make this pest the Garden Word of the Day.
Buffalo treehoppers (Stictocephala bisonia) get their name because they have a triangular head that looks like a buffalo in profile. Sort of. These native pests are only 1/4 inch long and bright green to brown. Because of the color and shape, they are difficult to see. Some individuals develop a horn-shape to the head that looks like a thorn. You can walk right up on one and not even know it’s there, until it leaps into the air and flies away.
Buffalo treehopper lifecycle
Every summer, male buffalo leafhoppers take to the trees and sing their tiny hearts out, but we can’t hear them. If we could, they would sound something like cicadas, or crickets. His song attracts females for the normal reproductive activities. Late summer through early autumn, females lay eggs using a blade-shaped ovipositor that cuts a series of slits in twigs and stems. Each cut may contain a dozen eggs. The next year, in late spring, nymphs emerge. They look like miniature adults, but with feathery spines. After several molts, they emerge as adults.
Damage caused by buffalo treehoppers
Well, they break off entire branches, right? Just kidding. These small pests begin their destructive behavior during the nymph stage when they drop to the ground and feed on grasses and herbaceous plants. As they mature, they begin feeding on many different fruit trees, particularly apple, pear, cherry, prune, and quince. They also feed on ash, hawthorn, elm, and locust, and a wide variety of herbaceous (non-woody) plants.
All stages of buffalo leafhopper are sap-suckers. They use piercing mouthparts to tap into the phloem for a sugar feast. This feeding results in a sticky sweet discharge called honeydew. Buffalo leafhopper damage is minimal, but big populations can cause problems with sooty mold fungi feeding on the honeydew.
Buffalo treehopper controls
Since they hop like crazy and can fly, control is difficult. A strong spray from a garden hose can dislodge insects from a specific host (for a while). While not nearly as interesting as trying to round-up a herd of forest-dwelling bovines, insecticidal soaps are effective. The best treatment you can give plants being sucked dry by buffalo leafhoppers is to hose them down to wash off the honeydew.
The heady aroma of summer nectarines and peaches means it’s time to be on the lookout for peach twig borers.
While examining my nectarines for ripeness, I spotted a reddish-brown larva with white bands undulating across a twig. Of course, I picked it up and dropped it in a little plastic bag and sealed it up tight, until I could look it up. That’s what I learned that even the nicest tree cage has its limits.
Peach twig borer description
The reddish brown larva I saw was relatively mature. They hatch out white with a black head. As they feed, the color darkens. Unlike other larval pests of peaches, the peach twig borer has white bands around its abdomen, though the bands are not always as obvious as they are in the photo above. The pupae are 1/4 to 1/2 inch long and brown. They do not have a cocoon. Adult moths are small, slender, and a mottled gray color, with fringed wings and a false snout. Oval eggs are yellowish-orange and laid on fruit, twigs, and leaves.
Peach twig borer damage
Not only do these pests kill off new twigs, buds, and blossoms, they can also damage existing fruit. Fruit damage is most likely to occur just before the fruit is ripe. Unfortunately, members of the stone fruit family do not ripen off the tree, so an early harvest won’t help. Peach twig borers feed on all members of the stone fruit family, including almonds, plums, and nectarines. Peach twig borers are not to be confused with peach tree borers, which do most of their damage deeper in the wood and at the base of the tree.
Peach twig borer control
Tachinid flies and braconid wasps provide natural controls. When that isn’t enough, you can spray environmentally sound insecticides, such as Bacillus thuringiensis (Bt) or spinosad, just as blossoms appear, for added peach twig borer control. Dormant oil can also be used in winter, when combined with the same insecticides, to kill off the overwintering larvae. The oil will not kill peach twig borers by itself. Pheromone traps can be used to interfere with mating and to monitor for these pests. Just be aware that hanging a pheromone trap can actually attract pests to your trees if handled incorrectly. Read the label.
So, as you check your nectarines and peaches for ripeness each summer, be on the lookout for these tiny pests. Also, add preventative treatments to your garden calendar while you’re thinking about it.
The summer songs of crickets and grasshoppers provide many of us with a comforting reminder of childhood. If you are a gardener, you might feel differently about those sounds.
Cousins to katydids and locusts, crickets (Gryllidae) and grasshoppers (Acrididae) are members of Orthoptera.
Both crickets and grasshoppers have a large head, long saltatorial* back legs, for jumping, a cylindrical body (pronotum), compound eyes, and a mouth able to bite and chew. They have two pairs of wings: forewings (tegmina) and hindwings. Beyond those similarities, there are many differences:
*For you word game and vocabulary enthusiasts, saltatorial is an adjective that describes the legs of jumping insects.
Lifecycle of crickets and grasshoppers
Both species start as eggs laid in late summer and early fall, in the top 2 inches of soil, in clusters of 20 to over 100 eggs. In spring, these eggs hatch as nymphs which begin feeding on nearby plants. When those food supplies are exhausted, they look for new feeding grounds, generally downhill from where they started. Grasshoppers will molt 5 or 6 times as they outgrow their exoskeletons. Crickets do it at least eight times. There is no pupal stage, so these insects are said to go through incomplete metamorphosis.
There are house crickets and field crickets, but both are collective terms for several cricket species. They all feed on seeds and plants, along with grasshopper eggs, moth and butterfly pupae, flies, and spiders.
House crickets (Acheta domesticus), often sold as lizard food, are usually brown or tan and one inch long or less. Field crickets tend to be black and slightly larger than house crickets.
While there are thousands of grasshopper species, two of the most common are the valley grasshopper (Oedaleonotus enigma) and the devastating grasshopper (Melanoplus devastator). Most grasshoppers can fly.
These parts are called the scraper and the file. Each species has a distinct stridulation, and males do most of the singing. When males are courting, they have a unique song different from their regular hey-I’m-over-here song. When females sing, they do it very quietly. The vibrations caused by this action remind us that it is summer and announces to other crickets and grasshoppers an individual’s presence.
Cricket and grasshopper damage
If their song didn’t tell you these pests had arrived, chewed holes in leaves certainly will. Grasshoppers and crickets will often hide in nearby weeds and brush, so keeping those areas mowed can reduce the likelihood of a visit. On the flip side, maintaining a lush, green border may provide all the feeding needed by a few individuals. In any case, a single cricket will not do significant damage. Several crickets can decimate a row of seedlings in just one night. Grasshoppers prefer green plants, so your lettuce, onions, carrots, corn, beans. melons, squash, and some annual flowers are vulnerable. Grasshoppers may also feed on citrus, avocado, and beets. In years with especially wet springs, cricket and grasshopper populations can explode, making all plants vulnerable.
Grasshopper and cricket controls
If these insects are causing damage in your garden or landscape, floating row covers, screened boxes, and cones are your best bet. Just be sure there aren't any individuals hiding out in the mulch around your plants, or you may create a virtual Club Med for the pest! Birds, robber flies, and blister beetles feed on crickets and grasshoppers, or their eggs, and many parasites, bacteria, and fungi attack these garden pests. You can handpick them if you are quick enough. Chickens are excellent at catching them, and it’s a riot to watch.
Flies with mohawks are out to save your garden!
A tachinid fly looks like a small, sturdy house fly with a mohawk on its rear end. Others are unassuming tan-colored triangular flies. While yet others are somewhere between those extremes. These tiny beneficial flies use many common garden pests to feed their young. Let’s find out how.
Like other true flies (Diptera), tachinids (Tachinidae) have two wings. They are usually a bit smaller than houseflies, with spiky hairs on their rear ends that point backwards. There are thousands of species of tachinid fly. They may be black, tan, brown, gray, or striped. Eggs can be dark, or pale, or white, and oblong. The larva, or maggot, is a stubby, naked white, yellow, or orangish wormlike creature. The pupae are hidden in hard, reddish-brown, oblong casings, often found in the soil.
Tachinids as parasitoids
Tachinid flies are second only to parasitic wasps in pest control. Different tachinid species make use of different hosts in a number of ways. Most are parasitoids, which means they end up killing their host, while some are parasitic, which means the host may live. Tachinid flies parasitoid host insects to provide a guaranteed food source for their offspring. To parasitoid a garden pest, tachinid flies use several different methods. They may lay eggs on leaves favored by preferred caterpillars. When the larvae hatch, they are consumed by the caterpillar along with the leaf. Once inside the host, the larvae (maggots) begin their own feeding. Other tachinid species glue their eggs to the body of a host. When the eggs hatch, the maggots start feeding. Yet others using a piercing ovipositor (egg depositor organ) to inject the host with the eggs. Maggots feed until they are ready to pupate. Then, they drop to the ground and a hard casing forms to protect them as they morph into an adult fly.
You can attract tachinid flies to your garden or landscape by providing pollen and nectar for the adults with insectary plants, such as flat-topped (carrot, dill, yarrow) and composite (rudbeckia and aster) flowers. These beneficial insects also feed on aphid honeydew.
So, before you grab the fly swatter, take a closer look to see if that picnic pest is sporting a mohawk on its rear end.
Big-eyed bugs are your friend.
There are several different members of the Geocoris, or big-eyed bug family, and all of them are predators. This means they love to eat the pests that suck the life out of your garden plants, spreading disease as they go. The more big-eyed bugs you have in your landscape, the better.
Big-eyed bug identification
Big-eyed bugs (or bigeyed, if you prefer) have, surprise, big eyes! Eggs are pale and oblong. They are normally laid singly or in clusters on leaves. The eggs develop red ‘eyespots’. Adult and nymph big-eyed bugs tend to be oval and slightly flattened. They can be brown, yellow, or orangish and are only 1/6 of an inch long. The prominent eyes are spaced wide apart on a head that is as wide as the thorax (shoulders). These beneficial insects are frequently mistaken for chinch bugs, which are pests.
Big-eyed bug diet
Gardeners should appreciate big-eyed bugs. These predators feast on small caterpillars, flea beetles, mites, cabbage loopers, whiteflies, and many different insect eggs. Research has shown that a single big-eyed bug nymph may consume up to 1,600 spider mites in its lifetime!
Attracting big-eyed bugs
You cannot currently purchase big-eyed bugs, but you can certainly lure them in with plants that provide nectar for when prey is scarce. While many beneficial insects prefer the flowers of carrot, fennel, and onion, big-eyed bugs prefer yarrow above all else. Yarrow is a sturdy, attractive border plant and it takes very little care to stay attractive.
Plant some yarrow today for your local big-eyed bugs!
Boing! A tiny insect launches itself and you never really see it clearly.
It’s probably a leafhopper. Let’s learn about these garden pests so we can reduce the damage they cause.
Leafhoppers are cousins to treehoppers and cicadas. The name “leafhopper” actually refers to twenty thousand different Cicadellidae insects. Most leafhoppers feed on a specific plant or group of plants. Eggs are laid in soft plant tissue, where they overwinter. Eggs begin to hatch in mid-April in warmer regions. These wingless nymphs will molt several times, each time their wings and hind legs getting larger and more functional. What makes leafhoppers particularly unique is that they cover themselves, after each molt, with a microscopic body armor made out of netted spheres called brochosomes. [It's one of those 'stranger than fiction' realities, isn't it?]
Plants preferred by leafhoppers
Leafhoppers enjoy many of the same plants that we do. In addition to many woody ornamentals, such as boxwood, local leafhopper species love to feed on sweet potatoes, squash, beans, horseradish, cucumbers, corn, melons, blueberries, grapes, and beets, just to name a few! Since leafhoppers can carry diseases with them, they put many plants at risk.
Leaf stippling is usually the first sign of leafhopper infestations. This damage is normally at its worst during the hottest months. While leaf stippling won’t harm a healthy plant, it does interfere with photosynthesis and it can compound water stress. Leaves may also appear pale or brown, and new shoots may curl up and die. As they feed, some leafhopper species produce honeydew, which provides the perfect growing medium for sooty mold. Also, leafhoppers are vectors for several plant diseases, including aster yellows, bean mosaic, and vivipary.
Since they are so mobile, complete control is pretty much impossible. Spiders, assassin bugs, and lacewings all eat leafhoppers, so avoid using broad spectrum pesticides that will kill off these beneficial insects. Severe infestations can be treated with insecticidal soap or horticultural oil, just be judicious with the application since oils can contribute to sunburn damage. These treatments are only effective on nymphs.
So, if you walk by a plant and get pelted by a bunch of tiny bugs, or you notice a lot of leaf stippling, take a closer look - it may be time for insecticidal soap.
Flies swarmed over my ornamental shrub and I was confused. One expects to see flies collecting around, well, around less desirable resting spots. I have dogs and chickens, so there were plenty of other, more odiferous opportunities, but the flies clearly were more interested in my shrub. What was going on? Let’s find out.
Crane flies, dragonflies, butterflies, fruit flies, whiteflies, hoverflies, you’ve heard plenty about these flying insects in the garden, but what about the lowly housefly? It turns out, houseflies (Musca domestica) are not necessarily the pests they have always been made out to be, not completely anyway.
True, nobody wants a fly landing on their food. There’s too many awful places they may have been. Those hairy legs of theirs may have been walking around in some nasty messes. You may be surprised to learn, however, that one of the most common places to find houseflies… is in the flowers of your garden.
The nature of flies
Most flying insects have four wings. Flies only have two. True flies are all members of the Diptera family. Unlike busy bees and industrious ants, most fly species are lazy. They are mostly meat eaters. They also feed on manure, rotting stuff, and even open wounds. (Ew!) What you may not know is that flies also enjoy cleansing their palettes with a sip of nectar now and then. When flies land on a flower for a sweet sip, their hairy/spiky legs collect pollen. Most of them don’t eat the stuff, or hoard it, the way bees do. It just sticks to them. When they fly to their next sipping/resting spot, the pollen goes with them and often pollinates that flower. The process continues at a surprising rate. It ends up that flies are probably one of the first pollinators of flowering plants.
Bees vs. flies as pollinators
We all know about honey bees pollinating our crops: the bees go from flower to flower, collecting nectar and pollen and they transfer the pollen to other plants, leading to pollination, fertilization, and food for us. The problem with bees, as pollinators, is exactly that - they take the pollen with them. Eventually, there is no more pollen in a particular flower. That means bees can visit a flower and not pollinate it. Flies, on the other hand, generally do not eat pollen, so there is more left behind as they move from flower to flower, looking for a place to rest and have a drink. In a study conducted by the North Central Region Plant Introduction Station (NCRPIS), it was shown that adding blue bottle flies (Calliphora sp.), along with honey bees, as pollinators, carrot production was significantly increased. Also, flies are active within a wider temperature range than honeybees.
Crops commonly pollinated by flies
There are a surprising number of crops regularly pollinated by flies, besides members of the carrot family. These include apples, raspberries, strawberries, pear, plum, cherry, peach, nectarine, blackberries, and pawpaw. There is a group, called flower flies (Syrphidae), that pollinate dozens of our food crops. One particular species of fly, Ornidia obesa, is the reason we have chocolate. Yes, I said it. Flies pollinate cocoa plants.
Flies may not pollinate as many crops as bees, but they are already a close second, and that claim is made with only minimal research. We may find they are responsible for far more pollination. That being said, flies can also carry disease. They are free to roam my garden and landscape, but my patio is draped overhead with fly paper. Simple, yet effective.
Braconid wasps are tiny heroes of the garden, though rarely seen.
The list of edibles protected by braconid wasps is too long to include here, but it would include grapes, peaches, nectarines, apricots, tomatoes, apples, prunes, plums, broccoli, rutabagas, turnips, and cabbage, just to name a few.
Braconid wasp identification
There are over 12,000 different named braconid wasp species, worldwide, with another 40,000 or so, yet to be identified. Most are dark brown or black with reddish accents. It is estimated that there are 1,700 different braconid wasps in North America and they are all stingless. Braconid wasps can be as small as 1/13 of an inch long, or as big as 5/8 of an inch. If you can get one to hold still while you go find a hand lens, you would be able to see that these tiny wasps have antennas with 16 or more segments! What you are more likely to see are their oblong, white or yellow eggs sticking out of a host insect.
Braconid wasp diet
Adult braconid wasps, while they eat mostly pollen and nectar, are beneficial because they parasitize many garden pests. This means that they lay their eggs on or in other insects. When the eggs hatch, the larvae eat their host. Garden pests vulnerable to parasitization by braconid wasps include:
Attracting braconid wasps to your garden
Parasitic and predatory wasps are attracted to mixed plantings that provide nectar and pollen, along with insect prey. To make your garden and landscape more appealing to these beneficial insects, be sure to include a wide variety of flowering plants at various stages of development throughout the growing season.
Cucumber beetles are major pests of cucumbers, melons, squash, and other cucurbits.
There are three major classes of cucumber beetle in California: spotted, striped, and banded. Banded cucumber beetles are mostly found in southern regions, while striped and spotted cucumber beetles begin emerging in late spring and can have as many as three generations in a single season in some warmer regions.
Cucumber beetle identification
Cucumber beetles are relatively easy to identify. They are small, only one-quarter of an inch long, and they have shiny black heads. The larvae are yellowish with a dark head. Other identifying marks, by species, include:
Cucumber beetle damage
Adult beetles overwinter in the soil and lay their bright orange eggs at the base of host plants. When these eggs hatch, ravenous larvae start feeding on plant roots. Adults will feed on roots, blossoms, leaves, and plant crowns, along with fruit, as they feed. This is especially true for tender, new growth. Cucumber beetles can easily kill seedlings, and they feed on far more than just your cucumbers. Other favorite plants are corn, beans, lentils, roses, and grasses, along with your melon and squash plants. They are also attracted to ripening stone fruit. Holes in leaves may be the first obvious sign of infestation. Cucumber beetles can also carry squash mosaic virus (for up to 20 days after feeding on infected fruit), and bacterial wilt, a fatal cucurbit disease.
Controlling cucumber beetles
Cucumber beetles are difficult to control. Parasitic tachinid wasps provide some assistance, so avoid broad spectrum pesticides, which will kill off your helpers along with the pests. Cucumber beetles prefer cool, moist places, such as under your squash or melon plants after they have been watered. That makes it the best time to look for these pests and squish them as soon as you see them. They can bite, so wearing gloves is a good idea. Since cucumber beetles can fly, battling them is an ongoing process. Regular monitoring is your best defense.
Wasps can transform a summer picnic into a mad scramble for safety, especially for those who are allergic. But wasps aren’t all bad. Really, they’re not!
Cousin to bees, ants, and sawflies, wasps come in an astounding variety of good, bad, and indifferent garden insects. There are over 100,000 different types of wasps (Vespidae) around the world and only some of them will hurt you. But, ass anyone who has ever been stung knows, once is more than enough!
Wasps tend to have relatively long, slender bodies with the telltale wasp-waist, between the thorax and abdomen. Most wasps have two pairs of wings, though some are wingless. The variety is really pretty amazing. It’s a shame they are so painful. Did you know that wasps dangle their legs as they fly?
Why the sting?
Male wasps do not sting. Much like carpenter bees, it is the job of the female to protect and defend. As she hunts down food for herself and her colony, she will protect herself, her family, and her food sources with extreme prejudice. The stinger is actually a modified egg-laying organ. A wasp can sting multiple times and it really hurts. As a child, I would get them caught in my long hair. It was terrifying at the time! Swarms can be deadly.
There are social wasps and there are solitary wasps. Social wasps live in colonies, led by a queen. Some wasps burrow in the ground, some use mud to create apartment complexes, while others build paper nests. In these nests, the queen begins laying eggs. These eggs hatch into female workers. In late summer, some eggs hatch into male drones, whose sole purpose (in their very short lives) is to mate with the queen, after which, they die. Most social wasps are predators, killing many garden pests each year. As resources become scarce and colony size grows, these wasps become scavengers. Those are the ones that cause the most problems for us.
You may be able to identify a yellow jacket by its tendency to fly side-to-side as it prepares to land. The colony consists of a queen, workers, and drones. Only the queen lives through the winter.
Hornets are a subspecies of wasp that are particularly aggressive. Hornets tend to have wider heads and more rounded abdomens than other wasps. Hornets can both sting and bite. There is a hornet in Japan, the Asian giant hornet, that has a stinger that is one-quarter of an inch long and it kills 30 to 40 people in Japan each year. Yikes! Scientists say that hornet stings are more painful than wasp stings, because they contain more venom (acetylcholine). I think they all hurt and are worth avoiding.
Tiny, umbrella-shaped paper nests are your first clue that paper wasps have arrived. Before you get rid of that papery umbrella, you might be happy to learn that paper wasps feed on beetle larvae, caterpillars, and flies, along with nectar. Paper wasps are effective pollinators. There are over 300 different types of paper wasps, but they all chew wood fiber and transform it into intricate papery nests. There are both solitary and social paper wasps. Paper wasps are not very aggressive, unless threatened.
Adult wasps mostly eat plant material, especially sweet nectar, sap, pollen, and rotting fruits. As they fly from flower to flower, collecting nectar and pollen, wasps also pollinate your crops. There are even wasps, called chalcids, that have evolved specifically to pollinate figs. No wasps, no fig bars!
Wasps are frequently released in agricultural fields as natural ‘biocontrols' of many common pests. The adult wasps lay their eggs on or in these pest insects. As the eggs hatch, they devour their host. (Gruesome, right? It’s brutal world out there.) Ichneumon wasps are commonly used in this form of integrated pest management (IPM).
Some wasps, such as the braconids and trichogramma wasps, are so tiny that you’ll never see them, but they are extremely helpful in your garden and landscape. These beneficials parasitize hornworms, apple maggots, orange tortrix moths, mealybugs, aphids, orangeworms, armored scale, armyworms, artichoke plume moths, and many other pests. Some species of wasp are believed to carry certain yeasts to grapes used in winemaking!
In the case of wasp stings, an ounce of prevention is, well, you know! Use these tips to prevent getting stung in the first place:
If you are unlucky enough to get stung by a wasp, you can reduce the discomfort with these tips:
If an allergic reaction occurs, get medical attention IMMEDIATELY.
Wasps with brighter and darker colors tend to be more venomous, so use those colors as a warning.
Did you know that the golden paper wasp (Polistes fuscatus) is the only insect on Earth that has been shown to use facial recognition to identify individuals? Maybe that’s why some people get stung more than others…
Inchworms fascinated us as children. We watched their measured steps with front legs, followed by back legs, giving them the characteristic arching motion.
Inchworms, also known as loopers, span worms, and measuring worms, aren’t worms at all. They are the larval form of Geometer moths. The Latin name, Geometridae, means to measure the earth.
Inchworms are generally smooth, hairless, and about an inch long. (Big surprise, right?) Inchworms have 3 pairs of true legs in front, like other caterpillars, but only 2 or 3 of pseudo ‘prolegs’ in back. Depending on the parent moth, inchworms can be brown, green, or black, and some have vertical racing stripes. Some species have camouflaging projections that make them look like twigs. When disturbed, they hold themselves upright, reinforcing that image. Most adult moths have slender bodies and wide wings that are held open when resting, similar to most butterflies. They tend to be a little over an inch wide and have intricate patterns on brownish wings. The antenna of males are often feathered.
The life of an inchworm
Inchworms start out as the eggs of Geometer moths, laid on the underside of leaves. In spring, the eggs hatch and inchworms start feeding, usually at night. It is this feeding that can cause some conflict between inchworms and gardeners, but we’ll get to that in a minute. Inchworms eat so much that they outgrow their skin and have to molt several times before they’ve eaten their fill. Then, they build a hard shell around themselves where they can pupate into adult moths.
Types of inchworms
Some inchworms, called omnivorous loopers (Sabulodes aegrotata), are particularly fond of avocados. Others, called cankerworms, are particularly destructive to plums and prunes. There are two varieties of cankerworm: the spring cankerworm (Paleacrita vernata) and the fall cankerworm (Alsophila pometaria). Some claim that English sparrows were first introduced into North America to check spring cankerworm populations in Central park, back in the mid-1800’s. Whoops. (When will we learn???) Actually, the St. Johnswort inchworm (Aplocera plagiata) was introduced to California in 2014 to help stop the spread of Canary Island hypericum. We’ll have to wait and see how that one backfires.)
There are over 35,000 different types of inchworms worldwide and 1,200 different kinds in North America. Each type of inchworm has a favorite food, or host plant. Common host plants include:
A single inchworm won’t cause noticeable damage in the garden, but a bunch of them can wipe out some of your favorite crops. Inchworms generally feed on tender new shoots, fruit, and the edges of leaves, creating a scalloped effect. When disturbed, some inchworms quickly spin a silken thread from their mouth and repel out of danger. Even if you do not see the culprits for yourself, you may see the dark fecal pellets (frass) they leave behind.
Birds and other natural enemies provide some control. Bacillus thuringiensis (Bt) can be used on heavy infestations. Since moths are attracted to lights at night, you can reduce the chance of infestation by selecting bulb colors that do not attract moths in the first place. According to recent research, warm colored LEDs (yellow/orange) are the best at not attracting pests at night, followed by ‘bug lights’, cool colored LEDs (blue/green), halogen globes, and CFLs, respectively. Providing good air flow and sun exposure with pruning can also reduce inchworm populations.
There’s an Old Wives Tale that says if an inchworm is crawling on you, it is measuring your coffin, but it’s really just looking for food. When I find an inchworm, I feed it to my chickens.
Tomato russet mites are too small to see without a 14X lens, but the damage is easy to recognize.
Symptoms of tomato russet mite infestations
The first symptom of a tomato russet mite infestation is leaf stippling (yellow dots), which spreads to include the entire leaf. Leaves will then begin to curl and turn, you guessed it, russet colored. Stems and fruit also develop the same rough brown skin, and flower abortion is common. Symptoms usually start near the bottom of the plant and work their way up. Left uncontrolled, these pests can kill your tomato plant.
More about mites
Mites have piercing mouthparts that are used to poke holes in a plant’s epidermis and to suck the life juices out of leaves, stems, and fruit. Like other mites, tomato russet mites (Aculops lycopersici) are more closely related to spiders than to other insects. They have eight legs and start out as an egg. These eggs are usually laid singly on the underside of leaves, in areas of new growth, cracks, or near pipes. When the eggs hatch, the larvae only have two legs. Then they go through two nymph stages. Unlike other common garden mites, tomato russet mites are in a separate family called gall mites. Gall mites are unique in that they create galls where they feed. The real problem with tomato russet mites is that they are so tiny (0.2 mm long and 0.05 mm wide); you can’t see them until the damage is extensive.
Mites love hot, dry conditions. They also seem to like dust, so keeping your plants relatively dust-free can reduce mite problems. Misting has also been shown to deter mites. These pests have many natural enemies, including predatory mites, predatory flies, and ladybugs. For this reason, broad spectrum pesticides should be avoided. These pests have demonstrated the ability to develop resistance to pesticides, so we don’t want to make them any more destructive than they already are! Sulfur dust and sulfur sprays can be used to get rid of mites organically.
Monitor your tomato plants weekly for signs of tomato russet mite infestation. Symptoms usually appear when the green fruit is 1 inch in diameter. Catching this pest early can save your plants!
Blue jays, scrub jays, and Stellar jays are beautiful, intelligent, bold, and noisy. And they can wreak havoc in your garden.
Thieves in the coop
I have a love-hate relationship with jays. I admire their intellect and their beauty. However, in the last two weeks, I have lost four purchased fertile eggs ($30!) plus three regular eggs to local scrub jays. They also go into my coop every day and gorge themselves on the organic laying pellets I put out for my hens. If you have young chicks, jays will easily kill them, whether they can carry them off or not. Jays will also pull baby birds from nests and nest boxes.
Jays are medium-sized blue passerines (perching birds) with a heavy beak. They use that beak to crack nuts, snail and egg shells, and to pierce fruit. Jays are members of the Corvidae family, which includes crows, ravens, and magpies. Baby jays are born gray, with a red comb, just like chickens. After about a week, the chick loses the comb and begins to turn blue. Most scrub jays live for 9 years, but the oldest known scrub jay, raised in captivity, lived for nearly 20 years!
Jay’s are very intelligent birds, like their crow cousins. They can find their way through mazes, into grain storage bags, and under fruit tree nets. Studies have shown that jays can retain and use information about the rate of food decay in over 200 caches. They also tend to collect shiny items. Jays have strong family connections that span multiple generations. Previous years’ offspring sometimes stick around to help care for the current year’s chicks, and extended family members come together to mourn the death of a relative. Scrub jays can be tamed to the point of feeding out of your hand, but their droppings are, shall we say, impressive.
Jay bird damage
If you have fruit or nut trees, you have already battled jays. These orchard pests will peck a large chunk out of several different pieces of fruit, rather than eating one at a time. This damaged fruit rots more quickly and it leaves the trees vulnerable to other infestations and infections. In the U.K., there are several very nice tree netting systems, but I have not found anything nearly as effective here in the U.S. (If you know of a supplier, please let us know in the Comments!) Jays can wipe out your berry, corn, pea, and grape crops. They can also carry West Nile virus and avian pox.
Jay bird controls
According to D. Whisson and M. Freeman, of UC Davis, “Jays are classified as migratory non-game birds according to federal regulations. They can only be controlled under a permit from the USFWS. Shooting is a possible control measure but is very labor intensive. Frightening devices are relatively ineffective. Trapping with rat traps using nuts as bait can be effective for a small number of birds.” Of course, in the Bay Area, shooting is not an option. You can avoid using bird seed mixes that attract jays and squirrels in bird feeders. My dogs like to chase the scrub jays away, but it is a very temporary fix.
Probably the most humane scrub jay control is to provide a distracting food source that fulfills their needs enough to reduce the potential for garden damage.
Apple maggots are a nasty surprise when biting into an apple.
Native to Canada and the northeastern U.S., apple maggots (Rhagoletis pomonella) originally lived and fed on hawthorn trees and fruit. Apples were introduced to those regions in 1710, but no mention of apple maggots was made until 1860, when infestations became heavy. Apple maggots have slowly spread across the country, reaching Oregon in 1979. Four years later, 101 flies in 38 orchards were found in California apples. Today, apple maggots are found practically everywhere in North America, which the exception of a few valleys in British Columbia. Being responsible for millions of dollars of crop losses each year, apple maggot quarantines are in place in several California counties.
Adult apple maggot flies are frequently mistaken for spiders, at first glance. Disturbed adults will turn their wings 90-degrees and move their body up and down while walking sideways. Why they don’t simply fly away, I’ll never know. Flies are less than 1/4” long, dark, with white stripes, a white dot on the middle segment (thorax), and yellow legs. The wings have black bands that look like a capital “F”. The head is yellowish and the eyes can be green or dark red. Larvae are white, legless, and 1/4” long, with two dark mouth hooks. The pupae are tan to dark brown hard cases found in the soil.
Apple maggot lifecycle
A female fly will lay up to 500 small, white eggs, each on a separate fruit, under the skin of apples, cherries, apricots, plums, pears, wild rose, Pyracantha, and crabapples. The maggots, or worms, will stay inside their host fruit, safely feeding until the fruit falls from the tree. The fattened larvae then burrow into the ground where they pupate in the soil over the winter. Adult flies emerge June through September and then feed on honeydew and bird poop. Yuck!
Apple maggot damage
You may see small dimples where eggs have been inserted under the skin of vulnerable fruits. From there, the larvae go unnoticed as they feed, until you take a bite. Then, brown tunnels and a (hopefully!) intact larvae can be seen. You can tell the difference between apple maggot and codling moth damage because codling moth larva prefer apple cores, while apple maggots prefer the fruit. Personally, I don’t want to see either one in my apple!
Apple maggot control
Apple maggots have many natural enemies, such as parasitic wasps, so broad spectrum pesticides should be avoided. Since the larvae are safe once inside the fruit, pesticides won’t work anyway. Instead, sticky traps can be used. These traps are usually a red sphere, like an apple, or a bright yellow panel. I”m not sure why so many insects are attracted to yellow paper, but it seems to be pretty common.
These are not pheromone traps, which can attract pests from several yards away. Instead, a protein-ammonia mix is used and it is only effective in the immediate area. These traps should be hung in the outer third of the tree canopy, in an open area. You may need to remove nearby foliage, up to 18 inches from the trap, to make it more visible (and alluring) to apple maggot flies. You can buy these traps at garden centers and they should be inspected every few days and replaced every 2 to 3 weeks, depending on how messy they get. The spheres should be cleaned and re-stickied every 4 weeks. If you catch any apple maggot flies in your traps, you really should contact your local County Extension Office or the Department of Agriculture. You can also participate in a fun civilian project called The Big Bug Hunt, which uses our inputs to create a warning system that alerts you when insect pests are headed your way. It’s pretty neat.
By monitoring where this pest is seen, the proper quarantines can be put in place to reduce the damage. If apple maggot flies are trapped, the traps should be kept in use until no more flies are trapped.
Protect your apple and other crops by monitoring for this relatively new pest.
Insectary plants are grown to attract and provide for beneficial insects.
There are many insect parasites and predators that can help control garden pests without the use of chemical pesticides. While they may not eliminate all of the pests, insect parasites have evolved into effective predators of the insects that plague our gardens and landscapes. By installing plants that attract and feed these beneficial insects, the need for more stringent measures is reduced. And, hey, who doesn’t want a garden filled with flowers?
What makes an insect beneficial?
Insects are called ‘beneficials’ when they help us get what we want. In the case of gardening, beneficial insects may be pollinators, predators, or parasites. Pollinators, such as solitary bees, increase crop yields by transferring pollen to female flowers. If you have a monochrome garden with no flowers other than your cucumber and tomato plants, you won’t get nearly the same production as you would with a diverse color palette and many other flowers besides your vegies. Other beneficials, such as lady beetles, chow down on aphids and many other pests, like they were a bag of potato chips. A third group of beneficials is the parasites. These insects lay their eggs in insect pests, killing them from the inside out. The syrphid wasp, or hoverfly, and many other tiny parasitic wasps, are very efficient killers and, no, they do not sting people.
The problem with buying predatory insects
Some beneficial insects are so well known that you can buy them. Lady beetles (ladybugs), lacewings, and praying mantis are purchased each spring by the millions, It is true, they are voracious feeders and they can put a serious dent in an aphid or other pest population. And they can fly, which means that if your landscape does not give them what they want and need, they will go elsewhere. This is where insectary plants comes in.
Color, shape, and height
Some insects prefer globe flowers, while other prefer flat landing strips. Most insects see a very limited range of color (even if that range is frequently beyond what we can see). Some insects prefer flowers and foliage that are low to the ground, while others seek out taller flowers with a better view. By planting a wide variety of flower colors, shapes, and heights, you can attract and retain the widest range of beneficial insects to your garden or landscape.
The trick to attracting and maintaining these beneficial insects is to plan for sequential flowering. Of course, your job will be even easier if you select plants well suited to your microclimate, while you’re at it! The choice of which plants to use depends on the pests commonly found in your garden or landscape. These plants are nearly always a good bet:
Where to put insectary plants
Your insectary plants can be used to create hedgerows that surround a garden plot, along a walkway path, or you can simply intersperse these helpers throughout the landscape. Most residential gardens, however, are too small to make this much of a concern, unlike agricultural fields, so you can put them wherever they will thrive and look nice.
Like other plants in the landscape, your insectary plants will need weeding, irrigation, and protection from vertebrate pests to stay healthy. The initial investment of time and effort will make your job as a gardener that much easier, once these plants become established. Be sure to provide your guests with water, while you're at it!
Orange tortrix moths, also known as apple skinworms, are common to western North America, northern Africa, and eastern European countries. Orange tortrix larvae are pests of grapes, citrus, strawberries, pears, apples, and avocados.
Cousin to the light brown apple moth (LBAM), orange tortrix (Argyrotaenia citrana; Argyrotaenia franciscana) and other tortrix moths all roll up leaves to create a protective place to feed.
Orange tortrix identification
Adult orange tortrix moths and their cousins (amorbia) are small, bell-shaped moths when at rest. They can be 1/2” to 3/4” long. Both male and female orange tortrix moths are orangish brown with a faint V-shaped marking midwing. Males have darker markings than females.
The larvae are 1/2 inch long and greenish to straw-colored. Larvae have a tan head and a prothoracic shield. Prothoracic shields are hard plates that wrap partially around the larva’s body where a neck would be (if they had a neck). Orange tortrix larvae are very active and will wriggle backwards or sideways, drop to the ground, or hang by a silken thread if disturbed.
Eggs are pale green, oval, and flat, with a patterned surface.
Each female lays overlapping clusters of 50 to 150 eggs per cluster, usually on the tops of young leaves and stems and on immature fruit. Nine days later, the eggs hatch. Young larvae move to tender new growth where they create a protective silk nest under which they can feed. Larvae go through 5 to 7 developmental stages, or instars, as they grow from 0.08” to 0.5” in length. Once they have eaten their fill, tortrix moth larvae spin a cocoon around themselves, where they go through a complete metamorphosis in 1 to 3 weeks, depending on environmental conditions. You might see any of these life stages throughout the year. Orange tortrix moths have 2 - 4 generations per year.
Orange tortrix damage
Tortrix larvae devour any soft plant tissue they can find, including vines and tendrils, developing buds, young fruit, and new shoots and bark. Twig girdling can occur and leaf holes may also be visible.
As they feed, tortrix moth larvae often create protective webbing around new leaf clusters or they may roll, fold, or tie a leaf down over a fruit to create a safe place to feed. Older larva will burrow deeply into mature fruit, providing an entry for organisms that cause bunch rot and other diseases (and a horrible surprise, if you don't notice the hole). Damage to fruit is most commonly seen at the stem end, often causing fruit to drop.
Orange tortrix management
Orange tortrix have many natural enemies, including assassin bugs, damsel bugs, lacewings, and pirate bugs, as well as birds. Several parasitic wasps and tachinid flies parasitize tortrix.
Pheromone traps can be used to monitor for male orange tortrix moths. These traps should first be used in late December. These moths prefer temperatures between 45°F and 80°F. Scorching summers usually send these pests into dormancy. If pheromone traps are used, you will need to know the difference between the orange tortrix pest and the garden tortrix, which is not a pest.
Garden tortrix have a light colored band in front of the dark V and they have dark, crescent shaped marks on the outer edge of each forewing. There’s no sense treating for orange tortrix if your trees are being visited by garden tortrix. If pheromone traps indicate that you have orange tortrix moths, use these tips to help protect your vines and fruit trees:
While the orange tortrix moth is generally not a big threat to your garden or landscape, it can cause problems, so keep a look out for those rolled leaves.
Leaf holes may indicate insect feeding, disease, or chemical or physical damage.
Leaf holes interfere with photosynthesis, which weakens the plant, and it becomes more vulnerable to other pests and diseases. Use the information below to learn how to identify the cause of leaf holes in your garden or landscape plants. Once you know the reason, you can select the best treatment.
Many citrus leaves exhibit holes caused by nearby thorns. Wind-whipped branches can also puncture leaves. In these cases, there is nothing you can do.
Chemical damage is usually caused by herbicide overspray, yours or your neighbors'. Using chemical herbicides more carefully (or not at all) can help prevent this.
Irregularly shaped holes and complete defoliation, with the central leaf vein left intact, are usually caused by these insects:
Irregular holes, chewed stems, leaf chlorosis (yellowing), and wilting
This recipe for disaster indicates the presence of cucumber beetles. Cucumber beetles can be striped or spotted. And they nearly always cause significant plant damage.
If your grape leaves look as though a tiny, knife-wielding slasher attack occurred, it was probably the Western grape rootworm (Bromius obscurus). Leaf slits are usually 1/4 to 1/2 inches long. Individually, these slits are too small to seem important, but the combined effect can be devastating to individual leaves. Grapes are also damaged.
This list is not exclusive but should give you a good starting point.
Insecticidal soaps are an easy DIY method of pest control in the garden.
People have been using soap sprays for a long time to protect their plants, but the science behind using soap has only begun to demonstrate just how insecticidal soaps work. Current research has shown that spraying soapy water on insects kills them off by:
Before jumping on the insecticidal soap bandwagon, however, you need to understand that not all soaps are created equally and that many soaps are actually detergents that can kill your plants.
Homemade insecticidal soaps
True insecticidal soaps contain potassium salts of fatty acids and are designed specifically for use on plants. These fatty acids are commonly found in fish oil, lard, and olive, palm, coconut and other plant oils. These fatty acids are mixed with potassium hydroxide, which is strongly alkaline, to create soap, much the way fatty acids are mixed with sodium hydroxide to make lye. While potassium salts and sodium salts will both kill insects, sodium salts are toxic to plants. [The same problem occurs when people use baking soda (sodium bicarbonate), rather than potassium bicarbonate, on plants to fight fungal disease. Baking soda is phytotoxic, whereas potassium bicarbonate is not.]
Not all household liquid soaps are safe for use on plants. In fact, I couldn’t find a list of any that are truly safe. Laundry soaps and dry dishwashing detergents are also too harsh to be used on your garden plants. Also, many liquid dishwashing soaps contain bleach, fragrances and colors, and other chemicals that can harm or kill your plants. As tempting as it may be to grab your bottle of dish soap from the kitchen sink, this is not a good idea. [I challenge you to take a close look at the ingredients list on your dishwashing soap and look up any words you don’t know.]
Effectiveness of insecticidal soap
Instead of burning up your plants with detergent, go to the store and buy a bottle of insecticidal soap. It is less expensive that many other pesticides, plus it is less damaging to the environment and other living things. Insecticidal soap that has been properly formulated and applied will kill many common pests, including:
Unfortunately, insecticidal soap can also kill off the larval forms of many beneficial insects, such as ladybugs and lacewings.
How to use insecticidal soap
Insecticidal soap only works when it comes in direct contact with and completely covers an insect pest. Use these tips to safely use insecticidal soap:
Insecticidal soaps have little or no residual effects, so treatments must be repeated regularly until the desired level of control is reached.
So, insecticidal soap isn’t the Quick Fix you might have thought it was before reading this post, but it is effective when used properly.
Caterpillars are the larval forms of moths and butterflies.
You generally won’t see moth or butterfly eggs, unless you look closely. During plant dormancy, these eggs may be on the underside of leaves, tucked into the crevice of bark, or hidden under leaf litter or in the soil. As temperatures rise, caterpillars invade our garden en force.
Hornworms (pictured below), cutworms, and budworms are all caterpillars. Caterpillars are often responsible for leaf damage, but some varieties feed on roots, buds, flowers, and tree trunks. There are even caterpillars that feed on your clothing, moths that feed exclusively on the hooves of dead ungulates, and caterpillars that eat other caterpillars! Caterpillars have only one purpose and that is to feed. Most caterpillar species molt their skin four or five times as they consume as much plant material as they can, before pupating. As much as we dislike the damage caused by adolescent caterpillars, adult moths and butterflies are good pollinators, so it’s a toss-up.
Some plants, such as lima beans, emit chemicals that call out to parasitic wasps whenever caterpillars start feeding. In this way, they protect themselves. Spiders, soldier beetles, green lacewings, praying mantis, pirate bugs, ground beetles, assassin bugs, bats, birds, lizards, frogs and toads all enjoy feeding on caterpillars. You can make their job easier by avoiding the use of chemicals and by providing a clean water supply.
If your caterpillar problem gets bad, you can apply Bacillus thuringiensis (Bt). Bt is a naturally occurring, pest-killing bacteria found in soil, animal feces, and in the gut of the caterpillar stage of some moths and butterflies! There are different types of Bt that can kill different types of caterpillars. [Don’t be confused. There are bacteria in our digestive systems that can kill us, too.]
Some caterpillars can be thwarted from climbing host plants by applying sticky barriers around trunks and stems. Row covers can also be used to protect vulnerable plants, just be sure there are no eggs under the leaves or you will be protecting destructive caterpillars from their natural enemies!
Horticultural oil works better at controlling caterpillar eggs, while neem oil can be effective against actual caterpillars. The best thing you can do is to be observant. Light or moderate feeding will not harm plants. Many of the larger caterpillars, such as hornworms, can simply be handpicked and tossed in the trash. I feed them to my chickens.
Not all bad
A few days ago, I noticed black flecks on my fennel leaves. Closer inspection showed nearly a dozen tiny black caterpillars with white saddles, and one particularly large specimen (below) that made identification easy. They were all the caterpillar stage of the black swallowtail butterfly. Well, I’m not a big fan of fennel, and the butterflies are lovely, so they can feed all they like and I will keep a look out for their chrysalis.
You can grow a surprising amount of food in your own yard. Ask me how!
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