Garden Word of the Day
Take $5 off planting calendars from Forging Time with the code DAILYGARDEN841. This is an excellent resource with some amazing photos.
Cherry leafhoppers are easy to miss, but they can cause big problems.
I can’t deny that leafhoppers are fascinating creatures because they are. I just don’t want them anywhere near my plants.
Cherry leafhoppers (Fieberiella florii Stål) are ¼” long and wedge-shaped. They have wide, flattened heads and narrow, upright rear ends. Depending on what they eat, where they are, and their developmental stage, they may be grayish-brown, green, orange, or tan.
Here is a list of the many diseases that can be spread by cherry leafhoppers:
They also leave collections of white crystalline frass on apples, pomegranates, and stone fruits.
Cherry leafhopper lifecycle
Leafhoppers lay their eggs in soft plant tissue where they are protected through the winter. Nymphs may also overwinter in tiny hideaways. Come spring, the eggs hatch, and nymphs go through several molts before reaching adulthood. These pests are most active during the hottest months of summer.
Leafhoppers are best managed with insecticidal soap.
Parasites feed on other organisms. Aphid parasites feed on aphids. Let’s see what we can find out about these tiny garden helpers.
Aphid parasites (Aphidius colemani) and greenhouse aphid parasites (A. ervi) are parasitic wasps, but you don’t have to worry about getting stung. These native North American braconid wasps are more interested in aphids, honeydew, and nectar.
Aphid parasite description
Aphid parasite adults are black or brown with a narrow waist. They have yellow legs and long antennae. These tiny predators are only 1/10” long, which means you could put 7 or 8 of them in a line across the top of an American dime. You’ll probably never see aphid parasite larvae. They are very tiny and white, grub-like creatures.
Aphid parasite lifecycle
Females only mate once. After mating, they fly in search of aphid hosts for their young. Aphid parasites insert single eggs inside 100 aphids, and their greenhouse cousins lay up to 300 eggs. When those eggs hatch, the larvae eat their host aphids from the inside out. Ouch!
Aphid parasites often cut holes in the underside of their hosts to attach anchoring threads to a leaf. After about a week, these parasitized aphids swell up like balloons and turn beige to brown. These puffed-up aphids are called mummies. The larvae pupate inside the aphid and emerge as adults, ready to continue the cycle.
Surviving aphids frequently emit “alarm” pheromones that cause neighboring aphids to jump ship, abandoning the host plant and falling to the ground where they often die of starvation. Just as well.
Adult aphid parasites only live for 2 or 3 weeks, feeding on aphid honeydew and nectar from small flowers, such as anise, dill, mustard, and parsley. Their offspring can parasitize a large number of aphids. Aphid parasites are most active when temperatures are between 64°F and 77°F. They prefer green peach aphids and melon aphids for their supper but eat other aphid species, too.
Aphid parasites are available commercially and are frequently used to control aphids in greenhouse environments. You can attract and maintain habitat for aphid parasites by planting clumps of rye or barley. These plants attract aphids, providing a long-term food source for your aphid parasites. You can also add the flowers mentioned earlier. Because aphid parasites can fly, they will regularly scan your garden for all sorts of aphids. You should start seeing aphid mummies 10 to 14 days after releasing these hunters into your garden.
A midge is a small fly. Most midges are food for frogs and swallows. Many of them eat debris and help with nutrient cycling. Two of them, sand flies and black flies, bite and are vectors for disease. But, aphid midges deserve our notice and appreciation. They eat aphids. They eat a lot of aphids. Once you see how tiny these predators are, you may wonder how they do it. Let’s find out.
Aphid midge description
Adult aphid midges (Aphidoletes aphidimyza) are only 1/8 inch long. This means that you could line up half a dozen of them across the face of an American dime. Aphid midges can be mistaken for large fungus gnats or small mosquitoes. This is understandable since they are all members of the Diptera (two-winged) order, but mosquito wings are thinner than aphid midge wings.
Aphid midge larvae look like tiny orange slugs.
Aphid midge diet
Aphid midges feed on more than 70 different aphid species, including the dreaded green peach aphid. And it is the larvae who eat the most. They do this by injecting a paralyzing toxin into the leg of their prey. Then they suck the life juices out through a hole they have chewed in their prey’s thorax, the middle portion. Because their prey is paralyzed, aphid midge larvae can kill insects much larger than themselves. In fact, aphid midges are known to kill more prey than they can eat, but we won’t hold that against them. Aphid midge larvae kill up to 65 aphids each day.
Working with aphid midges
February may feel too early to consider aphids (unless you live in the Southern hemisphere). But it’s never too soon to learn how to help your garden plants stay healthy. As temperatures rise, you may want to buy aphid midge pupae to help in your fight against aphids. Pupae arrive in the mail in containers filled with moist vermiculite or peat. Depending on the temperature, pupae emerge as adults in 3–7 days. This is important. You’ll want to time your aphid midge release to coincide with newly emerging aphid populations. If you release them too early in the season, they’ll run low on food.
Before you squish another cluster of aphids, you may want to take a closer look to see if aphid midges aren’t already at work.
Aphids spend their entire lives sucking sap from garden plants and spreading viral diseases, but those lives are fraught with danger.
Aphids are soft-bodied insects with piercing mouthparts. They insert their sharpened straws into plant tissue, where they slurp up copious amounts of sugary sap. They eat so much and so quickly, that much of what they eat simply goes in one end and out the other. This “honeydew” can be contaminated with pathogens and it attracts the attention of protective ants, but aphids have many enemies. We’re not just talking about gardeners here, either. In most cases, aphid killers are either predators or parasites, though there are exceptions.
Parasitoids are insects that lay their eggs in, on, or near host insects. Those hosts end up being the first meals for parasitic larvae. There are many parasitic wasps that bring death to aphids. They do this by laying an egg in every aphid they can. When the eggs hatch, they eat their aphid hosts from the inside out. Gruesome, right?
Eventually, the aphids die and the now-adult wasps fly away. All that’s left behind are dozens of tan or golden aphid husks known as mummies. If you use a hand lens, you may even be able to see wasp exit holes.
The most commonly seen parasitic wasps and their favorite aphids include:
Predators actively hunt and eat aphids. Aphid predators include:
Remember those exceptions I mentioned? One of them is the ichneumon wasp. Adult ichneumon wasps kill their prey outright and then lay eggs in the corpse. It’s a brutal world out there, make no mistake.
Many varieties of parasitic wasps and other aphid killers are available for purchase, but you can often attract these garden helpers to your landscape with plants that provide abundant nectar and pollen. Queen Anne’s lace, coreopsis, coneflowers, cosmos, coyote brush, dandelions, dill, goldenrod, sweet alyssum, and sunflowers look lovely and they create a natural welcome mat to insects that see aphids as the perfect meal. Hedgerows also provide beneficial insects with good hiding places.
Stop getting rid of soil mites!
There are certainly plenty of bad mites: dryberry mites, Eriophyid mites, plum bud gall mites, and two-spotted spider mites are just a few. But not all mites are bad. Like their predatory cousins, European red mites, soil mites are your helpers.
Soil mites are extremely beneficial when it comes to releasing nutrients into the soil and controlling pest populations.
Conduct an online search for ‘soil mites’ and you’ll see dozens [millions] of sites telling you how to get rid of these pencil-point size arachnids. But getting rid of them is the last thing you should do. So, what’s so great about soil mites? Let’s find out!
What are soil mites?
Mites are arthropods. This means they have an external skeleton, a segmented body, and jointed legs. They are also arachnids, like ticks and spiders, but very tiny. If you were to take a sample of soil that weighed about the same as a bar of soap, 100 g give or take, you might have 500 mites from 100 different genera in that sample. These buggers are really tiny. With the naked eye, they might look like nothing more than little brown or white dots. But these little guys are important.
While there are over 20,000 known soil mite species, with an estimated 80,000 total, it is easier to categorize soil mites by what they eat. They can be herbivores or carnivores.
Plant-eating soil mites
To something as small as a ballpoint pen tip, fungi make a great meal. So do bacteria and lichen. These scavengers are abundant in most soils and they help plants gain access to nutrients. As these soil mites graze on the fungi and bacteria that grow on root surfaces, they poop out those meals in the form of plant food. They also shred decaying plant material as they feed on the bacteria and fungi clinging to those plant surfaces. Fungal feeding mites (Oribatei) look like little orbs. Also known as turtle mites, moss mites, and beetle mites, these soil mites are very tiny. Let’s call them moss mites. Moss mites range in size from 0.2 to 1.4 mm long. This means you could fit 10-90 of them across a dime, end-to-end, depending on the species.
Insect-eating soil mites
Other soil mites are predators. Predatory soil mites feed on microscopic garden pests, such as nematodes, fungus gnat and thrips pupae, springtails, other mites, and the eggs and larvae of other insects. Most predatory soil mites are 0.5 mm long, brown, and found in the top 1/2” of the soil. [Unfortunately, I could not find any freely available photos of predatory soil mites.]
While not all mites are good, soil mites are your friends in the garden.
Let them be, and be glad they’re around!
Rough Stink Bugs
Stink bugs have shield-shaped bodies and most of them are plant pests. The rough stink bug, however, occasionally eats pests!
As true bugs, rough stink bugs (Brochymena sulcata) are cousin to aphids, leafhoppers, and scale insects. There are several different subspecies of rough stinkbug and none of them are 100% beneficial.
Rough stink bug identification
Their classic stink bug shield-shaped body is rather flattened and a bumpy mottled gray and black. This coloration makes them blend in well with bark. They average 1/2” to slightly more than 3/4” in length.
Do not confuse rough stink bugs with brown marmorated stink bugs (Halyomorpha halys.) or consperse stink bugs (Euschistus conspersus). Brown marmorated stink bugs pose a serious threat to gardens and orchards. They have white bands on their antennae and legs, the front of the head is more blunt than other species, and the thorax is smooth. Consperse stink bugs have no banding on the antennae, but dark spots on the legs, the thorax is smooth but somewhat convex, and this species is smaller than others.
Rough stink bug diet
Like other stink bugs, a rough’s favorite foods are plant-based. While other species prefer fruits and vegetables, the rough stink bug diet is predominantly the leaves and developing seeds of ash, boxelder, walnut, willow, and many other trees. The thing that makes the rough stink bug beneficial is that they also feed on caterpillars and leaf beetle larvae.
Rough stink bug lifecycle
Rough stink bugs spend their winters hidden under logs or the bark of trees. They may also try to get in your home. If they do, keep in mind that their name is an important clue. If you vacuum them up or squash them in your home, there will be consequences. Stinky ones. Instead, sweep them up with a dustpan and drop them into a container of soapy water or feed them to your chickens.
As spring temperatures rise, rough stink bugs become active again and start looking for a mate. Mated females lay clusters of 10 to 20 white, elongated eggs before they die. Two weeks later, the eggs hatch and pale colored nymphs emerge and begin feeding. There is one generation per year in most regions.
In most cases, getting rid of stink bugs is a good idea. The rough stink bug is an exception.
If you grow currants, you should know about currant sawflies.
Currants make delicious jellies, pies, sauces, and even wine, but currant sawfly larvae can completely strip the leaves from your currant plants in only a few days.
Also known as imported currantworms and common gooseberry sawflies, these pests feed on gooseberries and other members of the Ribes family. Native to Europe, this pest is now found throughout North America.
Currant sawfly identification
If you see chewed holes in the leaves of your currant bushes, take a closer look. There are several pests that can cause this damage. It may be currant borers (Synanthedon tipuliformis), currant spanworms (Itame ribearia), the Epochra ribearia maggot, gooseberry fruitworms (Zophodia convolutella), or currant sawflies (Nematus ribesii). Sawflies tend to feed in groups, while those other pests do not.
Like other sawflies, adult currant sawflies look like a cross between a wasp and a fly. The larvae grow to 3” in length, but their coloration makes them difficult to see. They start out green with black heads. As they grow, they develop yellowish ends and black spots.
Currant sawfly lifecycle
Adult currant sawflies lay tiny, oval white eggs on the underside of leaves and there can be three generations each year. The first brood emerges after the first leaves appear in spring, the second occurs in early summer, and a third generation may occur, weather permitting. In each generation, feeding is very heavy and rapid.
To make matters worse, feeding often begins on the lower, inner reaches of the shrub, so you may not even notice the damage right away. Be sure to inspect plants regularly for signs of feeding and look on the underside of leaves for eggs.
How to control currant sawflies
Before you take any drastic measures, you need to know that the larval stages of currant sawflies look a lot like little green caterpillars. The distinction is important because control measures are different for moth and sawfly larvae. Take a closer look. If you have one, grab a hand lens or magnifying glass. If if you see 6 or more pairs of hookless legs, it’s a sawfly. Caterpillars have tiny hooks on their stubby legs and they usually have only 3 pairs of prolegs.
You can treat moth larvae infestations with Bacillus thuringiensis (Bt). That treatment will not work against sawflies. Commercial growers spray plants with Malathion as soon as currant sawflies appear. Your best choice for controlling currant sawflies is to spray infested plants with insecticidal soap and handpick currantworms as they are seen.
Trichogramma wasps are small but mighty.
These microscopic parasitic wasps protect an astounding collection of edible plants.
It might be easier to list those they do not protect, but your almond, apple, avocado, beet, blackberry, blueberry, celery, cherry, corn, cotton, grape, orange and other citrus, legume, papaya, peach, peanut, pear, plum, pumpkin, quince, squash, strawberry, tomato, walnut, and zucchini plants and trees are better off when Trichogramma wasps are in the neighborhood. These tiny wasps protect your plants from damage by parasitizing the eggs of these garden pests:
Parasitic wasps lay their eggs in many common garden pests. This group of beneficial wasps includes braconids, chalcids, Goniozus wasps, ichneumon wasps, and Trichogramma wasps.
Female Trichogramma wasps seek out the eggs of pesky moths and butterflies and sawflies to use as nurseries for her own eggs. When she finds one, the first thing she does is drum on it with her antennae and ovipositor to see if it has already been used. Drumming also helps her determine how big and useful the host egg is. This dictates how many eggs she will insert.
After being inserted into a host egg, the wasp egg develops, pupates, and then hatches, after which it feeds on the contents of the host egg. This turns the host black. If you use a hand lens and see a healthy white host egg with a chewed hole, it means the egg was not parasitized and a healthy (destructive) caterpillar emerged instead.
Trichogramma wasp species
Unless you are a scientist with a very powerful microscope, you will never see a Trichogramma wasp. At 1/25“ to 1/50” long, you could fit 20 to 40 of them nose-to-tail across a dime. If you could see them, you might be struck by the simple beauty of a minuscule yellow wasp with red eyes. Or, you might not. There are over 200 species of Trichogramma around the world.
Before you order a shipment of Trichogramma wasps as a biocontrol, keep in mind that different species of Trichogramma parasitize different hosts. It is important that you order from a reputable seller to avoid releasing a threat to other beneficial insects into your garden. When reading product descriptions, take the time to do a little research before you buy.
Trichogramma wasp eggs are shipped as larvae in host eggs that have been glued to cards. If you buy Trichogramma wasps for release, these tips will give them the best chance at being successful:
Keep in mind that Trichogramma wasps will not kill all the pests they come across. What they do is provide one piece of an integrated pest management program that uses natural processes to reduce the overall impact of pests, rather than spraying chemical poisons on your food.
Watch out for the yellow jackets and hornets, leave mud daubers and paper wasps to go about their business, and add some insectary plants to attract and provide for beneficial wasps, such as the Trichogramma.
Goniozus wasps can sting, but you’ll never have to worry about that.
Like many other parasitic wasps, adult Goniozus wasps mostly feed on nectar, sap, and other sweets. The benefit they provide is that they also parasitize pests of almond, apple, citrus, fig, pistachio, walnut, and coconut trees, as well as blueberries, blackberries, grapes, and strawberries.
Navel orangeworm, obliquebanded leafroller, and light brown apple moth caterpillars are favorite egg-laying hosts, giving Goniozus the common name of navel orangeworm wasp. Personally, I prefer Goniozus - in my mind, it’s the Gonzo wasp. These garden helpers also use banana scab moths and several insect pests associated with galls as hosts.
Goniozus wasp description
There are 20 different Goniozus wasp species, and they all look like tiny flying ants. Walking through the garden, you may simply see a very small, shiny brown or black wasp-waisted insect. Most insects who fit that description are beneficial, so resist the urge to swat them away. Instead, take a moment and see if you can tell what they are up to.
Similar to cuckoo bird species, which lay their eggs in the nests of other birds, Goniozus wasps are also known as cuckoo wasps because they lay their eggs in the bodies of other insects.
Adult females use their stinging ovipositor (egg-laying tube) to paralyze their victims, injecting hosts repeatedly with venom. The venom of some Goniozus wasps is permanent, but not all. In those cases, the venom only lasts half an hour or so, so she has that much time to transport her victim, mostly by dragging the much larger host, to a good hiding spot. If necessary, she will continue to inject venom over several hours, if that’s how long it takes to get where she needs to go.
Once tucked safely into a crevice somewhere, some females will feed on the juices of said caterpillar over the next few days, aiding in the development of her eggs. This does not always kill the host. In some cases, the host simply walks away, a little worse for the wear, until the eggs hatch and begin feeding from the inside out.
Goniozus larvae go through several developmental stages over the next 2 or 3 days, attached to their host, ultimately spinning tiny cocoons around themselves before reaching adulthood. Apparently, Goniozus wasps have been observed paralyzing far more hosts than they can possibly use for egg-laying. No one knows why.
How to attract Goniozus wasps
Beneficial parasitic wasps can be attracted to your garden with insectary plants. Insectary plants provide the food and shelter needed by these garden helpers. Most insectary plants feature umbrella-shaped flowers commonly seen in carrot, dill, cumin, mint, and cilantro, or globe-shaped flowers, such as chives. Allowing these plants to go to seed not only attracts beneficial insects, but seeds then create perpetual, edible crops. Other insectary plants include cosmos, sweet alyssum, yarrow, dandelions, and borage.
Adding these useful plants to your yard looks nice, too!
Unlike beneficial parasitic wasps, hornets attack honey bees, steal honey, invade bat houses, girdle branches, and ruin summer picnics.
So why would we want to tolerate hornets in the garden? What good can they do? Let’s find out!
Worldwide, there are 22 hornet (Vespa) species, including:
There are also 3 species of nocturnal Asian Provespa, which are not actually hornets.
Despite their name, bald-faced hornets (Dolichovespula maculata) are not true hornets, either.
There is only one true hornet found in North America: the European hornet (Vespa crabro). Introduced in the 1800s, this hornet is now found throughout the U.S.
Hornets are highly social insects. They live in large colonies, housed in papery hives, that are commonly built in dark crevices, such as dead tree trunks, under house eaves, and in your garage. Hives are made up of interconnected brood cells. Both the queen and workers can lay eggs. Fertilized eggs laid by the queen develop into sterile females, called ‘gynes’ while eggs produced by workers develop into males, called drones. Drones mate with the queen during ‘nuptial flights’. As a result, a hornet’s nest is largely populated by two nearly distinct gender-dictated populations. Workers care for the eggs as they move through larval and pupal stages, ultimately emerging as adult hornets.
Hornets and yellow jackets are both types of wasps, though yellow jackets tend to be smaller, with more yellow and black, while hornets tend toward more black and white or yellow and brown coloration.
Most hornets average 3/4” to 1”, while queens can be 1-1/2” long. If you look closely, you might be able to see that a male hornet abdomen has six segments, while females have seven segments and a stinging ovipositor.
Hornet stings and allergies
Like many other stinging insects, hornets become aggressive when they feel accosted (swung at, stepped on, sat on, that sort of thing), or when they believe their food supply or the colony are threatened.
Hornet stings are more dangerous to humans that other insect stings because they contain higher concentrations of acetylcholine. Hornet stingers are not barbed and can be reused many times. Also, when one hornet stings you, it releases chemicals that tell other hornets to sting you, as well. These same chemicals are also released when you kill a hornet or spray a hornet’s nest with poison, so be forewarned.
If you are allergic to stinging insects, you should always carry antihistamines or an EpiPen with you. Signs of an allergic reaction include shortness of breath, swelling of the face, lips, or throat, severe itching, weak or racing pulse, nausea, wheezing or gasping. If any of these symptoms occur, get medical help immediately. Call 911, grab a family member, or a neighbor right away. These symptoms can quickly escalate into a life-threatening situation. Otherwise, follow these steps to ease your temporary pain:
You can also take aspirin or acetaminophen to ease the pain, just be cautious about mixing medications, as that can cause yet another medical problem. Generally speaking, you are going to feel really miserable for 30 to 45 minutes, moderately uncomfortable for the rest of the afternoon, and you may experience discomfort for a week or so. You may also want to apply hydrocortisone or calamine lotion to the area. Pastes made of baking soda or colloidal oatmeal can also sooth the area. If you haven’t had a tetanus shot in the past 10 years, that can be a good idea, as well.
So, why would we want hornets in the garden?
Adult hornets feed on sweets, such as fallen fruit, sap, and your lemonade. They also collect insects for their larvae. This is part of the reason why they cause us so much grief during picnic season. From a hornet’s point of view, it is simply defending a food source when it refuses to back down from your burger and fruit punch. In addition to your picnic, European hornets commonly chew up beetles, dragonflies, grasshoppers and crickets, katydids, locusts, mantises, moths, and other wasps. This pulp is then taken back to the colony, where it is fed to larvae in the nest.
If you start having a hornet problem while dining outside, you can reduce the chance of stings by placing a plate of meat and fruit somewhat away from the picnic table.
If hornets become a problem around your home, try excluding them before poisoning them. Those chemicals tend to create more problems than they resolve.
There is far more to wasps and hornets than you might expect.
This group of insects is massive and it contains many beneficial insects. You may not be familiar with chalcidoid wasps, but odds are pretty high they’ve been working hard in your garden all along.
The chalcidoid superfamily of wasps contains 22,500 known species, with an estimated 500,000 species yet to be named. One of those families in particular, the Chalcididae, gives us chalcid wasps. And figs.
Chalcid wasp description
Ranging from only 1.5 to 0.75 mm (1/50 - 1/100”), you could fit 12 to 24 chalcid wasps nose-to-tail across a dime, so you probably will never see one. If you could see them, you would understand how they got their name. The word ‘chalcid’ comes to us from the Greek word for ‘copper’ because most chalcid wasps are a metallic bronze or copper color, though some species are metallic blue or green, and some are the more classic black and yellow variety.
Beneficial chalcid wasps
Most chalcids are parasitic wasps. They lay their eggs in several common garden pests. When the eggs hatch, larvae feed on the host insect before pupating into adult wasps. [I know, it’s sounds awful.] Those hosts include the eggs and larvae of flies, beetles, moths and butterflies, some spiders and nematodes, and true bugs. Since true bugs (Hemiptera) include aphids, leafhoppers, spittlebugs, thrips, whiteflies, and scale insects, I am all for more chalcid wasps! [Plus, I love figs!]
Figs and tiny wasps
While most chalcidoid wasps parasitize all those pests, a handful of them are phytophagous, which means the larvae hide and feed in stems, galls, seeds, and flowers. Fig flowers, in particular, are hidden clusters found inside a hollow structure called a syconium. Fig pollination is usually completed by tiny specialized wasps, such as chalcid wasps.
But, not all chalcids are good.
Chalcids as pests
Other phytophagous chalcids are not so helpful. These tiny wasps are pests because they lay their eggs in seeds. When those eggs hatch, larvae eat the seeds of pistachios and alfalfa, among others, creating burrows and allowing fungal and bacterial diseases a point of entry.
In many cases, sticky barriers can be used to reduce the damage caused by these pests. Most chalcids, however, are beneficial.
You can attract chalcid wasps to your garden by installing insectary plants, such as yarrow.
Wasps may have a bad reputation, but there are beneficial wasps, and ichneumon wasps [pronounced ick-NOO-mon] are one of those Good Guys. Well, mostly.
Ichneumon wasps are parasitic wasps and they have been around for over 15 million years.
There are somewhere between 60,000 and 100,000 different ichneumon wasp species in the world, with 5,000 species in North America. Clearly, with those numbers, there is significant variety in appearance.
Ichneumon wasp description
Like other wasps, the ichneumons have a narrow body and an even narrower waist. Some females have an especially long ovipositor, which is often mistaken for a stinger. Ranging in length from 1/10” to over 5” long, they can be black, brown, yellow, or some pattern combination of those colors. These wasps have 16 or more segments in their longer than average antennae. Ichneumons are solitary wasps.
Common ichneumon prey
Adult ichneumon wasps eat little or nothing. Their larvae, on the other hand, are voracious feeders of beetle, butterfly and moth, wasp, ant, fly, and sawfly larvae and pupae or chrysalises. This is what makes ichneumon wasps so helpful in the garden. They also parasitize beet armyworms, some spiders, and wood-boring grubs.
Some ichneumon wasps do this by using their long antennae to detect prey, then inserting the ovipositor into the wood, plant, or soil, to strike their prey, piercing its skin and inserting an egg. Other ichneumon wasps crawl down the stems of aquatic plants to inject eggs into water-dwelling insects. Yet another ichneumon is the parasite of a parasite, making it a hyperparasitoid. This ichneumon lays its eggs in moth-eating ant larvae. She emits chemicals that confuse the ants as she does her deed.
Ichneumon wasp lifecycle
Most parasitic wasps lay their eggs on, in, or near their prey, but ichneumon wasps kill their prey outright and then lay eggs. When the eggs hatch, larvae feed on the host’s body. After hatching and eating their host, ichneumon larvae spin cocoons and pupate in or near the exoskeletons of their first meal. When they emerge from their cocoon, they are adult wasps who go in search of a mate.
These garden helpers do not sting and they are worth their weight in gold, so check before swatting at something just because it might be a wasp. [Swatting at wasps is usually a bad idea, anyway…}
One of the best ways to attract and provide for beneficial ichneumon wasps is to plant coyote brush (Baccharis pilularis) and to maintain hedgerows.
Rove beetles are a family of mostly elongated predators that protect your plants against a great many garden pests.
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.
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.
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?
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
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.
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.
Twicestabbed Lady Beetles
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.
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?
No, it's not a flying snake.
Introducing another beneficial insect on the garden scene: the snakefly.
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.
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.
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!
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? Let us know in the Comments!
Before you swat that tiny wasp away, take a closer look.
It may be one of the Good Guys.
These tiny wasps serve us well in the garden, so avoid using any broad spectrum pesticides and let nature take its course.
Many slender-bodied insects, such as thrips and leafhoppers, are garden pests. Damsel bugs are an exception. Damsel bugs are predators. And they are very quick.
Damsel bug actually refers to most of an entire family of insects (Nabidae). Most damsel bugs are Nabis species.
Damsel bug description
Damsel bugs are true bugs (Hemiptera), which makes them cousin to many of their favorite foods. Whereas the “beak” (rostrum) is used by most true bugs to pierce plant tissues and suck sap, damsel bugs use their beak to inject digestive enzymes into victims. In either case, the beak is usually held under the body when not in use.
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.
Like their cousins, the aphids, adelgids pierce vascular bundles to suck out nutrient rich 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.
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!]
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.
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.
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.
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.
Potato tuberworms are a minor to moderate pest, but they can make your potatoes inedible.
Also known as the potato tuber moth or tobacco splitworm, potato tuberworms (Phthorimaea operculella) love to feed on members of the nightshade family, such as eggplants, tomatoes, peppers, and tobacco, but they prefer potatoes.
The potato tuber moth is unique in the moth world in that her ovipositor (egg-laying organ) has sensors that can pick up chemical signals given off by potato plants. [If you are really into this sort of thing, the chemical signal is an amino acid called L-glutamic acid. But don’t worry, there won’t be a quiz.] She doesn’t necessarily have to be on the potato plant to lay her eggs, either, but you can be sure she will be close. These moths are usually seen an hour or two after sunset.
Potato tuberworm description
Potato tuberworms are the larval form of a small grayish-brown moth. The adult moth has a 1/2-inch wingspan and dark gray or black markings. At rest, both sets of fringed wings are held close to the body, giving them a slender appearance. Females moths have a distinctive “X” pattern on their forewings when at rest.
Eggs are very tiny, oval, and yellowish white. The larvae, or caterpillars, are just under 1/2 an inch in length, and their color can vary, depending on what they are eating, from white or gray, to tan, pink, or yellowish. Larvae have a brown head and prothoracic shield. [A prothoracic shield is the segment just behind the head.] Cocoons are 1/2 an inch long and pale colored.
Potato tuberworm lifecycle
Each female potato tuber moth will lay over 200 eggs in her short lifetime. Those eggs are normally laid next to a leaf vein, near a bud, or under a stem, though they can also be found in the soil near a host plant. In five days, those eggs will hatch. For the next two weeks, the larvae will eat as much as they can. The way they decide where to feed may surprise you. This is not a simple case of taking bites out of whatever is at hand. Nay, nay! Our newly hatched potato tuberworm larva will spend the first 5 to 15 minutes of its life walking around on its home plant. As it walks, it attaches a silk thread to the plant every few steps, turning this way and that way, taking an occasional bite as it meanders. If it has hatched on an unacceptable plant, the larva will walk faster and ultimately leave the plant altogether, until it can find an acceptable host plant.
Damage caused by potato tuberworms
Young potato tuberworm larvae might burrow through leaves and stems, causing stunting and reduced crop size. As feeding and tunneling continue, the tuberworms head for their favorite food: your potatoes. Webbing and frass (bug poop) deposits can be seen at entry holes, normally found at the eyes of a potato. While other pesky tunneling insects, such as wireworms and leaf miners, tend to keep their tunnels neat and tidy, potato tuberworms are slobs. Those dark tunnels are filled with excrement.
Controlling potato tuberworms
Row covers can be used to prevent adult moths from laying eggs on your potato plants. The deeper your potatoes are growing, the more difficult it is for tuberworms to get to them, so selecting a deep growing variety is helpful if you know tuberworms are around. Also, avoid furrow irrigation, which can cause cracks in the soil. These cracks are used as elevators to lower soil levels by tuberworms. Research has shown that insecticides do not prevent potato tuberworm infestations when erosion or soil cracks are present, or when potatoes are left in the ground longer than is necessary. Finally, harvest potatoes as soon as they are ready. Infested potatoes should be thrown in the trash and not added to the compost pile. Heavy infestations can be treated with spinosad.
You can grow a surprising amount of food in your own yard. Ask me how!
To help The Daily Garden grow, you may see affiliate ads sprouting up in various places.
You can also get my book, Stop Wasting Your Yard!