Now is the time when a small pest that has the potential to do a large amount of damage will be hatching. I am speaking of the Squash Vine Borer, the larval stage of the clearwing moth Melittia cucurbitae, an insect so synonymous with the squash family that it has cucurbit in its name.

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The adult clearwing moth, unlike many other moth species, is diurnal and is therefore active during the day. With its orange abdomen and clear wings it is often is mistaken for a wasp. The adults are now emerging from the soil where they have over-wintered as pupae. Anecdotally it is said that the squash vine borer lays its eggs when the blue chicory is in bloom and a drive along any of our major interstates will confirm that it is indeed blooming now. (image by Chris Evans, University of Illinois, Bugwood.org)

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The eggs, which are very small, are laid singly at the base of the stalks near the soil. This will make it easier for the newly-hatched larvae to enter the stalk. Seven to ten days later the larvae, which are white with a brown head, will emerge from the reddish-brown eggs and within hours instinctively burrow into the stem to begin feeding.(image by Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org)

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At this point symptoms will begin to appear starting with a wilting of the plant that recovers in the evening but progressing to a plant that does not revive in the evening or after watering. There may also be small entry holes visible at the base of the stem and sawdust-looking frass (waste). The larvae feed inside the stem for a little over two weeks, reaching 1” in length, at which time they exit the plant, burrowing 1-6” into the soil where they will pupate until next spring. I plant my cucurbits in upside-down coco coir liners that have a 2″ diameter hole in the bottom (now the top).

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The small opening and the protective coco coir make it easier to cover the base of the plant with row cover cloth and harder for the larvae to get to the soil to pupate. In warmer climates there may be two generations per year so we are fortunate that Connecticut only experiences one generation each summer.

It is almost impossible to control the larvae once they have entered the stems. If Bt (Bacillus thuringiensis) is applied to the plant tissue that is near the area where the larvae will hatch then they will feed on the residues prior to entering the stalk. Bt is a common soil-dwelling bacterial organism that forms crystals of insecticidal toxins called Cry proteins or crystal proteins. When consumed by the larvae, the Cry proteins undergo a series of chemical changes to the point that they paralyze the intestinal tract and the insect starves to death. Also good to know is that mammals have no toxic or allergic reactions to Bt, it only affects species in the orders Coleoptera, (beetles), Diptera (flies), Hymenoptera (ants, bees, sawflies, and wasps), Lepidoptera (moths and butterflies, and nematodes. Bt can also be injected into the stem where squash vine borer activity is suspected making it the only treatment that may work once the borer is inside. Additionally, normal exposure rates of Bt will not harm bees so that is good news for our pollinators.

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Butternut squash, cucumbers, and melons are not as susceptible to the squash vine borer as summer squash, pumpkins, and Hubbard squash, so plant the former varieties if you don’t want to deal with the borer. There are some practices that can be used if, like me, you can’t imagine a summer without freshly picked and grilled summer squash or a winter without home-canned ratatouille.

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The best protection is to prevent the clearwing moth from laying its eggs in the first place. Row covers placed during the egg-laying period starting in mid-June can be highly effective, just be sure to remove when the blossoms are ready for pollination (or leave them on and hand-pollinate). If possible, don’t plant in the same location as the prior year. If it’s not possible to rotate, at least turn over the soil at the end of the season to expose the pupae to the freezing temperatures of winter.

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For more information and control measures please check out our: Squash Vine Borer fact sheet.

Susan Pelton

 

Mid March and warmer weather is descending upon us bringing a few pests currently, and some that will no doubt make a return. Inside our homes, the over-wintering nuisance insects have begun to come out of their hiding spots in attics and wall voids where they spent their winter dormancy. Now they are awake and clamoring to get outside to feed, mate and lay eggs on the their host plants. They fly to the windows and any lights trying to go outside. It is best to open the window and let them go or just vacuum them up. The list of nuisance insects which invade our homes in the fall, sleep off the winter, and awake in the spring are boxelder bugs, Asian lady beetles, leaf footed bugs and the brown marmorated stink bug.

box elder bug on gazebo 10-21-15 Pamm Cooper photo (2).jpg

Boxelder bug, photo p.cooper

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Asian Lady Beetles.

 

Leaf footed bug

Leaf footed bug.

brown marmorated stink bug on gazebo 10-21-15 Pamm Cooper photo (2).jpg

Brown Marmorated Stink Bug, photo p.cooper

Other early season pests can be found in the vegetable garden. Asparagus beetle usually appears a few days after the first spears emerge. However now they are busy feeding below ground on the stems pushing their way up. If stalks curl around above ground, chewing damage by the adult beetle has happened below ground as the stalks were developing. Feeding on one side damages the developing cells, while the other side grows normally causing the distorted shoots. Not much can be done to correct the shape, although the asparagus is still edible, just funny looking. Scout the stalks and bed for the nearby asparagus beetles. Hand pick and squish any or spray with neem oil to reduce feeding.

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There are two types of asparagus beetles, the common and the spotted.

Another early season pest is flea beetle. They get their common name due to the way they move or jump like a flea. They feed on leafy crops of spinach, lettuce and chard of the cool season crops, and love eggplant, tomato and peppers once the soil is warm enough to accept these transplants. Row covers over the plants will keep them off of the leaves. There is a predatory wasp which does parasitize asparagus beetle eggs. The wasp is metalic green and tiny, about 1/8 inch long. The Latin name of the wasp is Tetrastichus asparagi.

What insects are appearing in you area of the world?

-Carol Quish

 

 

Through the Macro Lens

As the first month of 2016 nears its end it would appear that we are finally getting some true winter weather in the form of arctic cold and snow that will keep even the most ardent green thumb inside. Is it any wonder that January is a popular time for perusing seed catalogs and forcing paperwhite and amaryllis bulbs to bloom indoor? It also presents a great time to pay a bit more attention to our houseplants: cleaning the foliage, repotting specimens that have outgrown their current containers, and doing a visual inspection for insects. This year, however, checking for unwanted visitors took on a whole new meaning.

Poinsettia Flowers

I received a great present from my husband this Christmas in the form of a macro lens that clips over the camera lens of a smartphone (he knows how much I enjoy getting close-up images of insects and flowers). This tiny tool increases the magnification power of the ordinary camera lens by 10X allowing for some really incredible images from a phone camera. The first thing that I did with it was to start snapping pictures of just anything that was around such as the true flowers of a poinsettia that are usually insignificant, the new blooms of a paperwhite, and some fuzzy, cotton-like areas on a dieffenbachia.

What I saw in the lens was amazing. It was not just a cobweb substance on the dieffenbachia but a group of tiny insects that turned out to be the nymphs of the mealybug.

Mealybug nymphs 3

These tiny insects, along with scale and aphids, are a common pest of houseplants. They feed on the sap of the plant by piercing the outer layer of plant tissue with their long, slender beak. As a by-product they secrete a sweet honeydew that provides a base for the black fungus called sooty mold. Plant tissue that has been fed upon will be stunted, yellowed or malformed. A severe infestation can weaken a plant to the point of death.  I found that many of the mealybugs were in the crevices of the leaf axils or in the unfurled new leaf growth.

Mealybug nymphs 1

A bit of research showed me that one of the easiest remedies was to wipe the affected areas with an isopropyl alcohol soaked cotton ball. I did this, making sure to get both sides of the leaves as there were many nymphs on the undersides.

 

There are also many products such as insecticidal soaps and neem that can be used to control nymphs, scale, spider mites and aphids. These should be used with caution and always according to the label directions. A few more non-chemical approaches include spraying the plant with a forceful stream of lukewarm water, placing it near a cold window (only if the plant can tolerate the cold) so that the nymphs migrate to the leaf that is furthest from the cold and will therefore be easy to wipe off, or introducing a natural predator such as a ladybeetle (probably a good idea for greenhouse specimens, not plants in a home environment).

It is important to check for new generations of any insect pest that may not have been controlled with the first application. I have been scouting my houseplants every few days but I have not seen a recurrence. I can see, however, the results of the initial infestation. There are areas of foliage that are devoid of green, have turned brown and thin and almost appear like water spots. These areas are not much bigger than a quarter so I may leave that foliage on the plant and wait to see how it does.

I am really looking forward to getting outside in the upcoming seasons and getting some incredible close-up shots of flowers and insects, many of which will be shared with you in my blog posts. Happy New Year!

Susan Pelton

All images by Susan Pelton

Woolly Bear Caterpillar, photo by c.quish

Woolly Bear Caterpillar, photo by c.quish

Do woolly bear caterpillars really predict how intense and cold the coming winter will be? This is the often repeated folk tale heard upon spotting the readily recognizable, black and orange/brown colored, fuzzy caterpillar in the autumn. The theory is  that the wider the black end sections, and shorter the orange/brown section, the longer the winter will be. Well, it is not true folks! There is really no actual research proving it is fact. We do know that some years the center section is longer than other years. This is due to the weather, not future weather but past weather.

Isabella Moth Adults, photo from purdue.edu

Isabella Moth Adults, photo from purdue.edu

The woolly bears are the larval stage of the Isabella Tiger Moth, Pyrrharctia isabella. The caterpillar has four stages of life; egg, larva(caterpillar), pupa(chrysalis), and adult moth. The caterpillars molt several times during the summer and fall. At each molt, a portion of the black setae (hairs) are replaced with orange/brown setae, making the middle sections longer. So the older the caterpillar, the more molts it has gone through, therefore the less black areas and more orange/brown.

The caterpillars you see now will seek hiding places to over-winter. They will produce a chemical protein just like anti-freeze, allowing them to live through the winter in a resting state. When the spring comes they will break their dormancy to become active once again. To continue their life cycle in the spring, they will pupate into a chrysalis where they will turn into the Isabella Moth adult. Adults will fly around, mate and the female will lay eggs. Eggs hatch into the woolly bear caterpillar to complete the cycle. If you have an early spring, the cycle starts sooner than normal, resulting in a longer growing period for the caterpillar. So when we see a larger woolly bear with a less black and more orange/brown, it is just older and will have gone through another molt sooner, possibly, than at the same time the year before.

So the woolly bear is a reporter of past weather, not a predictor of what has yet to come.

-Carol Quish

Mourning Cloak Butterfly- out on a sunny winter day 2012

Mourning Cloak Butterfly- out on a sunny winter day 2012

During the cold New England winter months, we are blissfully ignorant of all the survival drama going on in the natural environment, at least as far as insects are concerned. Out of sight, out of mind, so to speak. While we have heated homes, running water and warm winter clothing, insects have only the bare necessities required to survive temperature extremes. Those that do not, such as the Monarch butterflies and some dragonflies, may migrate to more insect- friendly climates. Those insects that remain have special survival mode states or processes that will see them through even the toughest icebox conditions nature may throw at them.

While many butterflies can overwinter in the chrysalis form, there is one that ecloses as an adult in the fall and remains a butterfly for the winter. That champion of the deep freeze is the Mourning Cloak, Nymphalis antiopa). This butterfly find shelter under loose tree bark, in open sheds or tucks away in wood piles. Freeze tolerance is accomplished by small ice crystals that form outside the cells of vital organs. The small size of the crystals keeps them from damaging chemicals in the insect’s blood as well. Thus, the Mourning Cloak can survive freezing and thawing episodes and can even be seen flying about open woods during warm winter days.

Some insects produce chemicals resembling anti-freeze, like glycerol, that lowers the freezing point of the insect’s blood. Somewhat like cold- hardening that plants undergo, insects subjected to rapid freezes may die, but those that are physiologically prepared will tolerate the same conditions. When fully hardened to the cold, insects can survive in bark crevices or under mulch. Some, like lightning bugs, may come out from inside bark cracks if the winter temperatures rise above 40 degrees, especially on the south- facing sides of tree trunks. A few years ago, the winter was especially mild. On sunny days you could find many lightning bugs on trees, barely able to move, but still making a brief appearance

Lightning bugs (beetles) on the sunny side of a tree trunk in January 2012

Lightning bugs (beetles) on the sunny side of a tree trunk in January 2012

.Some insects survive by retreating in the soil below the frost line. Bumblebee queens, ants, beetle grubs and termites do not even have to go that deep in soils if there is as little as six inches of insulating snow cover. This is how scarab beetle grubs are able to return in the spring and resume feeding on lawn grass roots.

The Common Green Darner dragonfly migrates south and its offspring come north in the spring

The Common Green Darner dragonfly migrates south and its offspring come north in the spring

The social honeybees profit by their cooperative efforts to keep the queen war. The worker bees do this by crowding together around the queen and shivering so that their muscles generate heat. As the periphery cools, the worker bees constantly shift positions so each has a timely turn in the warm inner parts, the ultimate example of  the “ gung ho” principle in action.

The life cycle of insects may include a phase known as diapause where dormancy, similar to the hibernation period of some animals, keeps the insect in a state where it can survive adverse environmental conditions for long periods of time. This may include surviving as an egg or inside a puparium. Aphid eggs are often laid in twig or bark crevices or underneath growth buds. Moths often survive by pupating in leaf litter, under the soil or in leaf shelters. Woollybear and other tiger moth caterpillars survive winters under leaf litter and snow.

Baltimore Checkerspot butterfly caterpillars survive winter living together in a tent of leaves

Baltimore Checkerspot butterfly caterpillars survive winter living together in a tent of leaves

A final look at insect survival in our cold winters involves aggregation, which may also cause  aggravation, if they do so in our homes. Lady beetles and Box elder bugs are two such insects that utilizes this strategy, which is really more like a hop, skip and jump migration into a warmer place. A short flight to enjoy the  “Florida” of our homes until survivable outdoor conditions return.  While in a torpor, they may be well hidden, needing no food for the entire winter. Occasionally they venture out of hiding, but often fade away back into the shadows. It could just be a little spot check to see what is happening, with a quick retreat as they discover that nothing is.

As spring arrives with warmer temperatures, the little world of insects will slowly make its appearance, whether for good or bad. So enjoy their absence, or look forward for their return, as you see fit.

Pamm Cooper                   All photos © 2015 Pamm Cooper

 

A monarch caterpillar safely eating milkweed after  stopping the flow of gummy sap by clipping the midrib

A monarch caterpillar safely eating milkweed after stopping the flow of gummy sap by clipping the midrib

 

 

 

 

 

 

 

Historically, insects have been the most important bane of the plant kingdom. The fatal attraction that exists between plants and insects has woven an intricate balance between good and evil, survival and devastation, and benefits versus harm. While insects play a significant role in pollination, and while over 90% of insects are not a problem, the few that are plant pests can wreak destruction.

Some insects are vectors of disease, especially those that feed by piercing plant tissue. Aphids, plant hoppers and the familiar cucumber beetle may pass along viruses even though feeding damage is not significant. Introduced insects seem to have a field day and may prove to be more damaging than native insects in the long run.

But in all the dramas that occurs in nature, the ones that may be overlooked are the strategies plants can use to defend themselves against insects. Whether it is simply structural impediments such as thorns, prickles, thick bark, waxy cuticles and objectionable chemical compounds, plants are not helpless against attacks. While some defenses are always present, like the above physical qualities, there are other means by which plants can release substances as needed that either repel the feeding insects, or attract predators of the same.

One plant of interest is the geranium that produces a chemical in its petals that can temporarily paralyze the Japanese beetle while it is feeding. This may provide a window for any predator that happens by. Native wild tobacco plants change the time of day that flower buds open in response to caterpillar feeding. This discourages certain sphinx moths that pollinate by night as they are attracted to the scent and color of the flowers, and lay eggs on the plant, which doubles as both an adult and larval food plant. Pollinators such as butterflies and hummingbirds will visit by day and the plant loses no ground in reproduction and survival. Other caterpillars like the tobacco budworm have no problem feeding on geraniums, petunias, snapdragons and other tobacco relatives. Their saliva counteracts the production of induced defenses in the plants.

Some plants release hormones or other substances upon feeding injury that attract predatory insects or even birds. It is like a silent alarm calling in the troops. Many caterpillars may be parasitized because their feeding releases chemicals in the plants that attract predatory insects such as brachonid wasps. Grass releases a strong aroma when cut, either when cut when insects are feeding on it. Perhaps this is why starlings and other birds flock into a yard or pasture that is under attack from cutworms or other grass pests.

Starlings feeding on cutworms in a lawn

   Starlings feeding on cutworms in a lawn

Fawn sphinx with cocoons of exited brachonid wasps

Fawn sphinx with cocoons of exited brachonid wasps

Milkweeds contain strong chemical defenses that are passed along to insects that feed on leaves but are unaffected by them themselves. The monarch caterpillar and others avoid much predation because of the absorption of these chemicals which make them bitter to the taste of hungry birds. The latex released by milkweed as insects begin chewing hardens quickly when exposed to the air and may cause mouthparts to stick together so the insect starves. Monarch cats avoid this by clipping off the base of the midrib first which reduces sap flow to the leaf.

Some plants have high lignin or tannin content that makes them unattractive to insects later in the season. Window feeding is a way some caterpillars avoid higher concentrations of toxins in leaves or high lignin content that is difficult to ingest, such as leaf veins and midribs. Many beetles avoid ingesting high concentrations of toxins by feeding in large groups, thereby “sharing in the load”.

"Window feeding" helps a dagger caterpillar avoid high lignin in the leaf veins

“Window feeding” helps a dagger caterpillar avoid high lignin in the leaf veins

Pyrethrins are ester compounds produced by chrysanthemum plants which act as insect neurotoxins. Some commercially available insecticides are actually synthetic copies of pyrethrins, called pyrethroids. Tansy is a non-native escapee that has toxins repelling many insects. It has been used with some success as a companion plant with cucurbits, squash, roses and other plants to repel cucumber beetles, ants, Japanese beetles and other insect pests. Sprigs were used at windowsills to repel flies.

Tansy in full bloom in the wild

Tansy in full bloom in the wild

Trillium actually reproduces effectively by myrmecochory- using ants to carry away its seeds and thus protecting them from becoming consumed by various animals. Ants are attracted to eliaosomes attached to the seeds and bring them back to their nests. After consuming the eliaosomes, the seeds are discarded by the ants and they are still viable. Survival of the species is helped along by the little ant.

Red Trillium

Red Trillium

While we may be blissfully ignorant of all the events taking place among the plants surrounding us, at least where fending off insects is involved, there is at least as much drama as any to be found in the entertainment industry.

 

Pamm Cooper                        All photos copyrighted 2014 by Pamm Cooper

 

 

furcula- gray or hourglass Mt Rd power lines on aspenAugust 9, 2014 II

Furcula with modified anal prolegs used to wave away potential predators

Many insects never make it to adulthood to complete their life cycles because in the grand scheme of things, they are low on the food chain. Between birds and amphibians, mammals and other insects, there is no lack of creatures that rely upon insects to muscle up themselves or to ensure their young survive long enough to obtain food for themselves.

But insects are not necessarily limpid little defenseless victims of a more sophisticated life form. They have strategies to overcome the odds of becoming dinner for something else. Some use camouflage, others are cryptic in manner and color, some have mastered the technique of veiling themselves with material and others simply hide. When you become familiar with specific species and their means of surviving, then it becomes easier to find them or to at least recognize them when you see them.

One of the ways insects can hide in plain sight is by coloration and feeding techniques. Spring caterpillars that feed on new leaves are often green in color. Late season caterpillars are differently colored and often have colorations or body forms that imitate the dead leaf spots and edges that occur at that time of year. Some feed along leaf edges and appear to be part of the leaf itself. Careful scrutiny will reveal the ruse. Two of the prominent caterpillars, the Wavy- lined Heterocampa and the Lace-capped caterpillar are just two examples of this behavior.

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Wavy- lined Heterocampa feeding cryptically along the lower edge of a sweet birch leaf

Many assassin bugs that rely upon other insects as their food source will often lie in wait in places other insects are sure to visit. This includes flowers. Ambush bugs perch on flower heads, especially yellow and white composites, and wait for pollinators or nectar collecting insects to come to them. Ambush bugs are hard to spot on these flowers as they are the same color as the petals. They are motionless and are hard for even people to spot unless you look carefully for them. Often you will see butterflies that hang limply from flower heads. A close examination will reveal an ambush bug ( or a crab spider ! ) clasping the body and feeding off the insect’s fluids. Also, assassin bugs and predatory stink bugs often hide inside the folded seed heads of Queen Anne’s Lace and wait for other insects that use the structure as a hiding place to come inside. Opportunity may knock, but being in the right place at the right time is a better means of assuring survival.

Walking sticks are a good example of cryptic coloration and mimicry. Early nymphs are found on viburnum and filbert in New England. On these plants, both the insect’s shape and color allow it to blend so completely with that of the plant foliage that unless they move or cast a shadow, they are very hard to find. Later in the season, the older nymphs and adults change their food plants to oaks and cherries where they are able to blend in as their color changes to match the foliage of these trees. Camouflage loopers are small caterpillars that are found on composites. They take petals from the plant’s flowers and “ glue “ them on their body. They blend in so well that the only evidence of their presence will be that the flowers seems to be deformed.

walking stick blending in on filbert July 1, 2014

Early nymph of a walking stick on native filbert. Note how legs blend in with the leaf veins.

Caterpillars, especially the slug moth caterpillars, can have defense mechanisms that utilize urticating hairs or venomous barbs to ward off potential predators. Handling some tussock moth caterpillars. the familiar woolly bears, Io moth cats and others may prove a painful experience for some people. One especially to be avoided is the saddleback caterpillar- small,l but able to inflict severe pain or burning sensation that lasts for several hours or even a few days. The body is covered with hollow spines that release an irritant when brushed or touched. Handled gently, many of these caterpillars will not harm the handler, but use caution around any caterpillar having barbs, hairs or spines. While many caterpillars that have spines and hairs have no toxins, unless you know for certain they are harmless, avoid contact with the skin to be safe.

 

Another means by which insects can protect themselves is by mimicry. Many flies have coloration and markings that are very similar to wasps and bees. These flies can also feed on the pollen of many of the plants that bees and wasps also visit. Birds will tend to avoid any insect that may have  the potential to sting, so these bee mimics need not worry as they go about their everyday work acquiring pollen. The Virginia Flowerfly is one pollen- gathering bee mimic that is very common in Connecticut.

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Stink bug nymphs hiding in grape leaf shelter

 

Many types of insects use leaf shelters as a means of hiding from predators by day. Besides caterpillars such as the Spicebush Swallowtail, stink bugs routinely use abandoned leaf shelters for themselves. I have especially found them by day huddling in small groups in leaf shelters on grape, which, along with raspberry, is one of the most common plants they feed on in the wild. Some spiders will use the same type of shelters, so be prepared for that surprise when you open any likely hiding places. Queen Anne’s lace is an especially good place to look for caterpillars, insects, assassin or other predatory bugs and spiders late in the year. Or look on goldenrod flowers, both for predators and caterpillars that feed on the flowers.

 

Slapping old molted skins on or using their own frass piled on their body is another way an insect either protect itself or camouflage itself to get clser to potential victims. Tortoise beetle larva use both methods to keep their presence unknown . All that can be seen is a small blob that looks like debris or frass. If disturbed, they may tip the mess up in the air over the body, somewhat like opening the trunk of a car. Then it is lowered again to conceal the soft body once again. Lacewing larva use their molted skins and other detritus to cover their body in a similar way. They can be found especially on white oak leaves this year. Look for a small, light tan, fuzzy pile moving across a leaf. This is probably a lacewing larva.

lacewing larva with molted skins covering it Pamm Cooper photo

lacewing larva with molted skins covering it

camoulflaged looper plus tiny looper Belding

Camouflage looper on daisy

 

Well, that is a brief look at some ways insects survive or attempt to survive in the world. There are many other ways and means insects employ subterfuge and the rest that could probably fill a book, but this is simply a leaf through…

 

Pamm Cooper