Month: May 2020

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For the last two episodes we have been fascinated by the Asian giant hornet and what it’s potential introduction and establishment in North America might mean to bee keepers and average citizens. This week we bring it home to the front flower bed to learn about a member of the brachonid wasp clan, a tiny American wasp called Aphidius. Each spring I am treated to hordes of prolific aphids colonizing my bee-balm and other perennials. Their tiny beaks probe meristematic buds, sucking sap and curling and twisting expanding leaves. These rascals excrete gobs of sticky honeydew on leaves and branches below; altogether they are quite disagreeable. Rather than panic and pull out an insecticide, I wait a few days or a week, and usually papery brown aphids will appear amongst the other plump, juicy members of the aphid colony. These papery brown aphids go by the colorful name of “aphid mummies”. Aphid mummies are the exoskeletons of once living aphids, aphids that have had their internal organs consumed by an Aphidius wasp larva which developed within.

As aphids feed on plants, plants release volatile chemicals that can attract Aphidius wasps to an individual plant under attack. In addition to plant attractants, the very honeydew excreted by aphids may also serve as attractants to their lethal Aphidius enemy. Once a colony of aphids is located, the tiny female wasp begins her attack. By curling a marvelously jointed abdomen beneath her body and between her legs, the stinger at the tip of the abdomen faces forward just like the lance of a charging medieval knight on horseback. She deftly jabs with her stinger, a.k.a. ovipositor in entomological jargon, until she finds just the right spot to pierce the exoskeleton and deposit an egg inside the hapless aphid. Upon hatching from the egg, the wasp larva begins to consume tissues within the aphid, but its choice of meals is selective. It does not consume the vital organs immediately and does not kill its aphid host outright. It nibbles around the edges so to speak, allowing the aphid to survive and feed while the wasp larva develops within. And you thought James Cameron was the first to come up with that idea for Aliens.

Cool wet weather has spawned an outbreak of aphids on my perennial plants. Among the plump juicy aphids are brown, papery aphid mummies, the product of attacks by parasitic Aphidius wasps. These tiny braconid wasps play an important role in reducing aphid populations on many woody and herbaceous landscape plants. Watch as a wasp tangles with a hapless aphid. The aphid does its best to kick and push the female wasp away. Her articulated and highly mobile abdomen curls beneath her body, providing a frontal assault on the aphid. At the tip of her abdomen is an ovipositor and as she stings the aphid her eggs are inserted into the aphid’s body.

Parasitic (a.k.a. parasitoid) wasps developing within their host are called endoparasites and those that develop while their host continues to feed and move about are called koinobionts. Other species of parasitic wasps, including the steel blue cricket hunter, potter wasp, and cicada killer we met in previous episodes, first paralyze their host, arresting its development before depositing an egg. These undead but paralyzed victims soon become food for the wasp larva. Bad way to go. Wasps with this modus operando are known as idiobionts. As they develop, some species of Aphidius exert a zombie-like mind control over their aphid host, causing it to wander away from the rest of the aphid colony. By creating distance from the rest of the herd, these parasitized zombie aphids may be less likely to be consumed by predators that would also kill the wasp larva developing within. As if this was not enough abuse, the parasitized aphid has one final chapter in its doomed existence. As the larval wasp nears the end of its development, it finally consumes the vital internal organs and tissues of the aphid, leaving behind only the papery exoskeleton and thereby creating a mummy. Within the mummy, the larva pupates and with time a tiny adult wasp emerges from the pupa, still within the aphid’s exoskeleton. Ready for what’s up when aphids have a hole in their rear end? To free itself from the mummy, Aphidius uses sharp jaws to chew a near perfectly round hole in the aphid’s abdomen as an escape hatch. Once out, it’s off to find some food, maybe a mate, and hunt more unfortunate aphids.

 Aphidius wasps are not only important agents of biological control in my garden, but they also wage war on aphid pests found in many agricultural crops around the world. Some species can be purchased commercially and are released in greenhouses and conservatories to reduce aphid populations as an alternative to insecticides. While the larvae require aphid hosts in which to develop, adult wasps use floral resources like nectar as a carbohydrate source. So, be sure to have a season long diversity of flowering plants in your landscape to help sustain these tiny warriors and if you spot a papery brown aphid with a hole its rear end, you will have found your mummy.

Acknowledgements

Bug of the Week thanks Dr. Shrewsbury for providing inspiration for this episode. The fascinating articles “Host behaviour modification by the endoparasitoid Aphidius nigripes: A strategy to reduce hyperparasitism” by Jacques Brodeur and Jeremy McNeil,  “Identification of Semiochemicals Released During Aphid Feeding That Attract Parasitoid Aphidius ervi” by Yongjun Du, Guy M. Poppy, Wilf Powell, John A. Pickett, and Lester J. Wadhams, and “Ecological Interactions Affecting the Efficacy of Aphidius colemani in Greenhouse Crops” by Sara G. Prado, Sarah E. Jandricic, and Steven D. Frank, were used in preparation of this episode.

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Due to a seemingly unrelenting interest in recently discovered “murder hornets” in the Pacific Northwest, we are revisiting the story posted last week at Bug of the Week. First, I wanted to thank all visitors to Bug of the Week and folks that listened to, watched, or read about Asian giant hornets and sent images or descriptions of large wasps they encountered. Many of the accounts detailed the discovery of a hornet in a fireplace or basement. The good news: to date, all images and reports have been European hornets, not the dreaded “murder hornets.” So, thanks everyone for being on the lookout. Check out the image with this story and you should be able to distinguish between Asian giant hornets and European hornets. Please click on this link to see how European hornets roll.

For those of you who missed last week’s episode, here is the story as presented a week ago with minor modification. A couple of weeks ago, the New York Times set off a firestorm of interest in a fierce predatory hornet that was recently discovered in the Pacific Northwest. By the way, hornets are a type of social wasps that live in colonies with a caste system of queens, workers, and drones. In September of 2019, in the town of Nanaimo on Vancouver Island, a colony of Asian giant hornets (AGH) was discovered and destroyed. Three months later in Blaine Washington, the first confirmed detection of AGH in the United states was made. Several more potential sightings and suspected attacks on honeybee colonies were reported in Washington State during the latter part of 2019. How AGH arrived in North America from infested nations in Asia including Japan, China, Taiwan, Laos, Thailand, Cambodia, Myanmar, Vietnam, Nepal, India and Sri Lanka, remains a mystery. However, as with recent introductions of other invaders such as spotted lanternfly, brown marmorated stink bug, and emerald ash borer we met in previous episodes, it is probably a safe bet that they sailed across the seas as stowaways in a shipment of goods headed for a port on the Pacific coast. One disquieting aspect of these recent discoveries is evidence suggesting that hornets found in Canada were genetically distinct from those discovered in the US. This opens the door to the possibility that at least two independent introductions have occurred. Not surprising, but not good news.

Let’s take a quick look at four species of stingers that might be confused with the Asian giant hornet. The Asian giant hornet is large with queens about two inches long. A large yellow head at the front leads a yellow abdomen encircled with several dark bands with even margins. Queens of the next largest hornet, the European hornet, measure just shy of an inch and a half. Heads are chestnut or amber and the abdomen has a few dark bands with strange dots at the posterior margin. The Baldfaced hornet is a native with striking colors of white bands and markings on a black background. Queens are about three quarters of an inch long. Several species of native and introduced yellowjackets sport bold alternating bands of black on yellow. They range in size from about half to three quarters of an inch. The last wasp in this gallery is our native Cicada killer. Commonly seen in summer, these hunters of annual cicadas have a shiny black abdomen with yellow or creamy patches partially encircling the sides. They are quite large at an inch and a half or more. Image of Asian giant hornet by Allan Smith-Pardo of USDA APHIS PPQ and Bugwood.org; other images and video by Michael J. Raupp.

People have asked why they should be concerned about this invader. Two good reasons exist. First, even though these are not “generally aggressive” towards humans, like other social insects including paper wasps, yellowjackets, and honeybees, they will forcefully defend their colony if the colony is threatened. And their sting really packs a wallop. Descriptions of pain associated with the sting liken it to being stabbed with a hot nail, not something I have experienced but it sure sounds painful. The toxicity of AGH’s venom is actually somewhat less than that of the honeybee, however, due to their very large size, among the largest of all hornets on the planet, the volume of venom delivered per sting is quite large. Many deaths associated with stings from hornets, bees, and wasps result from severe allergic reactions called anaphylaxis. However, reports of human deaths from China and Japan have been linked to the toxic properties of the venom itself when people received multiple stings by many AGHs. The venom of AGH is a witches brew of chemicals, including cytolytic toxins that destroy cell membranes, and neurotoxins that attack the nervous system. One account from China claimed that 41 people had been killed by AGH stings with another 1,600 needing medical attention. To put this into perspective a bit, here in the US the CDC reports on average 62 deaths each year due to stings from hornets, wasps, and bees. And for the major gender demographic of Bug of the Week, the men, about 80% of these deaths are males. Figure that one out.

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The second, and perhaps more important reason for concern, is the potential effect AGH can have on the already beleaguered honeybee industry and non-commercial beekeepers. Already imperiled by invasive mites and diseases, climate change, and pesticides, honeybees now face a new enemy. AGH has been described as a specialist on social bees including our domestic European honeybee, Apis mellifera. In the typical seasonal progression of business in a colony of AGH, many different types of insects and other arthropods are captured by foraging workers, dismembered, and chewed into balls of flesh. These meat balls are taken back to the colony as food for the queen and developing hornet larvae. In a remarkable treatise on the biology of AGH, Matsuura and his colleague Sakagami described a unique and diabolical attack levied on honeybee colonies that begins in late summer and early autumn. Phase 1 of the attack, called the hunting phase, occurs when individual hornets lurk near a hive, capture and kill singular honeybees, macerate them into a ball, and take them back to their colony to feed the brood. Phase 2, graphically named the slaughter phase, happens when several hornets focus their attention on one beehive. As guard honeybees mount a counterattack to the pillaging hornets, the attackers grapple with the defenders, decapitate them with powerful jaws, and discard their victims in front of the hive. The slaughtered bees are not taken back to the hornets’ nest as a source of food. They are simply discarded on the ground. The slaughter phase can last several hours and decimate a hive. One report of an attack by 30 hornets resulted in the death of 25,000 honeybees. Phase 3 of the attack is called the occupation phase. After the slaughter is complete, with most honeybee defenders dead and most other workers and foragers having abandoned the hive, the killing of adult honeybees ceases. Attention turns to bee brood (immatures) developing in their cells. Asian giant hornets post guards at the entrance of the beehive ready to attack humans or other hornets not part of the same clan that approach the hive. Inside the hive, bee larvae and pupae are pulled from their chambers and transported back to the hornets’ nest to feed developing hornet larvae. This nightmare for honeybees leaves little wonder for why these marauders are called murder hornets.

Should the discovery of AGH on the west coast send shockwaves across our nation? Not at this point in time. The infestation on the west coast at the time of this writing consists of one colony in British Columbia that was completely destroyed last year. While the discovery of hornets and suspected colony raids on beehives nearby portend other colonies of hornets, this season awaits the discovery and confirmation of more established colonies. The critical issues now are to survey, detect, and delimit the extent of this introduction and to act swiftly to eradicate colonies of AGH before this invader becomes well established and spreads. This effort is already underway by agencies and scientists in the United States and Canada. Citizen scientists are being enlisted to help find the hornet and report its location to officials. Past history has proven that very few invaders that arrive on our shores actually become established and achieve significant pest status. Even if AGH were to establish in the Pacific Northwest, it would likely take years, if not decades, to become broadly distributed across our nation. However, as we have seen with other pests, like emerald ash borer and brown marmorated stink bug, spread of an invasive species can be greatly accelerated by inadvertent human assistance, including interstate transport of materials that may harbor hornets or arrival of new impregnated queens from Asia that can found colonies near ports of entry into our country.   

What should the general public and beekeepers do at this time? Learn to identify AGH and distinguish it from other hornets and wasps. Washington State University and USDA have excellent resources to learn about the biology and management of Asian giant hornet (see the links below). This week’s YouTube video and images should help with identification.

Please keep your eyes open and if you believe you have discovered AGH, snap a photo with your cell phone and send it to your state department of agriculture or local university extension service. Beekeepers, now is the time to learn about this new threat to your colonies and to learn what steps can be taken should it arrive in your area. So, is it time to panic? Nah, not here in the DMV for sure; for most of us it is time to become informed about this invader. For beekeepers throughout our country, particularly those in the northwestern United Sates, it is time to be vigilant and learn about the biology and management of this pest.  

Links to other websites with great information and video of Asian giant hornets include the following:

USDA New Pest Response Guidelines: Vespa mandarinia, Asian giant hornet

WSU scientists enlist citizens in hunt for giant, bee-killing hornet

SIZING UP THE ASIAN GIANT HORNET

Acknowledgements

We thank Kathryn Fink and Celeste Headlee for providing the inspiration for this episode. We also thank Allan Smith-Pardo of USDA APHIS PPQ and Bugwood.org for the amazing images of Asian giant hornet. “A Bionomic Sketch of the Giant Hornet, Vespa mandarinia, a Serious Pest for Japanese Apiculture” by Makoto Matsuura and Shoichi F. Sakagami, “Purification and properties of a presynaptically acting neurotoxin, mandaratoxin, from hornet (Vespa mandarinia)” by Takashi Abe , N. Kawai, and A. Niwa, “Cardioactive effects of hornet venom, Vespa mandarinia” by T. Abe, and “Giant hornet (Vespa mandarinia) venomous phospholipases” by Takashi Abe, Masato Sugita, Tsuyoshi Fujikura, Jiro Hiyoshi, and Michinori Akasu, provided valuable insights for this week’s episode.

This post appeared first on Bug of the Week

This article appeared first on Catseye Pest

This article appeared first on Catseye Pest

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Last week an article in the New York Times set off a firestorm of interest in a fierce predatory hornet that was recently discovered in the Pacific Northwest. By the way, hornets are a type of social wasps that live in colonies with a caste system of queens, workers, and drones. In September of 2019, in the town of Nanaimo on Vancouver Island, a colony of Asian giant hornets (AGH) was discovered and destroyed. Three months later in Blaine, Washington, the first confirmed detection of AGH in the United states was made. Several more potential sightings and suspected attacks on honey bee colonies were reported in Washington State during the latter part of 2019. How AGH arrived in North America from infested nations in Asia including Japan, China, Taiwan, Laos, Thailand, Cambodia, Myanmar, Vietnam, Nepal, India and Sri Lanka, remains a mystery. However, as with recent introductions of other invaders such as spotted lanternfly, brown marmorated stink bug, and emerald ash borer we met in previous episodes, it is probably a safe bet that they sailed across the seas as stowaways in a shipment of goods headed for a port on the Pacific coast. One disquieting aspect of these recent discoveries is evidence suggesting that hornets found in Canada were genetically distinct from those discovered in the US. This opens the door to the possibility that at least two independent introductions have occurred. Not surprising, but not good news.

Let’s take a quick look at four other species of stingers that might be confused with the Asian giant hornet. The Asian giant hornet is large with queens about two inches long. A large yellow head at the front leads a yellow abdomen encircled with several dark bands with even margins. Queens of the next largest hornet, the European hornet, measure just shy of an inch and a half. Heads are chestnut or amber and the abdomen has a few dark bands with strange dots at the posterior margin. The Baldfaced hornet is a native with striking colors of white bands and markings on a black background. Queens are about three quarters of an inch long. Several species of native and introduced yellowjackets sport bold alternating bands of black on yellow. They range in size from about half to three quarters of an inch. The last wasp in this gallery is our native Cicada killer. Commonly seen in summer, these hunters of annual cicadas have a shiny black abdomen with yellow or creamy patches partially encircling the sides. They are quite large at an inch and a half or more.  Image of Asian giant hornet by Allan Smith-Pardo of USDA APHIS PPQ and Bugwood.org; other images and video by Michael J. Raupp.

People have asked why they should be concerned about this invader. Two good reasons exist. First, even though these are not “generally aggressive” towards humans, like other social insects including paper wasps, yellowjackets, and honey bees, they will forcefully defend their colony if the colony is threatened. And their sting really packs a wallop. Descriptions of pain associated with the sting liken it to being stabbed with a hot nail, not something I have experienced but it sure sounds painful. The toxicity of AGH’s venom is actually somewhat less than that of the honey bee, however, due to their very large size, among the largest of all hornets on the planet, the volume of venom delivered per sting is quite large. Many deaths associated with stings from hornets, bees, and wasps result from severe allergic reactions called anaphylaxis. However, reports of human deaths from China and Japan have been linked to the toxic properties of the venom itself when people received multiple stings by many AGHs. The venom of AGH is a witches brew of chemicals, including cytolytic toxins that destroy cell membranes, and neurotoxins that attack the nervous system. One account from China claimed that 41 people had been killed by AGH stings with another 1,600 needing medical attention. To put this into perspective a bit, here in the US the CDC reports on average 62 deaths each year due to stings from hornets, wasps, and bees. And for the major gender demographic of Bug of the Week, the men, about 80% of these deaths are males. Figure that one out.

The second, and perhaps more important reason for concern, is the potential effect AGH can have on the already beleaguered honey bee industry and non-commercial beekeepers. Already imperiled by invasive mites and diseases, climate change, and pesticides, honey bees now face a new enemy. AGH has been described as a specialist predator on social bees including our domestic European honey bee, Apis mellifera. In the typical seasonal progression of business in a colony of AGH, many different types of insects and other arthropods are captured by foraging workers, dismembered, and chewed into balls of flesh. These meat balls are taken back to the colony as food for the queen and developing hornet larvae. In a remarkable treatise on the biology of AGH, Matsuura and his colleague Sakagami described a unique and diabolical attack levied on honey bee colonies that begins in late summer and early autumn. Phase 1 of the attack, called the hunting phase, occurs when individual hornets lurk near a hive, capture and kill singular honey bees, macerate them into a ball, and take them back to their colony to feed the brood. Phase 2, graphically named the slaughter phase, happens when several hornets focus their attention on one beehive. As guard honey bees mount a counterattack to the pillaging hornets, the attackers grapple with the defenders, decapitate them with powerful jaws, and discard their victims in front of the hive. The slaughtered bees are not taken back to the hornet’s nest as a source of food. They are simply discarded on the ground. The slaughter phase can last several hours and decimate a hive. One report of an attack by 30 hornets resulted in the death of 25,000 honey bees. Phase 3 of the attack is called the occupation phase. After the slaughter is complete, with most honey bee defenders dead and most other workers and foragers having abandoned the hive, the killing of adult honey bees ceases. Attention turns to bee brood (immatures) developing in their cells. Asian giant hornets post guards at the entrance of the beehive ready to attack humans or other hornets not part of the same clan that approach the hive. Inside the hive, bee larvae and pupae are pulled from their chambers and transported back to the hornets’ nest to feed developing hornet larvae. This nightmare for honey bees leaves little wonder for why these marauders are called murder hornets.

Should the discovery of AGH on the west coast send shockwaves across our nation? Not at this point in time. The infestation on the west coast at the time of this writing consists of one colony in British Columbia that was completely destroyed last year. While the discovery of hornets and suspected colony raids on beehives nearby portend other colonies of hornets, this season awaits the discovery and confirmation of more established colonies. The critical issues now are to survey, detect, and delimit the extent of this introduction and to act swiftly to eradicate colonies of AGH before this invader becomes well established and spreads. This effort is already underway by agencies and scientists in the United States and Canada. Citizen scientists are being enlisted to help find the hornet and report its location to officials. Past history has proven that very few invaders that arrive on our shores actually become established and achieve significant pest status. Even if AGH were to establish in the Pacific Northwest, it would likely take years if not decades to become broadly distributed across our nation. However, as we have seen with other pests, like emerald ash borer and brown marmorated stink bug, spread of an invasive species can be greatly accelerated by inadvertent human assistance, including interstate transport of materials that may harbor hornets, or arrival of new impregnated queens from Asia that can establish colonies near ports of entry into our country.   

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What should the general public and beekeepers do at this time? Learn to identify AGH and distinguish it from other hornets and wasps. Washington State University and USDA have excellent resources to learn about the biology and management of Asian giant hornet (see the links below). This week’s YouTube video and images should help with identification.

I have received several inquiries over the last week regarding insects thought to be Asian giant hornet. These have all turned out to be European hornets, which are quite common here in the DMV. Check out the image with this story to become an expert at telling these two rascals apart and click on this link to see how European hornets roll.

Please keep your eyes open and if you believe you have discovered AGH, snap a photo with your cell phone and send it to your state department of agriculture or local university extension service. Beekeepers, now is the time to learn about this new threat to your colonies and to learn what steps can be taken should it arrive in your area.  So, is it time to panic? Nah, not here in the DMV for sure; for most of us it is time to become informed about this invader. For beekeepers throughout our country, particularly those in the northwestern United Sates, it is time to be vigilant and learn about the biology and management of this pest.  

Links to other web sites with great information and video of Asian giant hornets include the following:

USDA New Pest Response Guidelines: Vespa mandarinia, Asian giant hornet 

WSU scientists enlist citizens in hunt for giant, bee-killing hornet 

SIZING UP THE ASIAN GIANT HORNET 

Acknowledgements

We thank Kathryn Fink and Celeste Headlee for providing the inspiration for this episode.  We also thank Allan Smith-Pardo of USDA APHIS PPQ and Bugwood.org for the amazing images of Asian giant hornet. “A Bionomic Sketch of the Giant Hornet, Vespa mandarinia, a Serious Pest for Japanese Apiculture” by Makoto Matsuura and Shoichi F. Sakagami, “Purification and properties of a presynaptically acting neurotoxin, mandaratoxin, from hornet (Vespa mandarinia)” by Takashi Abe , N. Kawai, and A. Niwa, “Cardioactive effects of hornet venom, Vespa mandarinia” by T. Abe, and “Giant hornet (Vespa mandarinia) venomous phospholipases” by Takashi Abe, Masato Sugita, Tsuyoshi Fujikura, Jiro Hiyoshi, and Michinori Akasu, provided valuable insights for this week’s episode.

This post appeared first on Bug of the Week

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After a relative lull in activity by eastern tent caterpillars in recent years, they seem to be back with a vengeance this season. So, this week we take a peek into the biology of these leaf-munching tent-makers. Just to avoid a bit of confusion, recall that last autumn we met a relative of the eastern tent caterpillar called the fall webworm, as it constructed massive tents on the tips of branches on a wide variety of trees. This week’s rascal is a creature of spring with a fondness for trees in the rose family like cherry, apple, and crabapple. Several weeks ago when forsythia’s bright yellow blossoms announced spring’s arrival, tiny caterpillars hatched from dark brown, Styrofoam-like egg masses in which they had survived winter’s chill. These egg masses were deposited last summer by female eastern tent caterpillar adult moths on small branches of favored hosts. A single egg mass can contain more than 300 hundred eggs. After hatching, larvae build small silken tents over the egg mass and the surrounding branch. From this bivouac they move along branches, spinning silken threads as they go to mark trails to the newly expanding leaves of their host tree, where they feed. Trail marking chemicals called pheromones are deposited by caterpillars on the silken trail to guide nest mates to the location of delectable leaf clusters. As larvae grow during March and April, they need more room and their silken tents are expanded. Tents are typically nestled in the crotch of large branches or where large limbs branch from the trunk.

The saga of the tent caterpillar began six weeks ago when more than 100 tiny caterpillars hatched from their egg mass. So began the daily ritual of following the silk trail from their tent to a meal of tender young leaves, followed by a return trip to the safety of their tent. Fast forward to last week when almost fully grown caterpillars devoured cherry leaves and beat a hasty retreat to their tent as a wicked rainstorm arrived.

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Eastern tent caterpillars are rather a chummy lot. Brothers and sisters from the same egg mass often participate in group activities such as communal foraging and enlargement of their remarkable tent. Tents help caterpillars conserve heat and enable the writhing metabolic mass of caterpillars to elevate body temperatures for more rapid growth and development during chilly spring days. Their silken homes may also provide protection from predatory or parasitic insects. These hairy caterpillars have a voracious appetite and can strip even large trees of their leaves when many tents are present. After the caterpillars have completed development, a mass exodus occurs from the tree and the larvae wander the land seeking protected spots beneath logs, leaves, stones, and under man-made structures to spin yellowish or white, silken cocoons. The adult eastern tent caterpillars emerge as moths from their cocoons in June or July, mate and lay eggs back on the small branches of rosaceous trees. These eggs house the next generation of caterpillars that will emerge with the bloom of forsythia next spring.

Managing caterpillars

How do you know if eastern tent caterpillars threaten your trees? The best predictor of a problem next year may be the problem you have this year. The images of this Bug of the Week came from a small stand of wild cherry trees that are perennially infested with eastern tent caterpillars. If you currently have eastern tent caterpillars on your trees and you do not intervene, it’s a pretty safe bet that you will have them again next year. Right now as the caterpillars enlarge their tents and move to the crotches of the tree, tents and their inhabitants can be removed with a gloved hand on a cool day, placed in a bag, and destroyed. The old school remedy of “burning them out”, though dramatic, went out with the storming of Frankenstein’s castle. Flames are very damaging to the bark of a tree and should never be used.  

Problems with tent caterpillars in your trees? No worries. Early in the season before eggs hatch, find egg masses on small branches and either crush the egg mass or prune it out and get rid of it. Do the same for small tents later in the season. And if you are really bold, you can simply grab the tent and the caterpillars inside, pull them from the tree, place them in a bag and dispose of them. Boom, problem solved.  

Tall trees festooned with tents may be totally stripped of leaves. While trees may recover and produce a second flush of leaves, repeated defoliation probably reduces the vigor of trees. If you have a tall tree from which you cannot safely remove eggs or tents, you may want to seek the help of a professional certified arborist. If you can’t get around to managing eastern tent caterpillars this season, sometime between August of this year and March of next carefully inspect the pencil-sized branches of your infested trees for egg masses and tiny silken webs. The egg masses are easily removed with a pinch of the fingers or, if you are a bit squeamish about touching bugs, simply get out your nippers prune them out, bag them and then dispose of them. Entomologists believe that eastern tent caterpillar populations run in cycles. After a few years of caterpillar plague, natural enemies such as predators, parasitoids, and pathogens reduce tent caterpillars to innocuous levels. Who knows, perhaps next year Mother Nature will send a tent caterpillar relief package and give our trees a break from these noisome creatures. 

Acknowledgements

The wonderful book “The Tent Caterpillars” by Terrence Fitzgerald, and “Managing Insects and Mites on Woody Landscape Plants” by John A. Davidson and Michael J. Raupp were used as references for this episode.

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