Garden Dilemmas, Delights & Discoveries, Ask Mary Stone, New Jersey Garden blog

Diehard Campers

Mary Stone, Garden Dilemmas, Ask Mary Stone,Gardening tips, Garden Blogs, Stone Associates Landscape Design, Tent caterpillars

Hello fellow readers,

It’s the unofficial start to summer which brings on outdoor activities and vacations including tent camping for diehards. Ben from Bangor asked what to do about the wormy things building tents in the crevices of his cherry tree, of course right above his grill.

Eastern tent caterpillars, or tent worms (Malacosoma americanum), are the larvae of a species of moth known as lappet or snout moths. They’re more of an eyesore than a threat. I think of them as diehard campers with a nifty lifecycle. It’s true though when they fall on your plate at a barbeque they’re rather icky.

Mary Stone, Garden Dilemmas, Ask Mary Stone,Gardening tips, Garden Blogs, Stone Associates Landscape Design, Tent caterpillars

Eastern Tent Caterpillars or Worms / Malacosoma americanum

Tent caterpillars prefer to camp in cherry and other hardwood trees. While they can significantly defoliate, they usually won’t kill trees. They say they can be toxic to horses, mules and donkeys. If need be, you can destroy the nests by dropping them into soapy water or opening them with a stick to expose the critters to the elements (away from your livestock to be safe). Or there are environmentally friendly pesticides such as Neem Oil or Bt (Bacillus thuringiensis) you can use.

Eastern tent caterpillars appear in early spring and rely on the heat of the sun to elevate their body temperatures to allow them to digest food. The tents act as miniature greenhouses that are water-repellent, trap the heat of the morning sun, offer protection from predators, and provide a respite for these social larvae who live in commune with others; until their last larva stage when the caterpillars leave the tent and each constructs a cocoon in a separate protected spot. The adult moths emerge about two weeks later.

The adult moth lays her single batch of 200 to 300 eggs in late spring. Within three weeks, fully formed caterpillars form within the eggs and lie inactive until the following spring when they chew their way out of the eggs, just as the leaves of the host tree develop. They feed three times each day, before dawn, mid-afternoon, and sundown. During each bout of feeding, the caterpillars emerge and add silk to the tent, move to distant feeding sites, eat, and then return to the tent where they rest until it’s the next time to eat. Eat, Rest, Eat. Sounds like a perfect vacation!

Garden dilemmas?


Side Notes:  While small infestations can be taken care of by dropping the nests into soapy water, contact insecticides work best for larger populations. Bacillus thuringiensis (Bt) is the most effective and is a naturally occurring bacterium common in soils. Its a selective insecticide that kills tent caterpillars while remaining safe to other wildlife. Apply the spray directly to foliage and tent worm nests.

It takes a few days but why it works:  Bt produces proteins that reacts with the cells of the gut lining of susceptible insects. These Bt proteins impact the digestive system causing insect to stop feeding within hours. They then die from starvation, which can take several days.

Another option is Neem Oil: Read about it here Finding Neem Oil


Mary Stone, owner of Stone Associates Landscape Design & Consulting. As a Landscape Designer, I am grateful for the joy of helping others beautify their surroundings which often leads to sharing encouragement and life experiences. These relationships inspired my weekly column published in THE PRESS, 'Garden Dilemmas? Ask Mary', began in 2012. I dream of growing the evolving community of readers into an interactive forum to share encouragement and support in Garden and Personal Recoveries - seeking nature’s inspirations, stimulating growth, weeding undesirables, embracing the unexpected. Thank you for visiting! Mary

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