Tent Caterpillars Bugging You?

WHAT’S BUGGING YOU?  by Eileen Novak

It’s spring… no, it’s winter… no, it feels like summer… no, it’s almost spring… maybe.

Whatever the weather, you must know that the calendar says that spring is on its way.  So let’s learn about another of the pesky things in the garden and what you can and/or should do about them.

Tent Caterpillars.  Eastern tent caterpillars are somewhat hairy and black with gold, white and blue markings. They mostly like to invade wild cherry trees, but they will settle for apples and crabapples too.  They are easy to identify when they leave the tent that they spin for their protection in the crotch of trees. There is a white stripe down the back. The caterpillars grow up to almost 2 inches long.  When they are that long, you will find them crawling everywhere: up the screens and window, in the garage, just everywhere.

When they are on the march like that, the caterpillars are looking for a place to spin a cocoon and morph into a moth that emerges two to four weeks later and looks to mate and lay eggs for the next generation.   Luckily there is only one generation per year of these pests. You most likely would never see an adult moth because Wikipedia says that they are nocturnal. They are ephemeral as well, poor things, because they emerge from the cocoons, fly, mate, lay eggs and then die.   The eggs they lay on the host tree are covered with a substance that hardens and turns brown, and the egg mass stays there until the first of the next spring’s warmth.

Interesting facts about the Tent Caterpillars is that they build layered nests and use the sun’s warmth within the tent like their own private greenhouse.   They leave the nest a few times a day to feed, then huddle back inside the tent to protect themselves from the cold.

I wanted to put in pictures of the adult moth and an egg mass, but the pictures of the adults were not on an NC State webpage, and we don’t recommend using other than NC State pages, because while the Web is World Wide, it’s not always truthful.  You can count on NC State-presented information to be factual, but the others…

So now that we have met them, we need to ask ourselves how to get rid of them.  Think about it: you can see the webs in the trees, and they hide in the webs to protect themselves from predators.  They are among the earliest of caterpillars in the spring, so if you get a stick and pull down the web, leaving it open to the birds, they might solve the problem for you.  Personally, I can’t recommend trying to adopt a crow to teach it to raid tent worm nests. The odds are not really in your favor.

Of course if you pull down the tent and toss it into the street, the cars will take care of smishing the bugs, but the birds won’t be thanking you.  A birding magazine that I was reading one time said that caterpillars are the hot dogs of the avian world – tasty snacks in a convenient, down-the-hatch tube shape.  

There are other ways to get rid of them too, if the tents are too high to reach.  Extension websites such as https://macon.ces.ncsu.edu/2018/04/eastern-tent-caterpillars-3/or https://pitt.ces.ncsu.edu/2013/04/eastern-tent-caterpillar/are full of good recommendations. One thing they have in common is that NONE of them recommend trying to burn the caterpillars out of the tents. Something about insurance.  And they also urge caution if you choose to try to spray chemicals high into trees to control the pests. Something about spitting in the wind???

However you do it, I hope you manage to get rid of them just so they won’t defoliate the trees – although the trees themselves seem to recover, unless they are defoliated several years in a row.  

Happy Bug-hunting!! --Eileen Novak