Those nasty tents of caterpillars that you see up in the trees in early summer have already begun to appear. The above average temperatures we have been experiencing has caused our local population of Eastern Tent Caterpillars to hatch from their egg masses during the last couple of days.
The egg were laid last fall by the adult tent caterpillar moth.
It is very easy to get rid of the caterpillars right now because they are only about one-eight of an inch long and very susceptible to sprays or even just squashing by hand. Look for the masses near the ends of the twigs of apple, cherry, plum and other related trees. The egg masses are a little difficult to spot, but once you have see one, it’s a lot easier to recognize them. Many times you can simply snip off the twig containing the egg mass and discard it.
This egg mass is already covered with a fine tent web spun by the caterpillars. The dark specks are frass (droppings) from the caterpillars.
The egg masses look like a blob of foam that has dried out and hardened. The caterpillars spend the winter in these eggs then hatch out the same time the trees begin to leaf out in the spring. These very tender newly “sprouting” leaves are like baby food to the newly hatched infant caterpillars.
The tiny caterpillars are clearly visible in this photo.
Sometimes, if a severe rainstorm occurs during this stage, many of the caterpillars will be washed away. Perfect timing of a storm doesn’t happen very often so I wouldn’t count on that to control your problem.
The “tent worms” will feed voraciously and devour a lot of leaves but generally won’t kill a tree or cause any lasting damage.
Bob
Hi Bob Im glad im not the only one seeing these pests. Will a hard frost help controll these or should I go right into pestiside controll. We do have storms in the forcast and Im hoping that they will rein havic on these caterpillers. thanks -andy-
Comment by Andy Bott — April 5, 2010 @ 6:08 pm
Hi Andy, The caterpillars on our trees are already nearly twice as big as when I first saw them. Their webs are well formed so I think it may be too late for rains to do much to them. Sprays however will be very effective against them right now.
Good luck. Bob
Comment by Bob — April 5, 2010 @ 8:08 pm
Hi, I was horrified today when I had my first experience with tent caterpillars on my Yoshino Cherry! There must have been about 50 of them in the “tent” and a couple on the trunk. I sprayed them with the only insecticide I had at the time and they did die eventually however they were not small, they were approx 2-3 inches long! There were tiny black things in the tent and then I was surprised to find another web or tent-stuck to the trunk of the tree that had hundreds of those black things as well. I’m trying to find out what the black things are as they don’t look like the foamy or glassy egg casings described. I did spray the tree with an insecticide for tent caterpillars and purchased a systemic protect and feed product I will use as well. Any advice or info on those black things would be most appreciated. Thank you
Comment by Dana — April 11, 2010 @ 11:18 pm
Hi Dana, When the weather is warm the tent caterpillars can grow very quickly, as you discovered. The black things you see in the tents are caterpillar droppings (excrement) also known as frass. I glad to hear you were able to take care of the situation. Bob
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