Caterpillars

March 2012

I saw this in the forest this morning: It has a bunch of caterpillars in it (you can see one near the top of the second picture). Should I be worried about this?

The culprit is the Eastern tent caterpillar. They are earlier than normal this year, as is everything else. They usually begin their feeding as the trees begin to grow in the spring, and build these webs or tents to protect them from predators and insecticides. These insects leave their web to feed, but if you can reach the webs on a cloudy day or in the evening when they return to it, you can pull out the web and destroy it. These hit early in the year, while the fall webworms appear later in the season and typically have multiple generations. Luckily for us, the eastern tent caterpillar doesn’t last a long time, but it can defoliate young trees before it leaves.

April 2010

I have a river birch in my backyard I planted 6-7 years ago. It is doing really well! Last summer in July we went on a one week holiday and upon returning every leaf on the tree was gone! Small green caterpillar with brown spots had attacked. I have never seen anything like that before or since. The tree is probably 16 feet tall so I don't know how I would spray it. Any thoughts on how I might control this infestation occurring again?

Let’s hope it was a one season problem. Monitor the tree this season and if you spot a problem, take a sample to your county extension office for diagnosis. There are numerous insecticides that kill caterpillars, but they are typically applied as needed, not as a preventative spray.

July 2007

We live in Conway, near Beaverfork Lake. For 2 weeks we have noticed that our oak trees are infested with green caterpillars; some have brown stripes on them. The infestation is so great that entire trees are nearly denuded of leaves. It sounds like rain is falling and their waste is leaving brown stains on any hard surface. What are these caterpillars, and how long should we expect them to stay? Is there a chance that the trees will be damaged?

You are not alone with this problem. We have had reports from all over the state about these caterpillars. Several have said their trees were raining poop! The culprit is the variable oakleaf caterpillar. They feed on a variety of deciduous trees, but tend to favor oaks, with the white oak preferred. In Arkansas we can have two generations of the insects, but with such a heavy first population, the chances of a second large population in August are slim. Their feeding cycle should be over now or coming to a close very soon, and they should pupate, typically on the ground. The larval or caterpillar stage produces a 1 ½ inch long caterpillar with the overall body color varying from green to yellow and red. The adult is a gray moth with a wing span no greater than 1 3/4 inches. While their feeding looks quite impressive, there should be no permanent damage from it. One theory about why the outbreak has been so significant this year is that many trees were damaged by the hard freeze in April and had more tender foliage on them. Whatever the cause, lets hope we don't have a repeat anytime soon. Sprays should not be necessary.

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