News article for April 8, 2019:

Over the weekend I opened my back door to see a new gray spot on the side of a gum tree. That spots was, as I suspected, a large mass of forest tent caterpillars.

My friends who are serious fisherman, tell me that when you see the caterpillars up in the trees it is time to head to the river to catch blue gill. As the caterpillars fall out of the tupelo gum trees the bream are under the tree ready for an easy meal. Rather than turning on their fish finders, the fisherman look up in the trees for caterpillars to help locate fish.

I am not sure how prevalent caterpillars will be this year, some years are worse than others. Your first clue is usually large gray masses on the side of oak, gum and maple trees.

Forest tent caterpillars are easy to recognize because of their colorful pattern. They have a brownish body with keyhole shaped white or yellow spots on a bluish back. This caterpillar is mature at 1½ to 2 inches long.

The caterpillars that are emerging and feeding on foliage now are a product of eggs that were laid up in the tops of trees last spring. These caterpillars that are present now will mature in 5 to 6 weeks and then will spin a cocoon in rolled up leaves and in the cracks of tree bark. Then a moth will emerge in about 10 days and fly around and lay eggs back in the top of the trees.

Egg masses are laid in groups of 100 -350 eggs which encircle branches or twigs. The eggs are cemented together with a glue like substance that hardens and turns a glossy dark brown. Caterpillars will emerge from the eggs next spring to complete the life cycle.

Fortunately forest tent caterpillars have no spines and do not cause harm except to defoliate plant material.

The buck moth caterpillar usually emerge about the same time, and he is a different story. He is also known as the stinging caterpillar and rightfully so. Buck moth caterpillars are black and covered in spines. If you are so unfortunate as to touch him you will be very aware of his presence. I personally see problems with mowing the grass under low lying limbs where they feed, going to get the newspaper early in the morning without shoes and for children unaware of their danger.

Buck moth caterpillars also emerge from the top of the hardwood trees, except those eggs were laid in the fall. The buck moths are usually out flying about the second week of December which coincides with deer season, and is how they get the name, Buck Moths.

To prevent either of the caterpillars is practically impossible. To control caterpillars is equally difficult because they emerge from high in mature trees. The ones that we encounter are not crawling to get up in the trees, those are the ones that fell out of the tree and then will begin eating other foliage.

You can spray horticultural plants that are being eaten with an insecticide to protect them. Sevin would give contact control for a few days whereas Orthene is systemic and would give up to 2 weeks of control. If you spray either insecticide directly on the caterpillars they will die but not instantly. Where pesticides are not wanted, Dipel or other Bt products (Bacillus thuringiensis) will give you control, but the mode of action is slower.

Putting aluminum foil around the tree and coating it with petroleum jelly may make you feel better but it will not prevent caterpillar from going up the tree, they are already there.

Take this as a sign that is time to go fishing!

For more information on these or related topics contact Kenny at 225-686-3020 or visit our website at www.lsuagcenter.com/livingston.