 |
| GYPSY MOTH TRAP |
 |
| ...YOUNG CATERPILLAR |
 |
| FIRST SIGNS OF DEFOLIATION |
 |
| CHEWING DAMAGE |
Wednesday, 8:30 AM. 67 degrees, wind W, calm. The sky is mostly clear but somewhat hazy. The barometer is down, predicting rain but I think not until possibly late this evening, if at all. It is a most pleasant morning.
Gypsy moths are being monitored in our region this year, small green traps hung here and there along major roadways, like this one on Hwy. 13 south of town. In the spring I had seen a few of the fuzzy, dime sized or larger egg masses clinging to bark and siding but not a significant amount. But yesterday I got a call regarding leaf damage on a young white oak, and upon inspection I found very young Gypsy moth caterpillars on the lover branches. At the size photographed they are not very obvious but they quickly grow into voracious critters two and more inches long. Since they often migrate on the ground a good, easy first control is to tie a piece of burlap around the trunk of oaks, their preferred food, and the caterpillars get stuck under the folds of the burlap and can be destroyed. A sticky commercial compound called Tangle Foot is very effective on larger tree trunks. A heavy infestation of caterpillars can of course be sprayed.
The State of Wisconsin has a control program of arial spraying with BT, a disease organism that attacks moth and butterfly larvae, but I have serious concerns about it because it is not specific to Gypsy moths, but affects many different species of Lepidoptera. The aerial dive bombing is very disconcerting as well. Gypsy moths can be very destructive, but unless they stay in the same area two or three years, which is not usual, they only defoliate trees, and there is always a second growth of leaves and the trees although weakened are not much harmed. The Gypsy moth has been in North America for well over a century and has proven impossible to contain, and most states have given up and simply live with the occasional infestation. The name Gypsy moth refers to the fact that they move around, seldom staying in one place. They are, however a huge nuiciance, and people living in cities which are hard hit usually demand action to control them, regardless of whether it is very effective or environmentally necessary. Gypsy moths are a political, not an environmental, problem.
No comments:
Post a Comment