Friday, June 20, 2008

Lymantria dispar, Lymantria dispar, where for art thou or... Where are those gypsy moths?

Many people in Bucks County fearfully awaited the 2008 crop of gypsy moths. In 2006 and 2007 this leaf eating caterpillar caused significant damage in isolated Bucks County locations... Buckingham, Bedminster, Doylestown. Since the infested areas were small, co-ordinated aerial spraying conducted by the Department of Environmental Protection was not in order. Folks with several acres of trees were sweating it out. Their properties are too small to treat by air and too large to treat from the ground.

But the anticipated devastation has not materialized. Why? Score one for Mother Nature. Those cold, wet nights in mid-May helped the natural enemies of gypsy moth do their work. A fungus and a virus that weaken and then kill the caterpillars is at work. Shrunken, oily caterpillars hanging upside down are infected with the fungus. Those that appear kinked in the middle were had by the virus. Penn State's Extension entomologist, Greg Hoover, and I chatted about this yesterday as we marveled at the collapse of this destructive pest. Greg says this is happening in several parts of the state.

So, a bullet dodged. Actually, this is a normal occurrence. When pest populations peak, they are soon prey to natural enemies. Happens all the time. Just in time this year.

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