Defoliation down in PA

Gypsy moth populations in the region are being crushed by a surge of deadly fungus.

For the second year in a row, a fungus has come to the rescue of forests around Pennsylvania. This deadly fungus attacks a major threat to trees: the gypsy moth. (Photo: U.S. Agricultural Research Service)

Listen: [audio:090821kgmoth.mp3]

Gypsy moths have caused just a third of the defoliation they wrought last year. Forest managers say a number of factors conspired to wallop caterpillar populations. Jerry Feaser is the spokesman for the Pennsylvania game commission.

Feaser: Heading into the past spring it appeared that Pennsylvania’s oaks might face a devastating hit by gypsy moth caterpillars. Fortunately for us it was the gypsy moths that took a hit. And in fact it was a triple hit.

In addition to the fungus, a virus and insecticide spraying teamed up to reduce moth numbers. The state sprayed nearly two hundred thousand acres with insecticide. Don Eggan is the head of forest pest management for the Pennsylvania Department of Conservation and Natural Resources. He says the cool, rainy summer favored the deadly fungus.

Eggan: We started to notice it in 2008. And this year it was really prevalent. A lot of populations literally stopped in their tracks. We had 220,000 acres defoliated this year. It sounds like a lot, but half of that was light to moderate. And the reason why it was light to moderate, because the caterpillars literally died and they stopped feeding.

Gypsy moth populations are cyclical, and Eggan is confident they are now in a down-swing. Pennsylvania has been experiencing moth outbreaks for the past four years. Budgets for state spraying programs may be cut significantly, but Eggan says since moth populations are in a down-swing, it’s pretty good timing. Eggan says forest tent caterpillars are now a bigger problem — having eaten the leaves off more than 300,000 acres of trees this year.