Gypsy Moths

From the Shawano Leader.

Looks like more spraying and more grants from the WDNR.

"Gypsy moth population sees growth during 2008 in Wisconsin, and locally
By Nathan Falk, Leader Reporter and Associated Press

A 32 percent increase in the number of gypsy moths trapped in Wisconsin this year may mean more aerial spraying next year, the state says.

More than 385,500 male gypsy moths were caught in 2008, surpassing last year’s total of about 293,000, the state Department of Agriculture, Trade and Consumer Protection reported last month.

But a tough winter might cut into the pesky creature’s numbers this year, said Allan Waelchli, consulting forester for the city of Shawano.

“At this point, we’re not anticipating a major explosion, but more than likely a buildup, unless we have a real severe winter — which we have a good start at,” Waelchli said.

About 30,000 traps were set in 52 counties this summer as part of the agency’s efforts to slow the moth’s spread. The invasive pest eats many species of trees and shrubs, especially oaks, and can cause defoliation when feeding in large numbers. It has spread westward since its introduction in 1869.

“Usually in cycles of about 4 to 5 years, the population builds up — then collapses,” said Waelchli. “I’m expecting where we had isolated pockets this last summer, those will be expanding.”

Trapping data help determine potential sites for egg mass surveys and aerial spraying. Nearly 80,000 acres in 13 counties were sprayed earlier this year. Treatment sites for 2009 are yet to be determined.

The state doesn’t know the reason for the increase, but one possibility may be the natural cycle of gypsy moth populations, said Chris Whitney, gypsy moth trapping coordinator.

“We saw similar results in 2003 when we had large increases of moth populations, but in the following three years, we had declining populations,” Whitney said. “In 2007, the populations started to increase again, and we are hoping that the cycle is reaching its peak this year and will start to decline in 2009.”

Other possible explanations for the increase include favorable weather conditions, better trapping lures, the natural progression of the moths’ movement westward and larval drift.

Waelchli said some areas in the city of Shawano may show less growth than has been seen previously.

“I’ve been checking oak areas in the city, where there’s the most potential for a population explosion. The egg masses are there, but nowhere near the amount as what we had about 7 years ago when we got hit pretty hard with gypsy moths,” he said. “We did some treatment of egg masses, but it’s not half as dense of an egg mass population as what it was.”

Waelchli said the moths will defoliate just about any tree species, but he’s not expecting major problems in the area.

“The populations are up from two years ago, but still we’re not going to see a major defoliation problem,” he said. “The egg masses are already laid. At this point the population can only go down based on the severity of winter weather.”

From now until spring, people can help decrease the number of next year’s caterpillars by treating or removing egg masses. A gypsy moth egg mass is tan, oval or tear-shaped and a little bigger than a quarter. It is flat and has a velvety texture.

Egg masses can be found on trees, vehicles, fences, playground equipment, buildings and outdoor items. An egg mass can hold 500 to 1,000 eggs.

Egg masses can be scraped off with a putty knife, stiff brush or similar hand tool and dropped into a container of warm, soapy water. Let them soak for a couple of days and discard them in the trash. Horticultural oil also can be sprayed on egg masses. Crushing the egg masses will not destroy the eggs." Shawano Leader