There are a lot of bare trees in Schuylkill County this summer and state forest officials are trying to figure out why.
While gypsy moth populations are higher than usual this summer, the insect may have had some help devouring the foliage.
"This year, we have lots of defoliation through the county and the whole district," Frank P. Snyder, a state service forester for the Weiser district, said Friday. "It might be a mixture, a complex of native insects plus the gypsy moth. Our mission now is to try and figure out what is doing the defoliation."
Snyder was flying over the forest district last week to map defoliation. He said bare trees are noticeable across the Blue Mountain area and on parts of Second Mountain and Broad Mountain.
"Almost every ridge has some (defoliation)," he said. "As we move north, there is less. Columbia County has a lot. You can see it about halfway through Carbon, then it stops. It's pretty widespread."
Gypsy moths were first seen in Pennsylvania in 1932 and pest management for the insect began in the 1970s. Infestations are controlled by a biological insecticide sprayed from the air on foliage in May. The caterpillars die as they ingest it.
However, Schuylkill County and many other areas have not had to participate in the state suppression program for many years because the insect has been controlled by naturally occurring viruses and parasite.
Snyder said "it's been many years" since Schuylkill County has had to spray for gypsy moths.
"We had some slight episodes of defoliation, but nothing like we had in the late '80s and '90s," he said.
Snyder said he plans to finalize the defoliation maps by the end of August.
"Hopefully by that time, we will be able to come up with an idea of what caused most of it," he said.
Despite higher populations, Snyder said the weather this year has not helped the gypsy moth and other native insects.
"The viruses and fungus have been working this year," he said. "We had a very cool spring and lots of moisture so I can see where that fungus really would have benefited from that weather."
It was also a cold winter, he said.
"We were thinking we would see less insects and less of a problem, then all of a sudden there is this outbreak of native insects."
Snyder said he noticed that a lot of gypsy moths are dying and has not seen a lot of egg nests, but the caterpillars may have been blown in to the area with the high winds this spring.
"Normally, peak foliation would be the first week of July," Snyder said. "Then we should start seeing moths flying around. If we don't see any of these moths, then we can say it was a natural collapse."
Other native caterpillars and worms have also been munching on leaves since May.
"What happened was they actually caused some defoliation, then the gypsy moth reared its head," Donald Eggen, a forest health manager for the Bureau of Forestry Division of Forest Pest Management, said Thursday.
Eggen said Pennsylvania usually experiences a gypsy moth outbreak every five to 10 years. He said there were no acres affected by infestation from 2009 to 2011, but populations started to build back up last year and now there are "hot spots" throughout the state.
It is up to the county to participate in the state suppression program. Eggen said only 42,000 acres in the northwestern part of the state were sprayed for gypsy moths in 2013.
Counties paid $25 per acre last year, while a private application was $50. He said counties typically pay for the costs by charging the landowners of the property being treated.
Eggen said residents wanting to participate in the program in May should contact their county officials.
"In the middle of the outbreak, there's not much you can do," he said. "Egg nests can be laid anywhere - under decks, trees, firewood, rocks, wherever the caterpillars hides. People can scrape off the nests when they see them, but truthfully the only thing you can do is spray."
Until then, Snyder said there is not much people can do for the trees in their backyards.
"The best thing they can do is to monitor what happens with the populations and if they are laying eggs because that's where they will be next year," he said.