In the summer of 2009, about 320,000 acres of forest tent and eastern tent caterpillar defoliation was visible from the air in McKean and Potter Counties. Eastern tent primarily defoliated cherry trees while the forest tent caterpillar fed on sugar maple and other hardwood species. Red maple was the exception. Andy Sidelinger of the DCNR/Bureau of Forestry District 15 office in Coudersport completed defoliation flights in early July 2009 defoliation was outlined topographic screen. Bureau of Forestry offices in Wellsboro and Emporium also reported defoliation in Tioga and Cameron counties. The concentration of the defoliation, however, in is McKean and Potter counties. Although diseases of the caterpillar stage and parasitism of the caterpillar pupae by friendly fly larvae took a heavy toll, there was still a tremendous moth emergence. Being nocturnal and attracted by bright lights, these moths converged on towns and brightly lighted rural buildings. Based on the number of emerged moths and the egg masses laid, the prognosis for 2010 is more of the same. The infestation may spread into new areas, collapse in some areas, and repeat in others. It is inevitable that diseases will bring this outbreak to a close, but when is the question. Normally, the forest tent caterpillar outbreaks run their course in 3 to 5 years. The trees have leafed out and barring a drought, little mortality should occur overall. Dieback in some tree crowns has been the history of these insect attacks. As previously mentioned, a native fly, Scarcophage aldrichi, or friendly fly, is an extremely important parasite of the pupae of the eastern tent and forest tent caterpillars. The flies reached a nuisance level this year even in areas where there was no defoliation. No State or Federal agency has released these flies.