. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Gypsy Moth cooperatively evaluating high- altitude infrared photography to obtain information on the location and intensity of gypsy moth defoliation (fig. 8). An advanced version of the U-2 aircraft, the ER-2, flies over the infested areas. The plane is equipped with an op- tical bar camera. From 65,000 feet above sea level, the camera scans an area 37 nautical miles long and nautical
. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Gypsy Moth cooperatively evaluating high- altitude infrared photography to obtain information on the location and intensity of gypsy moth defoliation (fig. 8). An advanced version of the U-2 aircraft, the ER-2, flies over the infested areas. The plane is equipped with an op- tical bar camera. From 65,000 feet above sea level, the camera scans an area 37 nautical miles long and nautical miles wide. Maps made from these photographs have been more accurate than maps plotted with the conven- tional sketchmapping techniques. A number of strategies have been tried to control populations of gypsy moth. These strategies include not only introducing parasites and predators but also encouraging native predators. Numerous birds, mammals, am- phibians, reptiles, and in- vertebrates feed on the various life stages of the gypsy moth and may keep populations at in- nocuous levels. Although these predators have little effect upon the sheer number of gypsy moths during outbreaks, a naturally oc- curring nuclear polyhedrosis virus often collapses populations in parts of an outbreak area. This virus has been produced in the laboratory and developed into a biological insecticide that is still being tested. Table 3 lists the States conducting cooperative suppres- sion from 1979 to 1983 and the acres treated. During these 5 years, the type of aircraft used to apply insecticides changed. In 1979, fixed-wing aircraft were used over 80 percent of the treated acreage; by 1983, helicopters were being used over 77 percent of the treated acreage. Another trend was toward greater use of biological insec- ticides. In 1979, approximately 84 percent of the acreage was treated with chemical insecticides; by Figure 7. Acres defoliated by gypsy moth. Year 1983 1982 1981 1980 1979. Millions â
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