. 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. Figure 8. The Fettes Method of calculating the percentage of foliage removed to determine which stands require protection. F-705646. Figure 9. Brown areas show defolia- tion by spruce budworm along the west branch of the Penobscot River in Maine. Photo courtesy of Maine Bureau of Forestry used against other insects, such as the gypsy moth. In addition to the bacterium, four viruses are kno
. 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. Figure 8. The Fettes Method of calculating the percentage of foliage removed to determine which stands require protection. F-705646. Figure 9. Brown areas show defolia- tion by spruce budworm along the west branch of the Penobscot River in Maine. Photo courtesy of Maine Bureau of Forestry used against other insects, such as the gypsy moth. In addition to the bacterium, four viruses are known to kill only the budworm larvae. These viruses, however, are all very costly to produce and need to be applied at high dosage rates in order to be effective. Outlook The spruce budworm kills trees—often very quickly—thus jeopardizing long-range wood sup- plies (Dimond 1984) (figs. 8 and 9). The budworm can be a critical problem in States, like Maine, that rely heavily on wood and wood products: wood and wood products make up one-fourth of Maine's current exports. In New England, defoliation is expected to continue over about 4 million acres ( million ha) per year. In Maine, much of the defoliated area will remain un- affected, despite annual suppres- sion projects on approximately 1 million acres (405,000 ha). The vast spruce-fir type in the Cana- dian Provinces to the east, west, and north of Maine is heavily in- fested. Moth flights from Canada will have a direct effect on defoliation in Maine. Future efforts will continue to emphasize the identification of high-value stands and the protec- tion of only those high-value stands that are known to be threatened by the budworm. Research will center on refining both chemical and biological in- secticides so that they have the greatest impact on the budworm and the least impact on nontarget organisms and the environment. Landowners who have begun to plant budworm-resistant trees will expand their efforts substantially. In
Size: 2195px × 1139px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
