. Eastern forest insects. Forest insects. larvae eat only the outer, tender parts of needles; older ones con- sume the entire needle and nibble the bark. First generation cocoons are usually spun among the needles, at the bases of small branches, or in bark crevices on the trunk, and pupation occurs in late July. Second generation larvae feed until September and then spin cocoons on the tree or in the duff. Under favorable con- ditions some pupate and emerge in late fall to produce a partial third generation. The remainder do not pupate until the following spring. Because of some overlap betwe
. Eastern forest insects. Forest insects. larvae eat only the outer, tender parts of needles; older ones con- sume the entire needle and nibble the bark. First generation cocoons are usually spun among the needles, at the bases of small branches, or in bark crevices on the trunk, and pupation occurs in late July. Second generation larvae feed until September and then spin cocoons on the tree or in the duff. Under favorable con- ditions some pupate and emerge in late fall to produce a partial third generation. The remainder do not pupate until the following spring. Because of some overlap between the first and second generations, all stages of the sawfly may be found during the summer (778, 520). Heavily infested trees may be completely defoliated in one season. When this happens late in the season after the buds are formed, many branches and occasionally trees may be killed. The introduced parasite, Monodontomerus dentipes (Dalm.), is occa- sionally very effective in control. Up to 75 percent parasitization has been recorded in New Jersey. Second generation larvae and cocoons located above the snow line on trees are particularly susceptible to low winter temperatures. Diprion frutetorum (Fab.) was discovered in North America in Massachusetts and Rhode Island in 1932, and now occurs throughout many of the Northeastern States and in southeastern I COURTESY CONN. AGR. EXPT. STA. Figure 182.—Larvae of the introduced pine sawfly, Diprion 451. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Baker, Whiteford L. (Whiteford Lee), 1903-. Washington : U. S. Dept. of Agriculture, Forest Service ; for sale by the Supt. of Docs. , U. S. G. P. O
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
