Title: Eastern forest insects
Identifier: easternforestins1175bake (find matches)
Year: 1972 (1970s)
Authors: Baker, Whiteford L. (Whiteford Lee), 1903-
Subjects: Forest insects
Publisher: Washington : U. S. Dept. of Agriculture, Forest Service ; for sale by the Supt. of Docs. , U. S. G. P. O
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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caused some mortality of the gypsy moth but the results were inconclusive. Higher mortalities of two species of loopers (Eran- nis tiliaria and Phigalia titea), which also were present in the sprayed areas, were recorded. CHEMICAL CONTROL The use of chemicals to suppress forest insect populations is a method of last resort. It is the policy to use them only when other forms of control, either natural or artificial, fail or threaten to fail in the prevention or control of destructive populations. Depending on the situation, chemicals may be applied to a single tree or to forested areas covering thousands of acres or square miles. The aim, therefore, is usually limited to the suppression of injurious populations to tolerable levels. Many different types of equipment and techniques are available for applying insecticides (601). Aerial applications are made by fixed-wing aircraft (fig. 3) or helicopters to large areas (29, 21U, 57, and 392). Individual trees, small groups of trees, and seed orchard trees (fig. 4) may be treated by ground equipment such as mist blowers (602) or by knapsack sprayers. Large individual trees may be treated by mist blowers and by hydraulic sprayers. Logs are treated by power sprayers. Fogging machines are sometimes used around resorts and campgrounds. Chemicals may be introduced into the tissues of living trees for bark beetle control (171, 52, and 762). Systemic insecticides may be applied by trunk implantation or injection, by banding or spraying of the circumference of the trunk, by spraying the foliage, by treating the soil around the base of trees, or by dipping cuttings prior to planting (570, 537, 199, 515, 36, and U7). The effectiveness of chemicals in suppressing many forest insect populations has been amply demonstrated during the past 25 years
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Figure 3.—Airplane spraying for spruce budworm control F-482299 25

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