. Eastern forest insects . F-519945 Figure 180.—Colony of lar- vae of the European pine sawfly, Neodiprion serti- fer. Larvae hanging head downward were killed by a polyhedral virus. Trees defoliated by the European pine sawfly are seldom killed, since the new foliage is never eaten and the tree is never entirely stripped of its foliage. Bark feeding may cause some twig mor- tality but it is not serious. Losses in height and diameter growth may be severe however, especially following repeated defoliations. Damage is most severe to Scotch pines grown as Christmas trees in plantations. During th
. Eastern forest insects . F-519945 Figure 180.—Colony of lar- vae of the European pine sawfly, Neodiprion serti- fer. Larvae hanging head downward were killed by a polyhedral virus. Trees defoliated by the European pine sawfly are seldom killed, since the new foliage is never eaten and the tree is never entirely stripped of its foliage. Bark feeding may cause some twig mor- tality but it is not serious. Losses in height and diameter growth may be severe however, especially following repeated defoliations. Damage is most severe to Scotch pines grown as Christmas trees in plantations. During the late thirties and early forties, colonies of the two European parasites, Dahlbominus fuscipennis (Zett.) and Exen- terus abruptorius (Thunberg), were received from Canada for release in eastern infestations of this sawfly. D. fuscipennis be- came established in New Jersey and within a few years became rather abundant locally (299). E. abruptorius also became estab- lished in New Jersey. So far, neither species has given adequate control. A supply of a European polyhedrosis virus of the sawfly was also received from Canada for use in its control (66). It has proved to be very effective when applied as a spray either by aircraft or by knapsack or hydraulic sprayers. Lyons (466) re- 448
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
