. An annotated list of the important North American forest insects. Forest insects. 14 EARMERS^ BULlLETIN 15 82 south some species have two generations and sometimes a partial third. The flat-headed borers, as beetles, fly about the same time that those of tlie roundheaded borers appear. Some species mature in a year; others take as long as two years. CONDITIONS FAVORABLE AND UNFAVORABLE FOR ATTACK The kind antl condition of wood attacked are largely dependent upon the species of insect. Some species prefer freshly cut wood that is in a moist condition, others partly seasoned wood, and still o
. An annotated list of the important North American forest insects. Forest insects. 14 EARMERS^ BULlLETIN 15 82 south some species have two generations and sometimes a partial third. The flat-headed borers, as beetles, fly about the same time that those of tlie roundheaded borers appear. Some species mature in a year; others take as long as two years. CONDITIONS FAVORABLE AND UNFAVORABLE FOR ATTACK The kind antl condition of wood attacked are largely dependent upon the species of insect. Some species prefer freshly cut wood that is in a moist condition, others partly seasoned wood, and still others require wood that is dry and well seasoned. CONDITIONS FAVORABLE FOR BARK BEETLES AND AMBROSIA BEETLES Two types of insects, the bark beetles and the ambrosia beetles, attack freshly cut logs on whicli the bark remains and in which the inner bark is still white and active and the sap is still present. The ambrosia beetles, however, like equally well logs, with or without bark, that have been submerged in Avater and which after being re- moved from the water remain in a moist condition, as when they are placed on the ground in the shade. Such logs may continue to be at- tacked until they dry out. Wood that is cut during the spring and summer months, when the weather is warm and damp, ma}' be sub- ject to severe injury, especially when placed in close piles on the ground so that it does not receive sfedequate ventilation. Wood which is cut in the early fall and dried out, or seasoned sufficiently during the winter months, is in an unfa- vorable condition for attack by bark beetles and ambrosia beetles when their active season Figure 21.—Adult Leetle of a flat- headed borer, CJirysobothris octocola Lee. Enlarged 4 tliameters CONDITIONS FAVORABLE FOR POWDER-POST BEETLES The powder-post beetles prefer wood that has been cut several months. They show a decided preference for wood that is cut either in the fall and slowly seasoned over winter, or that which is cut du
Size: 1108px × 2255px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorhopkinsadandrewdelmar, bookcentury1900, bookdecade1900
