粉拟青霉防治油(赤)松毛虫流行病研究

THE CONTROL OF PINE CATERPILLAR (DENDROLIMUS TABULAEFOR MIS AND D·SPECTABILIS)WITH PAECILOMYCES FARINOSUS AND ITSEPIZOOTIC PROBLEMS

越冬油(赤)松毛虫自然死亡的主要原因是真菌疾病,应用粉拟青霉防治越冬的油(赤)松毛虫比白僵菌更有效,多年的林地防治取得了70％以上的稳定杀虫效果,侵染以晚秋和早春为主,严冬季节很少。幼虫春季上树后仍有一部分死亡,这是疾病潜伏期造成的死亡滞后于侵染的现象,计算总死亡率应加上这一部分。影响该菌防治越冬幼虫效果的主要因子不是湿度,而是温度,表现在阳坡效果好于阴坡。

In the present paper,the natural fungal epizootic in the overwintering larvae of Dendrolimus tabulaeformis and D, spectabilis was extensively investigated and studied. Infective dynamics of overwintering larvae and its relation to soil temperature, humidity and precipitation under the function of P.farinosus were studied. The effectiveness of P.farinosus in controlling the overwintering larvae of the pine caterpillar on a large area was compared to that of Beauveria bassiana in the same conditions. The main results are as follows: 1.The natural mortality of overwintering larvae of Dendrolimus tabulaeformis and D.spectabis is mainly caused by fungal epizootic, in which P. farinosus play an important role. 2.Using P.farinosus and B,bassiana to control overwintering larvae of the two kinds of pine caterpillar are all effective, but P.farinosus is more effective. The precipitation in general years is content with the infecting overwintering larvae for P.farinosus. Therefore, the result of control can be stable, the results are always over 70%. 3.The period from the end of autumn to the beginning of winter (October to December) is very fuitabls for the infection of P.farinosus to the pine caterpillar, and so do spring, but there is less infection in winter. 4.There are some larvae died after going up the tree from the soil. The phenomenon that ihe death lags infection is caused by infective latent period. when we count the mortality, this part should be added. 5.The main cause which effect the protection of larvae through winter by P.farinosus is not moisture but temperature, so the effect of south slope is better than that of north slope