Application Of Beauveria Bassiana Against Pine Caterpillar And Sawfly In The North Area

Pinus tabulaeformis Carr. is the main plant species in the forest north of China. The Pine Caterpillar and the Sawfly are two serious pests in the pinus forest. In the past they were usually controled with pesticides resulting in the "3R"problem (Residue, Resistance and Resurgence). In the study the strain of Beauveria bassiana was isolated, cultured and identificated from the muscardine carterpillar collected from the pine forest in Xiaguan of Lingqiu county of shanxi in April, 2003.Some biological characteristics such as stiblity, growth-rate, spore and protease production of the strain were abtained through being successionally cultured in five generations on five kinds of medias. Meanwhile, a series of study in lab and forest were carried on with Pine Caterpillar and the Sawfly infected by adopting the two preparation of spore suspension solution and powder of varied concentrations. The results is showed as following: 1. That the colonial partial variation on PDA whose area covered 1/5 to 1/2 of the whole colony area was most obvious and only its hyphae growed faster and the production of spore and protease was least after Beauveria bassiana was cultured through five generations on five medias, i.e. PDA(M1), PDA containing peptone(M2), PDA containing dead larvae of Sawfly (M3), PDA containing dead larvae of Pine Caterpillar (M4), PDA containing dead larvae of Pine Caterpillar and peptone(M5).The average growth-rate of colony on M1 was 4.108mm/d, apparently larger than other four ones, i.e. 3.678mm/d, 3.640mm/d, 3.466mm/d and 3.550mm/d and its average spore production was 3.254 spores/cm2 and clearly lower than other four ones, i.e.5.082spores/cm2, 4.856spore/cm2, 4.178spores/cm2 and 4.084spores/cm2; the average protease production ratio was 1.094 which was obviously lower than other four ones, i.e. 2.046, 1.978, 1.254 and 1.208. It showed that adding the dead larvae of Pine Caterpillar and peptone in PDA can evidently improve its nutrition condition, reduce the partial variation of colony, accelerate the growth-rate with the average of 3.678mm/d, raise the spore production with the average of 5.082spores/cm2, increase the protease production with the average ratio of 2.046. 2. Each indexes of the strain becomes gradually little except for the growth-rate after cultured several generations. For example, the growth-rate separately were 3.73mm/d, 3.79mm/d, 4.11mm/d, 4.29mm/d and 4.62mm/d from the first generation to the fifth one on PDA, but the corresponding spore productions of each generation were 3.67spores/cm2,...