Study on Excellent Strains ofBeauveria bassiana againstNotodontidae inPopulus × euramer icana and Controlling by D ifferent Formulations in Forest

To decrease the damage caused byNotodontidae in Populus × euramericana, the seven strains ofB eauveria bassiana ( Bb)were tested on co lonymorphology, growth rate ofmyce lium, sporulat ion, spore germ inat ion rate and virulence,and the forms of o il formulation, emulsion, water agent and pow der of Bb w ere adopted to contro l in forestw ith differentfungus application amoun.t The results showed that the screened excellent strain named B jyw ere the best among others,w ith lawns were ch ick, co loniesw ere round, edgesw ere regu lar, thicknessw ere uniform and veinswere clear, and sporulat ion w as 3. 81×108 per square centmi eter and spore germination ratewas 96. 67% w ithin twenty－four hours. The tox ic itydetermination show ed that themortality reached 94. 4% and white cadaver rate was 92. 2% on the tw ent ieth day; the o ilformulation by ULV spray ing w as the best and 1. 5 ×1013, 2. 0×1013 spores per hectare w ere optmi a,l w hich had a goodcontro l effect ofmortality attained 95. 4% and 100%, white cadaver ratew ere 84. 6% and 90. 2%, damage rates of leafw ere 39. 7% and 32. 3%. Threem illilitres Fema lerate per hactarew ere added to oil formulation o fBb, the contro l effectofmortality attained 93. 8%, wh ite cadaver rate was 67. 9%, damage rate of leafw as 26. 1% were testified.