Biological characteristics of highly virulent strains of Beauveria bassiana for Dendrolimus punctatus

ObjectiveBiological characteristics of highly virulent strains of Beauveria bassiana were tested to provide theoretical basis for production and biocontrol of B. bassiana against Dendrolimus punctatus. MethodEffects of six different temperatures(17, 20, 23, 26, 29 and 32 ℃) on growth rate, sporulation quantity and spore germination rate of highly virulent strains of B. bassiana(B-2, B-14 and B-19) were measured respectively on PDA media. With Czapek media as the base, sucrose and potassium nitrate were replaced by three kinds of carbon sources or nitrogen sources of the same mass, in order to study the effects of different carbon sources and nitrogen sources on growth rate, sporulation quantity and spore ger-mination rate of highly virulent strains of B. Bassiana. ResultThe three tested strains grew differently under different tem-peratures. Extremely high and low temperatures were not beneficial to mycelial growth, sporulation and spore germination of B. bassiana strains. All biological indicators could reach the highest level under 26 ℃. The growth rate, sporulation quantity and spore germination rate were 3.36-3.77 mm/d, 9.33×104-16.33×104/mL and 92.67%-99.67% respectively. In terms of car-bon sources application, glucose was the most suitable for growth and sporulation, with growth rate of 3.56-4.35 mm/d and sporulation quantity of 1.00-1.33 ×104/ml, but spore germination rate was low. Peptone was the best nitrogen source for mycelial growth(4.40-4.81 mm/d) and yeast extract was the most suitable for sporulation(sporulation quantity 5.67×104-51.33×104/mL) and spore germination(spore germination rate 58.03%-100.00%). ConclusionStrain B-2 can be preferen-tially selected for industrial production of B. bassiana. At temperature 26 ℃ , carbon source glucose and nitrogen source yeast extract can increase production effeciency of B. bassiana.