Determination on Virulence of Beauveryia bassiana MZ050724 on Rhopalosiphum padi L

[Objective] The disease infection of Beauveria bassiana and its development potential were discussed for a theoretical basis of the strain-screening with highly toxic to Rhopalosiphum padi aphid.[Method] The PDA medium was used to culture Beauveria bassiana strain-MZ050724 spores.The toxicity effect of the different concentrations of spore solutions on Rhopalosiphum padi aphid was determined.The synergies of the combination of its best-effective concentration and four kinds of chemical pesticides(36% Eximi,30% Shengya,10% Biqile and 10% Sabi) the diluted solution by 10 times and 100 times was respectively measured.[Results] The Beauveria bassiana strain-MZ050724 with the concentration of 4.2×107 spores/ml showed better toxicity performing to Rhopalosiphum padi aphid(the cumulative correction death rate: 60.87%).In the optimal concentration of Beauveria bassiana strain-MZ050724 mixed with four kinds of chemical pesticides respectively,the efficiency of the solution mixed with 10% Biqile could be 4% higher;the minimum from 30% Shengya diluted by 100 times reached-25%;10% Sabi diluted by 100 times could be 6% higher and there was antagonism while it mixed with other manifestations.[Conclusion] The mixture of 10% Biqile and Beauveria bassiana strain-MZ050724 can achieve the complementary effect.