Abstract: Y9511 strain of Exserohilum rostratum is a potential bio-control agent of Leptochloa chinensis (L.)Nees.Effects of 5 carriers,9 surfactants,6 oil adjuvants,and 3 stabilizers on Y9511 colony diameter,spore production,and spore germination rate were evaluated using the PDA culture method,and dispersity,suspensibility,and stability were also detected,which serves to aid the preparation development of E.rostratum Y9511.The results showed that the 5 carriers,9 surfactants,6 oil adjuvantes,and 3 stabilizers all inhibited the mycelial growth of Y9511,but spore production differed between the treatments.Perlite,Nongru 700#,soybean oil,resulted in spore production of 5.3×10⁶,10.8×10⁶,and 4.3×10⁶ spores/mL,respectively.When the spore powder was mixed with perlite and soybean oil at 1:1 and 2:1,the germination rate was the highest,reaching 47.00% and 75.67%,respectively.According to dispersity and stability detection,Nongru 1601#showed the best dispersity,with a dispersity index of 0.35.Potassium alginate showed the best stability,with a slope of 0.0526.Nongru 1601#and potassium alginate were formulated in different concentrations and mixed with spore powder.When the concentrations of Nongru 1601#and potassium alginate were 0.3% and 0.1%,respectively,the spore germination rates were 54.33% and 88.67%,respectively.Based on the above results,the preliminary formula of Y9511 was recommended as spore powder 39.84%,perlite 39.84%,soybean oil 19.9%,Nongru 1601#0.3%,and potassium alginate 0.1%.From the perspective of biocompatibility,this study has screened out the best formula for E.rostratum Y9511,which serves as a foundation for subsequent development and application.

Key words: Exserohilum rostratum, oil solution, carrier, surfactant, oil adjuvants, stabilizer