Selection and Field Evaluation of Antagonistic Fungi against Tobacco Black Shank

In order to obtain more antagonistic fungi for prevention and control of tobacco black shank, 20 fungal strains were isolated from tobacco rhizosphere soil, among which ZP2-1, ZP2-3, ZP2-4, GZ3, and GZ7 had antagonistic effects on Phytophthora nicotianae. Molecular and morphological analysis showed that these strains were identified as Trichoderma reesei ZP2-1, Trichoderma koningiopsis ZP2-3, Aspergillus niger ZP2-4, Aspergillus fumigatus GZ3 and Hypocre rufa GZ7. ZP2-4 has a strong ability to secrete cellulase and protease and the ability of sporulation in solid fermentation was higher than that of the other 4 strains (p<0.01). The cellulase activities of the solid fermentation products of ZP2-1, GZ3 and ZP2-4 were fairly high and significantly higher than that of ZP2-3 and GZ7 (p<0.01). ZP2-1, GZ3 and ZP2-4 with high spore producing ability and cellulase activity in solid fermentation were selected for field trial. The results showed that the control efficiency against tobacco black shank of ZP2-1, GZ3 and ZP2-4 were 59.50%, 61.82% and 85.00%, respectively.