Abstract:
The screening of the high-efficient and safe mixtures is of great importance for the prevention and control of tobacco
Fusarium root rot. In this study, the mycelial growth rate method was used to determine the toxicity and compatibility and the toxicity coefficient of biocontrol agent
Trichoderma asperellum Tr-0111 and chemical fungicide 30% propamocarb·azoxystrobin against
F. oxysporum. In addition, their control effect on tobacco
Fusarium root rot was evaluated through pot experiments. The results indicated that both 30% propamocarb·azoxystrobin and
Trichoderma asperellum Tr-0111 had strong virulence against
F. oxysporum, with
EC50 values of 0.0643 mL/L and 2.36×10
2 cfu/mL, and showed good compatibility. The combination of 30% propamocarb·azoxystrobin and
Trichoderma asperellum Tr-0111 with different ratio showed synergistic effect, except for
V30% propamocarb·azoxystrobin∶
V Tr-0111=4∶6. The highest synergistic effect was obtained when 30% propamocarb·azoxystrobin and
Trichoderma asperellum Tr-0111 was mixed at the ratio of 7∶3, with the synergistic ratio 1.16 and antibacterial rate 68.37%. The pot experiment showed that, the best control effect (78.18%) against tobacco
Fusarium root rot was obtained when
V30% propamocarb·azoxystrobin∶
V Tr-0111=5∶5, followed by 7∶3 and 1∶9, with control effects of 77.27% and 72.73%, respectively. These control effects were all significantly higher than the single use of 30% propamocarb·azoxystrobin and
Trichoderma asperellum Tr-0111. Therefore, to reduce the use of chemical pesticides, the mixture of 0.0643 mL/L of 30% propamocarb·azoxystrobin and 2.36×10
2 cfu/mL
Trichoderma asperellum Tr-0111 at the ratio of 5∶5 is recommended for the control of tobacco
Fusarium root rot.