Synergistic biocontrol mechanism of Pseudomonas aeruginosa and Trichoderma longibrachiatum on Arthrinium phaeospermum

Pseudomonas aeruginosa and Trichoderma longibrachiatum can effectively antagonize Arthrinium phaeospermum. With the antibiotics and UV mutagenesis-germicide stresses cultivation, the mutation strains of P. aeruginosa and T. longibrachiatum were obtained. The differences were insignificant between mutant and the original strain in the morphological characteristics and the antibacterial activity, and mutants had long-term stable resistance. After spraying bacterial or spore suspensions in the field, the mutation strains could colonize rapidly on hybrid bamboo leaves. The affinity of P. aeruginosa and T. longibrachiatum indicated that both did not have significant inhibition but high affinity with the concentration under 108 cfu/mL, which was beneficial for two strains to generate the synergistic effects in the biological control of hybrid bamboo blight. The bacterial suspensions of P. aeruginosa and spore suspensions of T. longibrachiatum were used for the synergistic field test of biological control. The results showed that the antagonistic effects with pre-inoculation were best, then worse with simultaneous inoculation, and worst with post-inoculation, indicating that both P. aeruginosa and T. longibrachiatum had good control effects against hybrid bamboo blight. Moreover, the control effect of jointed utilization of two strains was best in three treatments; especially in the treatment of pre-inoculation, the effect had been vastly improved, which revealed that the jointed utilization of two strains had quite ideal antagonistic effect on hybrid bamboo blight.