Detection and Management of Resistance in Botrytis cinerea to Commonly Used Fungicides from Tomato in Tianjin

To investigate the resistance status of Botrytis cinerea on tomato in Tianjin, 21 B. cinerea strains were isolated from the diseased tomato fruits or leaves in different regions of Tianjin,and subjected to the mycelia growth inhibition assay of six frequently-used fungicides(carbendazim, pyrimethanil, diethofencarb, iprodione, procymidone, and prochloraz). The results showed that the resistance frequency of these strains to carbendazim was 76.19%, and the highly-resistant frequency was 19.05%; the resistance frequency to Pyrimethanil was 71.42%, and the highly-resistant frequency was 2.85%; the resistance frequency to Diethofencarb was 42.86%, and the highly-resistant frequency was 28.57%; the resistance frequency to Iprodione was 80.95%, but no highly-resistant stain was detected; the resistance frequency to Procymidone was 80.95%, the highly-resistant frequency was 19.05%; all isolates were sensitive to Prochloraz. Among these detected 21 isolates, 42.86% strains had resistance to five kinds of fungicides, 61.90% isolates had resistance to four kinds of fungicides. Taken together, among these six frequently-used fungicides in Tianjin, SYP-Z048,Difenoconazole and Fludioxonil of six new kind fungicides could be recommended for the management of B. cinerea owing to their good inhibitory effect to all detected strains even to resistance stains.