Benzothiadiazole Induced Resistance to Viruses in Watermelon and Melon

Benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester(benzothiodiazole,BTH)was applied to watermelon and melon plants to test systemic acquired resistance(SAR)in watermelon plants against Zucchini yellow mosaic virus (ZYMV)and Watermelon mosaic virus(WMV),and melon plants against Cucumber mosaic virus(CMV). The application of BTH was done before the plants were inoculated with ZYMV,WMV and CMV. The resistance was evident with reduced disease severity in BTH-treated plants. The average relative effectiveness 4 weeks after treatments was 55.6% ,56.8%,78.2% for ZYMV,WMV and CMV,respectively,when watermelon and melon plants were treated with BTH at concentration of 25 μg/mL 3 days before virus inoculations. Further research showed that the time between treatment with BTH and inoculation with virus also affected disease indices. The effectiveness of BTH was better than that of moroxydine hydrochloride copper acetate,K virusicide,Ningnanmycin and brassinolide.