Studies on the resistance induced by BTH and SA against Erysiphe cucur-bitacearum in muskmelon

Effects of BTH and SA on resistance of muskmelon to powdery mildew (Erysiphe cucurbitacearum) were investigated. The inductive effects of BTH and SA were investigated by applying BTH and SA to detached muskmelon leaves. The results showed: application of BTH and SA at different concentration to detached muskmelon leaves had no significant effect on germination and growth of Erysiphe cucurbitacearum. The reason why the ratio of disease plants and leaves reduced was mainly due to the BTH and SA-induced resistance. The effects of 50μg/ml BTH and 25μg/ml SA were significantly better than others. The average effect of induced resistance on muskmelon was 86.6% and 83.7% respectively. In addition, the induced resistance would last more than 17 days after BTH or SA treatment. The difference of effects was not evident at different growing stages of muskmelon. So BTH and SA could effectively induce SAR of muskmelon against Erysiphe cucurbitacearum.