Resistance induced by fluoro-substituted benzothiadiazole derivatives against cucumber damp-off and its effects on the physiological index of cucumber seedlings

The resistance induced by fluoro-substituted benzothiadiazole derivatives(1, 2, 3-benzothiadiazole-7-carboxylic acid-2, 2, 2-trifluoroethyl ester, FBT) spray against cucumber damp-off was determined by houseplants method. The effects of FBT on the physiological index through spray and pouring root on cucumber seedlings were determined. The results showed that the control effect of FBT against damp-off disease in cucumber reached 77.28% when the effective components was 25 mg/L, and it was sprayed 3 times at 7-day intervals. The results of the experiments revealed that by treating with FBT at different concentrations(15, 25 and 50 mg/L) using to spray and pouring root method, the inhibition effect on plant height, jointing length, fresh weight and dry weight various. when the effective components was 15 or 25 mg/L, the stem diameter and the root-shoot ratio during the seedling stage were promoted. However, when the concentration was 50 mg/L, the corresponding stem diameter and the root-shoot ratio were inhibited. This study demonstrated that FBT is effective for the cucumber damp-off disease, and has influence on the physiological index of cucumber in the seedling stage.