Comparison of the toxicity of four carboxylic acid amide fungicides against Phytophthora capsici at their three different life stages

The toxicity of four carboxylic acid amide fungicides (CAAs) against Phytophthora capsici at their three different life stages was investigated.The results showed that mandipropamid,dimethomorph,pyrimorph and flumorph could effectively inhibit mycelial growth(with EC50 values of 1.95×10-2,1.41,1.85,2.31 μ g/mL,respectively),sporangia production (with EC50 values of 2.00×10-4,1.50×10-3,2.60×10-3,4.30×10-3 μ g/mL,respectively) and cystospore germination(with EC50 values of 4.60×10-3,0.373,0.494,0.635 μ g/mL,respectively) of P.capsisi .The tested pathogen strain was more sensitive to four CAAs than to metalaxyl,pyraclostrobin and azoxystrobin.