闽南地区薏米叶斑病菌对吡唑醚菌酯的敏感性及吡唑醚菌酯的盆栽防治效果

采用菌丝生长速率法测定了闽南地区4个薏米产区72株薏米叶斑病菌对吡唑醚菌酯的敏感性，并通过室内盆栽试验测试了吡唑醚菌酯对薏米叶斑病的防治效果。结果表明:吡唑醚菌酯对供试菌株的EC₅₀值范围为1.11~5.06 μg/mL，平均值为 (3.44 ± 0.98) μg/mL，且其EC₅₀值频率分布为连续单峰曲线，符合正态分布，因此可将该EC₅₀平均值作为闽南地区薏米叶斑病菌对吡唑醚菌酯的敏感基线。盆栽防效结果表明，喷施有效剂量为250 μg/mL的25%吡唑醚菌酯乳油对薏米叶斑病的防治效果 (78.2%~79.7%) 较好，与喷施有效剂量为500 μg/mL的50%异菌脲悬浮剂的防治效果相当，显著高于喷施有效剂量为800 μg/mL的80%代森锰锌可湿性粉剂的防治效果。本研究结果为薏米叶斑病化学防治有效药剂的选择与合理使用提供了依据。

Sensitivity of Curvularia coicis to pyraclostrobin and its control efficacy against Coix leaf blight in South Fujian Province

Seventy-two Curvularia coicis isolates from 4 regions in South Fujian Province were tested for their sensitivity to pyraclostrobin using mycelial growth method. And the efficacy of pyraclostrobin for the control of Coix leaf blight (CLB) was evaluated under greenhouse conditions. The results indicated that the tested isolates were sensitive to pyraclostrobin. And the EC₅₀ values of these isolates to pyraclostrobin ranged from  1.11 μg/mL to 5.06 μg/mL, with the mean value of (3.44 ± 0.98) μg/mL. The frequency curve of pyraclostrobin was continuous and unimodal, and following the normal distribution. Hence, the mean EC₅₀ value of (3.44 ± 0.98) μg/mL can be recognized as the baseline sensitivity of C. coicis to pyraclostrobin. Results of pot experiments showed that the spray of 25% pyraclostrobin EC at 250 μg a.i./mL exhibited high efficacy for the control of CLB, with the control efficacy ranging from 78.2% to 79.7%. This efficacy was as good as that resulted from the spray of 50% iprodione SC at 500 μg a.i./mL, and significantly higher than the efficacy of reference fungicide (80% mancozeb WP at 800 μg a.i./mL). This study will guide the reasonable selection of fungicides for effective management of CLB in the future.