Baseline sensitivity and control efficacy of flutolanil in Rhizoctonia solani

Abstract

Rice sheath blight is one of the most important rice diseases in the world and the succinate dehydrogenase inhibitor fungicide flutolanil has potential for its control. In this study, a total of 112 Rhizoctonia solani isolates from Jiangsu province in China were characterized for their baseline sensitivity to flutolanil. The baseline sensitivity curve was unimodal with an average EC50 value of 0.0736 ± 0.0331 μg mL−1 for inhibition of mycelial growth. Flutolanil exhibited excellent acropetal movement in rice, and better protective and curative activity than validamycin against rice sheath blight. In field trials in 2011 and 2012, flutolanil used at a concentration of 150 g a.i. ha−1 provided control efficacy ranging from 63.7 to 88.9 %, and its control efficacy could reach 83.9 % ~ 96.5 % at a concentration of 300 g a.i. ha−1. These results suggested that flutolanil will be a good alternative fungicide to validamycin for control of rice sheath blight.