Control of chickpea blight disease caused by Didymella rabiei by mixing resistance inducer and contact fungicide

Abstract

Elicitors of systemic acquired resistance are well known to reduce severity of several plant pathogenic diseases caused by fungi, bacteria and viruses. Their field applications for management of plant diseases are, however, limited because of yield penalties. Our studies on affect of Benzo (1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), an elicitor of systemic acquired resistance, on chickpea blight caused by a fungal pathogen Didymella rabiei showed that multiple foliar applications of the chemical were effective in management of the disease under economic threshold levels. Multiple applications, however, affected chickpea grain yield adversely. The BTH induced yield penalties could be prevented by foliar spray schedule comprised of BTH and a contact fungicide mancozeb. One spray of BTH (50 ppm) followed by another of mancozeb (0.2%) was less effective (8.3% severity) than three sprays of BTH (4.2% severity) in blight control, however, this treatment enhanced grain yield significantly (1.241 t ha −1) over three sprays of BTH (0.922 t ha −1).