Investigations on Variability Compatibility of Pesticides and Host Resistance Against Turcicum Leaf Blight of Maize Incited by Exserohilum turcicum Pass Leonard and Suggs

Abstract

Maize (Zea mays L.) is one of the important cereal crops in the world which newlinestands next to wheat and rice. It is prone to several diseases and insect pests. Among newlinethem, turcicum leaf blight (TLB) disease and fall armyworm (FAW) insect pest are the newlinemajor biotic stresses in maize production. TLB is widely distributed in moderate to newlinesevere form in northern Karnataka. Five districts viz., Belagavi, Dharwad, Haveri, newlineDavangere and Uttar Kannada have recorded more than 40 per cent disease severity due newlineto favourable environmental conditions newlineThe various pesticides and their combinations were tested for physical newlinecompatibility, phytotoxicity and field efficacy against TLB and FAW. All the evaluated newlinepesticide combinations were physically compatible with each other. In vitro studies newlinerevealed that, Hexaconazole 5 EC, Propiconazole 25 EC, Tebuconazole 250 EC, newlineFluxapyroxad 167 g/l + Pyraclostrobin 333 g/l SC and Pyraclostrobin 13.3% + newlineEpoxyconazole 5% SE alone and their combinations with insecticides showed cent per newlinecent inhibition of mycelial growth of E. turcicum. Among the insecticides, Emamectin newlinebenzoate 5 SG completely inhibited the mycelial growth of pathogen. None of the newlinepesticide combinations showed phytotoxicity except copper oxychloride 50 WP alone newlineand in combination with insecticides, which recorded scorching phytotoxic symptoms newlineon foliage. newlineThe efficacy of pesticides and their combinations in the field condition revealed newlinethat, spraying of (Fluxapyroxad 167g/l + Pyraclostrobin 333g/l SC) at 0.1 % + newlineSpinetoram 120 SC at 0.05%, (Fluxapyroxad 167g/l + Pyraclostrobin 333g/l SC) at0.1 newline% + (Novaluron 5.25% + Emamectin benzoate 0.9% SC) at 0.2 %, (Fluxapyroxad newline167g/l + Pyraclostrobin 33 g/l SC) at 0.1% + Lamda cyhalothrin 5% EC at 0.5% and newline(Fluxapyroxad 167g/l + Pyraclostrobin 333g/l SC) at 0.1% + Cypermethrin 10% EC at newline0.2% were found effective in the management of both turcicum leaf blight and fall newlinearmyworm with higher grain yield (gt 76 q/ha) and maximum benefit cost ratio (gt 1.3). newlineThe best performed pesticide combinations under fi