Efficacy of selected insecticides for control of stem borers in maize

Abstract

Lepidopteran stem borers are important pests of cereal crops in sub-Saharan Africa. The stem borer species Busseola fusca, Chilo partellus and Sesamia calamistis are the most widespread and important stem borer species, damaging maize throughout sub-Saharan Africa. Bt maize was planted in South Africa for the first time during the 1998/99 growing season for control of stem borers. The first Bt maize resistant B. fusca in South Africa was recorded during the 2006/07 growing season and resistance has since spread to many areas in the country. As a result, renewed interests in insecticides for stem borer control exist. Neonate B. fusca and C. partellus larvae feed inside the whorls of maize plants and neonate S. calamistis larvae feed on the leaf sheath for a short time before penetrating the stem directly from behind leaf sheaths. The efficacy of 14 insecticide treatments was evaluated for control of these three borer species under greenhouse and field conditions. These evaluations were done in 9 greenhouse and 2 field trials. The insecticides evaluated were benfuracarb, benfuracarb in combination with lambda-cyhalothrin, bifenthrin, chlorantraniliprole in combination with lambda-cyhalothrin, chlorfenapyr, chlorpyrifos in combination with lambda-cyhalothrin, gamma-cyhalothrin, indoxacarb in combination with lambda-cyhalothrin, lambda-cyhalothrin 50, lambda-cyhalothrin 106, lufenuron in combination with lambda-cyhalothrin, nuvaluron in combination with lambda-cyhalothrin, spinetoram and spinosad. All these insecticides provided effective control of B. fusca, C. partellus and S. calamistis under greenhouse and field conditions.