Maydis leaf blight of maize: Historical perspective, impact and present status

Abstract

Maydis leaf blight (MLB) caused by the fungus Cochliobolus heterostrophus (Drechs.) Drechs. is a serious foliar disease of maize distributed widely in maize-producing areas throughout the world. The currently predominant form of C. heterostrophus is Race O, which can cause yield losses of up to 40 per cent. Damage is most critical if infection occurs prior to silking and if weather conditions are favorable for disease development during the reproductive growth stages. Host resistance is the most cost-effective and practical criteria for management of this disease. Till date, many studies have been published on mapping quantitative trait loci for field resistance to MLB in maize from populations derived from different crosses. The recessive gene rhm confers almost complete MLB resistance at pre-anthesis growth stages and a partial level of resistance at post-anthesis. In addition, various fungicides can also be used to provide adequate protection from MLB, but major emphasis is on development of maize cultivars with genetic resistance to MLB.