Host‐range and survival studies ofPeronosclerospora sorghiat two locations in Nigeria

Abstract

Abstract Several native grasses, sorghum lines and maize genotypes were tested for susceptibility to Peronosclerospora sorghi (Weston and Uppal) C. G. Shaw at two locations in Nigeria. In the southwestern location, neither the native grasses nor the sorghum varieties were infected, but most maize varieties were susceptible to downy mildew. In the north‐central location, differential sorghum lines T x 412, T x 430, FFBL, L1499, T x 415 and most maize varieties were systemically infected. Among the native grasses, only Dactylactenium aegyptium (L.) P. Beauv. and Roettboelia cochinchinensis (Louv.) Clayton were partially susceptible to downy mildew. Oospores from diseased sorghum and conidia from both infected sorghum and maize genotypes were found to be involved in the downy mildew disease cycle in the north‐central location, while only conidia from infected maize were detected and caused disease on maize in the southwestern location. This suggests the presence of a sorghum pathotype of downy mildew which i...