Sorghum diseases prevalent in Ghana

English

Field survey, screening trials and laboratory investigation were used to determine the prevalence of sorghum diseases in the major sorghum-growing climatic zones (Sudan, northern and southern Guinea savanna). Farmers\' fields were surveyed in 1997. Ten sorghum entries were evaluated under natural field conditions in 1997 and 1998 at Damongo for their reaction to foliar and panicle diseases while seed samples of field-harvested sorghum were assessed for fungal infection using the blotter method. Two main types of sorghum, viz. the early-maturing, brown-seeded, guinea or guinea-caudatum type and the late-maturing, photoperiod-sensitive, white-seeded, guinea or guinea-caudatum type were found in the sorghum-growing areas. The survey showed that sorghum was cultivated under a range of cropping systems in all possible crop mixtures. Grey leaf spot (Cercospora sorghi), oval leaf spot (Ramulispora sorghicola), zonate leaf spot (Gloeocercospora sorghi) and covered smut (Sporisorium sorghi) were prevalent in all the sorghumgrowing areas. Other diseases recorded were leaf blight (Exserohilum turcicum), sooty stripe (Ramulispora sorghi), grain mould (caused by a complex group of fungi), long smut (Sporisorium ehrenbergii), head smut (Sporisorium reiliana), rust (Puccinia purpurea) and rough leaf spot (Ascochyta sorghi). Anthracnose (Colletotrichum graminicola) occurred infrequently across the regions. Striga hermonthica was more prevalent in the two Upper regions than in the Northern Region. The sorghum entries varied considerably in their susceptibility to the field diseases, with severity mean scores ranging from 2.5 to 3.6. Eight species of fungi were recorded from seed samples. The occurrence of these varied with the sorghum entries, with the genera Fusarium and Phoma dominating, followed by Curvularia

Nutsugah, S. K.; Atokple, I. D. K.; Leth, V.