Assessment of yield losses due to early and late leaf spots of groundnut (Arachis hypogaea L.)

English

Early leaf spot (Cercospora arachidicola) and late leaf spot (sporidium personatum) are major limiting factors to groundnut productivity in northern Ghana. Fourteen groundnut entries were evaluated for two seasons (2003 and 2004) at Nyankpala with and without tebuconazole fungicide application. The objective of this study was to determine the yield losses due to combined attack of both diseases, with and without using tebuconazole (Folicur 3.6F) at 0.22 kg a.i. ha-1. The experiments were established in a split-plot design with three replications. Disease rating and pod yield were recorded at harvest maturity. Yield losses varied considerably, depending on entry and its yield potential. Pod yield losses due to both diseases ranged from 9.7 to 81.2 per cent in 2003, and from 19.5 to 65.9 per cent in 2004 when yield of protected entries was compared with yield of unprotected entries. The application of fungicide was effective in controlling leaf spots and improved pod yields across the two seasons. Some entries treated with fungicide produced pod yield of 1,860 to 2,081 kg ha-1, which is more than 2 to 2½-fold increase over present average yields in Ghana. Based on the high yield losses, chemical control and host-plant resistance options for managing both diseases in the north are recommended to enhance groundnut production.

Nutsugah, S. K.; Oti-Boateng, C.; Tsigbey, F. K.; Brandenburg, R. L.