Effects of improved practices on grain sorghum stalk borer and weeds: case studies from three regions of Ethiopia

Abstract

We conducted three different on farm experiments in three major sorghum producing areas of Ethiopia to find solutions to major grain sorghum pests (weeds and stalk borer) prevailing in the respective areas. These were: 1) effect of integrated technologies to control grain sorghum stalk borer, 2) screening early maturing grain sorghum varieties that could tolerate stalk borer, and 3) weeding effect on sorghum yield. These experiments were conducted on farm and demonstrated to farmers in south Tigray, west Hararghe and south west Ethiopia, respectively. In south Tigray, we found that grain sorghum yield increased by 68% (5600 kg ha−1). Whereas, among the five varieties introduced in west Hararghe, Gedo variety outstripped, and gave the highest yield (2162 kg ha−1) but, notably, with the highest infestation of stalk borer. In southwest Ethiopia, about three-fold yield increment was obtained by hand-removing weeds and applying 100 kg ha −1 DAP and urea. Applied the same amount and types of fertilizers, but without removing the weeds, resulted in total crop failure because broad-leaved weeds might have competed for nutrients and light and suppressed the crop. We conclude that weeds and stalk borer are significantly reducing grain sorghum yield in the respective areas, but they can be managed with integrated approaches to potentially enhance sorghum grain yield.