Management of witchweed, Striga hermonthica, and stemborers in sorghum, Sorghum bicolor, through intercropping with greenleaf desmodium, Desmodium intortum

Abstract

On-station and on-farm studies were conducted in western Kenya to assess the potential role of greenleaf desmodium, Desmodium intortum (Mill.) Urb., in a combined control strategy for witchweed, Striga hermonthica, and cereal stemborers in sorghum, Sorghum bicolor (L.). Treatments consisted of sorghum plots intercropped with D. intortum (intercrop), with sorghum monocrop plots (monocrop) serving as control. There were highly significant reductions in both S. hermonthica emergence (by up to 89% in the on-farm and 100% in the on-station trials) and the proportion of stemborer-damaged plants (by up to 85% in the on-farm and 67% in the on-station trials) in the intercrop compared to the monocrop in both trials during most of the study period. The sorghum plants were also significantly taller in the intercrop (by up to 88% in the on-farm and 58% in the on-station trials) than in the monocrop plots. Moreover, grain yields were significantly higher in the former (by up to 63% in the on-farm and 140% in the on-station trials) in both trials throughout the study period. These results demonstrate that intercropping sorghum with D. intortum offers an effective control of both pests, leading to higher grain yields.