Integrated Control of Verbesina encelioides in Common Bean Fields in the Central Rift Valley of Ethiopia

ABSTRACT

Verbesina encelioides is known to threaten the performance of crops like common bean in central rift valley of Ethiopia. A field experiment was conducted to investigate the effect of management on V. encelioides and common bean yield components and yield at Adamitulu and Melkassa. A randomized complete block design with four replications and twelve treatments was applied. Treatments included pre and postemergence herbicides (s‐metolachlor, pendimethalin, and sodium acifluorfen + clodinafop propargyl) and hand weeding. The density and biomass of V. encelioides were reduced by up to 94% and 81%, respectively, due to integrated control treatments. Beside the weed‐free plot, the use of s‐metolachlor plus hand weeding and pendimethalin plus hand weeding produced the lowest (3%–10%) weed index. Whereas these integrated controls gave the highest (74%–81%) weed control efficiency. Weed‐free plots yielded the highest grain (3.11 and 2.71 t/ha), followed by s‐metolachlor with two hand weedings (3.00 and 2.63 t/ha), while weedy check (0.49 and 0.45 t/ha) and sole pendimethalin 1.5 l/ha (1.28 and 1.12 t/ha) produced the least grain yield at Melkassa and Adamitulu, respectively. The use of s‐metolachlor plus one‐hand weeding, followed by two‐hand weeding, produced a maximum benefit‐cost ratio of 28.41 and 26.95 and an acceptable maximum marginal rate of return of 5689.06 and 5057.27 ETB, respectively. Thus, it is recommended that smetolachlor be used with one‐hand weeding followed by two‐hand weeding or sodium acifluorfen + clodinafop propargyl at 1 l/ha to achieve effective control, higher yield, and economic benefit in common bean production systems.