1Cocoa Health and Extension Division, Ghana Cocoa BoardPost Office Box 25, New Abirem-Eastern Region, Ghana
2Department of Horticulture and Crop Production, University of Energy and Natural Resources, Sunyani, Post Office Box 214, Ghana
*Corresponding Author: Novor Samuel, Department of Horticulture and Crop Production, University of Energy and Natural Resources, Sunyani, Post Office Box 214, Ghana. samuel.novor@uenr.edu.gh
This study evaluated the effects of herbicides on weed control and cowpea (Vigna unguiculata) performance in the semi-deciduous forest agro-ecological zone of Ghana.
Field experiments were conducted at Nkwanta (Ashanti region) and Abodom (Eastern region) using a single-factor, randomized complete block design with ten treatments and three replications. Treatments included one post-emergence herbicide (Agil 100 EC) applied at 2, 4 and 6 weeks after sowing (WAS), two pre-emergence herbicides (Butachlor 50% EC and Alligator 400 EC) and hand weeding at 2, 4 and 6 WAS as the control.
At Nkwanta, the tallest cowpea plants were recorded with 3.6 mL a.i/ha of Butachlor 50% EC, while at Abodom, 1.8 mL a.i/ha of Agil 100 EC produced the greatest plant height. Branching at Nkwanta was highest with Alligator 400 EC at 4 and 6 WAS, whereas Abodom showed consistent branching responses across all intervals with Agil 100 EC. The application of Alligator 400 EC at 2 WAS and higher concentrations of butachlor 50% EC improved the canopy cover in Nkwanta, while the use of Alligator 400 EC in Abodom had the highest canopy spread. In both locations, the use of Butachlor 50% EC recorded the highest flowering and podding. The highest pod length and pods per plant were observed with manual weeding at 2, 4 and 6 WAS at Nkwanta, while the use of Alligator 400 EC recorded the highest pod performance in Abodom. The findings revealed a significant difference in the efficacy of the herbicide. Butachlor 50% EC improved growth metrics at Nkwanta and Agil 100 EC was most effective at Abodom.
Agronomic performance, Cowpea, Herbicide weed management, Pre-emergence herbicides, Post-emergence herbicides, Weed control efficacy