Effect of Herbicides, seed dressing chemicals and spray regimes on germination, insect infestation and yield of Cowpea (Vigna unguiculata (L) Walp)

A field experiment was conducted in Samaru-Zaria located between latitudes11010ʹ and 10054ʹN and longitudes 07038ʹ and 07044ʹE within the guinea Savanna zone of North central Nigeria. The effect of seed treatment chemicals (Apron Star® 24WP, 20% w/w Thiamethoxoams, 20% w/w Metalaxyl-M and 20% w/w Difeno- conazole) and four spray regimes (5 days, 7 days, 10 days and 14 days after sowing) on the germination, insect infestation and yield of cowpea (Vigna unguiculata (L) Walp) (SAMPEA-7) were investigated during the 2006/2007 rainy season. The experiment comprised of five treatments replicated four times in a randomized complete block design (RCBD). The result obtained showed that seeds dressed with Apron Star® recorded higher germination counts (35 seedlings) compared to the undressed seeds, which had the least estimates (26.75 seedlings) and lower yields (366.7kg/ha). The SAMPEA-7 seeds dressed and protected with Cypermethrin and Dimethoate for the control of field insect pests gave significant (p<0.05) grain yield per ha under 7 days (1387.50kg/ha) and 10 days (1208.30kg/ha) spray regimes. Farmers could therefore adopt either the 7 or 10 days spray regimes in the zone.