Response of Root Knot Nematode to Three Systemic Herbicides and Their Effect on the Growth and Yield of Cowpea Grown in Umuahia South LGA, Abia State

Abstract

The effect of herbicides (pendimethaline, imazamox and atarazine) on root-knot nematode (Meliondogynespp) and yield of cowpea (Vigna unguiculata) were compared in the field and pot experiments (August-October 2021 and September-Novermber 2022). The pot experiment was arranged in a Completely randomized design using plastic buckets with four treatments replicated three times including the control. Each bucket was inoculated with 2,000 nematode eggs. The treatments included: two pre-emergence (Pendimethalin and atrazine) herbicides and one post-emergence herbicide (Imazamox). The pendimethaline, imazamox and atrazine were applied using a knapsack at 250ml/16l. Data collected included: grain yield (number of seeds per pod and weight of seeds), root parameter (fresh root weight and number of root nodules), nematode galls and population (gall index, number of eggs and number of juveniles). The field experiments (the two seasons) were conducted on land naturally infested with root-knot nematode and were laid out in a Randomized Complete Block Design with four treatments including the control (no application). Similar treatments in the pot experiment were used. The herbicides were applied at the same rate as in pots. Data similar to those in the pot experiment were taken. The data collected in the experiments were subjected to analysis of variance (ANOVA) and means were compared using the least significant difference (LSD) at a 5% probability level (P<0.05). Results obtained at the end of the experiments showed that pendimethalin significantly reduced the nematode population and increased the yield of cowpea.