ASSESSMENT OF YIELD LOSS INDUCED BY INSECT PESTS AT DIFFERENT GROWTH STAGES ON COWPEA (VIGNA UNGUICULATA L. WALP.)

This study investigated the impact of insect pests on the growth, yield, and leaf damage of two cowpea varieties: Oloyin and Olotu. Several insect pests were identified in the study area, including Labidomera clivicollis, Pycnopalpa bicordata, Urentius hystricellus, Dysdercus superstitiosus, and Scolypopa australis, which caused significant damage to the leaves, shoots, and stems of the plants. In contrast, the butterfly Azanus jesous was identified as a pollinator. The application of Lambda-cyhalothrin significantly reduced the number of damaged leaves in both cowpea varieties. Honey bean plants sprayed with the insecticide had 43.16% fewer damaged leaves than unsprayed plants, while drum bean plants showed a 37.26% reduction. Additionally, sprayed plants exhibited better agronomic traits, with honey bean showing a 25.48% increase in leaf number and drum bean showing a 40.99% increase. The reduction in insect pest damage was associated with improved vegetative growth, including greater numbers of leaves, flowers, and branches. The study also highlighted varietal differences in susceptibility, with Oloyin more vulnerable to flower damage and Olotu more susceptible to leaf damage. The results emphasize the effectiveness of Lambda-cyhalothrin in mitigating insect pest damage, ultimately improving cowpea growth and yield potential.