EFFECTS OF SWEET POTATO (Ipomea batatas L.) INTERCROP ON INFESTATION OF OKRA (Abelmoschus esculentus L.) BY FLEA BEETLE Podagrica spp. (COLEOPTERA:CHRYSOMELIDAE)

Abstract

ABSTRACT Okra (Abelmoschus esculentus L.) is an important fruit vegetable crop and source of calorie for human consumption. Its production is constrained by a complex of insect pests among which flea beetles alone cause more than 56% damage. This study determined the density of flea beetles, leaf damage and yield in A. esculentus intercropped with I. batatas and determined Land Equivalent Ratio (LER) of okra in the intercrop. The study was conducted at the Teaching and Research Farm, Federal University of Agriculture, Abeokuta in the late planting season, 2020 (Dry) (November - December) and was repeated in early planting season, 2021 (Wet) (July-August). The okra and sweet potato varieties NHAE 47- 4 and Saba were planted on ridges separated by a 1 m spacing. The treatments in the study are sole Abelmoschus esculentus, sole Ipomea batatas, single alternate row of A. esculentus and I. batatas, single alternate row of I. batatas and A. esculentus, double row of A. esculentus and single alternate row of I. batatas, double row of I. batatas and single alternate row of A. esculentus, double row of I. batatas and double alternate row of A. esculentus, double row of A. esculentus and double alternate row of I. batatas. The treatments were replicated three times and laid out using Randomized Complete Block Design. Data were collected from 6 tagged plants at 4,6 and 8 weeks after planting on number of insects, plant height, number of damaged and undamaged leaves, number of damaged and undamaged okra pod/plant, number of tubers per plot, weight of tubers per plot and percentage of damaged pods was determined. Data on insect numbers was transformed using √(x + 0.5), while data on percentage was log-transformed before analysis. All data collected were subjected to Analysis of Variance and significant means were separated using Student-Newman Keuls Test (SNK) at 5% level of probability. In the late and early planting seasons, number of flea beetles (1.76 and 2.92 respectively) in plots planted with sole okra were significantly (p< 0.05) higher than in plots planted with okra and sweet potato intercrop. In the late planting season, leaf damage (69.67%) was higher than the leaf damage (65.39%) in the early planting season. In the early planting season, the plot planted with sole okra had the highest yield (3.32 t/h) compared to (3.10 t/h) during the late planting season. In 2020, LER of the intercrop was 3.72, while it was 1.59 in 2021. The LER being above 1.0 indicates that higher productivity per unit area was achieved by growing the crops together than growing them separately. Sole okra plots had higher flea beetle infestation which affected growth, pod formation, fruit weight and pod yield. Intercropping okra with sweet potato reduced the flea beetle population hence reducing leaf damage caused by Podagrica spp. It is also concluded that okra intercropped with sweet potato at different arrangements significantly reduced and controlled the population of Podagrica spp compared to when okra is planted as sole.