ASSESSMENT OF OPTIMAL RATE AND FREQUENCY OF CYPERMETHRIN FOR THE CONTROL OF TOMATO FRUIT BORER (Helicoverpa armigera HÜBNER IN ABEOKUTA SOUTH-WESTERN NIGERIA

Abstract

The study was carried out at the Teaching and Research Farms of the Federal University of Agriculture, Abeokuta (FUNAAB) in 2017 and 2021. Trials were laid out in a split-split plot arrangement fitted into Randomized Complete Design with three replications. The main plots comprised of tomato genotype: “Kerewa” and Roma-VF; the sub-plots comprised of Cypermethrin spray-frequencies (twice-a-week, once-a[1]week, twice-a-month and once-a-month). The sub-sub-plots also consisted of five Cypermethrin applications rate: 20 %, 40 %, 60 %, 80 %, and 100 % using recommended rate (2.4 litres/ha). Data were collected on the population density of H. armigera larvae, fruit damage and fruit yield. All data collected were subjected to Analysis of Variance and mean significant differences were separated using Least Significant Difference (LSD) at P≤0.05. Cost benefit analyses of using Cypermethrin at different rates and frequencies were carried out. The results showed that population density of H. armigera larvae was not significantly influenced by genotype but by rate and frequency of application of Cypermethrin in both 2017 and 2021 cropping seasons. However, there was, reduction in TFB population, fruit damage and higher fruit yield when Cypermethrin was applied at 60 % and 80 % rate once-a-week in both trials. Higher economic returns were obtained with Cypermethrin applications at 60 % and 80 % rate once-a-week. 60 % and 80 % Cypermethrin application once-a-week was therefore, effective rates and frequency of Cypermethrin required for the control of H. armigera on tomato in the study area.