Efficacy of selected biopesticides against the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in Lusaka, Zambia

Abstract

The aim of this research was to evaluate the efficacy of four commercially available biopesticide for[1]mulations, Azadirachtin indica, Beauveria bassiana, Metarhizium anisopliae and Verticillium lecanii in the management of Tuta Absoluta (Meyrick)(Lepidoptera: Gelechiidae) under laboratory and field conditions. Analysis of variance (ANOVA) using Fisher’s least significant difference test (α = 0.05) showed that the mean percent mortality ranged from 41.3±6.8% to 77.9±14.3%. A. indica caused the highest mortality of 77.9±14.3% while mortality due to B. bassiana, V. lecanii, and M. anisopliae was 48.3 ± 2.8%, 44.8 ± 4.8% and 41.3 ± 6.8%, respectively. The estimated LC50 for A. indica was 30.4 µL±0.4, while LC50 for B. bassiana, M. anisopliae, V. lecanii were 107.1 µL±0.4, 193 µL±0.4 and 118.7 µL ± 0.4, respectively. Biopesticide efficacy on larval mortality from highest to least was A. indica, B. bassiana, V. lecanii and M. anisopliae respectively. Percentage corrected mortality ranged from A. indica (69.8 ± 8.1 to 88.4 ± 41.9%), B. bassiana (32.6 ± 4.0% to 60.5 ± 16.3%), V. lecanii (30.2 ± 1.7% to 55.8 ± 14.6%) and M. anisopliae (32.6 ± 4.0% to 53.5 ± 5.4%) respectively. The selected biopesticides significantly (P < 0.001) reduced T. absoluta egg count compared with the untreated control. Performance ranged from A. indica (2.8 ± 1.1 and 10.7 ± 1.2), B. bassiana (3.0 ± 0.6 and 10.7 ± 1.9), V. lecanii (4.3 ± 1.2 and 11.7 ± 1.4) and M. anisopliae (6.8 ± 1.4 and 13.0 ± 1.6) for egg mortality, respectively. The study showed that selected biopesticides were effec[1]tive and should be used by farmers as an integral component of Integrated Pest management (IPM) in the control of T. absoluta in Zambia. Further research should evaluate the effectiveness of the selected biopesticides in other agroecological zones of Zambia