Efficacy of mass trapping of tomato moth, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), using a new-designed light trap in reducing leaf and fruit damages in greenhouse-grown tomatoes

Abstract

The tomato moth, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is one of the most damaging pests of tomato crop in Turkey and is of great economic importance in greenhouse-grown tomatoes. Current control of this pest has heavily relied on the use of synthetic insecticides, inducing the selection of resistant T. absoluta populations and negative environmental impact. In this study, the efficacy of mass trapping using a new-designed light trap (so-called ecosav-D1) in reducing leaf and fruit damages in greenhouse-grown tomatoes was investigated in Antalya (in southwest Turkey). Trials were carried out in commercial plastic greenhouses equipped with insect-proof nets in both autumn–winter and summer–autumn tomato growing seasons in 2019 and 2020. In each season, the study greenhouse was divided into two equal plots using anti-insect net (40 mesh); in one of them, the new-designed light trap was tested at a density of 1 trap/250 m², and in the other one, conventional control system, based largely on the use of synthetic pesticides, was implemented for comparison. In the light trap plot, total number of adult T. absoluta, other pests and beneficial insects caught per trap was recorded weekly. The efficacy of mass trapping in reducing leaf and fruit damages was evaluated by comparing weekly damage on leaves (number of larval mines on 1 leaf per plant on 50 randomly chosen plants) and percentages of damaged fruits in each harvest date in both plots. Results showed that mass trapping of adult T. absoluta using the new-designed light trap was effective in reducing leaf and fruit damages at low/moderate T. absoluta population density in autumn–winter growing season. Considering the seasonal averages, significantly lower leaf and fruit damages were observed in the light trap plot (3.2 larval mines/leaf/plant and a fruit damage of 13.4%) than in the conventional plot (6.9 mines/leaf/plant and 18.3%, respectively). On the other hand, although the light trap significantly reduced leaf and fruit damages during the summer–autumn growing season, it was partially ineffective when the pest density soared at the end of the tomato cultivation. In both growing periods, higher densities of tomato moth resulting in much more leaf and fruit damages were observed in the conventional plot, compared with the trap plot. Overall results suggest that the new-designed light trap can be an effective tool for the integrated pest management (IPM) of this pest in greenhouse tomato cultivation.