Lethal and sublethal effects of botanical insecticide, tondexir (Tondexir®) and chemical insecticide, indoxacarb (Avaunt®) on the tomato leaf miner, Tuta absoluta (Meyrick) (Lep.: Gelechiidae)

The tomato leaf miner, Tuta absoluta (Meyrick) is the most damaging tomato insect pest. In the present study, the lethal effects of plant insecticide, tondexir (Tondexir®) and chemical insecticide, indoxacarb (Avaunt®) were assessed against T. absoluta under laboratory and field conditions. The sublethal (LC30) effects of the insecticides were evaluated on the life table parameters of T. absoluta. The potter tower was used for the bioassays. In order to define the effect of these compounds, an experimental field was carried out in a randomized complete block design with three treatments replicated four times during two consecutive seasons in 2017 and 2018. The LC50 values of tondexir and indoxacarb on eggs of T. absoluta were 837.9 and 1139.1 ppm, respectively. Sublethal concentration of insecticides affected life table parameters of T. absoluta significantly. Embryonic, larval, pupal and TPOP periods were significantly higher in tondexir than the control. Intrinsic rate of increase (rm) value in both insecticides treatments was significantly lower than control (P<0.05). The minimum value of λ (1.105 day-1) and the longest generation time (39.36 day) was observed in tondexir. The persistency effect of tested insecticides under field conditions was higher in tondexir than indoxacarb. Even 21 days after treatment, the percentage mortality of eggs and larvae of T. absoluta were significantly higher in plot that treated with tondexir than indoxacarb treatment. The total results revealed that tondexir had high lethal and sublethal effects on tomato leafminer and can be recommendable to be applied in an integrated pest management program (IPM) of this pest.