Inhibition of antennal response of the tomato leaf miner males, Tuta absoluta (Lepidoptera: Gelechiidae) to its sex pheromone under the influence of three insecticides in an electrophysiological study

The tomato leaf miner moth Tuta absoluta Meyrick is an invasive pest of tomato which damages this crop economically in greenhouse and field conditions. Due to the endophytic feeding habits of larvae and the high fecundity, the resistant populations has developed. Based on the effect of chemical pesticides on the mating disruption efficacy, it is therefore possible to exploit novel approaches on the use of insecticides against this pest. In this study, the efficacy of 3 insecticides, imidaclopride, indoxacarb and NeemAzal, with different mode of action, in 4 concentrations (0, 1, 10, 100 μg/ml) were assayed on Electroantennogram response of antennal receptors of 2-3 days old males to sex pheromone. The antennal responses rate to sex pheromone were measured during 6 time intervals, after insecticide spray and were calculated as inhibitory percentage in comparison to the response rate before spray and the data was analysis by repeated measure method. The results showed a significant difference between different concentrations of each insecticides compared to the control, the time of EAG assay and also the interaction effects of these factors, while, there was no significantly difference between tested pesticides. All insecticides were inhibited the antennal response in range of 18-20%. There was a dose- dependent relationship between concentration levels of each insecticides and the highest inhibition percentage was calculated in 100 μg/ml. The results confirmed the inhibitory effect of the tested insecticides on the antennal receptors leading to disruption of their response to sex pheromone.