Evaluation of Some Insecticides Against Citrus Flower Moth, Prays citri (Millière) (Lepidoptera: Hyponomeutidae) on Lime Trees

Abstract

A field experiment was conducted to evaluate and compare the effectiveness of two bioinsecticides, Bacillus thuringiensis kurstaki and Beauveria bassiana, and three chemical insecticides, belonging to two recently introduced and widespread groups, avermectin (emamectin benzoate and spinosad) and oxadiazine (indoxacarb), against the citrus flower moth, Prays citri (Millière), on lime trees. The results showed that, based on the general mean reduction percentages of P. citri immature stages, there were significant reductions in tree infestation and significant differences among the five insecticides. According to Chi square analysis, these insecticides could be separated into two groups; the first group included indoxacarb, which showed the highest mortality (77.6%), emamectin benzoate (74.9%), B. thuringiensis kurstaki (72.5%) and spinosad (71.3%). The second group was B. bassiana, which resulted in a low mortality (63.6%). The general trend was found in the second year (2023), where they were also divided into two groups. The first one included indoxacarb (74.1%), spinosad (70.2 %) and emamectin benzoate (68.2%). The second group, thuringiensis kurstaki and B. bassiana, showed low mortality (57.2% and 50.1%, respectively). In addition, all the applied insecticides significantly enhanced the yield based on the fruit weight and the number of fruits per tree.