Spatial Distribution of Lesser Date Moth Batrachedra amydraula (Meyrick) Infestation on Date Palm in Basra City and the Field Efficacy of Selected Chemical Insecticides and Their Synergistic Interaction with Silver Nanoparticles

Abstract

The lesser date moth, Batrachedra amydraula, is one of the most serious insect pests infesting date palm fruits, causing substantial losses in both yield and fruit quality. This is particularly critical in regions where date production serves as a cornerstone of food security and economic stability. The present study aimed to assess the spatial and temporal distribution of pest infestation across three districts in Basra Province (Abi Al-Khasib, Shatt Al-Arab, and Al-Qurnah), evaluate the susceptibility of five date palm cultivars (Halawi, Sayer, Khadrawi, Barim, and Barhi) to infestation, and compare the efficacy of five chemical insecticides (Abamectin, Alpha Cypermethrin, Actellic, Matrixine Plus, and Deltamethrin), as well as the synergistic effect of their combination with silver nanoparticles, applied at two different spray timings. The results revealed significant variation in fruit drop rates among the study locations, with Shatt Al-Arab recording the highest rate at 67.27%. The second sampling period (24 days post-pollination) was identified as the most critical period for infestation. Regarding cultivar susceptibility, Halawi and Sayer exhibited the highest fruit drop rates, reaching 47.73% and 41.15%, respectively. Among the tested insecticides, Matrixine Plus proved to be the most effective in reducing fruit drop compared to the other treatments. Notably, the combination of this insecticide with silver nanoparticles, particularly at the concentration of 1 ml insecticide + 0.5 g nanoparticles, significantly enhanced its efficacy, achieving a zero fruit drop rate under certain conditions. These findings suggest that integrating chemical insecticides with silver nanoparticles offers a promising strategy for improving pest control efficiency and minimizing the damage caused by B. amydraula. Early application timing is also recommended to ensure optimal fruit protection.