Cellular Immune Response of Rice Weevil Sitophilus oryzae to Nanospray and Nanogranule Formulations of Aspergillus flavus

Entomopathogenic fungi are a sustainable alternative for controlling stored product pests, emphasizing the need to identify highly virulent isolates for optimal efficacy. The bioformulations of nanospray (25, 50, 75 and 100%) and nanogranules (0.16, 0.48 and 1.04g) of Aspergillus flavus were prepared in different concentrations. The dose-dependent variation of the increase in mortality percentage was recorded in nanospray and nanogranules against Sitophilus oryzae. The 100% EPF nanospray was the most effective, achieving 100% mortality within 10-12 days. Among the different concentration of the nanogranules tested, 1.04g EPF nanogranule recorded 100% mortality. The impact of nanospray and nanogranules on the haemocyte of the S. oryzae, by giving 24 hr exposures changed the morphology of haemocyte, coagulation of cells, increased oenocytoids and degranulation. From the present study, it was evident that the 0.48g and 1.04 g concentrations of EPF nanogranules exhibited potent insecticidal activity by preventing pest emergence and minimizing grain weight loss during storage.