Studying the effectiveness of bio-prepared silver nanoparticles by the Beauveria bassiana fungus in some biological aspects for cowpea weevil (Callosobruchus maculatus (Fab)) in vitro

Abstract

ABSTRACTA laboratory study was conducted in the laboratories of the College of Agriculture, University of Tikrit, where the study showed that bio-prepared silver nanoparticles from the Beauveria bassiana fungus have an active effect in some biological aspects for cowpea weevil (Callosobruchus maculatus). The results of the study revealed the possibility of bio-preparation of silver nanoparticles using the biomass for the B. bassiana fungus. Silver nanoparticles (AgNPs) were diagnosed by changing the color of the fungus filtrate that added to the AgNO3 silver nitrate solution from colorless or aqueous white to pale yellow and red, and the absorbance peaks were recorded using UV-VIS Spectrophotometer, where it was observed that the highest absorption appeared at Wavelength of 418 nm, which represents the absorption peak for silver. The electron microscope images showed the sizes of the nanoparticles, which appeared in spherical shapes, and their sizes ranged between 18-23.5 nanometers. This indicates the efficiency of the biosynthesis for silver particles by the studied fungus. The study also showed significant effects for the bio-prepared silver nanoparticles by B. bassiana fungus on the biological aspects for C. maculatus, where the lowest average number of laid eggs was 19.33 eggs, the lowest average number of emerging insects was 7.83 insects, The lowest percentage of productivity amounted to 34.18% at the concentration of 100% for silver nanoparticles compared to the two control treatments, where the average number of eggs laid in them was 101.50, 110.16 eggs, the average number of emerging insects was 99.16, 108.33 insects, and the percentage of productivity was 97.99, 98.40% for both distilled and deionized water, respectively. The percentage of prevent laying eggs (repellency) and the percentage of decreasing the individuals of the first generation increased with increasing concentration and soaking time, where the highest percentage for preventing laying egg (repellency) amounted to 87.27%, The highest percentage of decreasing the individuals of the first generation was 97.56% at a concentration of 100% and a 20-minute soaking period. The results showed that the inverse relationship between concentration and the percentage of infection with insects, where increasing the concentration of AgNPs reduced the percentage of infection with insects, where it led to a significant decrease in the percentage of loss in weight of cowpea seed. The concentration of 100% gave the lowest percentage of loss amounted to 5.78%.