Synthesis , antifungal and insecticidal potential of Chitosan ( CS ) - g - poly ( acrylic acid ) ( PAA ) nanoparticles against some seed borne fungi and insects of soybean

Chitosan (CS)-g-poly (acrylic acid) (PAA) nanoparticles, which are well dispersed and stable in aqueous solution have been prepared by template polymerization of acrylic acid in chitosan solution. The prepared CS-PAA had a white powder shape and was insoluble in water and diluted acid. The mean particles size were found to be around 50nm. FTIR spectra of CS-PAA nanoparticles for CS, the intensities of the amide band were observed clearly. The board peak appeared at 2500cm -1 , which confirmed the presence of NH3 + in the CS-PAA nanoparticles. The percentage of fungal infection of soybean seeds was ranged from 78.57 and 92.00% for samples of clark and calland soybean cultivars respectively on PDA medium, while the number of fungi as cfu/100 seeds was 156.12 and 440 respectively. Isolation trails showed eleven fungi comprising seven genera namely, Alternaria tenuis, Aspergillus flavus, A. niger, A. terreus , A. versicolor, Fusarium oxysporum, F. solani, Mucor mucedo, Penicillium spp., Rhizoctonia solani and Sclerotium rolfsii detected and identified on PDA medium. Nanochitosan (CS-g-PAA) showed a remarkable antifungal effect against some fungi isolated from soybean seeds. The % inhibition of F. oxysporum for example was significantly high ( 41.04 mean % inhibition) than the other tested fungi, followed by A. terreus and F. solani ( 40.08 and 40.00 mean % inhibition respectively. Regarding zone of inhibition, nano-chitosan exhibited high inhibition against Aspergillus niger, followed by Fusarium solani and F. oxysporum, as the zone of inhibition were 20.67, 20.33 and 20.33 mm at 100 ppm respectively. Concerning the insecticidal activity the nano-chitosan (CS-g-PAA) showed highest effect against the three insect of soybean. as the means number of eggs deposited /female were significantly decreased. Under laboratory and semifield condition, Aphis gossypii were significantly decreased to 20.9±9.1 and 28.9±9.2 eggs/female respectively as compared to 97.3±4.9 and 90.3±4.9 eggs/female in the control, respectively. The same trends were also observed against Callosobruchus maculatus and Callosobruchus maculatus insects.