This study investigated the impact of chitosan & silver and their nanoparticles against the biochemical and histological aspects of the black cutworm, Agrotis ipsilon and the land snail Monacha obstructa. The activities of three vital enzymes [Aspartate amino transaminase (AST), Alanine amino transaminase (ALT) and acetyl cholinesterases (AChE)], total protein (TP) and total lipid (TL) were laboratory assayed. Results showed that chitosan and silver treatments increased the activity of AST, ALT and AChE in A. ipsilon and M. obstructa. On the contrary, chitosan and silver nanoparticles decreased the activity of these enzymes.
            On the other hand, the levels of total protein and total lipid were decreased after treatment with all tested materials. In general, chitosan and silver nanoparticles affected the activities of enzymes, total protein and total lipid compared with control when applied against the tested cutworm larvae and snail. Meanwhile, many histological changes were observed in mid-gut of A. ipsilon larvae and the digestive gland of M. obstructa after treatments with   LC₅₀'s of both nano chitosan and nanosilver.
            Obtained data from this study suggest the possible use of chitosan and silver nanoparticles as alternatives to conventional pesticides and compatible with integrated pest management practices.