Sublethal Effects of Chitosan-O-Arginine, a Chitosan Based Insecticidal Compound against Green Lacewing Chrysoperla zastrowi sillemi (Esben-Petersen)

Abstract

The widespread application of synthetic chemicals leads to the unintended negative impact to non-target organisms both directly or indirectly, as these chemicals can infiltrate new environments, disrupting established ecological niches. Laboratory experiments explored the effects of sublethal doses of Cs-O-Arg to the third instar grubs of Chrysoperla zastrowi sillemi when fed with treated and untreated larvae of diamondback moth (DBM). The results showed that when the untreated third instar C. zastrowi sillemi grub was fed with treated P. xylostella larvae at LC25, LC35 and LC45 concentrations, there was 6.67 per cent mortality of C zastrowi sillemi grub at all the concentrations, after 48 and 72 hours of exposure. but, when the treated C. zastrowi sillemi grubs (LC35 and LC45) were fed with untreated P. xylostella, there was only 3.33 and 10.00 per cent mortality of C. zastrowi sillemi grubs, respectively. Whereas, Cs-O-Arg caused 33.33 per cent mortality when LC45 treated grubs were provided with LC45 treated DBM larvae as feed, whereas the treatment with LC25 concentrations of Cs-O-Arg resulted in the highest pupation percentage (76.67%) and adult emergence rate (73.33%) in C. zastrowi sillemi grubs when fed with DBM larvae treated with the same concentration. Chitosan derivative insecticide causes a mild adverse impact on the survival of the economically significant insect predator C. zastrowi sillemi, which hold valuable implications for guiding decisions regarding the compatible utilization of insecticides alongside C. zastrowi sillemi or other natural predators within integrated pest management strategies.