Parasitism Rate and Intrinsic Rate of Increase of Aphidius colemani on Aphis gossypii Under Greenhouse Conditions

Abstract

Biological control using parasitoid wasps is an important component of integrated pest management programs targeting aphid infestations in protected cultivation systems. The present study evaluated the parasitism rate and intrinsic rate of increase of Aphidius colemani on Aphis gossypii under greenhouse conditions. Laboratory-reared parasitoids were introduced onto aphid-infested host plants maintained under controlled greenhouse environments, and observations were recorded on parasitism efficiency, developmental duration, adult emergence, longevity, fecundity, and population growth parameters. The results demonstrated that A. colemani effectively parasitized A. gossypii populations, resulting in significant reductions in aphid density and population growth. Parasitism rates varied according to aphid density, host plant conditions, and environmental factors within the greenhouse. Higher parasitism efficiency was observed at moderate aphid populations, indicating favorable host utilization and reproductive performance of the parasitoid. The intrinsic rate of increase of A. colemani indicated rapid population establishment and strong adaptation to greenhouse conditions. Successful parasitoid development within aphid hosts resulted in high adult emergence and effective suppression of aphid populations. Environmental conditions such as temperature and relative humidity significantly influenced parasitoid activity, survival, and reproductive capacity. The predator–parasitoid interaction demonstrated the potential of A. colemani as an efficient biological control agent against A. gossypii in protected cultivation systems. The findings highlight the ecological importance of parasitoid-based pest management approaches and support the integration of biological control agents into sustainable greenhouse pest management programs. This study provides valuable information for optimizing mass-rearing techniques and release strategies aimed at improving aphid control efficiency and reducing dependence on chemical insecticides.