Investigating the Natural Mortality of Aphis gossypii (Hemiptera: Aphididae) on Cotton Crops in Tropical Regions Using Ecological Life Tables

Abstract

Studies on the natural factors contributing to pest regulation are fundamental to developing efficient integrated pest management programs. Chemical control is the main management method used for pests [e.g., Aphis gossypii (Glover)]. The studies of pest management with chemical control provide information that can be incorporated into integrated pest management programs to promote more sustainable pest control approaches. Here, we report the critical stages of A. gossypii and its abiotic and biotic natural mortality factors in cotton crops as a function of plant phenology using a life table. The critical stages of A. gossypii were the first and fourth instars. Together, the abiotic and biotic factors caused 94.31% of the mortality in the A. gossypii populations in cotton crops with plants in the vegetative, flowering, and fruiting stages. The key mortality factors were rainfall and predation. Syrphidae Allograpta exotica (Wiedemann) (Diptera: Syrphidae) and Chrysopidae Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) larvae, many Coccinellidae species Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae), Eriopsis connexa (Germar) (Coleoptera: Coccinellidae), Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), Hippodamia convergens (Guérin-Meneville) (Coleoptera: Coccinellidae), Scymnus rubicundus (Erichson) (Coleoptera: Coccinellidae) and Stethorus punctillum (Weise) (Coleoptera: Coccinellidae), one Anthocoridae species Orius insidiosus (Say) (Hemiptera: Anthocoridae), and individuals from the Araneidae family were responsible for the predation of A. gossypii. The results obtained in this study provide support for the idea that efforts to preserve natural enemies (e.g., predators) and rainfall monitoring should be adapted due to their importance for the regulation of A. gossypii populations in all the phenological stages of cotton in tropical regions.

Keywords: cotton aphid; life table; natural mortality; predation; rainfall.