Coccinellids Associated with the Cotton Aphid (Homoptera: Aphididae) in Northeast Arkansas Cotton

摘要

Adult and larval coccinellids are important predators of the cotton aphid, Aphis gossypii Glover, in cotton, Gossypium hirsutum L. Adult and larval Coccinellinae and Scymninae were sampled by beat-pan method and identified to species in a 3-year field study (1999 - 2001) conducted in northeast Arkansas. The coccinellids observed in descending order of abundance were Hippodamia convergens Guerin, Scymninae (Scymnus spp. and Diomus spp.), Coleome-gilla maculata (Degeer), Harmonia axyridis (Pallas), and Coccinella septempunctata L. Population dynamics and community structure by species for C. maculata, H. axyridis and C. septempunctata were unpredictable within and among years. Based on population densities, timing of colonization, and consistent delayed density-dependent relationship with aphid populations, H. convergens and Scymninae genera (Scymnus spp. and Diomus spp.) were the most important predators of cotton aphids in northeast Arkansas.