Effect of Tillage on Cotton Aphids (Homoptera: Aphididae), Pathogenic Fungi, and Predators in South Central Georgia Cotton Fields

Two species of fungi, Neozygites fresenii Nowakowski (Batko) and Pandora neoaphidis Remaudiere and Hennebert (Humber), pathogens of the cotton aphid, Aphis gossypii Glover, were studied in 12 south central Georgia cotton fields under conservation or conventional tillage in 2003 and 2004. Aphids and ants on cotton plants were enumerated in both years, and aphid predators (coccinellids, lacewings, and spiders) were counted in 2004. Plant sampling began the first week of June and continued for 16 wks in 2003 and for 14 wks in 2004. Numbers of aphids on cotton plants increased until the first week of July and declined thereafter. More aphids were present on plants in 2004 than in 2003 for the first 9 wks of sampling, but did not differ thereafter. More aphids were present on plants under conservation tillage than under conventional tillage only between weeks 3–8. Pandora neoaphidis was detected in aphids in midMarch by monitoring with pan traps on field margins. Neozygites fresenii, in contrast, was not obser...