ABUNDANCE OF 2 WHITEFLY SPECIES (HOMOPTERA, ALEYRODIDAE) ON GEORGIA SOYBEAN

'Braxton' and 'Cobb' soybeans were surveyed every 7 to 10 days from mi d-July through September, 1993 and 1994, to determine the seasonal abu ndance of the silverleaf whitefly, Bemisia argentifolii Bellows and Pe rring, and the bandedwinged whitefly, Trialeurodes abutilonea (Haldema n). Population densities peaked in early September 1993, at over 31 eg gs and nymphs per 2.54 cm(2) of leaf area on Cobb soybeans (a Maturity Group Vm variety), and 15 eggs and nymphs on Braxton soybeans (a Matu rity Group VII variety). Silverleaf whitefly was the predominant speci es on all sampling dates throughout the season. At the population peak , there were 14.4 silverleaf whitefly and 3.3 bandedwinged whitefly ny mphs per 2.54 cm(2) on Cobb and 8.8 silverleaf whitefly and 2.0 banded winged whitefly nymphs on Braxton. Whitefly population densities peake d in late September 1994, at over 6 eggs and 59 nymphs on Cobb and 1 e gg and 18 nymphs on Braxton. The whitefly population in 1994 was compr ised almost exclusively of silverleaf whitefly, with 58 and 17 nymphs per 2.54 cm(2) on Cobb and Braxton, respectively, on 23 September comp ared to less than 1.0 bandedwinged whitefly on each of these varieties . At the population peak each year, there were significantly more eggs and silverleaf whitefly nymphs on the upper trifoliolate leaves than on the lower trifoliolate leaves.