Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Technical Abstract: An evaluation of silverleaf whitefly preference among 22 Pima cotton genotypes varying in pubescence, leaf shape, leaf size, foliar color, and maturity time was conducted in the field at Maricopa, AZ in 1995 and 1996. In 1995, test plots consisted of single row plots, 9.1 m long, separated by two rows of the commercial cultivar, Pima S-7. In 1996, test plots consisted of four row plots, 9.1 m long, separated by two rows of Pima S-7 Adult whiteflies were counted on the fifth mainstem leaf below the apical meristem on 10 plants per plot. Leaf discs were removed from 5 leaves per plot for determination of egg, nymph, and leaf trichome numbers. Reduced egg and nymph numbers which approached significant deviation from the established linear relationships were observed in two red plant genotypes. The extremely glabrous entries Sea Island St. Vincent, DPL 5415, and Gossypium thurberi exhibited very low whitefly egg and nymph populations which conformed to the linear relationships between trichomes, eggs, and nymphs. The use of the linear regression to identify trichome independent whitefly resistance sources appears to be a successful methodology and should prove useful in further efforts. Analyses of 1996 data continue, as does analyses of whitefly behavior in no-choice cage experiments initiated in 1996.