干旱区生态环境知识资源中心

Deltapine cotton cultivars are widely accepted for commercial production in the desert southwestern region of the United Stales. They also are good reproductive hosts for the silverleaf whitefly, Bemisia argentifolii Bellows and Perring (Homoptera: Aleyrodidae). This paper reports results of studies conducted to determine the relationship between depth of leaf vascular bundles from underleaf surfaces and B. argentifolii colonization. We also determined the effect of cotton cultivar on B. argentifolii nymphal parasitism and effects of B. argentifolii population densities on cotton yield and lint stickiness. Results showed that the distance from cotton underleaf surfaces to the center of minor vascular bundles was negatively related to whitefly adult and nymphal densities on cotton. This leaf character is important for breeding and selection of resistant varieties because the deeper minor vascular bundles may be beyond the reach of the stylets of first instars. Percentages of the nymphs parasitized were significantly different among tested cultivars indicating the potential for reducing whitefly colonization by breeding varieties that are more attractive to parasites, although percentages of nymphs parasitized were not correlated with numbers of adults, eggs, and nymphs. Cotton yields decreased with increasing whitefly populations, Cotton line stickiness increased with increased whitefly populations.