For several years west Texas farmers and entomologists have dealt with large populations of the cotton aphid. Control problems with all available classes of insecticides began occurring in 1989 and have spread and intensified since that time. The need for a cultural based system for cotton aphid management has never been greater than it is at present.

In one study, several cotton varieties were screened to determine the sizes of cotton aphid populations they are prone to develop and support. Although sufficient data was generally not available to define tight confidence intervals, the data indicate that generally lower cotton aphid populations are associated with some cotton varieties.

In another study, petiole nitrates were shown to differ between varieties. A non-significant trend toward higher aphid levels on the varieties with higher petiole nitrate levels was observed. Finally, petiole nitrate levels and cotton aphid populations were found to be negatively correlated during the period of rapid aphid population increase. Therefore, the aphid population is entering the rapid growth stage at the same time that petiole nitrate levels are in their steepest decline.