ABSTRACT
The development of cotton aphid, Aphis gossypii Glover, populations in relation to planting date, plant spacing, environmental variables, and plant nutritional status has been studied at Chillicothe and Lubbock, Tex. for the past four years. Average population density has increased each year in the Texas Rolling Plains, and these increases are thought to be related, in part, to a decrease in solar radiation. Planting date affects population density also; and greatest numbers are consistently found in cotton planted in late June, as compared with population densities in cotton planted in late April and late May. Rapid population increase occurs during August. There is a significant, positive correlation between aphid numbers and percent leaf moisture content. Greatest aphid numbers have been recorded in plant spacings of 0.5 plants per row foot.
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