Are Cotton Water Stress, Age, and Cultivars Moderating Factors of Cotton Fleahopper Abundance and Associated Yield Loss?

Field experiments were conducted in 2012 and 2013 during drought conditions in South Texas and the Texas High Plains to test whether cotton water stress, age, and cultivars are moderating factors that affect cotton fleahopper abundance and associated harvest loss. Irrigation and sequential plantings were used to simulate a range of water regimes and plant ages of several cultivars exposed to cotton fleahopper using natural and artificial infestation. Cotton cultivars had a strong influence on cotton fleahopper abundance. No water regime effects on cotton fleahopper densities were seen in 2012, while cotton fleahopper densities increased on older cotton grown under no water stress in 2013 in South Texas (P < 0.05). In contrast, yield response was primarily sensitive to soil moisture conditions (up to 50% yield reduction from 90% crop ET replacement water regimes to dryland mimic conditions), while there was much more modest yield loss attributable to cotton fleahopper activity. In the Texas High Plains, yield sensitivity to cotton fleahopper increased under dryland conditions. These trends were consistent across cultivars (no interaction with cultivar), even though cotton fleahopper populations varied significantly across cultivars. Overall, our data supported only a modest water stress influence on cotton fleahopper dynamics and cotton sensitivity to cotton fleahopper feeding. Strong cultivar influences on cotton fleahopper dynamics were seen but they did not correspond to yield reduction.