Wind Dispersal of the Twospotted Spider Mite (Acari: Tetranychidae) in North Carolina Peanut Fields

Abstract

The role of wind dispersal in the ecology of Tetranychus urticae Koch in North Carolina peanut fields was evaluated. Laboratory experiments demonstrated that even low-level infestations of T. urticae were dispersed by winds of only 8 km/h. However, the most mites were dispersed by 24-km/h winds when mites were massing. In the field the number of T. urticae caught was inversely proportional to trap height, and most mites are caught at about the height of peanut plants (0.6 m). More mites were caught blowing from southerly directions along with the predominant summer winds than from any other direction; however, mites were blown in all directions. Pesticides which caused T. urticae populations to increase in peanut fields resulted in significant increases in aerially dispersing mites. Mites were dispersed by wind in all treatments, on all dates, and with all populations measured.