Population Dynamics of the Wheat Curl Mite (Acari: Eriophyidae) During the Heading Stages of Winter Wheat.

The wheat curl mite (Aceria tosichella Keifer) is the only known vector of three viruses in wheat-Wheat streak mosaic virus, Wheat mosaic virus, and Triticum mosaic virus. The economic impact of this disease complex is linked to the presence of suitable hosts prior to winter wheat maturing in early summer and the movement of wheat curl mite from wheat to oversummering hosts prior to wheat harvest. Previous research has documented the prevalence and density of mite populations on maturing wheat heads; however, these studies were limited to a few late stages of wheat. A study was conducted to evaluate mite population densities across all stages of head development to determine when wheat curl mites are most abundant and the relative increase in abundance over time. In addition, a study was conducted to evaluate the impact of rainfall on mite populations during wheat heading. A final study was conducted to determine the potential for direct infestation of seedlings germinating from wheat curl mite-infested wheat heads. Results showed a rapid buildup in mite populations from low densities in early heading and peaking at the hard dough stage, with nearly all wheat heads having some mite presence. In addition, high mite populations resulted in direct infestation of germinated seedlings from the early through hard dough stages. Rainfall applications had no observable impact on mite population densities in wheat heads. These results demonstrate the increased potential for mites to infest hosts prior to winter wheat maturing and illustrate the increased risk for these hosts to serve as oversummering hosts.