Reproductive Capability of the Wheat Curl Mite (Aceria tosichella Keifer) on Alternative Hosts

Wheat is an important food crop worldwide, and it is the primary crop in dryland cropping systems in the western Great Plains. The wheat-mite-virus complex is the second largest cause of disease loss in winter wheat production in this region. This complex consists of three viruses, Wheat streak mosaic, Wheat mosaic, and Triticum mosaic viruses. All of these viruses are transmitted by the wheat curl mite (WCM). Widespread outbreaks of this complex are often linked to pre-harvest volunteer wheat; however, other grass species have been implicated as important over-summering hosts. Previous research indicates that there are over 90 reported hosts for wheat curl mites. Detailed research about these alternative hosts and their role in the wheat-mite-virus complex is limited. The objective of this study was to determine the reproductive capability of wheat curl mite on some of these alternative hosts and the reproductive rate of mites when returning to wheat from these hosts.  Winter wheat, jointed goatgrass, barnyardgrass, green foxtail and foxtail millet were infested with 10 mites from two distinct mite genotypes (Type 1 and Type 2) with population counts taken every seven days up to 42 days. Each treatment was replicated 16 times. Results indicate significant and consistent reproduction of mites on the primary host wheat, followed by jointed goatgrass, and barnyardgrass. Mite reproduction was erratic on green foxtail and very poor on foxtail millet. This study provides the first documentation of consistent mite reproduction on barnyardgrass, which could serve as an important over-summering host for the wheat curl mite.