Differences in Aceria tosichella population responses to wheat resistance genes and wheat virus transmission

Severe winter wheat yield losses due to infestations of wheat curl mite, Aceria tosichella Keifer, and mite-transmitted viruses occur in wheat production areas of the United States and Canada. Mite infestation alone causes stunted, chlorotic plants in susceptible wheat varieties, and mites transmit Wheat Streak Mosaic (WSMV), High Plains Wheat Mosaic (HPWMoV), and Triticum Mosaic Virus (TriMV). Wheat curl mites were collected from 25 sites in Kansas, Missouri, Nebraska, Texas, North Dakota, and South Dakota in 2014 and 2015. At each site, mite virulence was determined to wheat plants harboring the Cmc2 -, Cmc3 -, or Cmc4 mite resistance gene; or Cmc4 plus the Wsm2 WSMV resistance gene. Mites collected from 92%, 36%, and 24% of sites were virulent to susceptible Jagger wheat plants (no Cmc ), Cmc2 , and Cmc3, respectively. The mega-population consisting of all 25 mite sub-populations was avirulent to 80% of plants containing Cmc4 + Wsm2 or Cmc4 . WSMV, HPWMoV, or TriMV was present in mites at 76%, 16%, and 8% of the 25 sites, respectively. Our results will enable breeders to increase the efficiency of wheat production by releasing wheat varieties containing wheat curl mite resistance genes that reduce wheat yield losses.