An evaluation of management tactics for the wheat curl mite (Aceria tosichella Keifer) and the wheat-mite-virus complex

Wheat is an important food grain worldwide, and it is the primary dryland crop in the western Great Plains. A complex of three viruses (wheat streak mosaic, wheat mosaic, and triticum mosaic viruses) is the largest cause of disease loss in winter wheat production in the western Great Plains. These viruses are transmitted by the wheat curl mite (WCM) (Aceria tosichella Keifer). Once these viruses are established there are no curative actions; therefore, prevention is the key to successful management. The objective of the study was to evaluate the virus resistance of different varieties under different planting dates. A split-plot experimental design was used with four replications during four crop seasons at the Panhandle Research and Extension Center at Scottsbluff, NE (2007-08, 2008-09) and Agricultural Research and Development Center near Mead, NE (2009-10, 2010-11). The main treatments were three planting dates and the split plot treatments were three wheat varieties. The varieties were planted at three different times during the fall to simulate early, recommended, and late planting dates. The varieties evaluated in this study were Mace (virus resistant), Millennium (mild tolerance), and Tomahawk (susceptible). Measurements of fall mite activity, virus symptomology, and yield were used to determine virus presence and impact. The results indicate a significant effect among resistance varieties. The early planting of wheat showed significant virus impact (i.e. symptoms and yield) for all varieties, indicating the need for integrating management options for all varieties.