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Interactions between the wheat curl mite, Aceria tosichella Keifer (Eriophyidae), and wheat streak mosaic virus and distribution of wheat curl mite biotypes in the field
The wheat curl mite (WCM), Aceria tosichella Keifer, is a vector of wheat streak mosaic virus (WSMV), the causal agent for wheat streak mosaic (WSM), a serious disease of winter wheat in the western Great Plains in the United States. WCM utilizes volunteer wheat as a "green bridge" host to over-summer and re-infest fall planted winter wheat. Therefore, the primary management of WCM and WSMV relies on managing the vector by eradicating the "green bridge" host. In some growing areas, mite-resistant wheat varieties have also been used. ^ The transmission efficiency of WSMV by different developmental stages of WCM was investigated by transferring single mites from infected plants onto uninfected plants at various stages and allowing them to establish colonies. WSMV was transmitted by all stages of WCM except the egg. When single mites were transferred at various growth stages, WSMV transmission rates varied. Adults that were transferred onto uninfected wheat plants transmitted WSMV 52% of the time, but nymphal mites transmitted 83% of the time. Mites transferred while in the quiescent stage before each molt transmitted virus 94% of the time, indicating that mites maintain their ability to transmit WSMV through each molt. These results indicate that all stages of WCM have significant ability to transmit WSMV. ^ The relationship between WSMV and WCM was studied by determining the impact of the presence of four cereal viruses in wheat on WCM reproduction. This relationship was also tested for three WCM biotypes (Nebraska, Montana, and South Dakota) on WSMV-infected wheat plants. WCM have increased ability to reproduce and maintain their population on WSMV-infected plants compared to other cereal virus-infected plants. This reproductive response varies among WCM biotypes, with only the 'NE biotype' showing increased reproduction. Increased reproduction rates of mites leads to greater potential for virus spread. ^ Because of the important biological differences between WCM biotypes, Polymerase Chain Reaction-Restriction Fragment Length Polymorphisms (PCR-RFLP) of mitochondrial DNA (mtDNA) and ribosomal DNA (rDNA) was used to examine genetic variation of WCM at various spacial scales in Nebraska, Kansas, and Montana wheat fields in 2003-2005. The PCR-RFLP results showed that WCM can be separated into two types, type 1 (NE biotype) and type 2 (all other biotypes). The analysis of molecular variance (AMOVA) showed that the majority of the WCM genetic variability occurred within wheat heads (∼50%) compared to sites within fields, fields or states. Even though extensive mixing of populations occurred within wheat heads, a low amount of interbreeding was found in western NE in 2004 (8.4%). These results indicate that WCM biotypes are regionally mixed and the development and deployment of mite-resistant wheat varieties must account for the widespread presence of these biotypes.^
Biology, Entomology|Agriculture, Plant Pathology|Biology, Virology
"Interactions between the wheat curl mite, Aceria tosichella Keifer (Eriophyidae), and wheat streak mosaic virus and distribution of wheat curl mite biotypes in the field"
(January 1, 2006).
ETD collection for University of Nebraska - Lincoln.