Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2003
Publication Date: 9/23/2003
Citation: MOJTAHEDI, H., BOYDSTON, R.A., THOMAS, P.E., CROSSLIN, J., SANTO, G.S., RIGA, E., ANDERSON, T.L. WEED HOSTS OF PARATRICHODORUS ALLIUS AND TOBACCO RATTLE VIRUS IN THE PACIFIC NORTHWEST. AMERICAN JOURNAL OF POTATO RESEARCH. 80:379-385. 2003. Interpretive Summary: Corky ringspot disease (CRS) in potato is caused by tobacco rattle virus (TRV). This virus is transmitted by the stubby root nematode (Paratrichodorus allius) in the Pacific Northwest potato producing regions. Although rotation crops such as alfalfa and Scotch spearmint are good hosts of the nematode, it cannot acquire the virus from these crops. Nematodes infected with TRV shed some of the virus with each molt during their life cycle and eventually the population is cleansed after several generations raised on alfalfa or Scotch spearmint. However, weeds in these rotation crops may serve as hosts for TRV and furthermore, the virus may spread in the seeds of some weed species. Thirty-seven weed species were evaluated for host status of stubby root nematode and TRV. Twenty-four were good hosts of the nematode, but only 11 of those were infected with TRV. Virus-free nematodes acquired the virus from three nightshade species, volunteer potato, and prickly lettuce, and subsequently transmitted the virus to Samsun NN tobacco indicator plants. Thus, some weeds may play a role in the epidemiology of CRS by perpetuating TRV and its vector in a problem field. These weeds need to be targeted for control in crops of alfalfa or spearmint that are grown to suppress CRS disease.
Technical Abstract: The ability of several weed species to serve as hosts for tobacco rattle virus (TRV), the causal agent of corky ringspot disease of potato (CRS), and its nematode vector, Paratrichodorus allius, was investigated in greenhouse studies. Viruliferous P. allius multiplied on 24 out of 37 weed species tested, indicating they were suitable hosts of the vector. However, only 11 of these weeds were infected with TRV, as determined by ELISA. The nonhost status of a given weed species was not changed whether the viruliferous vector population originated from CRS problem field in WA, OR, or ID. Several weeds that served as hosts for the vector and virus included kochia, prickly lettuce, henbit, nightshade species (black, hairy, and cutleaf), common chickweed and annual sowthistle. Virus-free P. allius acquired TRV from the three nightshade species, volunteer potato grown from TRV-infected tubers, and prickly lettuce, and subsequently transmitted the virus to Samsun NN tobacco indicator plants. Thus, some weeds may play a role in the epidemiology of CRS by perpetuating TRV and its vector in a problem field.