|Riga, E - WASHINGTON STATE UNIV|
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2003
Publication Date: August 10, 2003
Citation: BOYDSTON, R.A., MOJTAHEDI, H., CROSSLIN, J., THOMAS, P.E., RIGA, E., ANDERSON, T.L. INFLUENCE OF NIGHTSHADE SPECIES ON CORKY RINGSPOT PERSISTENCE IN CROP ROTATIONS. POTATO ASSOCIATION OF AMERICA PROCEEDINGS. 2003. P31, p. 75. Technical Abstract: Corky ringspot disease in potato is caused by tobacco rattle virus (TRV) and vectored by the stubby root nematode, Paratrichodorus allius, in the Pacific Northwest potato producing regions. TRV rarely infects alfalfa (Medicago sativa) and Scotch spearmint (Mentha cardiaca) and viruliferous P. allius populations feeding on these crops are cleansed of TRV after one month. However, weeds in these rotation crops or in potato may serve as hosts for the virus and nematode. In greenhouse trials, over thirty weed species were tested for host suitability for P. allius and TRV. Hairy nightshade (Solanum sarrachoides), black nightshade (Solanum nigrum), and cutleaf nightshade (Solanum triflorum) were particularly suitable hosts of P. allius and TRV. Viruliferous P. allius added to mixtures of hairy nightshade with alfalfa and/or Scotch spearmint remained viruliferous over a 3- to 4-month period, whereas P. allius maintained on pure alfalfa or Scotch spearmint were rarely carrying TRV to transmit to tobacco or potato after 1 to 2 months. Potato grown in soil containing P. allius that were maintained on mixtures of hairy nightshade with alfalfa or Scotch spearmint for 3- to 4-months exhibited severe corky ringspot symptoms on new tubers. The presence of weeds that serve as hosts of both TRV and P. allius may nullify the positive effects of growing alfalfa or Scotch spearmint for corky ringspot control. Furthermore, transmission of TRV in weed seed could spread the disease to previously uninfected fields. Weed control efforts in rotational crops should target known hosts of P. allius and TRV to successfully eliminate CRS from fields.