ARS | Publication request: Role of Weeds in Persistence of Corky Ringspot in Crop Rotations

Submitted to: Proceedings Washington State Potato Conference
Publication Acceptance Date: February 1, 2004
Publication Date: August 1, 2004
Citation: Boydston, R.A., Mojtahedi, H., Crosslin, J., Thomas, P.E., Riga, E. 2004. Role Of Weeds In Persistence Of Corky Ringspot In Crop Rotations. Proceedings Of The 43rd Annual Washington State Potato Conference, Moses Lake, Wa. P. 1-10.

Technical Abstract: Corky ringspot (CRS) is a serious disease of potato caused by tobacco rattle virus (TRV) and vectored by stubby root nematode (Paratrichodorus allius) in the western U.S. CRS causes necrotic arcs, rings, or spots in potato tubers, which can result in crop rejection. The nematode vector is more prevalent than the virus in Washington and Oregon . Viruliferous stubby root nematode populations were no longer able to transmit TRV to the susceptible indicator plant tobacco, after growing for several generations on alfalfa, var. Vernema, or Scotch spearmint, var. 770. Although these crops may help reduce CRS in soils, the presence of weeds that are hosts of TRV and P. allius may contribute to disease persistence by maintaining the viruliferous vector population in the problem fields. Eleven of 37 common weed species evaluated were found to be host of both stubby root nematode and TRV. These weeds served as a reservoir of TRV when present in mixed cultures with alfalfa or spearmint and nullified the positive effect of growing these rotation crops. Nonviruliferous nematode populations were able to acquire TRV from selected weed hosts and transfer to susceptible tobacco and potato. Black and hairy nightshade (Solanum nigrum and S. sarrachoides) were a particularly strong hosts of TRV and the stubby root nematode.