Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2004
Publication Date: March 1, 2005
Citation: Boydston, R.A., Mojtahedi, H., Brown, C.R., Anderson, T.L. 2005. Hairy nightshade presence affects the durability of nematode resistance in potato. Western Society of Weed Science Meeting Proceedings. 58:11. Technical Abstract: Columbia root-knot nematode (Meloidogyne chitwoodi, race 1) (MC1) is a major pest of potato grown in the Pacific Northwest and is primarily controlled by soil fumigation at a cost of $400 per hectare. MC1 resistant potato lines have been developed which resist infection in roots and/or tubers. Nematode resistance in laboratory, greenhouse, and most field trials was excellent, but in some field trials MC1 damage occurred on tubers of some resistant lines. Some MC1 resistant potato lines appear to resist nematode reproduction on roots, but lack tuber resistance to MC1 infection, whereas other resistant lines possess both root and tuber resistance. Weeds that escape control measures and weeds emerging later in the growing season that are hosts of MC1 may act as nematode reservoirs, allowing tuber infection to occur in resistant lines possessing only root resistance. Green house and field trials were conducted to test the hypothesis that weed hosts of MC1 grown with potato could act as nematode reservoirs, which could result in tuber infection of nematode resistant potato lines. Three potato lines: Russet Burbank, susceptible to MC1 in roots and tubers; PO95B4-67, roots resistant to MC1, but tubers susceptible; and PA99N82-4, which appears to have both root and tuber resistance to MC1, were grown in the presence or absence of hairy nightshade, a known good host of MC1. Russet Burbank tubers were damaged by MC1 regardless of hairy nightshade presence. PO95B4-67 grown in the absence of hairy nightshade had little or no MC1 damage on tubers, but grown in the presence of hairy nightshade, significant tuber damage occurred. PA99N82-4 tubers were free of MC1 damage regardless of hairy nightshade presence. In greenhouse studies, MC1 applied to potatoes that had already formed tubers, infected Russet Burbank and PO95B4-67, but failed to infect PA99N82-4. These results demonstrate how weed hosts of MC1 may negate the positive impact of growing MC1 resistant potatoes that possess only root resistance.