Submitted to: Proceedings Washington State Potato Conference
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2006
Publication Date: June 1, 2006
Citation: Boydston, R.A. 2006. Potato disease, nematode, and insect problems worsened by hairy nightshade.. Proceedings 45th Washington State Potato Conference, pp 1-4. Technical Abstract: Hairy nightshade is a close relative of potato and therefore hosts many disease, nematode, and insect pests of potato. Hairy nightshade presence in rotation crops nullifies many of the positive effects of crop rotation. Idaho studies have shown that green peach aphids reproduce more readily on hairy nightshade than on potato and prefer nightshade over potato. PLRV disease transmission by green peach aphids from hairy nightshade to potato was four times the rate of disease transmission from potato to potato. Hairy nightshade is a reported host of PVY, PVA, PLRV, TRV, and late blight. In the Columbia Basin of Washington, powdery scab (Spongospora subterranea), a soil borne pathogen of potato, was found to infect hairy nightshade and formed galls on the roots. Colorado potato beetle readily feed and lay egg masses on hairy nightshade. Furthermore, hairy nightshade is a good host of Columbia root knot nematode (Meloidogyne chitwoodi) and stubby root nematode (Paratrichodorus allius) the later which transmits tobacco rattle virus (TRV) that causes corky ringspot disease of potato. Corky ringspot disease can be greatly diminished or eliminated from soils by growing alfalfa for several months. However, hairy nightshade and other weed hosts present in alfalfa, can nullify the cleansing effect of growing alfalfa. Potato resistance to root knot nematode has been introgressed into several breeding lines, but in field trials damaged tubers were observed when some resistant lines were grown in the presence of hairy nightshade. When grown without hairy nightshade, no tuber infection occurred. Hairy nightshade control in potato and rotation crops is important to help suppress numerous pests of potato that are hosted by hairy nightshade.