Submitted to: Potato Country USA
Publication Type: Popular Publication
Publication Acceptance Date: February 1, 2006
Publication Date: March 1, 2006
Citation: Boydston, R.A. 2006. Growers warned of the importance of controlling hairy nightshade.. Potato Country USA. March 2006 pp. 4-5. Technical Abstract: Three main nightshade species are present in potato rotations in the Columbia Basin; hairy nightshade (Solanum sarrachoides), black nightshade (S. nigrum), and cutleaf nightshade (S. triflorum) with hairy nightshade being the most prevalent. Hairy nightshade hosts many disease, nematode, and insect pests of potato and its presence in the rotation crops nullifies many of the positive effects of crop rotation. Hairy nightshade is a host of PVY, PVA, PLRV, TRV, and late blight. Powdery scab (Spongospora subterranea), a soil borne pathogen of potato, infects hairy nightshade and forms galls on the roots. 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. 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, weed hosts present in the alfalfa, such as hairy nightshade, 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.