Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/30/2007
Publication Date: 1/1/2008
Citation: Boydston, R.A., Mojtahedi, H., Crosslin, J., Brown, C.R., Anderson, T.L. 2008. Effect of hairy nightshade (Solanum sarrachoides) presence on nematode, disease, and insect pests of potato. Weed Science. 56: 151-154. Interpretive Summary: Three main nightshade species are present in potato rotations in the Columbia Basin; hairy nightshade, black nightshade, and cutleaf nightshade, with hairy nightshade being the most prevalent. Hairy nightshade is a close relative of potato and as such, hosts a plethora of disease, nematode, and insect pests of potato. Its presence in rotation crops nullifies many of the positive effects of crop rotation. Hairy nightshade is a host of PVY, PVA, PLRV, TRV, powdery scab, and late blight. Green peach aphids reproduce more readily on hairy nightshade than on potato and prefer nightshade over potato. PLRV disease transmission by aphids from hairy nightshade to potato was four times the rate of disease transmission from potato to potato. Furthermore, hairy nightshade is a good host of Columbia root knot nematode and stubby root nematode, 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 or Scotch spearmint for several months. However, hairy nightshade present in alfalfa or spearmint, can nullify the cleansing effect of these rotation crops. Tubers of potato breeding lines resistant to root knot nematode were damaged in field trials when grown in the presence of hairy nightshade. When grown without hairy nightshade, no tuber infection occurred. Nematode populations increased on hairy nightshade and damaged susceptible potato tubers later in the growing season. Management of numerous potato pests in which hairy nightshade serves as a host should include control of hairy nightshade.
Technical Abstract: Hairy nightshade is a common weed in potato rotations in the western United States. As a close relative of potato, hairy nightshade can host numerous potato disease, nematode, and insect pests. Hairy nightshade hosts three common parasitic nematodes of potato, Columbia and northern root knot nematodes, and stubby root nematode. Tubers of a potato breeding line with roots that are resistant to Columbia root knot nematode, race 1 were damaged when grown in the presence of hairy nightshade. The weed provided an alternate host for the nematode, which then allowed the nematode to infect susceptible tubers. Stubby root nematodes transmit tobacco rattle virus (TRV), the causal agent for corky ringspot disease (CRS) of potato. CRS disease was maintained in soil when hairy nightshade was present in rotation crops of alfalfa or Scotch spearmint that otherwise eliminated the disease. Hairy nightshade also is a host of potato leaf roll virus (PLRV), which is transmitted by green peach aphids. Green peach aphids preferentially land and readily reproduce on hairy nightshade. Aphid transmission of PLRV from hairy nightshade to potato was four times greater than the rate of disease transmission from potato to potato. Integrated management of these nematode, disease, and insect pests of potato should include hairy nightshade control.