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Disease Control and Pest Management

Use of Thermotherapy to Free Potato Tubers of Alfalfa Mosaic, Potato Leaf Roll, and Tomato Black Ring Viruses. Walter J. Kaiser, Research plant pathologist, Regional Plant Introduction Station, USDA, SEA, AR, 59 Johnson Hall, Washington State University, Pullman 99164. Formerly, Head, Plant Quarantine Station, Kenya Agriculture Research Institute, P.O. Box 30148, Nairobi; Phytopathology 70:1119-1122. Accepted for publication 3 June 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-1119.

Alfalfa mosaic virus (AMV), potato leaf roll virus (PLRV), and tomato black ring virus (TBRV) were eliminated from diseased tubers of several potato (Solanum tuberosum) cultivars by hot-air treatment at 37 C for 3–6 wk. This treatment also eradicated viruses in tubers dually infected with PLRV and TBRV. Virus could not be detected in plants grown from these tubers following repeated indexing by mechanical means and by serology (AMV and TBRV) or by aphid-transmission tests (PLRV); and tubers harvested from these plants produced normal plants that also indexed negative for virus infection. Similar hot-air treatments for up to 10 wk did not eradicate two strains of potato virus Y. Hot-water treatment at 50 C for 25–180 min or 52.5 C for 15–90 min did not free tubers of AMV, PLRV, and TBRV. Survival of tubers of eight potato cultivars in various hot-air treatment tests after 6 wk ranged from 44 to 87%. Hot-air treatment eliminated PLRV from tubers of over 50 imported and Kenyan potato lines. Potato cultivars freed of virus infection by thermotherapy have been distributed to various potato improvement programs in East Africa.