Petunia as an Indicator Plant for Use by Growers to Monitor for Thrips Carrying the Tomato Spotted Wilt Virus in Greenhouses. W. R. Allen, Agriculture Canada, Research Station, Vineland Station, Ontario L0R 2E0. J. A. Matteoni, Agriculture Canada, Research Station, Vineland Station, Ontario L0R 2E0. Plant Dis. 75:78-82. Accepted for publication 28 June 1990. Copyright 1991 Department of Agriculture, Government of Canada. DOI: 10.1094/PD-75-0078.

Petunia, gloxinia, globe amaranth, tomato, pepper, and three species of tobacco (Nicotiana tabacum, N. glutinosa, and N. benthemiana) were tested under growth room and greenhouse conditions as indicator plants for monitoring for western flower thrips (Frankliniella occidentalis) carrying the tomato spotted wilt virus. The percentage of leaves with feeding scars was consistently the greatest for petunia. Petunia and gloxinia developed the greatest number of viral lesions, and lesions developed as early as 2–3 days after exposure to thrips. The percentage of plants that became infected was greatest for petunia, followed by gloxinia. Thrips attraction and virus transmission to petunia were enhanced when yellow boards without adhesive were placed in the pots at plant height.