Lowering Incidence of a Virus Complex Dominated by Strawberry Mottle Virus by Reducing Numbers of the Aphid Vector with Oxydemetonmethyl. D. A. Raworth, Agriculture Canada Research Station, 6660 N.W. Marine Drive, Vancouver, British Columbia, Canada V6T 1X2. S. J. Clements, Agriculture Canada Research Station, 6660 N.W. Marine Drive, Vancouver, British Columbia, Canada V6T 1X2. Plant Dis. 74:365-367. Accepted for publication 20 November 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0365.

The efficacy of 24% oxydemetonmethyl was evaluated in relation to aphid control, strawberry yield, and virus incidence during 1987 and 1988 at Abbotsford, British Columbia. Numbers of Chaetosiphon fragaefolii in treated plots were significantly lower than in control plots. Yield was positively correlated and virus incidence was negatively correlated with the rate of application of oxydemetonmethyl in 1988 but not in 1987. Strawberry mottle virus was isolated from 83%, strawberry veinbanding virus from 27%, and strawberry mild yellow edge virus from 4% of the plants that tested positive for virus in 1988. The results suggest that the secondary spread of strawberry viruses may be significantly reduced by lowering aphid numbers and that nonchemical methods of vector regulation deserve greater attention for their potential in limiting virus spread.