EPIDEMIOLOGY OF COCKSFOOT MOTTLE VIRUS

Cocksfoot mottle virus (CFMV) was found to be widespread in cocksfoot seed crops in the East Midlands in the third harvest year and once present in the crop spread rapidly. Pot experiments with single cocksfoot plants showed that autumn infection with CFMV resulted in a significant reduction in the number of flowering tillers and weight and size of seed produced the following year. The spread of CFMV in experimental cocksfoot leys was studied; leys cut for conservation showed more infection than leys grazed by sheep, and increasing nitrogen application resulted in higher disease incidence. The disease increased rapidly in conserved leys in 1967 and its spread was associated with cutting by a forage harvester after the virus had been introduced into the crop in the autumn, possibly by the vector Lema melanopa. Animal grazing and cutting implements seemed to be more important agencies in disease spread than the vector. Copyright © 1969, Wiley Blackwell. All rights reserved