Responses to pest and pathogen control in linseed

The effect of pathogen and pest control on linseed (cv. Antares) was studied in the UK in 1988-90. In 1988, when the summer was wet, fungicide spray treatments decreased the incidence of Alternaria, both on the upper leaves before harvest and on the seed after harvest, and increased grain yields by 28%. In 1989, when the summer was dry, fungicides, increased yield by 10% and decreased disease incidence slightly. Thrips angusticeps and the chrysomelid Aphthona euphorbiae were identified as the most important potential pest insects. No yield response to insecticide treatments was detected in 1988 or 1989 when insects were few. There was evidence in 1988 that T. angusticeps encouraged flower abortion and in 1990 that A. euphorbiae hindered plant establishment.