Carrot motley dwarf virus

In this short account of the disease [40, 2] field experiments at Woburn exp. Farm, Beds., are reported in which carrot crops, though sprayed with insecticides, became infested with aphids and yielded only about 40.5 tons/acre, the same as the untreated, whereas 15 tons/acre are expected from a healthy crop. Carrots from 7 counties in England have been shown to be infected by motley dwarf, which appears to be of economic importance.