LETTUCE MOSAIC

Abstract

S ummary Previous records of lettuce mosaic are cited. The symptoms of the disease on lettuce are described, and the variation in the reaction of different varieties of cabbage lettuce indicated. The host range is extended to certain composite weeds (including groundsel, Senecio vulgaris ) and to members of the family Leguminosae (Pisum sativum. Laihyrus odoratus). Experiments in which the virus was seed transmitted through lettuce to the extent of about 6 % are described, and the results of experiments with aphis vectors reported. An account of field observations on the influence of the weather on the disease is given. Certain properties of the virus are described and the status of the virus is discussed. Control measures are suggested.