Studies on Wheat Bulb Fly, Leptohylemyia Coarctata, Fall

Abstract

A detailed quantitative study of the incidence and development of an attack of wheat bulb fly on a field in East Yorkshire is described. The numbers of larvae, puparia, plants, and shoots, and the percentage of plants and shoots attacked, were estimated on various dates. This information is graphically summarised in fig. 1. Similar information was obtained from other fields in 1944 and 1945. No single factor could be correlated with the effect of the attack on the crop.The number of larvae ranged up to nearly 600,000 per acre, but high numbers did not invariably result in a poor crop. A high percentage of plants or shoots attacked was not necessarily associated with crop failure. The number of shoots per plant at the time the larvae hatch was important and in some cases attack stimulated tillering. It is suggested that a study of the rate at which damage occurs would lead to a better understanding of the reaction of any crop to pest attack.