FIELD STUDIES ON WHEAT-BULB FLY INFESTATIONS

An account is given of two experiments done on commercial farms in Essex to study the effect of tilth, cultivation and seed rate on wheat-bulb fly infestation and the effect of infestation on yield. Heavier infestations developed on rough fallows and those cultivated during the oviposition period, than on smooth fallows and those not cultivated during the oviposition period. These results confirmed those of an earlier experiment done at Rothamsted. At each level of infestation, more larvae survived on plots sown at 3 bus./ acre than on plots sown at 8 or I bus./ acre. Although some plots had a high larval population no effect of infestation on yield was observed even at the lower seed rates. This is attributed to early sowing. The extent to which the cultural treatments studied can be used to control wheat-bulb fly infestations is discussed.