Observations on natural mortality, parasites and predators of Wheat bulb fly, <i>Leptohylemyia coarctata</i> (Fall.)

Abstract

Summary Observations in eastern England during 1957, 1958 and 1959 showed natural mortality of pupae of wheat bulb fly, Leptohylemyia coarctata (Fall.), to be high. The part of this due to parasitisation is considered in some detail. At Rothamsted, the main parasite was Trybliographa spaniandra Kerrich &amp; Quinlan, and this affected about 10 per cent, of the population in 1957 and about 5 per cent, in 1958. At Whittlesey and Peterborough, in 1959, parasitisation affected 5·5 and 13·7 per cent, of the populations, respectively. The two main parasites found were Aleochara bipustulata (L.) and A. inconspicua Aubé (Coleoptera, Staphylinidae). Phygadeuon trichops Thoms. (Hymenoptera, Ichneumonidae) also occurred but was much less frequent. Notes and original observations on the biology of these parasites are given. Several insects and other small arthropods were observed to prey on various stages of wheat bulb fly. Details of these and notes on the biology of some of them are given.