Interactions between three species of mushroom cecids (Diptera: Cecidomyiidae) and three hybrid strains of the cultivated mushroom Agaricus bisporus

The effect of three species of paedogenetic cecidomyiid larvae, at two infestation times, on the yields of three hybrid Agaricus bisporus strains is reported. The densities of larvae that developed, time of larval swarming and rates of pupation were recorded. Mycophila barnesi was the most damaging species, followed by Heteropeza pygmaea and Henria psalliotae. Time of infestation was important, with earlier infestations of all species more damaging, both in direct yield loss and by larvae contaminating sporophores. The hybrid strains also responded differently, with the U3 hybrid most susceptible, followed by U1 and the Intermediate hybrid. The exception was M. barnesi infesting the Intermediate hybrid at spawning, contaminating over 90% of the sporophores.