INTERACTIONS BETWEEN 3 SPECIES OF MUSHROOM CECIDS (DIPTERA, CECIDOMYIIDAE) AND 3 HYBRID STRAINS OF THE CULTIVATED MUSHROOM AGARICUS-BISPOROUS

The effect of three species of paedogenetic cecidomyiid larvae, at two infestation times, on the yields of three hybrid Agaricus bisporus st rains is reported. The densities of larvae that developed, time of lar val swarming and rates of pupation were recorded. Mycophila barnesi wa s the most damaging species, followed by Heteropeza pygmaea and Henria psalliotae. Time of infestation was important, with earlier infestati ons of all species more damaging, both in direct yield loss and by lar vae contaminating sporophores. The hybrid strains also responded diffe rently, with the U3 hybrid most susceptible, followed by U1 and the In termediate hybrid. The exception was M. barnesi infesting the Intermed iate hybrid at spawning, contaminating over 90% of the sporophores.