Effects of the paedogenetic mushroom cecid, Heteropeza pygmaea (Diptera:Cecidomyiidae) on cropping of the cultivated mushroom (Agaricus bisporus)

Abstract

SUMMARYWhen introduced into a mushroom crop at rates of 2, 20 or 200 larvae/tray (0.56 m2), the mushroom cecid, Heteropeza pygmaea, caused significant reductions in both yield and number of mushrooms in relation to the infestation level. The reductions were greater when the larvae were introduced at spawning rather than at casing. The yield and number of infested (unmarketable) mushrooms increased significantly in relation to the initial infestation level.Just two H. pygmaea larvae, introduced at spawning, resulted in cecid populations that caused a 12% loss in total yield in addition to a 7% loss due to spoilage. Loss assessment in the future, therefore, should take into account both yield suppression and spoilage.There was little effect of cecid infestation on flush timing and mushroom size was only affected in the fourth flush, when a significant reduction (27%) was shown at the highest infestation rate at spawning.