Photo Source: IPM Handbook
Cecid larvae are legless maggots, bluntly pointed at both ends. The head and tail are not easily distinguished, except by the direction of travel. The small, sticky larvae are spread by workers and on tools and equipment. Initial entry to the growing room may be by transport of infested peat or substrate, movement with personnel, or through the rare flying adult. Small infestations may not be readily apparent at first. The larvae feed on the mycelium as well as on the stipe and gills of mature mushrooms. If large populations develop, the larvae may mass together on the floor and disperse in large groups. Larvae also can be found on mature mushroom caps packed for market. This species has the potential to significantly reduce yield when it becomes established on a farm. Cecid larvae have the potential of feeding on mycelium within wooden structures inside growing rooms. Because the wood offers some insulation from the heat of cookouts, they may survive the high temperatures and infest the next crop. Direct treatment of wood with insecticides and fungicides may be necessary to reduce between-crop survivors if there are high populations of cecids on the farm.