Sciarid flies (Lycoriella spp.) and phorid flies (Megaselia spp.) can be a major problem in mushroom production. Adult flies enter mushroom houses through openings and cracks. They are attracted by the smell of substrate (compost) and growing mushrooms. They lay eggs in the substrate, casing layer and mushrooms. Each female can lay up to 170 eggs. At a temperature of 24.5degC development from egg to adult takes about 21 days. Emerging larvae (maggots) feed on the substrate, mushroom mycelium and developing mushrooms. Damaged mycelium results in the formation of pins brown in colour and having a leathery surface. Developing pins and young mushrooms may not survive after larval attack.
Infested young mushrooms become hollow and shrink, and may eventually die. Larvae may also tunnel ripe mushrooms forming many passage ways and holes, which makes the mushrooms unsuitable for human consumption. The affected substrate areas turn into swampy masses with a foul odour in which mushroom mycelium will not be able to grow. Adult flies are known to spread mushroom diseases and mites. They are also a nuisance to workers.
- All windows or ventilating vents should be covered with insect proof net
- Use yellow sticky traps (yellow polythene sheets coated with vegetable oil) to detect and monitor presence of flies in the growing house
- In India, yellow coloured bulbs of 15 W and yellow polythene sheets coated with vegetable oil (e.g. mustard oil) have been widely adopted and proven very effective in management of mushroom flies without use of synthetic pesticides
- Remove from growing houses and farm all used substrate (compost). The spent substrate can be used as compost manure for other crops
- Disinfect growing rooms with household bleach (sodium hypochlorite) (e.g. Teepol) after harvesting (end of cultivation cycle)
- Remove weeds and rotting materials near mushroom growing facilities