Mushroom-Mushroom fly

House fly

Musca domestica Linnaeus

Immature

House fly

Musca domestica Linnaeus

Female adult

Stable fly

Stomoxys calcitrans Linnaeus

Adult

Cecid flies (Mycophila speyeri, Heteropeza pygmaea)
House fly (Musca domestica)
Phorid fly (Megaselia halterata)
Sciarid fly (Lycoriella mali)
Stable fly (Stomoxys calcitrans)

Pest Biology and Crop Damage The morphology of most mushroom flies have four distinct life stages: eggs, larvae, pupae and adult. The major insect pest of mushrooms is the sciarid fly, a small black insect about 0.25 inch long, with long antennae and gray wings folded over the back. Sciarid larvae attack compost, spawn, mycelia, pins, and mushroom stems and caps. Phorid flies are very small, 0.125 inch long (half the size of a fruit fly), with a humpback appearance and very small antennae. They are stockier than sciarids and are very active, running and hopping erratically. These flies feed on mycelia, depressing crop yields. Both sciarid and phorid adults carry disease organisms into the crop. Cecid species are rarely seen as adult flies, because under the warmth of mushroom culture larvae become "mother larvae" giving birth directly to 10-30 daughter larvae. Cecids feed on the mushroom stems or gills, reducing marketable yield. Stable fly and house fly are common pests in compost wharves.

Management-cultural control

Cultural control, including sanitation, composting and pasteurization is the basis for successful mushroom culture. Cultural practices that can reduce pest fly populations include exclusion, sanitation (washing and sanitizing), shortening crop cycles and post-harvest steam cleaning. In compost wharves, fly populations can be reduced by promoting drainage and reducing of standing. Fly exclusion is critical: rooms should be sealed and properly screened to exclude breeding flies. Attention should be paid to doors, fans, ceiling joints, drains and ductwork. Lights and traps near doorways may be of value. Equipment and personnel should not move from older culture rooms (where infestations tend to exist) to newer, uninfested rooms. Limit the amount of time that doors are left open.

Management-biological control

A number of entomopathogenic nematodes are used successfully against mushroom flies because of the moist organic growing media. Steinernema feltiae is effective against sciarids. Howardula hussey occurs naturally in phorid populations. Bacillus thuringiensis israelensis (Bti) is a bacterium used widely in biocontrol of flies: Bti appears to be more effective against earlier instar sciarid larvae.

In compost wharves, augmentation of naturally occurring pteromalid wasps is used for control of house fly and stable fly: Spalangia endius, Muscidifurax raptor, M. zaraptor, and M. raptorellus are commercially available.

Management-chemical control

Note: Some labels specify Agaricus bisporus (the button mushroom) as the intended crop. In such cases, the product is registered legally for use only on Agaricus mushrooms.

Mushroom sites, pests, and controls
Site	Controls -follow label rates-	Comments and cautions
Empty mushroom house and premises	azadirachtin DDVP (empty house only) MGK 264 (empty house only) pyrethrin + PBO permethrin (empty house only)
Filling	azadirachtin Geranium oil; peppermint; rosemary
Spawning	azadirachtin Bacilllus thuringiensis sp. israelensis Beauveria bassiana GHA cyromazine1 Geranium oil; peppermint; rosemary Isaria fumosorosea	To be effective, pesticides must be incorporated thoroughly into the compost. It is important that end sections and sides be treated completely.
Casing	azadirachtin Bacilllus thuringiensis ssp. israelensis Beauveria bassiana GHA Geranium oil; peppermint; rosemary Isaria fumosorosea S-methoprene	Drench onto casing layer with sufficient water for good penetration.
Growth-Pinning	Azadirachtin malathion pyrethrin + PBO permethrin	Adult fly control.
Picking	pyrethrin + PBO (aerosol)	Use effectively to knock down adult flies prior to pickers entering rooms.
1Cyromazine-treated spent compost cannot be used to grow food crops.

Pesticides registered for use in mushroom houses and/or on mushroom crops
Common name	Brand names	Class1	Toxicity class	Uses and precautions
azadirachtin (neem)	Azatin, Align, Azasol, Debug Tres	BP	IV; very low	Sciarid and phorid fly control incorporated into compost or casing soil; disrupts fly development. Some formulations are OMRI-listed for organic use.
Bacilllus thuringiensis ssp. israelensis	Gnatrol DG	MI	IV; very low	Sciarid and phorid fly control incorporated into compost or casing soil; disrupts fly development at the larval stage.
Beauveria bassiana GHA	Botanigard	MI	IV; very low	Sciarid and phorid fly control incorporated into compost or casing soil; fungus infects fly larvae. Some formulations are OMRI-listed for organic use.
cyromazine	Armor, Aegis	IGR	III; low	Sciarid fly control incorporated into compost; disrupts fly development. Spent, treated compost cannot be used to grow food crops.
DDVP, dichlorovos	Nuvan Fog 5%	OP	I; high	Phorid flies. Empty houses, and no less than 10 days before mushrooms in beds
Geranium oil; peppermint; rosemary	Brandt Ecotec Plus	BP	IV; very low	Controls larval stage of flies.
Isaria fumosorosea	Ancora, PFR-97TM 20% WDG	MI	IV; very low	Sciarid and phorid flies, at spawning, casing and during case hold. Some formulations are OMRI-listed for organic use.
malathion	Malathion	OP	III; low	Sciarid and phorid flies, applied after picking.
MGK 264	Alto Cirrus, Cirrus Fogging	synergist	III; low	Fly control in empty mushroom houses. Use as diluted space spray or contact for accessible stages of flies.
permethrin	Ambush, Pounce	SP	II-III; medium-low	Sciarid and phorid fly control as a fog, aerosol, or dust treatment for adult flies. Do not use when mushrooms are present.
piperonyl butoxide (PBO)		synergist	IV; very low	Improves activity of other ingredients; usually combined with pyrethrins.
pyrethrin, pyrethrum	many	NP	III; low	Aerosol or liquid; general insect control; very rapid knockdown. Some formulations are OMRI-listed for organic use.
S-methoprene	Apex	IGR	III; low	Intended as larva and egg control. Use adult knockdown for high infestations.
1BP = biopesticide; IGR = insect growth regulator; MI = mycoinsecticide; NP = natural pyrethrum; OP = organophosphate; SP = synthetic pyrethroid. Note: Some labels are labeled for use on Agaricus mushrooms only.