Management of stable fly and other nuisance flies breeding in rotting vegetable matter associated with horticultural crop production

Stable-fly (Stomoxys calcitrans L., Diptera: Muscidae) and other nuisance flies breeding in horticultural substrates around the Perth metropolitan area of Western Australia were investigated with regard to their larval habitats and relative abundances. Substrates were found to comprise either crop residue (i.e. stalks, leaves and fruit) left in or on the ground after harvesting, or harvested crop waste (i.e. reject produce or processing scraps dumped into open pits or fed to livestock). Stable-flies were the predominant species (>85%) developing from a wide variety of trashed vegetable crop residues. Other flies developing from these materials included house-fly, lesser house-fly, false stable-fly, blue-bodied blow-fly, black carrion-fly and flesh-flies. Stable-fly development was reduced by >90% when crop residues were sprayed with diazinon or chlorpyrifos, either prior to or immediately after incorporation of the residue into soil. Untreated crop residues yielded several hundred to >1,000 stable flies/m2 of production. Insecticides applied several weeks after crop residue incorporation into soil did not significantly reduce stable-fly emergence.