A concise review of chironomid midges (Diptera: Chironomidae) as pests and their management

Increasing eutrophication of inland urban and suburban natural and man-made aquatic ecosystems resulting from natural and anthropogenic factors in recent years has been conducive to population increases of aquatic chironomid midges in many parts of the world. Adult midges from these habitats frequently emerge in large numbers, causing nuisance problems, human allergies, and also have severe adverse economic impact. Globally, nearly 100 of the 4,000 known chironomid species are documented as pestiferous. Numerous laboratory and field studies to reduce midges by physical and cultural, biological, and chemical means have been conducted. Organochlorines, organophosphates (OPs), pyrethroids, and insect growth regulators (IGRs) have been evaluated against midge larvae in the laboratory and/or used in the field. The best results for chemical control have come from OP insecticides (chlorpyrifos and temephos), and IGRs (diflubenzuron, methoprene, and pyriproxyfen). The OP insecticides have generally provided larval field control for two to five weeks at rates <0.56 kg AI/ha resulting in insecticidal concentrations of <1 to 5 ppm, but increased tolerance by midge larvae to some materials has been reported. Insect growth regulators (especially pyriproxyfen) have provided >90% suppression of midge emergence for several weeks at <0.25 kg AI/ha. Pyriproxyfen, methoprene, and diflubenzuron warrant registration for chironomid control in the USA. Attempts at physical and cultural control of chironomids have given mixed results. Biological control agents, such as Bacillus thuringiensis serovar. israelensis, the flatworm Dugesia dorotocephala, as well as several fish species are useful but only in smaller habitats. The midge habitats, which cover hundreds or thousands of ha, require appropriate investigations on the biology, ecology, and behavior of larval and adult pestiferous midge species to formulate suitable control strategies.