WSU Extension

Hortsense

Predatory Flies : Predatory midges
(revision date: 10/11/2018)


Biology
Predatory midges are tiny (< 1/8 inch) mosquito-like flies with a couple of species preying as larvae on aphids and mites. The predatory gall midge (Feltiella acarisuga) specializes in feeding on spider mites while Aphidoletes aphidimyza attacks aphids. Predatory midge larvae are similar to those of hover flies but much smaller and live in colonies of their prey.

Prey or Pest Targeted
  • Mites, aphids, scale insects, thrips, caterpillars, beetle larvae, flies, wasps, grasshoppers, bees
     
Attracting and Keeping Natural Enemies & Pollinators in Your Yard
  • Avoid regular use of synthetic, broad-spectrum pesticides. Infrequent use of certain narrow-spectrum pesticides is more compatible with some beneficials but generally the less chemical inputs there are, the greater and more diverse the beneficial insect community will be. Extensive lawns are also not conducive to attracting and retaining a diversity of beneficial insects, mites and spiders. Minimize lawn areas and maximize shrub and bush plantings. Many beneficials reside naturally in riparian and other ‘natural’ areas near to many back yards. Natural dispersion from these refuges ensures that some beneficials will visit back yards but they will not stay unless food, host and shelter resources are available. Native plants have closer affinities with native insects and therefore provide most of these resources. A garden with a good diversity of local native flora in and around back yards, will improve the abundance and diversity of local, beneficial arthropods. Native flora also provides natural overwintering sites for many beneficial insects and it is useful to leave at least a small area of native vegetation undisturbed during fall and winter.
  • Some kinds of beneficial insects (e.g. lady beetles, lacewings, predatory mites) are available for purchase from commercial suppliers. However, benefits from introducing these beneficials are usually limited and short-lived. Upon release, commercially obtained lady beetles and lacewings often disperse and may rapidly leave your backyard despite the presence of prey and suitable nectar resources. Generally, it is more effective and sustainable to create a garden habitat that will be colonized by beneficials naturally.
     

Images
    - hide images

+ Show larger images

 
Caption: Larva of the predatory gall midge (Feltiella acarisuga) (Cecidomyiidae)
Photo by: D.G. James