Predatory thrips

Biology

The majority of thrips seen in gardens are plant feeders but these only occasionally cause significant damage beyond leaf speckling. The western flower thrips is the commonest species and has a wide host range including feeding on insect and mite eggs, making it a true omnivore. Other garden thrips species are true predators feeding on mites, aphids, small caterpillars and other thrips. Most of the predatory thrips in the Pacific Northwest are about 1/16 inch in length and dark colored, banded in white or are red/orange. Closer observation with a hand lens will show that the forelegs of these thrips are enlarged for handling prey.

Prey or Pest Targeted

• Thrips, mites, aphids, scale insects, small caterpillars

Attracting and Keeping Natural Enemies and Pollinators in Your Yard and Garden

• 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.