Biological control agents or Beneficials are natural enemies or competitors of crop pests. They do not harm your crop but they prey on or compete with crop pests.
Beneficials may occur naturally in and around your farm. Biological control agents are natural enemies of crop pests which have been bred in commercial insectaries and can be purchased and released into crops to control specific pests.
Predatory insects eat the eggs and/or larvae or grubs of the pest. Parasitoid insects lay eggs in the eggs or larvae of the pest. Pathogenic beneficials are diseases which affect pests.
All beneficials need to be recognised and encouraged on your farm and in your greenhouse. Beneficial organisms which occur naturally on your farm are a free method of pest control.
It is important to note that some pesticides can harm beneficials. Always look for pesticides that are compatible with biological controls before you spray.
Using biological controls requires good production and management skills. As part of an integrated pest management program, biological controls can significantly reduce the need for toxic pesticides.
Note that all of the following beneficials are available commercially in Australia.
Encarsia (Encarsia formosa)
Encarsia is a tiny wasp which parasitises the eggs of greenhouse whitefly. It is available commercially and comes on small cards (from which they hatch and emerge). The cards are hung on plants throughout the greenhouse.
Entomopathogenic nematode (Steinernema feltiae)
Steinernema is a nematode which attacks the larvae of fungus gnats and some caterpillars. It is available commercially as a powder that is mixed with water and added to the substrate.
Hypoaspis (Stratiolaelaps (Hypoaspis) miles)
Hypoaspis is a predatory mite which feeds on the larvae of fungus gnats and even some western flower thrips pupae. It is available commercially in a bran mix which is added directly to the substrate.
Montdorensis (Typhlodromips montdorensis)
Montdorensis is a predatory mite which feeds on the larvae of western flower thrips, tomato thrips and onion thrips. It also feeds on broad mites and tomato russet mite. Montdorensis prefers warmer situations. This biological control was developed at the National Centre for Greenhouse Horticulture and is distributed onto the leaves.
This is a new beneficial for use in greenhouse cucumbers. It is a predatory mite that can be used to control thrips. It prefers cooler areas. It is purchased in vermiculite which is sprinkled onto crop foliage
Occidentalis (Typhlodromus occidentalis)
Occidentalis is a predatory mite which feeds on two-spotted mites.
Persimilis (Phytoseiulus persimilis)
Persimilis is a predatory mite which feeds on two-spotted mites and bean spider mite. It is available commercially and comes in a small plastic bucket on bean leaves that are distributed into the crop foliage.
Trichogramma (Trichogramma pretiosum)
Trichogramma is a tiny wasp which attacks some species of caterpillar. It is purchased inside small cards which are placed in the crop. The wasp emerges from the cards.
Green lacewing (Mallada signatus)
The green lacewing is a general predator insect and its larvae feeds on soft bodied insects such as aphids and mealy bugs. Although available commercially, it does not reproduce in greenhouses.
Aphidius (Aphidius colemani)
Aphidius is a small wasp which is a parasite of many aphid species. It lays an egg into the body of aphids which then hatches and feeds on the aphid before it emerges to find more aphids. It is a new bio-control agent for greenhouses and comes in small vials that contain about 500 mummified aphids with young Aphidius inside them.
Biorationals are substances used to control pests (or diseases) which have very limited or no affect on non-target organisms. These pesticides are safe to the user and are compatible with biological controls due to their selective nature or short residual activity. Biorationals are almost the ideal pesticide.
Biorational products include oils, soaps and insect growth regulators. Many of the new chemistries as well as microbially-derived products and living microbes such as fungi and bacteria are classed as biorationals.
There is on-going research in Australia including at the NCGH to identify and develop biorational pesticides.