Chapter 26

Integrated Pest Management in Greenhouses

Biological Pest Control in Greenhouses

Biological methods are the use of beneficial organisms that can be used in a greenhouse to reduce insect and mite pest populations. Biological control of greenhouse insect and mite pests can be achieved through the release of bio-control agents like predatory mites, pirate bugs, soil-dwelling mites, and parasitic insects. Biological control agents (natural enemies or beneficials) typically will not eliminate the target insect or mite pest. Many growers can use biological control as their primary pest management method. Other growers will try to integrate pesticides with few or no harmful effects on beneficials into their program or apply pesticides only to localized areas where pest infestations are above acceptable levels. Some growers will use biological controls for part of the year, changing to pesticides if pests become too numerous.

Predators

A predator is typically an insect or insect-related animal that attacks or feeds on a host or individual pest. This attack is typically part of the predator's natural feeding cycle. The ladybird beetle, also known as the ladybug beetle, is the most common greenhouse predator feeding on aphids (Figure 26.6). Lacewings feed on aphids, scales, mealybugs, thrips, mites, and insect eggs. The larvae of syrphid flies (also called flower flies) consume aphids and small ants.

Parasites

A parasite or parasitoid is an organism that attacks and kills a single host. Typically, the parasite completes all or part of its life cycle in or on this individual pest. When the eggs hatch, the immature or larval stages of the parasite develop by feeding on and killing the pest. Parasitic insect species will usually attack only one species of pest because they are highly specialized. Encarsia formosa, a parasitic wasp, is an example of a parasitoid that oviposits its eggs into an immature stage of a whitefly (Figure 26.7).

Click on the following topics for more information on integrated pest management in greenhouses.