Increasing beneficial insects for enhanced pollination and biological control using insectary plants

Published: December 30, 2015

Increasing beneficial insects for enhanced pollination and biological control using insectary plants

Honeybees, bumble bees, and ladybeetles are beneficial insects that most producers are able to recognize easily. However, there are many other types of beneficial insects such as predatory insects (lacewings, larvae of hover flies, minute pirate bugs, etc.) as well as parasitic flies and wasps which often are more difficult to recognize. Predatory insects and parasitic wasps kill many of the insect pests that otherwise would reproduce and damage your vegetables.

Encouraging natural enemy activity might reduce the oscillations in pest populations and regulate insect pests and mites below economic thresholds. Make sure to have insectary plants during the entire growing season. This may require re-seeding some plant species such as buckwheat and mustard.

Most species of beneficial insects require food in the form of pollen (a source of protein to reproduce), nectar (a source of energy to survive), as well as prey / hosts and shelter. Their effectiveness -- either, as pollinators or for natural pest control -- may not be met in agricultural landscapes if those types of resources are lacking. Thus, establishing flowering plants in and around fields to provide pollen and nectar resources for natural enemies has shown promise as a strategy to enhance biological control of crop pests.

Vegetable producers can increase the abundance of natural enemies of insect pests by planting insectary plants. Beyond providing effective natural pest control, the friendly insects also assist in pollination. For example, the larvae of hover flies are predators while adults assist with pollination.
What types of plants attract the most beneficials?

The top five plants that can be planted annually* are:

1. Sweet alyssum (white variety). It belongs to the mustard family. Flowering period is long (several months). Natural enemies attracted include minute pirate bug, lacewings and ladybugs (predators) as well as small parasitic wasps that can attack aphids and other small insects.
2. Buckwheat. It is very attractive to honeybees, hover flies, soldier beetles, parasitic wasps and parasitic flies. Plus, predatory insects including assassin bugs, shield bugs, and predatory stink bugs.
3. Fennel. This plant attracts many ladybeetles, wasps, and hover flies. Fennel is also a host plant for the caterpillars of the anise swallowtail butterfly.
4. Sunflower. This plant can attract predatory insects such as big-eyed bugs, wasps, lady beetles and predatory bugs.
5. Mustard. It is very attractive to lacewings, ladybeetles, and parasitic wasps that attack aphids and other small-sized insects.

*This list includes plant species that consistently have been identified through research and are also easy to establish / maintain. Dozens of other plant species can supplement this list.