New Biocontrol Agents: Expanding Pest Management Options

Biological control is a safe and sustainable method for managing pests, particularly in controlled environments such as greenhouses and high tunnels. Many well-established biocontrol agents, such as predatory mites, minute pirate bugs, and nematodes, have been widely used for years, with their effectiveness well-documented.

However, some promising biocontrol agents that have been successfully utilized in other countries have not been available in the U.S.—until now.

Two newly approved biocontrol agents, now accessible through U.S. biocontrol suppliers, are the brown lacewing (Micromus variegatus) and the crazee mite (Anystis baccarum). These beneficial insects have demonstrated strong efficacy in pest management and are now commercially available for use in integrated pest management (IPM) programs.

It is important to note that, while exciting, these new agents are currently expensive, which may limit their widespread use in some cases. Additionally, they are not yet available in all states due to permitting requirements, so growers should check availability before planning their use.

Below are the key details about these newly introduced biocontrol agents:

Brown lacewing - Micromus variegatus (Neuroptera: Hemerobiidae)

Brown lacewing adults resemble green lacewings but are smaller. They have large, membranous wings covered in fine hairs and long antennae.

Their eggs are oval, white, and laid singly. Unlike green lacewing eggs, they are not attached to stalks. The larvae are small and similar in appearance to green lacewing larvae. They have large, sickle-shaped mouthparts used to puncture prey. Once they reach about 10 mm in length, they spin a silk cocoon and pupate on the leaf. Brown lacewings are multivoltine, producing between 1 and 10 generations per year under natural conditions.

Unlike green lacewings, which are mainly predatory as larvae and feed on nectar or pollen as adults, brown lacewings retain their predatory behavior into adulthood, extending their usefulness in biological control programs.

Brown lacewings prey on various soft-bodied insects and insect eggs, including aphids, leafhoppers, mealybugs, mites, psyllids, scales, small caterpillars, thrips, and whiteflies.

They remain active in temperatures ranging from 48°F to 98°F and thrive in humidity levels of 50% to 60%.

Crazee mites - Anystis baccarum (Trombidiformes: Anystidae)

The crazee mite is a highly mobile, are relatively large when compared to other mites, and bright red, with noticeable hairs on their legs and abdomen. Nymphs are smaller, paler, and move more slowly, making them harder to spot.

Crazee mites are all female and reproduce without mating. Their life cycle includes one larval stage and three nymphal stages. Each stage is separated by a short pupation period, and the full development from egg to egg-laying adult takes approximately four weeks. Once mature, adults continue to feed and lay eggs for up to three weeks.

Unlike other predatory mites that specialize in a few prey species, all their motile stages actively hunt a wide range of pests. Their diet includes aphids, adult whiteflies, leafhoppers, thrips, spider mites, fungus gnats, psyllids, springtails, mealybugs, and more.

Crazee mites are larger than other commonly used predatory mites, about twice the size of Phytoseiulus persimilis. They are highly aggressive hunters, often killing more prey than they consume and actively harassing pests. They are not deterred by natural defenses such as wax coatings or webbing, making them effective against pests that are typically difficult to control. Due to their size and activity, they are easy to spot during scouting. The crazee mite is highly adaptable and can survive and reproduce across a wide range of temperatures and humidity levels.

References

Cuthbertson AG, Qiu BL, Murchie AK. 2014. Anystis baccarum: An Important Generalist Predatory Mite to be Considered in Apple Orchard Pest Management Strategies. Insects. 24;5(3, 615-28.

Parrella MP, and Lewis E. 2017.  Biological Control in Greenhouse and Nursery Production: Present Status and Future Directions, American Entomologist, 63:4, 237–250.

Pérez-Rodríguez J, Valstar R, Leman A, Messelink G.J. 2023. Micromus variegatus and Scymnus interruptus: two new promising candidates with potential for early aphid control in sweet pepper crops. IOBC-WPRS Bulletin Vol. 167, 2023.