Mealybugs: Identification and Biological Control

First signs: Distorted leaves, weakened plants, and white cottony clusters on leaves and stems. At first glance, a mealybug colony may look like a patch of cotton or wax. On closer examination, the individual soft-bodied insects can be seen beneath their protective waxy coating.

About mealybugs: Mealybugs commonly gather in protected areas such as leaf axils, stem joints, and other plant crevices. Although their populations may build more slowly than some other greenhouse and garden pests, established infestations can become dense and cause significant plant damage.

Several beneficial insects will feed on mealybugs, but Mealybug Destroyers are our primary biological control for established mealybug infestations.

Best Biological Control for Mealybugs

Mealybug Destroyers (Cryptolaemus montrouzieri)

Mealybug Destroyers are small predatory lady beetles, about 1/8 inch long, that feed aggressively on mealybugs. Both adults and larvae are predators. The larvae develop a white, waxy covering that can make them look surprisingly similar to the mealybugs they are hunting.

Originally from Australia, Cryptolaemus montrouzieri has been used in biological pest control for more than a century and remains one of the most important commercially available predators of mealybugs.

Application: Release the beetles directly onto or near infested plants. We typically recommend approximately 2-5 Mealybug Destroyers per infested plant. For best results, release them as soon as possible after arrival.

Other Beneficial Insects That Feed on Mealybugs

Green Lacewing Larvae (Chrysoperla carnea)

Green Lacewing larvae are aggressive generalist predators that feed on many small, soft-bodied pests, including mealybugs, aphids, thrips and whiteflies. Their elongated bodies and prominent jaws give them a distinctive tiny-alligator appearance.

Lacewing larvae actively search foliage for prey and can be especially useful where several different soft-bodied pests are present at the same time.

Green Lacewings are available in several forms, including eggs on cards and pre-hatched, ready-to-release larvae.

Application: Lacewing eggs or larvae can be distributed throughout infested plants. Typical release rates vary according to crop, growing area and pest pressure, and repeated releases may be useful where infestations are severe.

Ladybugs (Hippodamia convergens)

Ladybugs are best known as predators of aphids, but they and their larvae will also feed on a variety of other small, soft-bodied insects. They can provide supplemental control where mealybugs occur along with aphids and other suitable prey.

Because adult ladybugs can disperse after release, they are generally better suited to broad, general-purpose pest control than to targeted control of a serious mealybug infestation.

Minute Pirate Bugs (Orius insidiosus)

Minute Pirate Bugs are small generalist predators used primarily against thrips, aphids, spider mites, insect eggs and other small pests. They can be useful in a broader biological pest management program when several pest species are present, but they are not our first choice for targeted mealybug control.

Choosing a Mealybug Predator

For an established mealybug infestation, start with Mealybug Destroyers. Green Lacewing larvae can provide additional control, particularly when aphids, thrips, whiteflies or other soft-bodied pests are also present.

For best results with beneficial insects, avoid broad-spectrum pesticide residues that may kill predators after they are released.