Cryptolaemus montrouzieri

Description

Crytpolaemus is the most commonly used biological control for mealybugs. Adult beetles are dark brown with orange heads and tails, 1/6 inch long. Larvae are alligator shaped, up to 1/2 inch long, and covered with white waxy hairs that make them resemble mealybugs. The adults can fly and cover large areas to search for food. 

Target Pest

Citrus mealybug (Planococcus citri), other related mealybugs and soft scale. 

Life Cycle

The complete life cycle takes about 31 days at 81°F and 45 days at 70°F. Sex ratio in the population is about equal, with somewhat fewer females than males (40% females). 

Eggs are laid among the cottony egg masses of mealybugs, hatching in 5-6 days at 81°F. Females lay 5-10 eggs per day for a total of 400-500 eggs in their 50 day lifetime. Larvae feed on mealybugs for 12-17 days, and can consume 250 small mealybugs during this time. Larvae pupate in sheltered places on stems or on greenhouse structures and adults emerge in 7-10 days, mate, and females begin laying eggs in 5 days. 

Adults and young larvae prefer to eat mealybug eggs, but older larvae will feed on all stages of mealybugs. If food is scarce, they will also eat soft scales and aphids. 

Use in Biological Control 

Crytpolaemus is used to control mealybugs mainly in interior plantscapes. They can be used outdoors, but will not survive sub-freezing temperatures. They are less effective on long tailed mealybug (Psuedococcus longispinus) because this species lacks the cottony masses Cryptolaemus requires for egg laying. 

Optimum conditions ar 82°F with relative humidity 70-80%, but they can be used between 61-91°F. Below 48°F they are completely inactive, while above 91°F they stop searching. They are most active in sunlight and therefore not as effective during the dull winter months. For control of citrus mealybug, Cryptolaemus can be used along with the parasitic wasp Leptomastix dactylopii and the green lacewing Chrysoperla rufilabris. 

Monitoring Tips

Close examination is necessary to distinguish the beetle larvae from mealybugs. The beetle larvae are more active and have distinct body segments with six true legs, just visible under the waxy covering. 

 

Product Information

Cryptolaemus are sold as adults and are often shipped with shredded wood or paper to protect them en route. Do not chill the beetle below 50F and release as soon as possible upon receipt.

Introduction Rates

Cryptolaemus should be introduced at the first sign of the pest. In general, 2-3 smaller releases are better than one big release. This decreases risk, helps the Cryptolaemus establish, developing multiple generations. Release on a regular basis if pests are continually present. 

Interior plantscapes and greenhouses

5 beetles/infested plant or 2-5/m2

Outdoors

500-5,000 bottles/acre near the mealybug infestation. First outdoor release should be in early spring. 

Orchards

1,000-2,000 beetles/acre for mature fruit trees. Repeat as needed. Release in early morning or evening as Cryptolaemus may fly towards the sun and out of the area. Because many foliage plants grow very slowly, it may take several months before results of mealybug control programs are apparent. Uninfested new growth is a sign of control. 

For Best Results

Release in early morning or late evening and do not wear light colored clothing (Cryptolaemus is attracted to light colors and will fly to you intstead of the plants). Screen vents and windows to prevent escape of Cryptolaemus. To keep mealybug populations down to acceptable levels in greenhouses, several releases of Cryptolaemus may be necessary, particularly during winter months. 

Using Chemicals

Pesticide residues may slow are halt the establishment of Cryptolaemus, including PGR's and spreader-stickers. Contact Sound Horticulture for more information.