M e a l y b u g  C o n t r o l

 

 

Cryptolaemus is the most commonly used biological control for mealybugs. 

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Cryptolaemus are small ladybird beetles. They are 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 longtailed mealybug (Pseudococcus longispinus) because this species lacks the cottony masses Cryptolaemus requires for egg-laying. 

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Adult beetles are dark brown with orange heads and tails, 4 mm (⅙ inch) long. Larvae are alligator shaped, up to 1.3cm (½ 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. 

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Optimum conditions are 28°C (82°F) with relative humidity 70-80%, but they can be used between 16-33 °C (61-91 °F). Below 9°C (48°F) they are completely inactive, while above 33°C (91°F) they stop searching. They are most active in sunlight, therefore are not as effective during dull winter months. 

 

Cryptolaemus are most effective when mealybug populations are high. Repeated releases are advisable if mealybug populations are low. 

 

Rate

Interior plantscapes & greenhouses – 5 beetles/infested plant, or 2-5/m² (yd²).

Repeat as needed. 

 

Because many foliage plants grow very slowly, it may take 2-4 months before results of mealybug control programs are apparent. Uninfested new growth is a sign of control. 

 

How to release

Release in early morning or late evening, and do not wear light-coloured clothing when releasing because this predator is attracted to light colours. 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.

Life cycle

The complete life cycle takes about 31 days at 27°C (81°F) and 45 days at 21°C (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; they hatch in 5-6 days at 27°C (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, then pupate in sheltered places on stems or on the greenhouse structures. A single larva can consume 250 small mealybugs. 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.

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