Our Greenhouse IPM (Integrated Pest Management) program is falling into place. Beneficial insects and nematodes have been released in the greenhouses. (See https://uribotanicalgardens.wordpress.com/2012/01/11/the-good-the-bad-and-the-ugly.) But this week I found an unlooked for ally: Cryptolaemus montrouzieri, commonly known as “mealybug destroyer”. “Crypts” are in the order Coleoptera, which are beetles. This particular ladybird beetle is native to Australia and was introduced to the United States in 1891 by one of the early biological control pioneers, Albert Koebele, to control citrus mealybug in California. It cannot overwinter in our climate outside but does survive in the greenhouse.
The adult is a small dark brown beetle with a reddish brown head — no spots. The larvae strangely enough look very much like mealybugs — covered with waxy white filaments. They are distinguished from mealybugs by their size, almost twice as big as mealybugs, and by the fact that unlike mealybugs, they move quickly. They are gobbling up mealybugs and scale insects in the greenhouses. The Cornell University biocontrol website says that a single “Crypt” can eat up to 250 mealybugs.
Because it does not over winter, techniques for mass rearing this beetle were developed for its release during warmer months. It is readily available from beneficial insect suppliers but tends to disperse when released. Finding a Cryptolaemus population already living in the greenhouses is a bonus!