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!
March is here, “coming in like a lion” with blustery winds (though mild temperatures). This past winter may have felt like March, but one thing has changed: the light. The angle of the sun through the still-bare trees allows me to see farther into the distance. It illuminates the first leaves coming up through the warming soil. Clouds and sun shift quickly, creating shadows that appear and disappear on the wind.
Slowly but surely the greenhouses are all being updated. New (safety) glass went in this summer. Over the past few years, the old mechanical vent controls have been mostly replaced with computer controls. There’s no doubt these are an improvement. Finding the delicate balance of temperature, moisture, and light can be tricky especially with tiny seedlings. The new controllers are able to use current weather data as well as the temperature/humidity data from sensors in the greenhouse to control opening/closing vents and “curtains”. They’re saving energy too, by opening and closing at accurate temperatures, and by using smaller and lighter motors. The only thing I will miss about the old equipment is how much more interesting it is to photograph….