Gardening in north Orange County, California

Sunday, September 30, 2012

Saturday, September 29, 2012

Mealybug destroyer larva?



This is probably the larva of a mealybug destroyer, a beneficial insect introduced into California in 1891, and a little later into Florida as well, to help control the mealybugs harmful to citrus trees.  This one was crawling along the trunk of our lime tree; it is head-down in both photographs.  Cryptolaemus montrouzieri is native to Australia, and is a beneficial predator in both the larval and adult stages.  It does not often survive cold winters, and has to be reintroduced annually.

This one looks a little different from other mealybug destroyer larvae in photographs, especially this one at What's That Bug?, because I thought ours looked white all over, where the others look more like a dark roly-poly with weird white tentacles stuck all over it, like some insectal Halloween costume.

The Bugman finds it interesting that the mealybug destroyer larva looks very like the mealybug it preys on.  Mother Nature News has an article on how to tell "good" bugs from "bad" ones, including the mealybug destroyer larva and the mealybug.

It may also be a Scymnus larva, a ladybeetle; this is a beneficial insect as well.  Apparently the two are both members of the ladybeetle family anyway.  The Scymnus larva does not look at all like the more common ladybeetle larvae, which do not have the white "tentacles".  Of the Scymnus, the University of Florida writes with feeling, "Many owners of plants have sprayed the larvae with chemicals in the mistaken belief that they are pests. This misidentification must be overcome by education."  In the interests of such, here are a few pictures from other sources:

Mealybug (this one is Phenacoccus solani). Source: Wikipedia.

Mealybug destroyer in larval and adult stages, with mealybugs for comparison. Source: Cornell University.

A beneficial ladybeetle (Scymnus) larva. Source: UTIA.