Small beetles are causing big problems in Southern California. Two closely related species, the polyphagous shot hole borer and the Kuroshio shot hole borer (collectively referred to as invasive shot hole borers), have been attacking more than 60 species of trees. These invasive beetles create a series of tunnels, or galleries, where they lay eggs and cultivate a Fusarium fungus to use as a food source. The fungus causes branch dieback, general tree decline, and can result in tree death. The beetles have been found in Los Angeles, Orange, Riverside, San Bernardino, Ventura, Santa Barbara, and San Diego counties.

What should you look for?

Invasive shot hole...

[Originally published in the Fall 2018 issue of the Green Bulletin. Modified slightly from original.]

Invasive wood-boring beetles are attacking hundreds of thousands of trees in southern California, including commercial avocados, and trees within urban landscapes and wildland environments.

The invasive shot hole borers (ISHBs) consist of two closely related and morphologically identical species of beetles in the genus Euwallacea: the polyphagous shot hole borer and the Kuroshio shot hole borer. Despite their small size (1.8–2.5 mm) (Figure 1), these beetles are causing big...

Originally posted August 26, 2016; edited July 10, 2018

Have you seen big green beetles in your California yard or garden? Or beetles feeding on your roses or other plants? There are many kinds of beetles commonly found in our landscapes, but the Japanese beetle is not one of them.

Japanese Beetles

Many people think they've seen the Japanese beetle, a small scarab beetle with metallic green wings with white spots on the margins. However, Japanese beetles are generally not found in California.

The Japanese beetle is an exotic and potentially invasive pest for which the California Department of Food and Agriculture (CDFA) is conducting eradication efforts to limit its spread...