Don’t be fooled! This is NOT a green ladybug! The cucumber beetle is a common pest that feeds on the vegetable gardens and may also attack ripening stone fruit, although it’s not fussy and can be found in many parts of the yard, even on roses. These beetles may spread cucumber mosaic virus or wilts in cucurbits (plants in the gourd family).
Adult beetles are shiny with black heads, long antennae, and about 1/4 inch long, and may be striped or spotted, depending upon species. The most abundant species in California is the western spotted cucumber beetle, Diabrotica undecimpunctata; however, the similar western striped cucumber beetle, Acalymma trivittata, may also cause damage.
Management of these little bugs can be tricky. Most older plants can support significant numbers without serious damage. Protect emerging vegetable plants with cloth (often called floating row cover) and remove it when plants are old enough to tolerate damage. On stone-fruit trees, early harvest may be the only option. Providing a habitat for general predators is a good first step.