How was the invasive plant the Saint-John's-wort controlled in California?

Question

Quizplus · Accepted Answer

A leaf-feeding beetle called Chrysolina quadrigemina was introduced as a biological control agent to control the invasive Saint-John's-wort weed in California. The beetle feeds on the leaves of the weed and reduces its growth and seed production. This method of using natural enemies to control invasive species is considered an environmentally friendly approach to manage invasive weeds.

How Was the Invasive Plant the Saint-John's-Wort Controlled in California