The red imported fire ant, or RIFA for short, is no ordinary red ant. This invasive pest lives up to its name, delivering a sting that causes a burning sensation when its venom is injected into the skin.

People sometimes confuse RIFA with the native southern fire ant. Both can become very agitated when their nest is disturbed but RIFA are more likely to attack. RIFA can bite and sting its victim repeatedly, and its sting is more serious, causing a burning and itching sensation. This is followed by the formation of a white pustule, which can take several weeks to disappear. If not kept clean, the pustules can become infected and may leave permanent scarring. A small...

Shot hole borers are tiny insects the size of a sesame seed that don't look particularly harmful, but don't let their diminutive size fool you. Two of these borers are invasive—the polyphagous shot hole borer and the Kuroshio shot hole borer. They carry pathogens and are spreading them throughout southern California. Together, the borers and the fungi are a deadly combination that are killing many trees. Trees affected include avocado, sycamore, white alder, box elder, cottonwood, and willow.

The two shot hole borers are nearly identical in appearance, and both have a symbiotic relationship with several pathogenic fungi. The female borers lay eggs which introduces fungi into trees. The fungi grow and provide food for...