The Invasive Pest Spotlight focuses on relevant or emerging invasive species in California. In this issue we are covering brooms, a group of invasive shrubs.

Invasive Broom facts

Brooms are upright shrubs in the legume family that typically produce small, yellow, pea-shaped flowers. Shrubs range from 3 to 10 feet tall. They produce flowers from mid spring to summer and produce seed pods in late summer. All brooms are prolific seed producers, with a single shrub producing as many as 2,000 to 3,500 pods containing up to 20,000 seeds. 

While brooms are attractive plants, they grow in dense stands that outcompete many native plants. These dense stands are highly...

They may seem too tiny to do much damage to a mature, healthy tree, but invasive shothole borers (ISHB) are responsible for the deaths of tens of thousands of trees in Southern California. These beetles bore into trees and infect them with Fusarium dieback, a fungal disease that kills the trees. Many native California trees like California sycamore, valley oak, and arroyo willow can be killed when invasive shothole borers attack them.

While these pests are currently only found in Southern California, they could spread to many other parts of the state. Limiting the infestation will reduce their impact. Controlling the beetles is difficult but includes regular monitoring of trees to quickly identify sources of...

During summer swarming season, homeowners urged to check for signs of Formosan subterranean termite

In the lottery of troublesome termite infestations, “Roger,” a Rancho Santa Fe homeowner, hit the jackpot (a pseudonym is used to protect his privacy). In 2021, his house in San Diego County was identified as home to only the fourth documented colony of the Formosan subterranean termite (Coptotermes formosanus) in California.

“FST is one of the most destructive urban pests in the world,” said University of...

Although all cockroaches in California are considered pests, the Turkestan cockroach is of particular concern. This cockroach has become increasingly common in California's residential outdoor areas because it has faster growth and higher reproduction rates compared to other cockroaches that live outdoors. Like other cockroaches, the Turkestan cockroach is considered both a nuisance and a public health issue.

What does the Turkestan cockroach look like?

Adult Turkestan cockroaches are about 1 inch in length. Females are slightly larger than males, dark-colored, flightless, and have distinct pale stripes right below their heads on their wing buds. Males are light brown with fully developed wings....