The mere sound of their name produces the ewwww factor – cockroaches! These insects thrive in both indoor and outdoor environments where there is food, water, and shelter. During the day, roaches hide in dark, moist areas like cracks, water meter boxes, sewers, and crawl spaces. They come out at night to feed. Good sanitation and exclusion are important for effective control.
There’s a rather new one in town – the three-lined cockroach. It’s the smallest cockroach species in California, with adults averaging less than a quarter inch long. Native to North Africa and the eastern Mediterranean, it was first detected in California around 2004 in Marin County, and positively identified in 2009.
Living in some of the most densely populated parts of northern California, it’s not a domestic pest species and is rarely found indoors. Instead, these cockroaches prefer to live outdoors in natural or ornamental landscapes and can be found in matted thatch, compost bins, and leaf litter. Occasionally in late summer and early fall, adults will wander indoors through poorly sealed exterior doors and windows.
In the San Francisco Bay Area, this species has been observed feeding on the juices from overripe fruit in trees, and various food scraps from compost bins. Though these food items may be delicious treats for the cockroaches, they’re not their typical meals, since large populations of this insect have been found far from fruit or human food resources.
Though the three-lined cockroach may be considered a nuisance pest when found in large numbers, it may never call for control measures.