Identification

• adult female is shiny black with a red hourglass on the underside of the abdomen (there are beneficial lookalikes without the red hourglass)
• immature females have a pale brown to black body with white to orangish banding; they get progressively more solid black as they molt toward adulthood
• males are about 1/3 the size of females and are pale brown with white markings, resembling immature females

Nesting Habits

• prefer pre-existing holes in dark, undisturbed areas
• hide during the day and are in their cobwebs at night
• common around building foundations, rock piles, wood piles, outbuildings, water meter/irrigation boxes and around exterior lighting

Diet

• insects and spiders

Significance

• can be a serious health risk, especially to children and elderly people
• bite can cause pain, nausea, cramping or death (rare)

IPM Recommendations

• Minimize nesting habitat around property.
• Seal exterior cracks and crevices to reduce hiding places.
• Regularly vacuum individuals and webs.
• Reduce clutter indoors and outdoors.
• Install tight-fitting door sweeps.
• Install tight-fitting screens in windows.
• Reduce other insects that serve as food.
• Change exterior lighting to sodium vapor bulbs.