Black Widow Spider

Pest: Black Widow Spider (Latrodectus hesperus)

Pest Type: Beneficial Predator

Major Identifying Features: Most common harmful spider in California, can cause painful and serious reactions, female has a shiny black body, slender back legs, red or orange mark in the shape of an hour glass on the underside of the large, round abdomen, body is 5/16 to 5/8 inch long, male is much smaller, olive-green gray abdomen with cream-colored areas, same hourglass pattern (yellow) on the underside of abdomen, female only eats male rarely after mating, irregular tough-stranded web, sticky cobweb mesh, spherical egg sacs are creamy in color and paper like

Life Cycle: Egg sac contains about 255 eggs, young spiders emerge from the egg sac after 26-30 days, usually in spring, spiderlings are dispersed through “ballooning”, many will be eaten by predators or siblings, female live 1 year, males 4 months

Pest Rating: Beneficial!

Management Rating: Beneficial!

Host/Season/Outbreak Information: Hides during the day under an object at the edge of the web or stays in a silken retreat in the center, prefer dark, dry, sheltered, relatively undisturbed places such as among wood piles, rubbish, or stones, garages, sheds, barns, meter boxes, outhouses

Support Information/Common Prey: Eat mainly insects, other spiders, arthropods

Management/Attraction Options: Provide undisturbed areas, not commercially available, wear gloves and boots in undisturbed areas, seek medical attention in case of a bite

Sources:

http://www.aces.edu

http://www.ipm.ucanr.edu

 

 

 

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