Spiders

Pestgon FactSheet

SPIDERS: (arachnids)

Description:
Spiders come in various colors and sizes. All have eight legs instead of six like an insect. For the sake of this discussion, Pestgon, Inc. will explain the poisonous black widow as well as the brown widow spider (pictured). Black widow spiders are very common and are approximately one half inch wide and have large abdomens, they are mostly dark brown to shiny black. The larger ones are the females. Males are significantly smaller with small abdomens. Females are often seen hanging on the web upside down, exposing the red hourglass shape on their belly.

Biology:
Most spiders are harmless and even beneficial but their webs on buildings can become an unsightly nuisance by collecting dust and debris. Black widow spiders though are poisonous and the venom from the bite can cause severe pain and swelling. Such a bite often requires medical attention. The black widow spider builds a loose and irregular web in dark areas like warehouses and closets. The web is always near a light source like the space under the door or the crack around a warehouse roll-up door or garage door. On one occasion, in a large vacant warehouse, a Pestgon technician killed more than one hundred black widow spiders around the roll-up doors. This species is quite prolific, from the commonly seen, pea-size white egg sac, they can produce hundreds of young in a short time.

Economic Impact:
Arachnophobia means fear of spiders. Spiders and snakes are the two most feared creatures in our environment. So the sight of spiders on a commercial project can be costly in terms of public relations and tenant retention. When a building becomes unsightly due to spider webs it lowers the aesthetics and overall appearance of the building. Some spiders even leave droppings on the sidewalks and ledges that appear as tiny bird droppings. These also stain dark paint requiring additional maintenance.

Management Methods:
First of all, a thorough inspection, and identification of the spider species by a Pestgon professional, is essential. Spiders are predators that feed on insects in their environment. Pestgon's management strategies first address the elimination of insects around the buildings, thus reducing or eliminating their foood source. In addition, Pestgon uses non-toxic monitoring traps along with residual dusts and insecticides in areas most likely to harbor spiders. Removal of old spider webs, along with sanitation and harborage removal is necessary for long-term results.

Addional Links:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7442.html
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