Pestgon FactSheet
“ If they fly they die…if they crawl they fall”

SPIDERS: (arachnids)

Description:
Urban 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 spider. Black widow spiders are all too common and are approximately one half inch wide and have large abdomens, they are mostly dark brown to shiny black. The large 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 are poisonous and the venom from the bite of a black widow can cause severe pain and swelling. Such a bite usually 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. They prefer warm areas. On one occasion, in a large warehouse left empty for awhile, 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. Keeping in mind that spiders are predators and that they feed on insects, Pestgon’s management strategies first address their food source— the elimination of insects on, in and around the buildings. Then, the strategic placement of, non-toxic, monitoring traps followed by use of non-staining residual dusts and insecticides in areas most likely to harbor spiders. Removal of old unsightly spider webs, along with sanitation and harborage removal is necessary to long-term results.

Addional Links:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7442.html
Brown Recluse
Hobo Spider