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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