Spiders
By Mary Bernard, Master Gardener
Many people fear or dislike spiders, but most are not harmful. In fact many of them are beneficial because
of their role as predators, and most cannot harm people.
Spiders are arachnids, not insects. They
eat mainly insects and other spiders, not plants. Most spiders have toxic venom, which they use
to kill their prey. However, only those
spiders whose venom typically causes a serious reaction in humans are called
"poisonous" spiders.
Spiders that might injure people spend most of their time hidden. The spiders commonly seen out in the open
during the day are unlikely to bite people.
The black widow spider is the most common harmful spider in
Black widow spiders occur in most parts of
Tarantulas are long-lived spiders that occupy burrows in the ground but often
come out at night to hunt insects. You
may also see tarantulas wandering around in the fall. These are males looking for a mate. They may be fearsome looking, but are not
aggressive. The bites of
The common house spider and the marbled cellar spider are frequently found
indoors, and make a cobweb in corners of rooms, in windows, and in similar
places. These spiders are incapable of
biting humans because their fangs are too short to pierce people's skin; they
primarily cause problems by producing messy cobwebs.
For control of spiders outdoors, eliminate places for them to hide by keeping
the area next to the house free of trash, leaf litter, heavy vegetation, and
other accumulations of materials.
Trimming plant growth away from the house and other structures will
discourage spiders from first taking up residence near the structure and then
moving indoors.
Outdoor lighting attracts insects, which in turn attracts spiders. Sweep, mop, hose, or vacuum webs and spiders
off buildings regularly. Insecticides
will not provide long-term control and should not generally be used against
spiders outdoors.