Staying protected from brown recluse spiders

The name "brown recluse" describes the color and habits of this venomous spider that has earned a reputation for having a painful bite.

According to John Hobbs, agriculture and rural development specialist with University of Missouri Extension, this spider is usually found in structures that contain dry, cluttered space that is undisturbed and has a supply of insects or other small organisms to serve as suitable prey.

"These spiders are reclusive, but they will bite if they are against your skin and movement is restricted," said Hobbs.

Human reactions to a brown recluse bite vary considerably and depend on the amount of venom injected by the spider as well as the victim's sensitivity to the venom.

A painful reaction can occur almost immediately, but often the victim won't realize they have been bitten for an hour or more. Victims usually describe a stinging sensation followed by intense pain.

A small white blister usually develops at the site of the bite. The affected area swells and becomes hard to the touch. This tissue dies and eventually sloughs away, leaving a sunken, ulcerated sore of various sizes.

The typical reaction has been described by physicians as unremarkable or mild and covers an area less than the size of a dime. In a small percentage of cases (less than 5 percent) the sore covers a larger area.

"Unfortunately, a brown recluse bite may be serious requiring a visit to a doctor," said Hobbs.

Brown recluse spiders vary in color with abdomens that may be straw-colored, pinkish-gray, pale to medium brown or slate gray. They have one distinctive characteristic -- a dark, violin-shaped pattern on the front of the back. The neck of the violin points toward the rear of the arachnid.

Two strategies may help to control the brown recluse spider according to Hobbs.

First, take advantage of the spiders' daily routine. Brown recluse spiders normally hide during the day and don't come out until an hour or two after dark.

"The search-and-destroy strategy may prove effective if timed to coincide with their activity. Carry a crawling insect spray as you search for the spiders within a foot or two of walls," said Hobbs.

Two, roach or mouse glue traps can also work well. Place these in spots the spiders are likely to be, such as dark areas, around boxes, and close to walls and room corners.

More information on the Brown Recluse Spider can be found in the G7386 guide sheet titled, "Spiders," which is available at the nearest county extension center or online at extension.missouri.edu.