Forest Pests: Insects, Diseases & Other Damage Agents

Spiders Forest Health Guide for Georgia Foresters Written by Terry Price, Georgia Forestry Commission Adapted for the web by the Bugwood Network

All spiders are considered venomous but most species do not cause serious reactions in people. The black widow and brown recluse are exceptions. The brown recluse is easily recognized by a violin or fiddle-shaped mark on the top of its body (Figure 200). Three other species of spiders frequently found in the forests are the golden silk spider, garden spider, and spiny-bellied spider (Figures 201-203).

Figure 200 photo by James O. Howell

Figure 201 - Golden Silk Spider photo by Ray Simons

Figure 202 - Garden Spider photo by James H. Jarratt,

Figure 203 - Spiny-Bellied Spider photo by John S. Heiss

Brown recluses are shy spiders that prefer quite, undisturbed places. People are often bitten while cleaning out closets, basements, or other storage areas. Shoes and clothing in storage are often infested.

Reactions to brown recluse venom may be mild to very severe. The venom is classified as a necrotoxin. The bitten area becomes painful and swollen in a short period. Blisters often form on the skin around the bite site (Figure 204). The next day the skin at the bite begins to turn purple. During the next week or more the skin turns black as the cells die (Figure 205). Later the blackened area sloughs off leaving a depression in the skin (Figure 206). The depression slowly fills with scar tissue (Figure 207). Many times the bite site has to be repaired by a surgeon to promote healing otherwise an unsightly scar often remains. Brown recluse spiders can become a nuisance in untidy areas at home or on the job. Closets, basements, and other storage areas should be periodically cleaned and straightened to discourage spiders from taking up residence there. Work gloves, shoes, boots, and coveralls should be sealed in plastic bags when not in use to inhibit the invasion of spiders.

Figure 204 photo by Beverly Sparks

Figure 205 photo by Terry Price

Figure 206 photo by Center for Disease Control Archives

Figure 207 photo by Center for Disease Control Archives

The black widow is considered an extremely poisonous species. The mature female is easily identified by a red hourglass mark on the underside of the abdomen (Figure 208). Younger females will be variously marked with white and red on the upper abdomen (Figure 209).

Figure 208 photo by James O. Howell

Figure 209 photo by Center for Disease Control Archives

Outdoors, black widows build their webs close to the ground under houses, stones, wood, tin, in tall weeds and grasses, in water meter boxes, around playground equipment, and many other un-likely places. In-doors, the spiders often are found in attics, basements, and under cabinets.

Reactions to a black widow bite are unique and usually follow a similar pattern among all victims. The venom is classed as a neurotoxin. The bite itself is very seldom felt but immediate pain soon follows. Victims suffer with severe muscular pain, stiffening of abdominal muscles, weakness, tremor, sweating, and salivation. Convulsions may occur in small children. Death is rare but does occur more frequently in children and older persons. In one study, large, muscular adult men seemed to be affected the most. Local treatment of the bite site is usually not effective. The victim should get immediate medical attention. Try to capture the spider so physicians can make a positive identification. This will aid in treatment.

Rubbish piles, old boards, and tin should be removed from around buildings. Grass and weeds should be mowed frequently. Children’s play areas should be inspected weekly during the warm months for spiders. It is not uncommon to find black widows under sandboxes, around playhouses, benches and tables, and various types of homemade and commercial playground equipment.

The golden silk spider is chiefly a Coastal Plains spider. It inhabits dense bottomland woods and can number many hundreds per acre. The bite is painful but severe reactions are not reported.

The spiny-bellied spiders are probably the most commonly encountered spiders in the forests. Their webs can be obnoxious when they get entangled in the hair and face area. Their bite is nothing to fear, however.

The arboreal orb weavers (not pictured) are common in forests too. They often suspend silk threads across wide areas such as roads and fireline breaks. An orb web is then spun in the center of the silk strand in the evening hours and then removed before daylight. The strand of silk remains attached between two objects during the day and then again in late evening the spider crawls out and reconstructs the orb web in hopes of catching a night flying prey. During the day, these spiders hide in folded leaves in trees.

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