Yellow Sac Spider
Cheiracanthium inclusum
Quick ID Markers
Habits & Biology
Nocturnal active hunter. Builds a flattened silken sac (retreat) in upper wall-ceiling junctions, in folded curtains, or in plant foliage. Bite is the most common spider bite in the US — causes mild to moderate local pain and irritation. Wanders at night looking for prey.
Typical Hiding Areas
Upper wall-ceiling corners, behind picture frames, inside folded curtains, in houseplants, under furniture, in vegetation outdoors.
Signs of Activity
🗓️ Seasonality
Year-round indoors. Most active at night. Enter structures in fall.
⚠️ Mistaken Identity
🧪 Treatment Plan
Yellow Sac Spider control uses residual spray targeting wall-ceiling junctions and sticky traps. They are the most common biting spider in homes.
Spray a residual pyrethroid along all wall-ceiling junctions, around window frames, and in upper corners — the primary hunting and retreat-building zones.
Prevention After Treatment
- •Quarterly spray of wall-ceiling junctions
- •Regular vacuuming of upper corners and curtain folds
- •Exterior perimeter spray in fall
- •Seal all exterior gaps