The grass spider (Agelenopsis aperta) is the most common and widespread funnel weaver spider in Arizona and is found throughout the state in lawns, grasslands, desert scrub, and gardens. It is a medium-sized spider — females reach about 3/4 inch in body length — with a brown to tan coloration and two dark longitudinal stripes on the cephalothorax. Like other funnel weavers, it builds a flat sheet web with a funnel retreat, waiting for insects to stumble onto the web. Grass spiders are particularly common in Arizona's higher elevation grasslands and are most conspicuous in late summer and fall when populations peak. They are fast runners and retreat quickly into the funnel when disturbed. Grass spiders are completely harmless to humans and are important predators of ground-dwelling insects.
👁Warning Signs
Flat sheet webs with funnel retreats in lawns and grasses. Webs covered in dew in the morning. Brown spider with two dark stripes on the cephalothorax.
⚠Health & Property Risks
Not medically significant. Completely harmless.
Prevention Tips
Not a pest. Regular mowing reduces web density in lawns.
🛡Professional Treatment
No treatment necessary.
Frequently Asked Questions — Grass Spider
The Grass Spider (Agelenopsis aperta) is brown to tan with two dark longitudinal stripes on cephalothorax and typically measures Female: ~3/4 inch body. The grass spider (Agelenopsis aperta) is the most common and widespread funnel weaver spider in Arizona and is found throughout the state in lawns, grasslands, desert scrub, and gardens. It is a mediu.
The Grass Spider is generally low-risk, but caution is still advised. Not medically significant. Completely harmless.
In Arizona, grass spiders are most often encountered in the following situations: Flat sheet webs with funnel retreats in lawns and grasses. Webs covered in dew in the morning. Brown spider with two dark stripes on the cephalothorax.
The Grass Spider is most active during: Year-round; most active late summer through fall. Arizona's warm desert climate can extend activity periods compared to other states, so year-round vigilance is recommended in the Phoenix metro and surrounding areas.
Not a pest. Regular mowing reduces web density in lawns.
No treatment necessary.
If you spot a Grass Spider indoors, avoid handling it directly. Capture it under a glass if possible for identification, or photograph it for reference. Contact Pest Control Bros for a professional inspection — we can confirm the species, assess the severity of the infestation, and recommend targeted treatment.
Dealing with Grass Spider?
Pest Control Bros LLC serves Maricopa, Chandler, Casa Grande, Tempe, Gilbert, and Mesa. No contracts. Free inspections. Same-week service.
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