Managing Hobo Spiders and Centipedes in Strawberry Patches

An Idaho gardener described hobo spiders infesting a strawberry patch and centipedes eating strawberries and laying eggs inside them, making harvest frightening.

Species Identification and Risk Assessment

Hobo Spider (Eratigena agrestis)

• Idaho status: Common; often misidentified
• Venom toxicity: Debated; CDC doesn't list as medically significant
• Behavior: Funnel-web builders; ground level; poor climbers
• Beneficial: Eat insects, other spiders

Centipedes (Likely Stone Centipedes - Lithobiomorpha)

• "Eggs in strawberry": Actually centipede brood care — females guard eggs/young in moist cavities
• Strawberry damage: Centipedes are carnivorous — eating insects IN fruit, not fruit itself
• Beneficial: Predators of slugs, insects, small pests

Why They're in Your Strawberry Patch

• Ideal habitat: Mulch, dense foliage, consistent moisture, abundant prey
• Strawberry mulch (straw, pine needles) = perfect shelter
• Prey base: Slugs, earwigs, sowbugs, mites, aphids

Management Strategies (Risk Reduction, Not Elimination)

Habitat Modification

• Mulch management: Use plastic mulch or landscape fabric instead of straw
• Row spacing: Increase air circulation; reduce humidity
• Irrigation: Drip tape vs. overhead; morning only
• Sanitation: Remove rotting fruit promptly

Physical Barriers

• Raised beds with hardware cloth bottoms
• Copper tape around bed edges (deters slugs → reduces prey)
• Harvest containers: Shake/tap berries before bringing inside

Targeted Control (If Necessary)

• Diatomaceous earth: Food-grade; band around beds; reapply after rain
• Sticky traps: Along bed edges; monitor populations
• Pyrethrin spot treatment: Only for confirmed hobo spider concentrations
• Avoid broad-spectrum insecticides — destroy beneficial predators

Original Answer's Recommendations — Corrected

The original answer suggested diazinon and Bt. Important corrections:

• Diazinon: Banned for residential use (US 2004, Canada 2004)
• Bt (Bacillus thuringiensis): Targets caterpillars — ineffective on spiders/centipedes
• Correct approach: Habitat modification + exclusion + targeted pyrethrin if needed

Personal Safety

• Gloves: Wear when harvesting, weeding
• Lighting: Headlamp for early morning/evening work
• Shake clothing before coming indoors
• First aid: Clean bites; monitor; seek care if necrotic lesion develops (rare)

Coexistence Perspective

Both species provide significant pest control. The centipede "eggs in strawberry" observation actually indicates they're hunting pests INSIDE the fruit. Complete elimination would likely increase slug, earwig, and mite damage.

When to Seek Professional Help

• Confirmed hobo spider bites with necrotic symptoms
• Population densities preventing garden use
• Structural invasion (spiders entering home)
• Uncertainty about spider identification

University of Idaho Extension and Idaho Dept of Lands provide current, region-specific guidance on spider management.