California Root Borer
MODERATEPrionus californicus
Overview
Found flailing in circles in the grass and flipping itself upside down. One of its back legs wasn’t working and then other legs started twitching a few minutes later. Think it’s at end of life.
- Type
- Insect
- Severity
- MODERATE
- Source
- iNaturalist
Symptoms
Geographic Spread
Treatments
Targeted Insecticide Application
Apply appropriate insecticide following label directions. Timing is critical — treat during the vulnerable larval or adult emergence stage for maximum effectiveness.
Biological Control Agents
Introduce or encourage natural predators and parasitoids. Options include releasing predatory beetles, parasitic wasps, or applying Bt (Bacillus thuringiensis) for caterpillar pests.
Infested Material Removal
Prune and destroy infested branches and plant material. Remove fallen debris that may harbor eggs or larvae. Dispose of material away from healthy trees.
Recommended Products & Tools
Helpful supplies for managing California Root Borer. Always read and follow label directions, and confirm a diagnosis before treating.
Knocks down soft-bodied pests like aphids, mites, and scale crawlers.
Smothers overwintering eggs and crawlers; dormant or summer rates.
Soil-applied protection taken up by the tree for season-long control.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Frequently Asked Questions
What is California Root Borer?
Found flailing in circles in the grass and flipping itself upside down. One of its back legs wasn’t working and then other legs started twitching a few minutes later. Think it’s at end of life.
What are the symptoms of California Root Borer?
Where is California Root Borer currently found?
California Root Borer is currently active in California, Utah, Washington, Colorado, Oregon. It has been reported in 5 total states across the United States.
How do I treat California Root Borer?
Treatment options for California Root Borer include: Targeted Insecticide Application, Biological Control Agents, Infested Material Removal. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.