Oleander Aphid in Washington
MODERATEInsect
Oleander Aphid is currently active in Washington. Watch your susceptible trees closely and act early.
About Oleander Aphid
Observed on a 15 minute walking survey at Kirk Park. This survey is part of the Paired Garden Study project associated with Biodiversity in Urban Gardens (BUG) and is run by the California Native Plant Society. This observation is from the native plant garden. My survey here ran from 4:44PM-4:59PM. More info about BUG is available at the link below (scroll down to Santa Clara Valley Research Project for more info about the Paired Garden study) https://www.cnps.org/education/bug Umbrella projec
Symptoms to watch for
Treatment options
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 Oleander Aphid. Always read and follow label directions, and confirm a diagnosis before treating.
Direct-contact control for soft-bodied sap feeders.
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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Need help with Oleander Aphid in Washington?
Connect with ISA Certified Arborists serving Washington:
Browse all Washington arborists →Frequently asked questions
Is Oleander Aphid in Washington?
Oleander Aphid is currently active in Washington. Watch your susceptible trees closely and act early. It was first recorded here on September 21, 2026.
What does Oleander Aphid look like?
How do I treat Oleander Aphid?
Options include: Targeted Insecticide Application, Biological Control Agents, Infested Material Removal. Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.