Russian Olive
(Elaeagnus angustifolia)
Russian Olive is a drought-tolerant tree historically planted across Colorado but now considered invasive and generally not recommended. While hardy, it is prone to scale, borers, Verticillium wilt, and environmental stress.
Seasonal Pest & Disease Calendar
| Problem | Type | Active Season |
|---|---|---|
| Scale insects | Insect | Spring crawlers; year-round visibility |
| Borers | Insect/borer | Summer |
| Verticillium wilt | Fungus | Spring–Fall |
| Leaf spot | Fungus | Spring–Summer |
| Aphids | Insect | Spring–Fall |
| Suckering / invasiveness | Biological | Spring–Fall |
| Drought stress | Abiotic | Summer–Fall |
Pest & Disease Guide
Scale
- Bumps on twigs
- Honeydew + sooty mold
- Treat crawler stage
- Dormant oil
Borers
- Exit holes
- Sawdust/frass
- Maintain tree vigor
- Preventive treatment if needed
Verticillium Wilt
- One-sided dieback
- Yellowing leaves
- No cure
- Remove declining trees
Leaf Spot
- Dark spots
- Leaf drop
- Usually cosmetic
- Clean up leaves
Aphids
- Sticky residue
- Leaf curling
- Rinse foliage
- Encourage predators
Invasive Growth
- Root suckers
- Rapid spread
- Remove aggressively
- Consider removal
When to Worry
- Heavy dieback
- Verticillium symptoms
- Aggressive spreading
Mostly Cosmetic
- Light spotting
- Minor aphids