Tiny Invaders. Big Trouble.
If your trees look healthy on the outside, don’t get too comfortable—because summer is peak season for some of the most destructive pests in California. With warmer weather, stressed trees, and longer dry spells, invasive insects like aphids, borers, and beetles are thriving across the South Bay and Central Peninsula.
At West Coast Tree Care, we’ve already seen a sharp rise in calls this season for pest-related damage—and it’s often more advanced than property owners realize.
So which pests should you watch for, and what can you do to protect your trees?
Meet the Summer Offenders: Top Pests in The Bay Area
1. Invasive Shot Hole Borer (ISHB)
This tiny beetle targets a select list of tree species—including sycamores, willow trees, valley oaks, and maples. The real danger? It brings a fungal disease with it, boring deep into the wood and killing trees from the inside out.
2. Bark Beetles
Bark beetles lay eggs under tree bark, cutting off water and nutrient flow. Stressed or drought-weakened trees are especially vulnerable. Look for reddish dust or leaking sap.
3. Bronze Birch Borer
This flatheaded borer attacks birch trees and is active throughout the summer. Early infestations are hard to detect until the top branches begin dying back.
4. Aphids (and Sooty Mold)
Aphids cluster on new growth and excrete honeydew, which attracts mold and pests. While they don’t bore, they can weaken trees and cause cosmetic and structural issues.
Why Summer Makes Pest Problems Worse
Warm, dry conditions allow many insects to reproduce faster—and they’re drawn to trees already struggling with drought stress or compacted soil. Without a proactive inspection, infestations often go undetected until leaves yellow, limbs die back, or irreversible damage is done.
Tree Species Most at Risk in the South Bay & Peninsula
- Sycamores
- Coast Live Oaks
- Birch Trees
- Maples
- Willows
- Liquidambar (Sweetgum)
If you have any of these on your property, now’s the time to get ahead of the problem.
What You Can Do Now
- Schedule a tree health or pest inspection. An ISA-certified arborist can identify hidden pest activity before damage spreads.
- Strengthen your trees. Healthy trees resist pests better. Soil care, tree pruning, watering, and fertilization all play a role.
- Act early. The earlier you catch pest activity, the easier—and less costly—it is to treat.
Our professional crew is ready to help with any of your tree service needs. Just call us now at 408-351-6155.
Don’t Wait for Damage to Appear
By the time you see visible signs of decline, pests may have already taken hold. That’s why summer is the ideal time to schedule an inspection and take preventive measures.
Contact West Coast Tree Care today at 408-351-6155 to schedule a professional evaluation and treatment plan. Pro Tip:
If you’ve noticed increased bird activity around a particular tree, it might be a sign they’re feeding on pests below the bark. That’s nature’s red flag—don’t ignore it.
