Tree Care Tips for a Pest-Free Summer
As temperatures rise in the Treasure Valley, so does pest activity. Insects like aphids, borers, and spider mites become more aggressive during the summer months, targeting vulnerable trees and shrubs throughout Boise, Meridian, Nampa, Kuna and the surrounding areas.
Left unchecked, these pests can weaken your trees, stunt growth, and open the door to disease. Fortunately, preventative care and strategic maintenance can make a significant difference. This article outlines how to reduce pest infestations through proper tree care and when to call in a certified arborist for help.
Why Pests Thrive in Summer
Warm weather accelerates insect life cycles, increasing population growth and feeding activity. Drought-stressed or damaged trees are particularly susceptible. When trees are already weakened by heat, lack of water, or pruning mistakes, pests can cause even greater harm.
Aphids and spider mites feed on leaves, sapping nutrients and causing discoloration or leaf drop. Borers, such as the bronze birch borer, flatheaded appletree borer, AND lilac ash borer, tunnel into the vascular layers of the tree and disrupt nutrient flow, often leading to canopy dieback or tree death.
Common Summer Tree Pests in Idaho
Understanding which pests are most active can help you spot early warning signs:
Aphids: Small, soft-bodied insects that cluster on leaf undersides and produce sticky honeydew, which attracts ants and promotes mold growth.
Spider Mites: Microscopic pests that thrive in hot, dry conditions, causing stippled or bronzed foliage.
Borers: Invasive beetles that burrow into bark. Look for exit holes, frass (sawdust-like material), or sudden branch dieback.
Scale Insects: Hard or soft-bodied pests that attach to twigs and bark, feeding on sap and weakening branches over time.
Healthy, well-maintained trees are far more resilient to pest pressures.
Pruning as a Preventative Strategy
One of the most effective ways to reduce pest risk is through strategic pruning. Removing dead, diseased, or infested branches limits habitat for pests and improves airflow, making conditions less favorable for their spread.
Late spring and early summer are good times to assess branch health and remove problem limbs. Prune back any areas with visible signs of infestation or decay. Always sanitize pruning tools between cuts to avoid spreading pathogens or pests.
Avoid heavy pruning in the peak of summer unless directed by a professional. Over-pruning during high heat can stress the tree further, compounding vulnerability to insects.
Best Practices to Keep Trees Pest-Free
In addition to pruning, follow these key practices to protect your trees:
Water deeply and consistently: Hydrated trees are better able to resist pest infestations.
Apply mulch: This helps retain moisture and reduce soil temperature, benefiting root systems.
Avoid over-fertilizing: Excess nitrogen promotes tender new growth, which pests prefer.
Inspect regularly: Early detection is key. Look for discolored leaves, webbing, tiny insects, or boreholes.
When to Call a Certified Arborist
Some infestations spread quickly or affect tree structure below the surface. A certified arborist can diagnose pest problems, recommend treatments, and perform safe pruning or injections where needed.
You should contact an ISA certified arborist if:
You see significant leaf damage or canopy thinning
You find borer holes or sap oozing from bark
Treatments haven’t resolved the issue
You're unsure which pest is present or how to address it
Professional inspections are especially important for high-value or mature trees, where damage could be costly or irreversible.
Keep Your Trees Healthy This Summer
Summer pests can be aggressive, but with the right care, your trees can stay healthy and strong. By pruning early, inspecting regularly, and keeping your trees hydrated, you can prevent infestations before they start.
If you're unsure where to begin or need help identifying signs of trouble, Double J Tree Services is here to help. Our ISA certified arborists serve Boise, Meridian, Nampa, Caldwell, Kuna and the surrounding Treasure Valley, offering thorough inspections and tailored tree care to keep your property pest-free.