Tree Insect Control

Leading innovator in systemic tree injections.

Ross Tree is Denver’s leading innovator in tree insect control. We were the first tree company to offer systemic insecticide treatments for tree borers, beetles, aphids, and scales in the late 1990s. Ross Tree’s motto, “Integrity in Action,” means we are committed to minimizing environmental impact when treating tree insects. We promise only to use what is necessary and nothing more. Trunk injections ensure that only the tree gets the product, not the surrounding environment. However, we use spray applications for insect infestations that need immediate treatment, or it is the standard protocol for certain tree insects. Our arborists visit a property, observe tree bug damage, and present a quote to the property owner. Ross Tree has three Qualified Supervisors licensed by the Colorado Department of Agriculture to do tree insect pesticide applications. Why not call a licensed, insured, trusted tree tree healthcare company with an A+ BBB rating? For convenience, we accept all major credit cards. Click the request service button above to fill out a request tree service form or call 303-871-9121.

Tree Insect Calendar

Ross Tree created a tree bug calendar to assist property owners in identifying what insects are munching on their trees. The calendar also tells what months are best for treating each tree bug. Be sure to download the useful PDF version of our Tree Insect Calendar.

What Are Systemic Tree Injections?

Trunk injections treat your trees for various tree insects found in the Denver area, including Aphids, Emerald and Lilac Ash Borers, Mountain Pine, and Ips Engraver Beetles. We also inject nutrients and antibiotics to correct deficiencies or control tree diseases. Ross Tree uses systemic products to treat two common tree insects found in Denver, as well as others.

• Emerald Ash Borer (EAB): At Ross Tree, we believe that prevention is the best tactic when it comes to saving high-value Ash trees against the Emerald Ash Borer (EAB). The EAB arrived in Colorado in 2013 and officially found in the city limits of Denver on June 17, 2025. American Ash trees have zero immunity to the EAB and will die if not treated. Our EAB tree injections, also effective against the Peachtree, Lilac, Ash Borers, and the Zimmerman Pine Moth, are a testament to our proactive approach. Click here for our Emerald Ash Borer  Handbook to learn more about our prevention strategies.
• Elm Leaf Pests: Ross Tree uses tree injection products to control the Elm Leaf Beetle and the Elm Leaf Miner, European Elm Flea Weevil, and Japanese Beetles.  Elm Leaf pests typically become active when Denver has wet springs. Click here to link to our Elm Leaf Pest Handbook.
• Soft Body Tree Insects: Wet springs usually mean tree aphids and scales will become a problem for some trees in Denver. Most aphids and scales are tree species-specific. Applying dormant oils in the winter or systemic injections in the early spring will control these tree bugs.