Why H-W-A needs treatment N-O-W

Posted on April 2nd, 2024.

View from the tree stand, with CEO Billy Collins

Collins Tree recently posted (while donning our arborist hat) to educate on the importance of prevention, maintenance, and treatment of Hemlock Wooly Adelgid (HWA). Here, we’re jumping into the tree stand 1:1 with CEO Billy Collins for a higher-level look at a topic for tree owners throughout New England: how climate affects HWA management.

Collins Tree:

HWA is tricky enough already, so how does area weather complicate things even more?


New England’s crazy temperatures and diverse ecosystem encourage a range of adelgid predators that aren’t found everywhere else. From Cape Cod to Acadia and the States in between, this region’s climate creates extra challenges for dealing with HWA.

Cold winters help a bit by killing off some of the adelgids, but we can’t only rely on that. Many will survive, especially in milder winters like this year. Applying treatment at the right time is important. While late winter to early spring is ideal for applications because it targets adelgids before they begin spring feeding and reproduction cycles, the sooner you start the better.

Because there are so many hemlocks in local forests and landscapes, there is strong community support for controlling adelgid infestations. Encourage others in your ecosystem to stay ahead of prevention, maintenance, and treatment. Keep an eye out for advisories, consult the town gardening club, talk to your neighbors, and ask professional tree treaters. They all can provide information on adelgid infestations, biological control options, and tips tailored to New England’s unique conditions.

Collins Tree:

That pesky bug seems to be an issue for residential, commercial, and even protected properties. How can we stop HWA from chomping up the landscape?

Yeah, adelgids are troublemakers. Timing and consistency are key to dropping the hammer on their feeding frenzy. Look out for white, wooly masses on the undersides of branches. Take notice of color changes from earthy green to yellow and brown. Pay attention to needle count and appearance – do they look full and lush or bare and shocked.

Catching HWA early is how to manage the problem. Give us a call and we’ll remove affected branches and prune appropriately for smaller cases. For more expansive situations, we use specially formulated applications effective at wiping out critters, while staying kind and respectful to the surrounding environment.

Collins Tree:

What can people do to give themselves the best chance for avoiding HWA altogether?


Having healthy hemlocks is really the secret. To maintain strong trees that have the greatest possible resistance you need to care for them year round. Adequate watering, quality mulching, and avoiding stress (like over-pruning) can make trees less inviting to adelgids. Work with a tree expert to regularly check your landscape and don’t wait if you spot signs of adelgid activity. Do something immediately before an infestation gets out of hand, so you can manage it and minimize damage.

If you don’t move quickly they’ll multiply fast. Unfortunately, the lifecycle of the adelgid allows for multiple generations in a 12 month period. So, even if you do treat an infestation, monitoring and vigilance are required to squash resurgence. With a tree management partner working with you to give hemlocks the attention they need, they can stand tall, sometimes reaching 30+ feet, and stay adelgid-free for years to come.

Contact Collins Tree Service to learn more about HWA prevention and management, and many other ongoing tree care services. Reach Billy directly at 603-485-4761 or [email protected] .


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