Bug Defense Tips | Tree Health Blog | Front Range Arborists

Bug Defense Tips

Welcome Spring…

It’s been a dry winter! For trees, it’s not good because lack of moisture is stressful. Drought stress predisposes trees to borers and bark beetles. Right now, these secondary opportunistic insects are flying and searching out stressed trees to attack. As always, good cultural practices are the first line of defense – especially once a month winter watering. But when borers/bark beetles and stress occur at the same time, like now, trees need protection with preventative spraying.


Some common insects to be aware of this spring…


  • Oaks: Agrilus species borers.
  • Ash: Podosesia syringae, Ash/lilac borer.
  • Spruce: Ips hunteri, Spruce ips; Pissodes strobi, .White pine weevil.
  • Ponderosa pine: Ips species, commonly known as Ips beetle.


Sprays of Permethrin, Bifenthrin, or Carbaryl applied to the trunk at label rates until point of run-off will provide protection if applied before adult flight and egg laying. General timing for spray application is late March/April. For Ips beetle on spruce or pine, apply a second application in summer.

For larger trees, hire a professional licensed tree service to apply preventative sprays at the correct time and rate with a hydraulic sprayer. If you are a do-it-yourselfer and have smaller trees, you can use a backpack sprayer. Always read and follow the insecticide label. If borers/bark beetles are already in the tree, it’s too late for prevention.


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