Avoid Pruning Oak Trees in Summer – Oak Wilt Causes

Avoid Pruning Oak Trees in Summer – Oak Wilt Causes

Oak trees have long been an American favorite. They're one of the best shade trees out there, and many varieties grow fast!

If you love oak trees as much as us, you’ve likely dreaded the deadly oak wilt disease.

Well, pruning oak trees in summer increases their risk of oak wilt. Read on to learn why.

Why You Should Avoid Trimming Oak Trees in Summer

Sap beetles – such as the picnic beetle, dusky sap beetle and strawberry sap beetle – buzz around your yard from April to August and are most active in June and July.

These beetles are attracted to the sap that seeps from wounds and holes in trees, like those from storm damage and pruning. They also love the sweet smell of oak wilt. 

After munching on a tree with oak wilt, these beetles fly to unaffected trees with pruning cuts or holes. Carrying oak wilt spores, those bugs unknowingly infect another tree – most often from April through mid-July. That’s why they're nicknamed the oak wilt beetle.

Because of this added risk, Davey experts avoid pruning oaks from April through August. Just to be safe.

Some tree trimming companies still do trim oak trees during this timeframe, which unnecessarily puts your trees and wallet in danger.

The Worst Case Scenario – What Happens Next

If one tree gets oak wilt, all oak trees in your yard are at risk.

You have to remove the infected tree and treat the other oak trees with a fungicide to protect them. And, your arborist may recommend a mechanical intervention since oak wilt most commonly spreads between root systems.

As you may have guessed, these treatments add up – as Emily in Akron, Ohio recently learned.

Last June, Emily had three red oaks pruned by a local tree company. This spring, Emily was devastated when her 100-year-old oak returned with fewer leaves and soon died.

The local tree care company didn't mention that pruning oaks in summer could lead to oak wilt. If Emily had known, she would have invested in a TCIA-accredited company with professional arborists to avoid these hefty removal and treatment costs.

Keep an Eye Out for Oak Wilt Symptoms

If your oak was pruned from April through July, watch it for signs of oak wilt.

Now, in early August, is when you’ll start to see symptoms, such as the wilting, browning or excessive shedding of green leaves and branch dieback.

If you see these warning signs, scrape off 1-2 inches of bark on a branch that has wilted leaves or premature leaf drop. Under the bark, look for streaking, which is a tell-tale sign of oak wilt.

Suspect oak wilt? Click to learn more about identifying and controlling this deadly disease.

  • chris Walker August 6, 2016 >Great article, thanks for sharing it.
  • Mike Hale August 5, 2016 >I am a salesman arborist in the Akron office of Davey Tree, I have 2 lab confirmed cases in the ravenna area and 2 more samples being cultured. Please do not prune your Oak trees now! Wait until late fall or winter when transmitting insects are not flying and the trees are going dormant for winter. If you live in the Summit or Portage County area please call our office (330) 928-4911 if you see symptoms in your Oak trees.
Add a comment:
Featured or Related Blog Posts
  • Windy Cities

    When powerful winds come through with a storm like Hurricane Isaac, they can do more than just cause a bad hair day. They can delay flights, cause power outages and result in varying kinds of damage to trees, ranging from foliage loss to broken limbs.

    Trees differ in their ability to withstand strong winds. The density and strength of the wood, the branch structure and expanse of the roots are factors influencing wind tolerance.

    Ways to minimize storm damage to your trees include pruning to reduce deadwood and canopy density, along with installation of flexible steel support cables to strengthen weak or problematic branch unions. These are not a guarantee but are proven to minimize wind damage.

    Read More
  • Fear of the Swarm

    Within the past few weeks, we've finally witnessed some consistency among the temperatures we experience day-to-day. They have warmed, telling us summer is near, and, at last, we can breathe a sigh of relief.

    But just when we assume summer will wash all our worries away, the creepy crawlies that have burrowed beneath our landscapes for nearly two decades detect that same warmth and emerge, their metallic tin-pan shriek reminding us that our trees might require a bit of extra attention.

    Once the ground temperature reaches above 64 degrees, 13- to 17-year-old periodical cicada broods surface from below to breed. We expect a majority of this year's cicada brood - which could contain millions of cicadas that emerge in the same synchronized generation - to affect trees within states along the East Coast. States that predict an encounter with an excessive cicada population include Connecticut, Maryland, North Carolina, New Jersey, New York and Pennsylvania, as well as Washington, D.C.

    Read More
  • 20/20 Vision

    I could stare at fall foliage for hours at one time, mesmerized by its variety and vibrancy.

    It's exciting to witness the transformation from a lustrous, yet static, bright green canopy to a cornucopia of color among the leaves. The warmer shades of the color spectrum begin to take over, with a few glimpses of purples and plums sprinkled in throughout the leafy scenery.

    But when the winds begin to pick up, even the slightest breeze detaches a few fragile leaves from surrounding tree branches - one by one - gradually revealing the bark and hinting winter is near.

    Read More
  • Shaping Up a Shaken Site

    When heavy winds and rain and bouts of hot, humid air subside, it's the perfect time to take advantage of the otherwise pleasant summertime conditions and enjoy what your favorite local park has to offer.

    Whether you're seeking a shaded spot on the ground to settle into your favorite book, an open lawn for impromptu ball games, or a scenic view of the town, parks provide us with a variety of special places and spaces for countless seasonal activities. But without a bit of extra TLC, the grass grows a little less green, the tree tops tremble a bit in the breeze and sometimes, the most invasive plants take over the land you look forward to frequenting through the end of summer's sunshine.

    That's when local arborists can help. The tree care skills and abilities demonstrated by Guy Pardee, district manager with The Care of Trees, a subsidiary of The Davey Tree Expert Company, when a local park grew awry, for example, offered a solution to restoring one of park lovers' most prized local getaways for the sake of increased future visitations and enjoyment.

    Read More
  • The Best Way to Prune Palm Trees (Step-by-Step)

    Because palm trees exude such bliss, it’s our job to give them the best care possible. Proper palm tree trimming is key to keeping these treasures healthy and thriving.

    Follow the link to learn how to prune palm trees – step-by-step.

    Read More

Request a consultation

What do you need services for?
Sorry, we can’t seem to find the zip code you specified. Our residential tree care offices may not service your area. If you believe this is an error, please try again. Need help? Email us at info@davey.com.
  • Email newsletter
  • Woodchips
*Please fill out all required fields.