How to Prevent Oak Wilt When Trimming Your Oak Trees

Prevent Oak Wilt

How to Prevent Oak Wilt When Trimming Your Oak Trees

With temperatures still skirting triple digits, you’re more likely to think about spending time at the lake than trimming your oak trees. But right now is the perfect time to think about your oak trees–especially if you want to prevent oak wilt contamination.


oaks2Central Texans love their oaks, but you can’t mention oak trees without someone bringing up oak wilt. Oak wilt is a fungus, scientifically known as Ceratocystis fagacearum, which is introduced to a tree’s vascular system through open cuts in the tree’s protective layer. The fungus is transported from diseased tree to healthy tree by sap beetles. This beetle is attracted to the sap that seeps from open wounds on oak trees. As it feeds on the sap, it leaves behind the dreaded oak wilt fungus.


The fungus then takes over the tree’s vascular system. blocking the flow of water and nutrients to the plant. Dying veins, leaves dying and dropping rapidly, and chlorosis are all symptoms associated with oak wilt. Red Oaks are the most susceptible, with a 100% mortality rate. Live oaks fair better with 10-20% chance of survival.

oaks1Because oak roots can extend for hundreds of feet and are often grafted together, the fungus can quickly spread. Treatments are expensive, time consuming, and rarely work. Before you know one diseased tree takes out an entire neighborhood of oaks. With it goes shade, beauty, and as much as 20% of your property’s value!


Needless to say no one likes oak wilt. As with anything prevention is better than a cure. The best thing to do is to prevent oak wilt in the first place. Here’s how:

#1 Avoid trimming when oak wilt is at its peak–usually February to June. Many municipalities place bans on oak trimming during this time. That’s why now is a great time to do any necessary trimming.

#2 Only trim when necessary. Oaks don’t need annual trimming as a matter of practice. Only trim when you need to remove dead limbs, raise or brighten a canopy, or to encourage new growth.

#3 Disinfect your tools. Make sure to disinfect your tools between each use and between each tree. Lysol spray is just as effective as any expensive garden supply disinfectant.

#4 Use sharp tools and appropriate size blades. Hacking and chopping away at your tree creates dozens of gashes from which the beetle can feed and infect your tree. Use sharp blades and equipment that can handle the girth of the limbs you are trying to remove.

#5 Seal your cuts. Spray over any cut that is wider than an inch with either a tree sealant or an acrylic spray paint. The general rule is any cut larger than your finger gets sprayed. Spray immediately–don’t wait 30 minutes to an hour and come back to it. It’s too late.

#6 Properly discard of any diseased limbs. Don’t reintroduce the fungus or any other disease into your yard through compost or mulch. Instead, send diseased limbs off to TDS or Austin Wood Recycling. They use heat treatments that kill off diseases without adding more organic material to our landfills.

Above all think safety first. Gravity is always at work, so use a sturdy ladder, properly secure any equipment and limbs, and clear the area below the tree to avoid damaging cars or people. Also wear safety goggles and if using power equipment consider using ear covers and good fitting gloves.

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