Oak Wilt

Did your oak die suddenly this past summer? If so, oak wilt could have been the culprit. Oak wilt is a deadly tree disease that is spreading north in Minnesota. Right now, it is reaching into Pine and Morrison counties. There are a few important things you can do to stop its spread.

If you have already cut down that dead oak, make sure you don’t move it anywhere that oak wilt doesn’t exist (roughly in an east-west line from Little Falls to Cloverton). You wouldn’t want to be responsible for killing a patch of forest at your lake property your cabin. Even if you’re in an area that is heavily impacted by oak wilt, there are still a lot of zones free of the disease everywhere, even in infested counties.

Your fool-proof option is to leave the oak where you cut it for a year. If you do that, cut it up, stack the wood, and tarp the pile from April through August to prevent oak wilt spores from spreading from the infected wood. Make sure you bury the edges of the tarp in soil so spore-spreading beetles can’t reach the oak wilt fungus inside and escape, covered with spores, to kill yet another oak. After the following summer, the wood will never produce spores again.

If you haven’t cut the tree down yet, cut it down before April. Don’t move it from your property. Simply cut it up into firewood-sized segments, stack, and tarp from April through August. If you don’t want to deal with the hassle of tarping, burn the wood between August and April. Make sure you have a burning permit if you need it! If tarping or burning aren’t good options for you, another is to haul the wood somewhere where it will be chipped between August and April.

Do your part to prevent the spread of oak wilt. Leave infected oaks in place for a year. Tarp, burn, or chip them in the winter. And definitely avoid moving infected oak logs between April and August. For more information, check out the DNR’s oak wilt webpages (MNDNR Oak Wilt). Don’t miss the section on Management (MNDNR Oak Wilt Management) that contains information on how to properly handle infected wood.

Oak Wilt Leaves

Emerald Ash Borer

Emerald Ash Borer is an invasive bug that borers into Ash Trees kills the tree. The symptoms won't show until it's too late. If you are experiencing any trees that look to be lacking leaves or a very thin canopy of leaves, EAB may be the culprit. This bug has been found throughout Pine County and found in border counties as well. It is only a matter of time when most if not all of our Ash trees will be gone. This is very similar to the Dutch Elm Disease that wiped most of Minnesota's Elm tree population.

When managing for EAB, it's important to try and slow down the bugs ability to infect new trees. In general, cutting trees down between May 1st and September 30th is never a good idea. This is when our bugs native and invasive, are most active. They are drawn to wounds. This makes it important to not cut down or trim your Ash trees during this time period. The best time to cut down or trim your Ash trees is when the air temperature is below freezing. 

Common bugs similar to the EAB

Here are some links to resources that are useful to identifying EAB as well as what to do management wise:

MN Dept of Ag. EAB Info Main Page

Does my Tree have EAB?

Recognizing EAB Eating Galleries

Insecticide Options

Disposal

There is some hope in controlling EAB with the help of biological control! More on biological control is found here: Biological Control Link