Dangerous fungus affecting oak trees in Minnesota
(ABC 6 News) – Oak wilt is a dangerous fungus for oak trees, both for the tree and its roots.
According to the Minnesota Department of Natural Resources, oak wilt is caused by a non-native fungus that invades the water-conducting vessels of oaks which is where trees get nutrients and water for the stems and leaves.
“It impacts trees in red oak group as well as the white oak group,” Forest Health Specialist Evan Otto said.
Red oaks die much faster and can be killed off in just a couple of months.
White oaks have a better defense mechanism against fungi and can live longer up to twenty years.
“Just due to the anatomy of red oaks compared to white oaks, that is the difference in why red oaks are gonna succumb to mortality much faster,” Otto explains.
As for how you can defend your oak trees, make sure not to prune or cut down any trees between April and July, as sap beetles are able to infect wounded trees.
Trees damaged from storms are at greater risk. Experts say you should cut down any infected trees or put a barrier between those and healthy ones, including their roots. Spraying fungicide also helps.
Luckily, the spread of oak wilt has been slowed in recent years, but it’s never expected to be completely eliminated.
Oak wilt was first discovered in Minnesota around 1945. Today, oak wilt is widespread in the southern half of Minnesota and continues to expand its range northward.