How to Treat Dutch Elm Disease?

Dutch elm disease is categorized as a vascular wilt disease. After infecting a tree, its growth will rapidly decline within a few weeks of infection. The most commonly affected elm trees are American and European elms through the elm bark beetles or fungi transmitted through root grafts. 

This disease is aggressive that it can always cause fatal result to the host tree. 

But the rate of movement of the disease will depend on the tree size, location and time of infection in the tree. It also varies with the defensive response of the affected tree, as well as climatic conditions. 

It was in 1961 when the fungus that caused this disease was first introduced in Minnesota. The history of Dutch elm disease was recorded by David W. French, a plant pathologist. 

Today, Dutch elm disease is found in every county in Minnesota. But there are still one million elms remaining in this state. If properly cared for, elms can survive for many years despite the infection. 

What are the symptoms of Dutch Elm Disease? 

One of the symptoms that you’ll notice if your tree is infected with this disease is flagging. The tree will also show signs of yellowing and browning. When you look at its sapwood, you’ll find brown or purple discoloration under its bark. 


Dutch elm disease should be treated proactively. It means that treatment must be applied immediately before the disease presents some symptoms in the tree. The reason for this is that the disease can spread quickly that any treatment may no longer be useful. 

Experts recommend injection of its trunk with a fungicide as a proactive treatment. However, if the disease is already present, prune flagging of the branches must be immediately performed. Strip those barks from the branch that show flagging symptoms. 

Clear the wood by cutting the branch up to 10 feet beyond the discolored or wilted area. 

You must dispose the infected wood properly or debark it completely. 

All tools used in the removal of the infected branches must be disinfected properly using a bleach solution. 

It’s also necessary that you trench between infected and non-infected elm trees to slow the spread of Dutch elm disease. 

When is the best time to treat Dutch elm disease? 

Experts recommend application of fungicide before the beetle flight. The best treatment response is when there’s still less than 15 percent of the tree is affected. During dry condition, watering the tree will enhance uptake of the injection. 

But the best seasons for injection are spring and fall. The soil must have adequate moisture with high humidity. 

After Treatment 

The elm tree will recover from being infected with Dutch elm disease will depend on the severity of illness at the time of treatment and the extent of pruning. Fungicide is best used as a proactive treatment. That is before signs of infection show up. 

When you use pruning and other treatment techniques, up to 60 percent of infected trees could recover. 

To make the long story short, you must treat those trees infected with Dutch elm disease before they get even infected.


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