How to treat Cytospora canker on fruit trees

SALT LAKE CITY – Need help treating Cytospora canker on your fruit trees? Here are some tips that hosts Taun Bennes and Maria Shilaos discussed on the KSL Greenhouse show last week.

Cytospora canker tends to be more common in stone fruit trees

Because a lot of stone fruits don’t completely adapt to Utah’s climate, you’ll often see Cytospora on the tree trunks from winter sun damage.

“If you’ve had problems with Cytospora, you may need to do some fungicidal treatments after you’ve pruned to try to prevent it from getting worse,” Bennes said.

How do you know if your fruit trees have Cytospora?

In the summer, check the trunk and the limbs for sappy cankers.

“You might need to cut underneath them because it’ll be a dark brown or black underneath. Sometimes trees, especially stone fruits, are just prone to being a little bit sappy like that,” Taun said.

There are three ways you can help treat or prevent Cytospora canker

One is by painting the trunks with water-based latex paint. Do this every year to two years, and that white color will keep the sun from heating the trunk.

Another suggestion is to make sure to have bare ground at the base of the tree.

“You want a good 3- or 4-foot wide ring around the tree with bare soil, or you might be able to put some bark mulch on it. That will prevent mechanical injury from string trimmers and mowers,” Taun said.

The third thing to do if you have a history of Cytospora canker in your orchard is pruning sooner rather than later because the trees are more prone to it as it gets warmer. The ideal time is mid-March for stone fruits and mid-February for apples. After you’re done pruning, you can spray it with a fungicide.

The most important thing to remember is to keep your tree healthy so the disease doesn’t happen.

The KSL Greenhouse is on every Saturday from 8 a.m.-11 a.m. You can follow the show on Facebook, Instagram, YouTube, and on our website.