News release: Disease-Resistant Apples

Tim Baker, MU Extension Horticulture Specialist
102 N. Main, Suite 1, Gallatin, MO 64640
660-663-3232, bakert@missouri.edu

Release Date: September 17, 2015

Headline: Disease-Resistant Apples

I often get calls from folks who are having a disease problem with their fruit trees.  They’ve been tempted by those mouth-watering pictures of tree-ripened fruit in nursery catalogs, and have planted trees that they expect will bring bumper crops of those same delectable fruits.  Instead, they are getting lots of small, disease-ridden fruits... and wonder what went wrong.

What they may not realize is that to get those picture-perfect fruits, a lot of work is needed, including a regular spray schedule to keep diseases at bay.  While careful management is a must, the backyard fruit grower now has another tool to use in fighting tree fruit diseases: disease-resistant apple trees.

This, of course, does not help someone with an existing tree.  But if you are considering planting an apple tree, I would suggest you pick up our guide sheet on the subject, Disease-Resistant Apple Cultivars.  Trees with the proper resistance to common diseases in our area will require far fewer fungicide applications, reducing your work load greatly.

This guide sheet describes the most common diseases in Missouri, including apple scab, cedar-apple rust, fire blight, and powdery mildew.  It also gives an excellent chart listing each apple cultivar and qualities such as color, ripening date, fruit size, taste, uses, growth habit, storage potential, and ratings for resistance to each disease.

Apple scab is a common disease, which affects both the foliage and the fruit.  It’s caused by a fungus.  Cedar-apple rust is common in areas where eastern red cedar is found, which includes all of Missouri.  As the name implies, it has two hosts, a nearby cedar and your apple tree.  Fire blight is a bacterial disease which affects both apples and pears.  It can be devastating to your tree, killing back branches in bad cases.  Powdery mildew is another fungal disease, which is found on a wide range of hosts. 

The guide sheet also discusses other diseases which may infect your apple tree, which there no resistance for.  If these diseases infect your tree, you will need to spray them with the appropriate material.

As you might suspect, there’s no perfect apple.  You will have to balance your desires for taste, size, and intended use with the resistance for diseases found in your area.  But a good selection will mean less work and greater satisfaction with the fruit it produces.  If you would like a copy of this excellent guide sheet, give me a call at 660-663-3232.  Ask for G6026, Disease-Resistant Apple Cultivars.