Apple trees are popular additions to home landscapes. However, many home gardeners are not prepared for the onslaught of diseases that bombard this fruit tree every year. To minimize the risk of disease and reduce reliance on preventative fungicide applications, home gardeners need to consider selecting disease resistant varieties.
“Although backyards do not have the immense disease pressure experienced in commercial orchards, a proactive disease-control program is still essential,” said Nicole Ward Gauthier, extension plant pathologist with the University of Kentucky College of Agriculture, Food and Environment.
“Apple production requires a dedicated gardener and often a preventative spray schedule, which could include 10 or more fungicide applications throughout the growing season. Without some type of preventative program, disease loss will be extremely high.”
Some of the most destructive diseases affecting apples include fire blight, apple scab, cedar apple rust and powdery mildew.
Fire blight and cedar apple rust are the most prevalent. Fire blight causes twig and branch dieback, which can result in death of the entire tree within two to three years. Cedar apple rust causes leaf drop and fruit infections. Infected fruit are inedible, and leaf drop for three years in a row may stress a tree to the point of death.
“It is safe to say that nearly every homeowner will see some damage from those two diseases on a regular basis,” Gauthier said. “In years with warm, rainy springs, trees can become severely damaged.”
Selection of disease-resistant apple varieties will provide some disease resistance in Kentucky and reduce numbers of required fungicide applications. Gauthier recommends Enterprise, Liberty, Priscilla and Winecrisp.
For a full list of apple varieties that have some disease resistance, go to www.uky.edu/hort/document-list-home-fruit and click on Home Fruit Variety Recommendations. You will find the letters MP next to the names of some apple varieties. That means those are can be grown with minimal pesticide.
Information is also is available in UK extension publication ID-21: Disease and Insect Control for Homegrown Fruit in Kentucky, Including Organic Alternatives at www2.ca.uky.edu/agc/pubs/id/id21/id21.pdf.
If would like hard copies of the publications mentioned in this article, contact the Franklin County Extension Office at 502-695-9035.