University of Missouri Extension

G6026, Revised January 2012

Disease-Resistant Apple Cultivars

Michele Warmund
Fruit State Specialist
Division of Plant Sciences

Disease infection is a major limitation to growing apples in Missouri. Several cultivars with apple scab immunity or resistance are currently available for planting. Although these cultivars can reduce pesticide usage, apples are susceptible to other diseases and insect pests. All the cultivars listed below are immune or resistant to apple scab. Because temperatures often reach 100 degrees F in August, early-ripening disease-resistant cultivars are excluded. Also, some cultivars have not yet been evaluated in Missouri and may have unidentified limitations to fruit production.

Appple treeFigure 1. Planting apple cultivars that are resistant to prevalent diseases may eliminate the need to apply fungicides. (Sketch by Barbara Barkwell Long)
 

Apple cultivars

Common disease symptoms

Summer diseases and insects

Although some apple cultivars have resistance to apple scab, cedar-apple rust, fire blight and downy mildew, they are still susceptible to summer diseases, such as fly speck and sooty blotch, and to insect pests. Fly speck and sooty blotch occur together on the fruit surface under warm, humid weather conditions. Fly speck is identified by distinct groups of tiny, shiny black spots. Sooty blotch appears as olive green to black smudges. Both of these diseases are superficial blemishes that can usually be removed from the surface of the apple with mild scrubbing. In contrast to the summer diseases, control of insect pests on disease-resistant apple cultivars may require trapping, mating disruption or insecticide application.

Rootstocks

Most of these scab-resistant cultivars are available from nurseries on rootstocks that that produce relative large to very large trees such as M.26, M.7 and MM.111. However, M.26 is very susceptible to fire blight and, therefore, is not recommended for planting in Missouri.

G6026 Disease-Resistant Apple Cultivars | University of Missouri Extension

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