The Importance of Disease Resistant Varieties and Disease-Free Planting Material for Small Diverse Fruit Farms

raharris

Gordon Johnson, Retired Extension Specialist; gcjohn@udel.edu

For small diverse fruit farms and organic fruit farms managing diseases can be a challenge. Two important tools to start with are using disease resistant varieties and disease-free planting materials.

Start with disease-free planting materials from reputable nurseries that have disease indexing programs. Growers are often tempted to propagate their own plants or to get plants from other growers. Not only are there often patent issues with propagating some varieties but you are often inviting diseases, particularly viruses, into your new planting.

Choose varieties that have been bred or selected for disease resistance whenever possible. Examples include:

  1. Fire blight resistance in pears and Asian pears. European pears with fire blight resistance include Bell (new release), Harrow Crisp, Harrow Gold, Harrow Delight, Harrow Sweet, Harvest Queen, Kieffer, Magness, Maxine, Moonglow, Old Home, Orient, Seckel, Starking Delicious, and Warren. Asian pears showing some degree of resistance are: Chojuro, Kikusui, Kosui, Seuri, Shinko, Shinsui, Singo, Tsu Li, and Ya Li.
  2. Scab and fire blight resistance in apples. Scab resistant apples include Williams’ Pride, Jonafree, Liberty, Enterprise, Prima, Pristine, and GoldRush. Fire blight resistant apples include Britegold, Dayton, Enterprise, Freedom, Gold Rush, Honey Crisp, Liberty, Melrose, NovaEasyGro, Novamac, Prima, Priscilla, Red Delicious, Redfree, Runkel, Sundance, Viking, Wellington, William’s Pride, and Winesap. There are many apples with moderate resistance to fire blight. Go to https://blogs.cornell.edu/khanlab/extension/fire-blight-susceptibility-of-common-apple-cultivars/ for a list.
  3. Bacterial spot resistance in peaches and nectarines. Peaches with excellent or good bacterial spot resistance include Biscoe, Blazing Star, Candor, Contender, Harrow Beauty, Harrow Diamond, PF1, PF12A, PF24-007, PF27A, Starfire, Blaze Prince, Desiree, Encore, Garnet Beauty, Gloria, Glowingstar, John Boy, Messina, PF5B, PF14 Jersey, PF24-007, PF19-007, PF28-007, Redkist, Redstar, Summer Serenade, Victoria, PF 11 Peach, PF9A-007, Manon, Saturn*, Scarlet Pearl, and Southern Pearl. Only Emeraude nectarine has a good rating for bacterial spot. See https://www.canr.msu.edu/news/management_of_bacterial_spot_on_peaches_and_nectarines for ratings.
  4. Black knot resistance in plums. Plum varieties with some resistance to this disease include Shiro, Castleton, Santa Rosa, Methley, Early Italian, Fellenberg, Seneca, Damson, Blufree, NY9, Au Rosa and President.
  5. Anthracnose and Phytophthora diseases resistance in strawberries. Anthracnose resistant varieties include Flavorfest and Sweet Charlie. Phytophthora resistant strawberries for plasticulture include Camarosa, Fronteras, Sweet Charlie, and Strawberry Festival.
  6. Anthracnose, cane blight, and rust resistant brambles. Most blackberries are resistant to these diseases. Red raspberries are resistant to rust and cane blight. The red raspberry cultivars Heritage, Chilcotin, and Nootka are considered resistant to anthracnose.
  7. Phytophthora resistant blueberries which include Aurora, Clockwork, Legacy, Liberty, Overtime and Reka.

Bell pear is fire blight resistant. This new release from the USDA ARS Appalachian Fruit Research Station in Kearneysville, WV is named after the longtime pear breeder, Richard Bell.

Bell pear is fire blight resistant. This new release from the USDA ARS Appalachian Fruit Research Station in Kearneysville, WV is named after the longtime pear breeder, Richard Bell.