Backyard Apple Disease Management Using Cultural Practices
Backyard Apple & Pear Disease, Pest, and Cultural Practices Calendar
Introduction
Backyard apple production requires a proactive approach to disease, insect, and weed management. Preventative practices are recommended to minimize inputs. While intensive culture may result in the highest quality fruit, reduced inputs can result in acceptable fruit with minor crop losses or aesthetic maladies. This guide focuses on preventative cultural practices with options of low-input pesticide applications. Refer to the homeowner fruit spray guide (ID-21) for a more complete pesticide spray schedule.
Cultural Practices
Cultural practices should always be considered when planning, planting, and maintaining a backyard orchard. Some practices keep plants healthy and assure the lowest risk for disease outbreaks or insect infestations. Other practices eliminate and eradicate sources for fungal and bacterial pathogens or insects, thereby reducing risk for disease or infestation. Combine cultural practices with a pesticide preventative program or use them alone for a no-spray alternative.
- A well-drained site located in full sun is required.
- Maintain plant vigor by watering during drought, mulching to regulate soil moisture and temperature, and amending soil nutrients according to soil tests.
- Minimize insect and wildlife damage.
- Prune to open canopy and increase air circulation.
- Utilize specific cultural practices listed in the table to eliminate disease-causing pathogens or insects and reduce risks for infections/infestation.
- Bagging developing apples when 3/4 inch in size is an effective way of managing pests without spraying. Use the method outlined in EntFacts-218 (bagging apples); remove bags 3 weeks prior to harvest so fruit will color properly.
Resistance
A healthy orchard begins with planning. Disease resistant cultivars can reduce the need for many fungicide and bactericide applications. Growers should focus on cultivars that are resistant to the most devastating apple diseases in their area. Fire blight and cedar apple rust are often the most challenging apple diseases in Kentucky. Refer to Table 1 in ID-21 (page 2) for a listing of disease-resistant apple cultivars.
Weed Management
Cultural practices, such as mowing, mulching, and applying landscape fabric, are the primary methods for weed management. These will be cost-effective for backyard growers while also providing the proper environment for tree growth. Mulch/landscape fabric reduces vegetation that can harbor pests and diseases or compete with trees for water and nutrients. If landscape fabric is used, it should be removed during winter to reduce vole hiding places. There are few organic herbicides labeled for use, and these may not be economical for growers with just a few trees. Herbicides that can be used include pelargonic acid (OMRIapproved contact herbicide) and glyphosate (a systemic herbicide); neither of these herbicides provide residual weed control. Herbicides, in combination with mulch during summer, will improve weed control beneath trees and help prevent mower damage to trunks. Herbicide applications should be made with low spray pressure to avoid drift and precautions should be taken to avoid contact with tree trunks, leaves, and fruit. Check labels for full use information and pre-harvest intervals.
Using the Tables
The following tables focus on cultural practices as a means for eliminating or reducing risk for tree and fruit diseases and insects during various times of the year. Cultural practices should be considered for each plant growth stage, and should be utilized regardless of pesticide programs. Always read and follow label instructions when using pesticides, including pre-harvest intervals. Organic products (OMRI-approved) are marked with an asterisk (*). Organic fungicides are generally less effective for managing diseases than synthetic products. Bagging is the most effective cultural practice for managing diseases and insects on apple fruit. \
February/Early March
Growth Stage: Dormant (before buds swell)
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Fire Blight | Prune cankers and dead, dying and diseased wood; Prune to allow for increased air movement, to speed drying, and allow for thorough spray coverage; Remove fruit mummies; Plant resistant cultivars. | Copper* | N/A |
| Fruit Rots/Spots | Prune cankers and dead, dying and diseased wood; Prune to allow for increased air movement, to speed drying, and allow for thorough spray coverage; Remove fruit mummies; Plant resistant cultivars. | N/A | N/A |
| Scab | Prune cankers and dead, dying and diseased wood; Prune to allow for increased air movement, to speed drying, and allow for thorough spray coverage; Remove fruit mummies; Plant resistant cultivars. | N/A | N/A |
| Insect/Mite | Prune cankers and dead, dying and diseased wood; Prune to allow for increased air movement, to speed drying, and allow for thorough spray coverage; Remove fruit mummies; Plant resistant cultivars. | N/A | N/A |
Late March
Growth Stage: Green tip to half-inch green (1/2 inch of green buds are visible)
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Fire Blight | Remove alternate hosts | Copper* | N/A |
| Scab | Remove alternate hosts | Copper* or Immunox or Mancozeb or Lime sulfur 3* or Sulfur* or Sulforix | N/A |
| San Jose Scale | N/A | N/A | Dormant Oil* |
| Aphids | N/A | N/A | Dormant Oil* |
| Insect Eggs | N/A | N/A | Dormant Oil* |
Late March/Mid-April
Growth Stage: Pink (just before blooms open)
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Cedar-Apple Rust | Prune and destroy cedar apples found on ornamental junipers and cedars; Remove new leaf growth that is tightly curled | Immunox or Mancozeb | N/A |
| Scab | Prune and destroy cedar apples found on ornamental junipers and cedars; Remove new leaf growth that is tightly curled | Captan or Mancozeb or Lime sulfur3* or Sulfur or Sulforix | N/A |
| Rosy Apple Aphid | Prune and destroy cedar apples found on ornamental junipers and cedars; Remove new leaf growth that is tightly curled | N/A | Malathion |
| Leafhoppers | N/A | N/A | Malathion |
Mid-April/Early May
Growth Stage: Bloom (20-60% of blossoms are open)
Do not use insecticides during bloom.
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Cedar-Apple Rust | Remove alternate hosts. | Immunox or Mancozeb | N/A |
| Scab | Remove alternate hosts. | Captan or Immunox or Mancozeb or Sulfur3,4* | N/A |
| Fire Blight | Remove alternate hosts. | N/A | N/A |
May
Growth Stage: After petals fall
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Cedar-Apple Rust | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | Immunox or Mancozeb | N/A |
| Scab | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | Captan or Immunox or Mancozeb or Sulfur3* | N/A |
| Fruit Rots/Spots | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | Captan or Mancozeb | N/A |
| Aphids | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | N/A | N/A |
| Codling Moth | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | N/A | Malathion |
| Plum Curculio | Thin dense fruit clusters by hand; Bag developing fruit when they are 3/4 inch in size; Remove fruit with crescent shaped scars. | N/A | Malathion |
| Oriental Fruit Moth | N/A | N/A | Malathion |
| San Jose Scale | N/A | N/A | Horticultural oil* |
June - July
Growth Stage: Summer growth
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Fruit Rots/Spots | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Pick up and dispose of fallen fruit; Remove fruit with insect frass protruding. | Captan or Mancozeb | N/A |
| Scab | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Pick up and dispose of fallen fruit; Remove fruit with insect frass protruding. | N/A | N/A |
| Codling Moth | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Pick up and dispose of fallen fruit; Remove fruit with insect frass protruding. | N/A | Alternate Malathion and Spinosad every 2 weeks |
| Oriental Fruit Moth | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Pick up and dispose of fallen fruit; Remove fruit with insect frass protruding. | N/A | Alternate Malathion and Spinosad every 2 weeks |
| Plum Curculio | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Pick up and dispose of fallen fruit; Remove fruit with insect frass protruding. | N/A | N/A |
| Stink Bug | N/A | N/A | Alternate Malathion and Spinosad every 2 weeks |
| Japanese Beetle | N/A | N/A | Sevin |
| Mites | N/A | N/A | Insecticidal soap* |
August - September
Growth Stage: Late summer/fall growth
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Fruit Rots/Spots | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Dispose of fallen fruit; remove fruit with protruding insect frass; Remove fruit bags 2 weeks before harvest. | Captan or Mancozeb | N/A |
| Scab | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Dispose of fallen fruit; remove fruit with protruding insect frass; Remove fruit bags 2 weeks before harvest. | N/A | N/A |
| Codling Moth | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Dispose of fallen fruit; remove fruit with protruding insect frass; Remove fruit bags 2 weeks before harvest. | N/A | Alternate Malathion and Spinosad every 2 weeks |
| Oriental Fruit Moth | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Dispose of fallen fruit; remove fruit with protruding insect frass; Remove fruit bags 2 weeks before harvest. | N/A | Alternate Malathion and Spinosad every 2 weeks |
| Plum Curculio | Remove any diseased or rotted fruit from trees or the ground; Irrigate and mulch, especially during dry seasons; Dispose of fallen fruit; remove fruit with protruding insect frass; Remove fruit bags 2 weeks before harvest. | N/A | N/A |
| Stink Bug | N/A | Alternate Malathion and Spinosad every 2 weeks |
October - November
Growth Stage: After harvest
| Target Disease or Insect | Cultural Management | Fungicides | Insecticides |
|---|---|---|---|
| Scab | Remove all fruit from tree and clean up all fallen fruit; Rake fallen leaves and destroy (do not compost); Remove cedar galls from juniper. | N/A | N/A |
| Cedar Apple Rust | Remove all fruit from tree and clean up all fallen fruit; Rake fallen leaves and destroy (do not compost); Remove cedar galls from juniper. | N/A | N/A |
| Fruit Rots/Spots | Remove all fruit from tree and clean up all fallen fruit; Rake fallen leaves and destroy (do not compost); Remove cedar galls from juniper. | N/A | N/A |
| Codling Moth | Remove all fruit from tree and clean up all fallen fruit; Rake fallen leaves and destroy (do not compost); Remove cedar galls from juniper. | N/A | N/A |
| Oriental Fruit Moth | Remove all fruit from tree and clean up all fallen fruit; Rake fallen leaves and destroy (do not compost); Remove cedar galls from juniper. | N/A | N/A |
1The growth stage indicated typically occurs during this time of year; however, this may vary from year to year depending on environmental conditions.
2Products noted with an * indicate those that may be used in organic production. For a list of products approved by Organic Materials Review Institute (OMRI) please see University of Kentucky publication Homeowner's Guide to Fungicides (PPFS-GEN-07).
3Either a liquid or wettable formulation is appropriate.
4Use of lime sulfur affects fruit by causing russetting; switch to sulfur (liquid or wettable formulation) for the remainder of growing season.
Resources
Entomology Extension Publications/Fruit Pests
Horticulture Extension Publications/Home Fruit
Plant Pathology Extension Publications
Bagging Apples: Alternative Pest Management for Hobbyists (EntFacts-218)
Disease and Insect Control Program for Homegrown Fruit in Kentucky (ID-21)
Fruit, Orchard, and Vineyard Sanitation (PPFS-FR-T-05)
Homeowner's Guide to Fungicides (PPFS-GEN-07)
University of Kentucky and Southern Sustainable Agriculture Research and Education.
Nicole W Gauthier, Extension Plant Pathologist; Kimberly Leonberger, Plant Pathology Extension Associate; Ric Bessin, Extension Entomologist; and John Strang & Shawn Wright, Extension Horticulturists.
July 2019