These apples and pears were grown in North America during the Colonial Era and through the time of the American...
Fruit Tree Diseases and Pests
It’s not just humans that enjoy fruit. All the fruits we grow are also considered delicious by a variety of other animals and insects. Furthermore, fruit trees are subject to a range of fungal, bacterial, and viral diseases. See our list of common diseases and pests.
What this means in practical terms is that your trees will require some time and work to keep them healthy. But while you are pruning and raking and fencing, just remember all the sweet, sun-ripened fruit that’s coming your way!
Basic Preventative Care
While the different species and even the different varieties of fruit tree each have their own particular sensitivities, there are some generalizations that can be made about all fruit trees when it comes to preventative care:
- Your trees will need to be protected from wildlife (deer and rodents) and mechanical damage (mowers, weed eaters, etc.).
- A tree that is subject to injury, drought, lack of sun, or poor soil will be weakened by these conditions. Weak trees are more susceptible to disease and less able to recover from injury.
- Removing organic debris from the growing area will also remove a major disease vector.
- Thoughtful annual pruning is essential to maintaining the health of any fruit tree.
- Trees want to be looked at! Inspect your trees regularly, especially during the growing season. Early detection of any disease or pest damage will improve your chances of being able to successfully resolve the issue.
Disease-Resistance and Susceptibility
One of the easiest preventative steps is to plant varieties that are disease resistant. When starting an orchard, it is advisable to contact your local university cooperative extension or another local grower to find out what are the most prevalent disease and pest issues in your area. You can then look for varieties that are resistant to diseases you wish to avoid. If a tree has known resistances or susceptibilities, we have listed these on its variety page. Natural disease resistance is an especially important consideration if you are planning on organic cultivation.
Growing trees on disease-resistant rootstocks will help prevent a range of problems. Although a fireblight-resistant rootstock does not make the whole tree fireblight resistant, it will protect the root system from this disease. Similarly, there are some issues, such as replant disease, that affect only the root system. In short, resistant rootstocks play a huge role in tree health, but they are not the solution to all a grower’s problems.
The table below is designed to help you spot the most common diseases and pests that affect fruit trees; it’s a Greatest Hits of fruit-tree afflictions. There are plenty of other diseases, but these are the most likely culprits for many problems. Not all symptoms of a disease will appear at the same time, as diseases and insects have their own life-cycles. More information can be found on each disease by clicking on the links.
|Tree Type||Symptoms||Disease or Pest|
|all fruit||chewed or disappeared shoots; bark damage; broken limbs||deer or rodents (mice & voles)|
|all fruit||white powder-like mold||powdery mildew|
|all fruit||visible holes or damaged areas in tree bark that ooze gum||any of the borers: American plum borer and dogwood borer, peach tree borer and lesser peach borer|
|all fruit||scarred, malformed, rotted fruit; crescent-shaped punctures on fruit skin; larvae in fruit||plum curculio|
|apple and pear||wilted shoots; well-defined areas of burnt-looking, dead foliage or bark; sticky amber ooze||fireblight|
|apple and pear||cottony masses at the base of leaves; galls on shoots; general decline in tree health||woolly apple aphid|
|apple||spots on leaves; brown-black spots on fruit||apple scab|
|apple||red-black spots on leaves; visible spores on undersides of leaves||cedar-apple rust|
|apple (and sometimes other fruit)||puncture marks on fruit holes in fruit surrounded by waste; larvae in fruit, rotted fruit||codling moth|
|all stone fruit (cherry, peach, plum, apricot)||brown, rotted bloom; water-soaked, sunken lesions on twigs; brown or grey mold on fruit||brown rot AKA blossom blight|
|peach (and sometimes other stone fruit)||an area of darkened and sunken bark that expands every year; amber ooze coming from this area||perennial canker|
|peach||malformed, puckered and “bubbly” leaves that turn red||peach leaf curl|
|plum||wart-like fungal growth that starts green and matures to black over several seasons||black knot|
As mentioned above, your best resources are often other local growers or the local cooperative extension. Many of the chemical products that larger orchards use are not available to home growers, but if you are a backyard grower who just wants a basic fungicide to apply to their peach tree, your local garden supply store should be able to provide plenty of guidance.
America’s larger horticultural research programs also offer lots of literature to the public. The following are very useful resources:
- Cornell Cooperative Extension
- WSU: Backyard Fruit Trees
- Penn State Extension: Fruit Production for the Home Grower
- University of Illinois Extension: Small Fruit Crops for the Backyard
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