Apples are some of the most popular and healthiest fruits out there, and they are enjoyed around the world by people of all ages. Children and adults alike love the good crunch of an apple, and there are upwards of 7,500 varieties to choose from.
It’s great to have such a wide range of yummy apples, but unfortunately as is the case with many fruits, apple trees may be susceptible to pests and diseases like fire blight. Keeping apples healthy and safe to eat is important, and for home growers, it starts with knowing more about the different diseases that affect apple trees and which areas are affected.
When it comes to apple diseases, here’s everything you need to know so you can protect your trees and continue successful home growing with disease resistant apple trees.
Understanding Apple Disease Pressure
There are several key terms to remember in regards to apple diseases, including apple scab and powdery mildew. Understanding these dangerous conditions and what they can do to your apple crops is essential to long-term growing success.
Common Apple Diseases By Region
With apples grown on all continents except Antarctica, some types thrive in both warm and cold conditions. Depending on the location, different diseases may be more of a threat, which is why it’s best to plant trees that are more resistant to those diseases and well-suited to their environment.
Black rot is a prime example. Most common in northern areas, this disease is caused by a fungus called Botryosphaeria obtusa. This plant pathogen is responsible for significant rotting on certain apple varieties in addition to leaf spotting and trunk cankers on other plants.
Other concerns like apple scab can occur anywhere, although this fungal infection is most prevalent in temperate regions with cool, moist springs. Meanwhile, powdery mildew thrives in high humidity but can appear in dry climates, too. Watch out for rust, cork spot, and many more kinds of rot that could devastate your crop if left unaddressed.
Susceptible Apple Varieties
Whether you’re just beginning on your first season of home apple growing, or it’s another year of family planting traditions, it’s best to be aware of the apple trees that are most prone to problems. While you can definitely still grow these susceptible types, you need to be especially careful and conscious of the risks.
Some of the most susceptible apple cultivars to fire blight, apple scab, powdery mildew, and rust include:
Although those types are more likely to experience multiple diseases across the board, many other varieties are resistant to one disease but not another. For example, bright red and green McIntosh apples are naturally strong against rust and mildew, but vulnerable to apple scab and fire blight.
Nova Easygro and Nova Spy apples are susceptible to rust but not scab or mildew. Then there’s the Paulared and Scarlet O’Hara apple tree types that are scab resistant but often fall victim to fire blight.
The list of disease-prone apples goes on and on, so keeping tabs on which ones are in your garden is very important. If you’ve had previous experience with summer diseases, then you may want to choose one of many high-quality apple tree varieties that better resist pests.
Important Disease Resistant Cultivars
Fruit losses are never fun, especially when you’re keeping a close eye on your garden for signs of pests and disease. Whether you’re focusing on a few fruit trees for delicious food and desserts, or you’re interested in a cider variety, it’s in your best interest to at least consider a few moderately resistant trees. The stronger the natural resistance in your garden, the higher chances of successful fruit production.
You can learn a lot from the PRI breeding program, which is a joint effort between researchers at Purdue University, Rutgers University, and the University of Illinois. The program studies disease resistance, specifically breeding cultivars with greater resistance to apple scab. Some of the most popular apples for home garden use have come out of this program.
More research has been done in the past few decades to understand apple cultivar diseases and how to prevent them as much as possible. Of course, choosing more tolerant varieties is a great place to start, but careful pruning and preventative pesticide treatments are also effective. Pruning affected areas when dormant and burying or burning infected trimmings is one of your best defenses to stop the disease from getting more of your crops.
When placing orders for fruit trees, keep the following varieties in mind as some of the best for disease resistance.
Fruit from the Liberty apple tree is usually bright and vibrant, thanks to the plant’s relation to similar crab apple trees. It’s possible to grow these deliciously tart fruits in U.S. zones 4-7 with a solid natural defense against fire blight and cedar apple rust.
Apple scab is no match for Liberty apple trees either. While insects may attempt to invade and attack these trees, they won’t have much luck against one of the top apples with impressive resistance that doesn’t compromise the flavor.
As with any cultivar, it’s important to know which plants to pair it with. For a low-maintenance garden, consider growing the Liberty tree with other mid or late-season fruit like McIntosh and Golden Delicious. You can use fewer pesticides and still enjoy a crisp, juicy crop.
Freedom is also a hardy mid season apple with reliable tree growth and protection against juniper rusts and powdery mildew. It has an even stronger defense against fire blight and apple scab. This apple stock lasts for a couple of months in storage and suits both snacking and cooking.
With a pale yellow background colour and bright to dark red skin, this apple variety tastes great as applesauce or fresh cider. The fruit size is large with a crispy flesh for optimal flavor. To get the most out of this tree’s growth habit, pair with Cortland, Liberty, or UltraMac apples.
This scab resistant cultivar hails from the Czech Republic and is used for salads and as an ingredient in cream or cheese dips. The Institute of Experimental Botany created this dessert apple from Rubin and Vanda cultivars as one of the success stories from its breeding program.
The sharp flavor and hints of spice mellow during storage as the dynamic dessert apple lives up to its name as one of the most durable disease resistant cultivars available today. With natural protection against powdery mildew, this apple tree variety is popular for home growers who want to enjoy a wide range of fruity food.
Dorsett Golden Apple Variety
Planting a Dorsett Golden apple tree gives you deliciously fresh fruit with relatively low maintenance stock. This tropical apple with a sweetly tart flavor and crispy flesh is a good choice for home growers who want to make the switch to more pest-resistant trees. It’s popular in Florida where the disease pressure is high.
The Enterprise apple is another good choice for preventing disease, with solid resistance to apple scab, rust, and fire blight. The main threat to this tree is powdery mildew, although it does have some resistance. It’s the ninth cultivar to come out of the PRI breeding program and does remarkably well in storage, with the slightly acidic flavor mellowing over time.
Goldrush Apple Tree
With fabulous flavor, the goldrush apple is easy to stock up on thanks to its very high resistance to apple scab. It’s moderately resistant to fire blight too, although rust and mildew are a possibility. This late bloomer does well in storage with a semi-tart flavor that suits hard cider and fruit pies.
Pristine apple fruit is used to make applesauce, cobbler, cakes, and other yummy food. Planting these apple trees gives you a hardy crop with impressive resistance to apple scab, mildew, and bacterial diseases like fire blight. Rust may appear on this apple tree so it’s important to still monitor throughout the season, although apple tree orders including Pristine are often successful.
Keeping Williams Pride apple trees safe and free from pests is easy as this dessert apple has a very strong defense against juniper rust and apple scab. Its reliable resistance to fire blight and mildew make it one of the more well-rounded disease resistant cultivars.
Out of the many dessert apple cultivars, this one ripens fairly early, but the fruit stays on the tree for around a week. The extended time for picking coupled with the disease resistance makes this tree a good choice for busy home growers.
Arkansas Black Apples
Another worthwhile choice for plant disease prevention and control is the Arkansas Black dessert apple tree. These dark red to black apples are highly resistant to dangerous rust that affects so many other apple cultivars. With a complex tart taste and an eye-catching color, fruit from the Arkansas Black tree can be kept refrigerated for at least a month before making dessert or cider.
What is cedar apple rust?
Cedar apple rust is a fungal disease causing bright orange and red spots on many different apple tree types. Nova Easygro, Florina, Ginger Gold, Idared, Prima, Rome Beauty, Golden Delicious, and York Imperial are some of the more susceptible apple trees.
What is sooty blotch?
Sooty blotch refers to dark smudge appearing on apple stock in humid environments. This summer apple disease may affect both heirloom apple trees and newer types. The blemishes and discoloration on fruit nearing maturity is caused by a fungal infection and often associated with fly speck. It’s relatively superficial and still safe to eat compared to rust and fire blight. You can discourage fungal growth by cutting weeds and grass under the tree to maintain dry conditions.
Where can you buy disease resistant apple trees?
While most people used to buy their preferred tree type in-person from nurseries, now you can order your favorite fruit tree directly online. Amazon has a great selection of disease resistant apple trees to help you avoid cedar apple rust and strengthen your garden stock. This 4-5 foot tall McIntosh apple is a popular choice for resisting cedar apple rust, as well as the Liberty apple tree.
How can you keep apple trees safe from disease?
Generally, the higher the natural disease resistance, the better. Some cultivars are genetically advantaged to handle bacteria and fungi more strongly than others. Leading producers of fruit crops recommend you follow a solid maintenance routine during the dormant season to ensure any affected leaves and branches are properly disposed of, minimizing disease transmission to the rest of your crops.
Prioritizing optimal growing conditions and making your garden a tough place for fungi to thrive also assists in protecting every apple tree. You can apply insecticides and bactericides to deter pests and disease. As with anything, the more regularly you can check your tree garden, the higher the chances you will spot signs of disease early on.
How do you know if your apple tree has a disease?
Most people who put apples in their shopping cart check for signs of rust and rotting. When it comes to home garden use, you should do the same. There are some tell-tale signs of disease compromising fruit quality and you can check the fruit and leaves for signs of problems. Cedar apple rust causes orange-yellow spots across the fruit and the tree branches.
Black rot may appear at the end of the blossom while turning fruit brown and eventually black. It can also cause cankers on the tree that could kill the entire plant if left unaddressed. If you see warty bumps or a silky covering on the fruit, you may be dealing with apple scab or mildew.
What does PRI mean?
PRI stands for the Purdue, Rutgers, and University of Illinois disease resistance breeding program. Proven successful in many instances, this program has carefully bred new types from traditional heirloom apple trees. By choosing PRI apple stock, you can look forward to plentiful fruit growing at home, free from some of the serious threats affecting more susceptible types. Daytona, Jonafree, Scarlett O’Hara, Sir Prize, and Sundance are a few popular PRI trees.
What can you make with disease resistant apples?
Fantastic fruit production is made easier with apples that resist insects and hold up well in storage. You can use hardy apple tree fruit to make delicious drinks like hard cider and apple juice, as well as tasty desserts for the holiday season like apple pie, tarts, muffins, or bread. Applesauce is another popular option.
Are there disease resistant cider apple trees?
With a flavor that truly packs a punch, hard cider apples are in demand, not so much for snacking but rather for tasty drinks to soothe the soul. Depending on your apple orders, some cider variety will do better than others at preventing disease. The best dessert apple trees for preventing disease every season include Winecrisp and Sansa.
Now You Know All About Disease Resistant Apple Trees
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