Preventing cedar apple rust on apple trees
Cedar apple rust is a spore that grows on apple tree leaves when apple trees are within a 5-mile radius of cedar.
We moved into our home almost a decade ago. During that first year I decided to plant a handful of apple trees. By now those trees would be producing fruit, however, I removed the trees after they developed cedar apple rust, a condition I didn’t know about when I went through the time, expense, and effort of planting and caring for those initial trees. Today, the area that the original apple trees had occupied is where my bee hives now stand.
After learning about cedar apple rust, which produces itself as yellow-ish spores on the underside of apple tree leaves, which can spread through the leaves and appear on the top side, I started to research different types of apple trees that show resistance to the spore. We have many cedar trees across our property and surrounding properties, so it would be impossible to site an apple orchard location on our land that was an adequate distance from cedar trees.
What’s the downside of cedar apple rust? Apple trees will still grow if they have rust, but they won’t produce as much fruit and they will struggle growing the rest of their lives.
Heirloom apple trees resistant to cedar apple rust
When I researched apple trees, I found these varieties showed promise at resisting rust in the Piedmont area of North Carolina:
Grimes Golden
Arkansas Black
Virginia Winesap
Johnson’s Keeper
Once I narrowed down a list of resistant varieties, I started to look at apple uses and maturity dates. For example, I wanted to make sure I didn’t select varieties that would all mature in the same month. I also didn’t want to grow all cider-production apple trees. Instead, I wanted a variety of baking, cider, and snacking apples.
Many apple trees can only fruit if another apple tree is within 10 feet. I ordered a mix of these types of pollinated trees, plus Grimes Golden, which is a variety that can self-pollinate. I planted all of the trees within 10 feet of each other in a space between our home and the chicken coop. I intentionally selected this site so that I can keep a consistent eye on the trees since it’s a high-traffic pathway.
A way to prevent cedar apple rust
When cedar apple rust appears on an apple tree, the tree will always remain afflicted by the spore, so the best approach is to prevent the spore from starting in the first place. One way to do this is to coat the apple tree leaves in neem oil during the time that cedar trees are in pollen and apple trees initially leaf out for the season. In the Piedmont region of North Carolina this time usually runs from the first week of April to the last week of April.
During this time, I apply neem oil weekly to the underside of all leaves. I try to time the application after a big rain so that it can remain on the leaves as long as possible without the threat of being washed away. I dilute neem oil per the application instructions on the bottle, and apply it by hand with a general spray bottle. I also only apply the neem oil at sunset, which prevents day-time pollinators from getting exposed to the fresh application.
Since I only have 10 young trees, this process generally takes less than 15 minutes each week. As the trees have matured though, some branches have become too tall for me to reach. Some commercial producers use large sprayers, in which case you would need extra protective equipment. I generally wear gloves when applying with the hand spray bottle.
This method isn’t a guarantee that you’ll completely prevent cedar apple rust. Over the past 3 years that the orchard has been growing I’ve seen about 3 of the 10 trees start to develop cedar apple rust. The idea though is that you can help prevent the condition while the tree is young, which can help it flourish as it becomes mature enough to flower and fruit.
Where I sourced my heirloom apple trees
I ordered my trees and had them delivered by mail from Century Farm Orchards in Reidsville, North Carolina. You can also order and pick up your trees at the farm. They have an incredibly helpful apple tree library with resources about cedar apple rust, deer protection, pest control, and blight management.
Happy apple tree hunting!