Knowledgebase
What will help my apple tree yield undamaged fruit? #864491
Asked April 14, 2024, 2:50 PM EDT
Chittenden County Vermont
Expert Response
Good Morning Barbara,
How frustrating! Fruit trees can suffer from a lot of issues, and Macintosh Apples are particularly challenging.
What the photos show is a combination of multiple issues. The first and most pronounced is Apple Scab. This is the most common apple disease and unfortunately there are relatively few treatment options. You can take a deep dive into the disease right here: https://extension.umn.edu/plant-diseases/apple-scab
It's fairly common for conventional commercial growers to spray fungicide 15 to 20 times per year to deal with it! I definitely don't recommend that on the home level (nor would I recommend it for commercial growers if they asked me, but they never do).
There are a couple big thing you can do other than A) Giving up on the tree and planting a disease resistant variety or B) Spend your life spraying barely-effective poisons on your tree.
The big things you can do fall into the category of "cultural practices," meaning the way that you take care of your tree. First, remove all of the fallen leaves at the end of the season. They can harbor the fungus and reinfect the tree in the spring.
The other, often overlooked factor in apple scab is proper pruning. Getting rid of all of the suckers (a type of pruning that you can perform any time of the year) and doing a winter/early spring pruning to open up the canopy will allow more air movement preventing the conditions that allow apple scab to thrive.
Additionally, Ann Hazelrigg, Director of the UVM Plant Diagnostic Clinic, thinks that you may have Plum Curculio which is setting in due to the weakened state of the tree.
Here's some info on this little pest: https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/insects-pests-and-problems/insects/beetles/plum-curculio
Again, you should be able to make some major improvements with good culture practices like cleaning up fallen leaves and apples at the end of the season.
As for fertilizing with tree spikes, it's probably not making much of a difference either way, but if you focus on keeping the tree clean and nicely pruned, the investment in fertilizer will go much further!
Good luck with everything this season! Hope this helps.
Ann
On 04/16/2024 6:01 AM EDT Ask Extension <<personal data hidden>> wrote:
