I have for some time been attempting to develop a ranked list of the most disease resistant apple trees. I have very little personal experience so I must rely on research only. I think I have exhausted all possible research. I’m hoping those of you with experience will help me develop a consensus for a ranked list.
I created and attached a spreadsheet with what I came up with based on research.
Please suggest any omissions and how you might rank them.
I will update the spreadsheet as information comes in.
At suggestion I added a column for summer rots but thus far information on that aspect remains somewhat elusive. I will add any input I receive on rots.
I think that lists like this are useful, with the caveat, that resistance is relative and dependent on disease pressure, as well as probably other stresses, like adaptability to various climates. For example, Liberty is in my experience definitely not “very resistant” to Rust, if you have Cedar hosts right next to it. Maybe avoid the “very resistant “ category and call it more tentatively VS/S/R?
I understand. Its a difficult problem. I’ve toyed with more complex ratings (and have built some spreadsheets as you suggest), but find a single generalized rating is easier to grasp especially for comparisons. The back-cross cultivars have been tested and rated, the heirlooms have not.
Thanks for the list, but also: I hate you for the list, now I am going to have to buy even more scion wood, I definitely won’t see my family for the whole month of April, too busy grafting
These are some other varieties you may have missed (unless overlooked by myself), hopefully the format doesn’t get mangled once I post
At your suggestion I added Chestnut Crab and Dolgo Crab as well as 39th Parallel Apple. I edited my spreadsheet and post with those suggestions. Thanks
Pixie Crunch is field immune to scab. I would personally rank Pixie Crunch higher than Goldrush, at least for my location. Both are susceptible to CAR but with Pixie Crunch it affects the leaves but not the apples, and yield is not compromised. With Goldrush the apples get hit hard by CAR and end up rotting if not sprayed.
I am in the hot humid south east (southern middle TN) and there are no apples that prove to be very fire blight resistent here.
Purdue may proclaim them to be so… But Naaaaaa .. it is not so here.
Any apple that is actively blooming late March into early April here (FG3/FG4 apples) is going to get fire blight.
About the best you can do… Is find one or two that will get it almost every year.. and you whack it out… and it continues to live and fruit.
Novamac … so far.. is working like that for me. Since it started blooming.. it has gotten FB each year… I take off fruit spurs, sections of branches…. and it continues to live and produce fruit.
Purdue proclaims it to be Very Resistent to all 4 of the top apple diseases.
Oh well.. it is still alive and fruiting.. and the severity of FB seems to be calming down some. Last year was better than the year before.
For me the #1 issue by far is rots and it’s not even on your list. So your data is largely meaningless for me. Commercial growers are spraying every two weeks all summer and they can solve the rot problem with sprays, but home growers should not need to do that. The problem with the standard resistance classifications is they are more aimed at commercial growers.
Anyway my suggestion is to add a rots column to your spreadsheet. In my orchard with just a couple spring disease sprays the things you list (blight, scab, rust, mildew) are almost never a problem. Maybe every 4th year I get some fireblight strikes, and I’ll get a little scab on a few spots I missed with the sprayer. Mildew in particular I never understood, I have never had any powdery mildew on an apple tree in my 25 years of growing apples.
Yes rots are a concern for sure. I just got a new batch of spray for fireblight. Should not be a huge problem dusting blooms and green tip buds after rain storms.
Which is not an option for wildlife trees of course.
We will not be “no spray”. But we will be “ frugally pragmatic sprayed”.
Are you sure its both car? At least for me I have both cedar quince rust and cedar apple rust. Quince rust will mess the fruit, branch nodes and is worse overall. Car just messes up the leaves as you say
