I have two apple trees next to each other. The big tree in the front is the...
I have two apple trees next to each other. The big tree in the front is the haralyson and is loaded with apples and a healthy g.ree color. The one next to it is a honeycrisp which had flowers early spring but now has no apples and leaves are dropping and the tree is lightening in color. See picture of the leaves.
Stearns County Minnesota apple trees
It looks like this tree is suffering from cedar apple rust, a fungal disease.
The Honeycrisp is not as resistant to this disease as the Haroldson. I suspect that there is a cedar tree in the area - this disease needs both kinds of trees (something in the apple family, and something in the cedar family) to complete its life cycle. It will often cause the new apples to abort.
Here is a fact sheet that describes this problem:
I hope this is helpful. Please contact AaE again if you have further questions.
Thank you and yes, I have a lot of ugly cedar trees. I read the information now would like clarity....do I need to treat the cedars and the apple tree? How and what do I treat? What chemicals? And will my haralyson tree stay safe?
The best solution is to remove the cedar trees. There is no chemical to treat them. The fungus can travel for quite a distance so there may be other trees in the area that are suspect as well.
This is a quote from the website I'd sent you:
Management of rust on Rosaceae plants
- For control of cedar apple rust on apple and edible crabapple cultivars, see the IPM guide for home apple growers at ">
- Plant disease resistant cultivars of crabapple and apple when possible (see Table 2 and 3). Rust resistant cultivars of hawthorn are difficult to find. Often a cultivar will have resistance to one of the Gymnosporangium rusts (i.e cedar apple rust) and be highly susceptible to a different Gymnosporangium rust (i.e. hawthorn rust).
- Do not plant eastern red cedar and juniper plants within a few hundred yards of susceptible Rosaceae plants. This will reduce but will not completely eliminate disease problems.
- Prune and remove brown woody galls found on the eastern red cedar and juniper plants before orange gelatinous spore producing structures form in spring to reduce the level of infection on nearby Rosaceae plants.
- Prune and remove infected twigs or branches on Rosaceae plants when they occur.
- If applied before infection occurs, protective fungicides can be used to control the disease on Rosaceae plants. Typically, this occurs when flower buds first emerge and continues until spring weather becomes consistently warm and dry. Nearby infected junipers can be monitored and fungicides applied when gelatinous orange spore producing structures appear on galls and branches.
- Chemical treatments with listed active ingredients include*:
- Myclobutanil- most effective!