Questions on: Apple Environmental Damage
Ron Smith, Horticulturist, NDSU Extension Service
Q: We have two apple trees that did bear well but half of the apples fell off of the trees before they were ripe. They weren't wormy but they did have black spots on them. We sprayed them but it did not help. Why did the apples fall off before they were ripe? They were on the green side but not too sweet. (Northville, S.D.)
A: Apple drop can be caused by environmental factors such as wind, moisture fluctuations, drought or early insect damage. The black specks you mentioned should not have caused the apples to fall early. That is simply cosmetic damage.
Q: I have a 17-year-old apple tree. The bark is coming off in several places and the trunk is starting to split. I would love to save this tree so I would greatly appreciate any help you can give me. (E-mail reference)
A: Wrap the tree this fall before freeze up with Kraft paper. This protects the tree from a freeze thaw cycle in the plant tissue during the sunny but cold days of winter. Be sure to remove the wrapping next spring as new growth is beginning to unfold. If you cannot locate the paper wrap (best in my opinion), then find some coiled plastic that would do the job.
Q: The bark on the trunk of my apple trees has come off over the winter and there are little holes bored (almost in alignment) on the trunk of these trees. Can you tell me what to do? (E-mail reference)
A: I'm willing to bet those holes that you describe are from the yellow-bellied sapsucker. Apple trees, among others, are a favorite for these very beautiful, but sometimes pestiferous birds. Unless their damage is extensive and they return each year to the same tree, healthy trees can usually handle any damage they do. I have a birch tree in my yard that is visited each year by these characters but it has survived, thus far, without noticeable damage. Control is often impractical -- spreading sticky or tangle foot material on the bark where their feeding is most frequent. You can also attempt scare tactics which sometimes work. But unless your tree is already weakened, it should recover nicely.
Q: I have two apple trees that have flowered and produced fruit the four years I have lived in this house. This year is no different; each tree has flowered and is in the process of growing fruit. However one apple tree's bark is turning green. I am not sure what the problem is. I regularly prune the trees in winter, apply bands and have one of those moth attracting tents. (E-mail reference, London, England)
A: Not a problem. It sounds like algae or moss growing on the bark. You folks have quite a bit of rainy, foggy weather conducive to such growth, which is not harmful to the woody plants. Enjoy your apples.
A: Here is what I would suggest:
Remove the stakes. I'm betting you have more material in the stakes than you do wood in the trees. I promise you they will not blow over at this stage in their lives. Natural movement is better for them, as it will help to build caliper (trunk thickness and strength) faster. Staking, which inhibits natural movement, slows down this process.
Do not prune anything for now, and probably not for the next two or three years. Those trees will need every square inch of leaf surface area possible to get established. After that, prune lightly about this time of year--late March or early April.
Don't worry about whether they are straight or crooked right now. Nature will take care of that in time. Consider how we humans come into the world, and look at how we develop! Simply give them a chance to get established and adapt to where they are.
Q: The wind keeps blowing the apples off of my trees, and I am wondering how to keep them on the trees? (Jamestown, N.D.)
A: Generally, the procedure is to plant fruit trees in a protected location from excessive winds. Get a shelter belt or tree row planting started ASAP that will run perpendicular to the prevailing winds. In a few years, the new trees will begin providing adequate protection to cut down on fruit loss.
You must really have an open site to lose so many apples to the wind!
Q: Can you tell me how to get the birds to stop eating half of the apples off of my trees? (McVille, N.D.)
A: A couple of suggestions: try "scare balloons," that are available where most garden supplies are sold or try netting the trees before the apples ripen.
Q. I really enjoy your column in the Farm Forum of the Aberdeen American News. It is the first thing I look at in there.
Could you please tell me what this is on the apples? I had some last year, but much worse this year. I know I have sooty blotch, but what is on the flower end? I always rake up leaves in the fall, but since the leaves didn't fall until after the snow last fall, it didn't get done. I also keep all the windfalls picked up all summer. We juice the apples so don't want that in the juice as we use it raw and freeze it.
Can I spray with lime sulfur this fall even before the leaves all fall? Thank you. (Faulkton, S.D.)
A. Your fruits have been dimpled from apparent hail damage and some apple scab. You have nothing to worry about as far as consumption goes. Simply cut out the affected parts around the blossom end and you should be able to use the rest.
Spraying with lime sulfur is more effective in early spring when the spores are becoming active.
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