How to care for your apple tree

August 20, 2018

Apple tree questions range from what to do about heavy fruit loads to leaves yellowing and dropping to how to know when apples are ready to pick.

With no late spring freeze this year, fruit trees may have heavy fruit loads that lead to branch breakage. To help avoid breakage, branches can be propped up with boards or tied up with a wide, belt-like material.

To support limbs with a board, cut a V into the end of a one-inch thick board. Place the board under limbs with heavy fruit loads so the branch is resting in the V. Long branches may require two boards, one near the center of the limb and one near the end.

To support a branch by tying, use a plastic belt-like material that is two inches wide. Tie it around the limb to be supported and then tie it to a larger limb above the branch, or to the trunk if feasible. Again, longer branches may need to be tied in two or more locations.

Check trees often to see if adjustments need to be made to the support method. To help reduce heavy fruit loads that lead to breakage and alternate year bearing, hand thin excess fruit on trees in mid to late June.

Apple scab and cedar apple rust are common diseases of susceptible apple trees. If a resistant cultivar is planted, these diseases are a minor problem and rarely require control.

If a tree is susceptible, disease can lead to severe leaf drop. While both diseases rarely kill trees, they weaken them, reduce yields and fruit quality, and shorten the trees life.

Apple scab symptoms begin as greenish-black spots on leaves. Cedar apple rust causes bright yellowish-orange spots on leaves. As disease develops, leaves yellow and drop in mid to late summer.

Apple scab fungus overwinters on infected leaves and fruit left near the tree. Cedar apple rust overwinters on a secondary host which is Juniper. All cedars are Junipers so they are a common host. Fungal spores are released during spring rains and blow to nearby trees.

The best control of apple scab and cedar-apple rust is planting resistant cultivars. Ask about these when selecting trees. Nebraska Extension does have a NebGuide listing fruit tree cultivars for Nebraska.

Fungal spores require moisture on leaf surfaces to infect leaves. Plant trees where there is good air circulation to encourage leaf drying after rainfall; and prune correctly to encourage air movement within the tree. Use good sanitation to reduce scab by raking and removing fallen leaves and fruit.

If fungicide control is used, apply a fungicide labeled for use on fruit trees during spring. Make the first application at bud break, then repeat application according to label direction as long as spring weather remains rainy. Three to four applications seven to 14 days apart are usually sufficient.

Knowing when an apple is ready to harvest is based on ground color, seed color, and in some cases how easily the apple releases from the tree.

Ground or background color is the color that can be seen wherever the apple is not red. For red varieties, check the color of the apple facing the tree. When it changes from leaf green to yellowish green or creamy, most are ready to pick.

When an apple is ready to harvest, the seeds are usually brown but this is not a reliable method to use. Seeds can turn brown before the apple is fully ripe. Typically, apples ready to be picked will release from the tree when you lift the apple up and give it a twist.

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