Monday, August 15, 2022
Aug. 15, 2022

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Gardening with Allen: Spray needed versus apple worm


Last year my apple tree produced a lot of small, wormy apples. What do I need to do to get larger apples without worms?

If you want apples without worm holes, regular biweekly spraying is necessary. You can use one of the combination fruit tree pesticides or if you want an organic approach, use Spinosad. You will find Spinosad at full-service garden stores or online.

If you do not have a lot of untreated apple trees nearby, you can probably protect most apples from worms by hanging codling moth traps in the trees. It takes about three traps for a medium-sized apple tree. Codling moth traps contain a sex attractant that traps the male moths. Without fertilization, the female moth’s eggs are sterile.

Now is also a good time to thin apples to increase fruit size and quality. By looking carefully as you thin, you can often eliminate apples that have already been entered by a worm. The holes are very apparent while fruit is small.

Apples have clusters of five flowers in a group. If all five flowers are well-pollinated, they may all develop to maturity. More typically, three or four will continue to develop while one or two will remain small and fall off. The tree can only produce enough food to develop one large apple per cluster. If two are allowed to develop, most fruit will be medium size. When three or more mature, they are generally all small, unless there are no other nearby fruit clusters within 6 inches.

In thinning, I generally only leave one fruit per cluster and remove the others. If there is more than 6 inches to the next cluster, I leave two fruits. Leave the largest apple in the cluster, which is usually the center one. Of course, those which have worm holes or other damage should be removed even if they are the largest so a better quality fruit can develop.

June is a critical time to remove those fast-growing vertical sprouts that occur on apple and other fruit trees. This is particularly true for trees that have been heavily thinned so light can reach the lower fruiting branches. Sprouts can be quickly and easily snapped off with your fingers when they are soft, flexible and less than 12 inches long. Snapping is preferable to cutting because it removes tissue that can regrow another water sprout, sometimes in the same growing season. Larger water sprouts from previous years can also be removed. If you wait until fall or winter to remove those sprouts, new ones will grow to replace them next spring. Stop the sprout cycle now. And if you do happen to have more new water sprouts later, snap them off while they are young and soft.

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