Why Do My Apple Trees Yield Only Blemished Fruit?

Have you noticed that your apple trees are producing fruit with various blemishes? It's not uncommon to find apples with discoloration, scabs, or pest damage. But before you just write it off as a minor issue, it's important to understand the potential causes. This article will explore the reasons behind blemished apples and provide practical solutions to help you improve your apple tree care.

Common Causes of Blemished Apples

A multitude of factors can lead to blemished apples on your trees. In this section, we'll discuss some of the most common issues and how to address them.

Apple Scab

Apple scab is often considered the most detrimental fungal disease affecting apples. It appears at the stage of fruit set and spreads rapidly, especially during frequent rains. Continuous spraying with a fungicide like Captan is recommended to control this disease. Alternatively, you can opt for scab-resistant apple varieties, such as 'Liberty'. This will help prevent the onset of apple scab before it spreads.

Cedar Apple Rust

Cedar apple rust is another significant threat to your apple fruit, particularly if junipers, including Eastern red cedar, are planted near your apple trees. Junipers act as an alternate host, and the pathogen requires both junipers and apple trees (or crabapple) to complete its life cycle. To avoid this issue, it's best to keep apple and juniper species well-separated, ideally by at least 200 feet.

Plum Curculio Beetles

Plum curculio beetles can cause significant damage to young apples early in the season. In severely affected areas, you might lose up to 100% of your fruit to this insect. The beetle leaves distinct semicircular bites and lays its eggs in the fruit, causing further damage. Pesticides like Imidan are recommended for control, but organic control methods are also available. Here is an organic control option.

Codling Moths

Codling moths are the quintessential "worm in the apple" pests. They are particularly rampant later in the season, especially in regions like Wisconsin. These moths lay their eggs on the fruit, and the resulting larvae tunnel through the flesh. Control measures include spraying with insecticides like Imidan. For more detailed information, refer to the Minnesota extension page.

Proper Spraying Techniques for Apple Trees

To prevent blemished apples, regular spraying of your apple trees with insecticides is necessary. The timing of these sprays is crucial:

First Spray: Apply an insecticide immediately after the bloom falls and cover the tree with a protective layer. This initial spray should be administered about two weeks after most petals have fallen. Second Spray: Repeat the spraying process after two weeks, or around late July or early August, whenever you notice new larval holes appearing on the fruit.

Using a systematic approach to spraying will help ensure that your apple trees are protected from both diseases and pests. By following these guidelines, you can significantly reduce the incidence of blemished apples and improve the overall health of your orchard.

Conclusion

Understanding the causes of blemished apples is the first step in addressing the problem. Whether it's apple scab, cedar apple rust, plum curculio beetles, or codling moths, there are practical measures you can take to prevent these issues. Proper care and regular spraying will go a long way in ensuring that you have blemish-free, delicious apples. Happy gardening!