Apples that are deformed and undersized are the result of various biological, environmental and physical factors. Typically, deformities occur in trees that are older than three years old, have insect infestation and / or poor nutrition, or are exposed to different stressors at some point during the growing season. Deformed apples bring attention to underlying issues that can reduce agricultural yields and reduce the overall health of apple trees.
Malfunctioning hormones, either naturally occurring Cyclopentenones or artificially induced ethylene, can be indirectly responsible for deformed apples. When hormones are imbalanced, apples become small and undersized, with smaller leaves. Air temperatures, sunlight, and stress during flowering can also contribute to hormonal imbalances, leading to the production of deformed fruit.
Lack of nutrition may also contribute to the deformities of apples. Nutrient deficiencies in the soil, such as decreased levels of nitrogen, zinc, and magnesium, can cause smaller and deformed fruits. Low levels of moisture can also reduce the quality of fruits, as well as reduce fruit size, making them more susceptible to deformities.
Insects can infect apples in two main forms. Apple flea beetles and mites can cause fruits to be undersized and deformed. In addition, apple maggot flies can also cause damage to fruits. Infected apple tree limbs may display deformed fruits, leading to high crop losses.
In some cases, physical stress such as pollination, thinning and pruning may contribute to deformed apples. Poor pollination may result from lack of bees, bad weather or chemical sprays. If the size of the fruit is not reduced in the thinning process, the apples become too heavy for the tree, causing pressure and swinging movements which can lead to deformities. Pruning that is done too early or too late may disrupt the normal growth of the fruit.
Hormones
Hormones are essential to the growth of plants, determining the size and structure of apple fruits. If Cyclopentenones or ethylene hormones are disrupted, the outcome could be deformed apples. Scientists discover these hormones in the fruits by measuring their chemical composition. Such hormones not only affect the size of the apples, but also have a detrimental effect on the quality of the fruit. Temperature, sunlight, and different types of stress are possible causes of lowered hormonal levels.
Applicators of plant hormones can result in a reduced size of the apple. Farm workers and researchers use ethylene to increase the number of apples per tree, as well as to induce uniform ripening in unripe fruits. Such applications may unintentionally lead to deformed and small fruits instead, causing crop losses.
In some cases, apples may be affected by the natural process of ethylene. High concentrations of ethylene gas in the air may lead to a more uniform ripening of apples and reduce the size of fruits.
In extreme cases, the inability of apples to respond to hormones may lead to deformation as well. Factors such as high temperatures and insufficient amounts of water may reduce the plant’s ability to regulate the hormones, leading to the production of deformed fruits.
Nutrition
Good nutrition is necessary for the proper development of apples on a tree. In areas where poor topsoil inhibits the trees from accessing essential nutrients, their fruits may become deformed. Nutrition deficiencies like low levels of nitrogen, zinc, magnesium, and potassium can reduce the quantity and size of fruits.
Although supplemental fertilizer may be a viable solution to combat nutrient deficiencies, it also can lead to deformed apples if not used in the appropriate manner and dosage. Too much fertilizer may cause a buildup of nitrogen and potassium which can inhibit the plant’s growth, leading to apples that are small and deformed.
Water plays an equally important role in the development of apples. Too much water can reduce the amount of oxygen that is available to the roots, leading to weakened apples. Then, the trees will not be able to provide enough nutrition to their fruits, resulting in deformed apples.
On the other hand, if apple trees receive too little water, their leaves will not receive enough nutrition to produce apples. This may cause the development of smaller sized fruits that are also deformed.
In some cases, specific types of apples may have genetic propensity to have deformed fruits in spite of receiving the necessary amount of nutrition. These varieties require special care in order to maintain their health and prevent them from producing deformed fruits.
Insects
Insects and mites can cause a variety of issues to apple trees, including the production of small, deformed fruits. Apple flea beetles are tiny insects that feed on young fruits and puncture their skin to feed on the contents inside. This can result in the marked decrease in the size of the apples and their eventual deformity.
Mites can also affect the size of apples by causing them to develop deep cracks. These cracks are filled with water which can lead to a decrease in the size of the apple.
Apple maggot flies can infect fruits and cause them to be disfigured and distorted. In some orchards, apple maggot flies could become a serious problem, resulting in decreased yields and quality of fruits.
Conserving beneficial insects is one of the most effective ways to reduce the effects of pests on apple trees. By encouraging predators to feed on the pests, it is possible to reduce their numbers and the damage they cause to fruits.
Fruit trees need to be consistently monitored for early signs of infestations or damages caused by insects. When the orchid is sprayed to kill the pests, it is important that the pesticide applications are done using the right dose and timing. Excessive application of pesticides can cause more harm than good, leading to deformities in apples and other fruits.
Physical Stress
The physical stress of handwork during the growing season of apples can contribute to deformed fruit as well. Without proper care and attention, the fruits may be deformed while they are still growing on the tree.
In the apple pollination process, the insects have to transfer the pollen between the flowers in order to create fertile fruits. Poor pollination may result from lack of bees, bad weather or chemical sprays, leading to small and deformed apples.
Stress during the thinning process is another factor that may lead to the production of small and distorted apples. If the size of the apples is not reduced, it can lead to the apples being too heavy for the tree, causing deformities along the area of the branches that is stressed by the weight.
The timing of pruning is another important factor which may contribute to the production of deformed apples. Pruning too early or too late can disturb the natural growth of apples, causing them to become smaller and distorted.
In orchards where hand picking is done, the apples can be damaged during the process. Poor technique or unqualified workers may remove parts of the apples while they are being picked, resulting in deformed fruits. It is important to ensure that workers that pick apples understand the correct techniques and the importance of avoiding damage to the fruits.
