Fruit shape is affected by many factors. Mis-shapen fruit can result from insect or disease damage. Tarnished plant bug and plum curculio attack very young fruit. When that fruit matures, it often develops abnormally.
Probably, one of the most common causes of mis-shapen fruit is the development of seeds within the fruit. If seed development is dispersed around the core of the apple, usually the fruit will develop well and symmetrically. If the seeds develop only on one side of …