Moderate fruit density

High levels of corking and bitter pit may be found on trees with a light crop. When trees bear a light crop of apples, the fruits are normally very large and low in calcium. They are prone to low-calcium physiological disorders. Apples on trees with an excessively large crop usually have little corking and bitter pit but seldom reach optimum size to maximize profitability. Table 1-14 contains a list of factors that need to be managed to produce annual crops of moderately sized fruit. Some factors to be managed for uniformity of cropping are frost protection, pollen source, bee population, and pollinating weather.

A prerequisite for achieving moderate annual fruit density is the annual production of high-vigor fruit buds. An essential ingredient in this program is the effective use of growth regulators to thin excessive crops and to encourage the production of highvigor flower buds for the following year's crop. Many registered growth regulators are available for this purpose, including NAA, NAAm, Ethrel, and Sevin. See other sections of this guide for current recommendations in the proper use of these products.