Apple trees, Malus domestica, grow one of the most recognized and beloved fruits in America (as well as the rest of the world). During colonial times, the fruit was often called ‘melt-in-the-mouth’ or ‘winter banana’ for its texture and flavor.
Despite their popularity in America, apples can be found in European archaeological records dating back to before the Greeks. Indeed, scientists recently traced the apple back even farther along the Silk Road to an early species in Kazakhstan, which cross-pollinated with the European crabapple.
Today, apples are an integral part of daily life and consumed fresh or processed in myriad forms—from drying, baking, and pickling to freezing and juicing. Apples can vary in color from yellows to greens to reds based on cultivar, of which there are more than 7,500 globally. Green and yellow varieties tend to be more tart in flavor, while red varieties are often sweeter.
References: Clemson Cooperative Extension, Maine State Pomological Society, Smithsonian, University of Illinois Extension.
TYPES, VARIETIES & CUTS
Although all types of apples are for fresh consumption, some varieties are better suited to making pies and sauces or drying. Among the more familiar varieties are Ambrosia, Braeburn, Cortland, Crispin, Empire, Fuji, Gala, Golden Delicious, Granny Smith, Honeycrisp, Jazz, Jonagold, McIntosh, Pink Lady, Red Delicious, Snap Dragon, Winesap, and Zestar. About 100 varieties of apples are grown commercially in 36 states with Washington, New York, and Michigan dominating U.S. production.
Apples range in flavor from sweet to very tart, and color depends on the variety. Red Delicious are juicy, heart-shaped, ruby red apples with a mildly sweet flavor and among the most popular for fresh consumption. Granny Smith apples are green, crisp, tart, and juicy, and good for baking, sauces, juicing, eating raw, or for caramel apples. Galas are a pale red, round, and sweet, and are frequently dried or used in cider. Golden Delicious apples are yellow-green, crisp, and sweet; they are excellent for cooking as they maintain their shape well. Although organic varieties are gaining marketshare, conventionally grown apples command the vast majority of retail sales.
References: New York Apple Association, Rutgers University, University of Georgia, U.S. Apple Association, University of Illinois Extension, Washington Apple Commission.
PESTS & DISEASE
The apple maggot typically strikes in late June to mid-July. Adult maggots lay eggs in the summer inside fruit. Apple aphids appear in May through early July; the most prominent symptom is curling leaves. Shiny black eggs will be visible in early spring. Leafhoppers appear at the end of May or early June. They are white and feeding produces a stippled effect on leaves. The spotted lanternfly, an invasive insect from Asia, typically sucks sap from plant stems and leaves after hatching in the spring or early summer. Adults grow to about an inch in length with large brightly colored wings. A number of other pests can affect apple trees and fruit including the codling moth, plum curculio, mites, and scale, as well as small mammals and deer.
Fire blight is a bacterial disease spread by insects, wind, and rain. Entire trees are at risk once infected, making this disease economically destructive for commercial growers. Apple scab is typical in humid, cool weather during the spring and is common in the eastern United States, with the appearance of brown or green mold-like spots on leaves and fruit. Powdery mildew coats shoots and leaves with a white powder, stunting growth and causing leaves to curl. Phytophthora crown and root rot are possible in wet conditions and often lead to brown leaves and wilting. This water fungus is best prevented by ensuring good drainage in all parts of the orchard.
Other diseases that may affect apple production include bacterial spot, black rot, bitter rot, cedar apple rust, collar rot, and sooty blotch.
References: Clemson Cooperative Extension, Colorado State University, Rutgers University, University of Idaho, USDA, University of Tennessee Institute of Agriculture, Utah State University.
CULTIVATION, STORAGE & PACKAGING
Well-drained soil with moderate to high levels of organic matter and ample sunshine is best for growing apple trees. Loamy soils with a pH level of 6.5 are optimal. Soil should be tested two years prior to planting to determine fertilizer and nutrient application levels. At least six months prior to planting, a permanent sod cover should be established to prevent soil compaction and allow for easier equipment movement within the orchard, especially during periods of rain. It is also important to control broadleaf weeds, as they lure bees away from the trees during bloom and can harbor harmful insects. Apple trees typically become productive depending on type, with dwarf trees fruiting in 2 to 3 years and standard trees in 8 years.
Preparation of the orchard floor is important before harvesting. Remove brush and tripping hazards, and cut grass short. All orchard roads should be graded to reduce jostling or bouncing during transport. Apples should not be pulled off of spurs, as this may cause other fruit to fall. If spurs are taken with fruit, it may reduce the next year’s crop. If fruit is ready to pick, it will separate easily if rolled or turned upside down on the spur. Fruit should not be jostled or dropped in containers as this will cause bruising. Bins and receptacles should contain only fruit, not leaves or spurs as this can impact quality.
Apples can fall into a number of different U.S. grade categories, ranging from U.S. Extra Fancy, U.S. Fancy, U.S. No. 1, and U.S. Utility, to combination grades. The highest quality grade, Extra Fancy, will be of one variety, mature, clean, fairly well-formed, free from decay, browning, internal breakdown, scald, scab, freezing injury, visible water core, or broken skin. After harvest, cool apples as soon as possible. Optimal storage temperature is 30 to 32°F with 95% relative humidity. Ripening apples give off ethylene, which can hasten fruit softening.
References: Ontario Ministry of Agriculture, Rutgers University, University of Georgia, University of Minnesota Extension.