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How Do You Like Them Apples?By Ray Novitske, Fairfax Master Gardener

Our saying “An apple a day keeps the doctor away” issupposed to have been based on an old English saying, “Toeat an apple before going to bed, will make the doctor beghis bread.” Bananas have recently replaced apples as themost popular fruit in America based on sales. We cannotgrow bananas in our backyards, but with little being done tocontrol climate change, who knows about the future? Youcan grow apples in your yard, but know that you would needto purchase the plants from a nursery in order to have thetypes of apples you find in the stores.

BackgroundThe history of the apple is long. Apples (Malus) originated in Asia, in the forests of the region aroundKazakhstan. The native trees (Malus sieversii) were large, growing up to 50 feet in height, and probablyproduced fruit the size of cherries. It is believed that they were the first trees cultivated by humans.

To understand the rest of the history, you need to know the biology of apples. Apple trees are cross-pollinated by bees. The fruit produced is the result of pollination with another variety, or with crabapples,which are of the same Malus species. The plants generally need pollen from a different tree, and will notproduce much fruit unless pollinated with other trees. As a result, seeds that do develop in the fruit will notproduce plants true to the parents, but will be quite different from the parent. Therefore, planting appleseeds will give you a completely different type of apple tree.

Apple trees eventuallyspread along the Silk Roadthrough Asia. Travelersprobably picked the bestfruit and discarded theseeds that then sproutedand hybridized with othertrees and crabapples,producing millions of applevarieties over the years. Theapple genome contains over57,000 genes, about twice

as many as human genes and the highest number of any plant found to date. There are more than 7,500known apple cultivars today.

Apples have been enjoyed for thousands of years throughout Asia and Europe and in the temperate regionsthroughout the Northern Hemisphere. They were brought to America by European settlers. We know thelegend of Johnny Appleseed planting apple trees throughout the country. Settlers enjoyed fermented applecider that can be made from any type of apple. Due to the apple’s reproductive traits and the resulting fruitbeing inedible or small, his seed-planting legend more likely resulted in keeping settlers stocked withingredients for booze. In reality, he actually helped plant orchards with grafted apple trees, but the legendis a more romantic idealization.

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SelectionTo assure a consistent type of apples and to reproduce the types of apples humans want, plants must begrated onto root stock. Every cultivar we know and grow today started as a single plant that someoneselected as having desirable traits in fruit, size and taste. The root stock can determine the size of the tree,whether full size, dwarf or semi-dwarf. So, if you want to grow good apples, or almost any other type offruit in your backyard, you cannot plant seeds. You must purchase plants that have been grafted onto rootstock.

Cultivar selection should be based onwhat type of apple you want, and whattypes might offer some resistance todiseases and pests. After all, you want touse as few pesticides as you can. Somecultivars are available in several strains.Strains are mutations that have developedon certain cultivars that may havedifferent characteristics in growth orfruit.

CareFertilize the trees to help withestablishing the transplants and with fruitproduction in subsequent years. If treesbecome stressed and produce poor fruitquality, they can become moresusceptible to pests and diseases.Overfertilization can produce excessive,weak growth, attractive to attack by sap-sucking insects.

Follow recommendations from the publication Growing Apples in Virginia and fertilize each spring ifnecessary. A soil test will let you know if fertilizers need to be applied. Be careful if trees are near turfgrass,which should be fertilized in the fall. Late fertilization can lead to growth as the plant is hardening off toprepare for winter. Very late fertilization as the trees are going into winter dormancy can lead to thefertilizer being leached through the soil before it can be used.

Watering is important for establishing the trees during the first few years of growth. Be sure to waterdeeply and not let the roots dry out.

Thinning and pruning the trees is important. Thinning out will remove some of the fruit so thatremaining fruit will develop adequate size. Thinning will also increase flower buds for next year. Withoutthinning, biennial bearing problems can crop up such asoverproduction one year followed by low yields the next. Thinningfruit reduces weight on branches, reducing breakage and the needfor supports. Thin out fruits that are less than 1 inch in diameter.

Pruning will reduce the number of branches and will open up thetree to allow spray application to reach the interior, and will alsoallow in sunlight. Prune dead and dying branches that can harborinsects and diseases.

tree size determined by rootstock type

apple scab

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Common DiseasesLike a lot of the fruit trees, apples require a bit of attention to grow the crop you expect. There are over 20insects and diseases that you must be on guard against. It is virtually impossible to grow apples withoutsome pesticides. Timing the pesticide applications is important to coincide with the appearance of thepests.

Apple scab is a fungus that causes as much damage as all otherdiseases combined, attacking leaves, fruit and stems. Itoverwinters in the dead apple leaves under the trees. It releasesspores that are carried by air currents to the new green leavesand opening fruit buds in the spring.

Powdery mildew, a fungal disease, attacks the leaves, blossomsand fruit, and resembles a powdery coating. Terminal buds in thespring can become stunted or killed, and blossoms can beinfected and fail to fully develop, thus preventing fruit fromforming.

Apple rusts such as the cedar apple rust and quince rust are bothcaused by a fungus. Both can attack leaves and cause extensive defoliation and reduce the plant’s healthduring dry periods. They are most prevalent in warm, wet conditions and controlled by fungicides.

Black rot, another fungus disease, attacks the fruit, leaves and branches. On the fruit, it develops slowlyand appears on leaves as small purple spots.

Virginia Tech identifies the following problems and the cultivars that have some resistance to certaindiseases. They all offer some resistance to apple scab.Cedar Apple Rust — Dayton, Redfree, Liberty, Sundance, EnterpriseQuince Rust — Pristine, Redfree, SundancePowdery Mildew — Pristine, Williams Pride, Dayton, Jonafree, Liberty,Enterprise

Common Insect PestsMany of the insect pesticides must be applied at just the right time theinsects are out or are susceptible in order to be effective. Note thatweather may delay or promote the scheduled arrival or developmentof a certain pest, so application times for pesticides are given relatedto the phase of annual plant growth.

The codling moth is usually recognized by a small hole bored into theside or bottom of the apple. The damage caused by the larvae cancompletely destroy the fruit. The larva exits the apple, falls to theground and climbs to the tree to mature into a moth under or withinthe bark after it overwinters. There can be two or three generations inVirginia.

Apple maggots are small flies whose larvae damage the apples andthen overwinter and pupate in the ground after the fruit has fallen.Adults will then emerge next year to start the cycle again. Applemaggot traps can control infestation.

cedar apple rust on apple leaf

codling moth larvae

apple maggot

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There are several types of aphids that cause damage. Some will feed on the trees and leaf shoots, andothers will infect the root system, severely stunting the growth of the tree. Rosy apple aphids attack thefruit, woolly apple aphids attack the root system, and green aphids attack the leaves and are mostcommon. Predatory insects provide protection from these.

Growing apples at home requires a lot of vigilance and patience. With the help of information from VirginiaCooperative Extension and Virginia Tech, you can keep the diseases and insect pests under control.

ResourcesGrowing Apples in Virginia, Publication 422-023, Virginia Cooperative ExtensionHome Fruit: Disease and Insects, Home Grounds & Animals Guide, Virginia Cooperative ExtensionA Grower’s Guide to Organic Apples, Cornell University Cooperative ExtensionA Curious Tale: The Apple in North America, Brooklyn Botanic GardenAll About Apples, History Channel, Mariel Synan, September 13, 2013Apples, University of Maryland ExtensionApples in America, Cornell UniversityRootstocks and Dwarf Fruit Trees, University of Maine Cooperative Extension