Apple trees produce delicious fruit with a sweet pulp along with crisp flesh. Based on the species, apple trees grow in U.S. Department of Agriculture plant hardiness zones 4 through 9, and therefore are susceptible to certain pests. Various sprays are designed to control apple tree diseases and pests, and help keep the plants healthy. Choose the proper spray to the intended function or you can accidentally harm your apple trees.

Dormant Oil

Through the apple tree glacial stage, apply dormant oil to control overwintering pests. Horticultural oil is a well known insecticide that can be implemented at anytime throughout the calendar year, and applying this oil during the dormant period will prevent unintended harm to beneficial insects such as bees and ladybugs. The University of California recommends spraying apple trees with dormant oil in the winter to control San Jose scale, and aphid and mite eggs.

Insecticidal Soap

Insecticidal soaps include long-chain fatty acidsthat can be far less toxic than chemical insecticides. Insecticidal soap controls various common garden pests like mites, aphids, scales, whiteflies, thrips and leafhoppers. It is safe to use around people, pets and wildlife but can harm beneficial insects such as ladybugs and lacewings. This nontoxic insecticide must come in contact with the insects to dominate them. The soap breaks down the protective coating covering the pest and interrupts the cell membranes, causing the insect to die. Once insecticidal soap dries, it is no more toxic and fast breaks down in the environment. Insecticidal soap can be applied to apple trees up to the day of harvest.

Bacterium Insecticide

Bacillus thuringiensis is a bacterium insecticide designed to target only certain kinds of pests without harming beneficial and predatory insects. The strain of Bacillus thuringiensis determines that pest is controlled. The kurstaki strain controls larval stages of butterflies and moths that feed on apple tree leaves and fruits. The israelensis strain targets mosquito larvae and fungus gnats. Bacillus thuringiensis is implemented as a foliar spray; after the targeted pest consumes the bacteria, it stops feeding and will die in a couple of days. This insecticide is nontoxic to mammals, humans, birds, fish, mammals and valuable predators.

Fungicides

Fixed copper sprays are a garden staple used to control a wide collection of fungal and bacterial diseases that attack apple trees. The copper fungicide disrupts the enzyme system of the pathogen and prevents the spores from germinating. Apple scab, European canker, fire blight and brown rot are a couple of diseases attacking apple trees that copper fungicides can dominate. Generally, copper fungicides can be used up to 24 hours prior to the date of harvest and aren’t toxic to bees or birds. They are, however, toxic to fish and other aquatic organisms.

Fertilizer

The University of California recommends applying fertilizer to apple trees prior to the initial irrigation throughout the spring bloom stage, during the summer growing season and then again after harvest. Fertilizers can be found in various forms including liquid sprays and slow-releasing granular. A foliar spray fertilizer created for apple trees must thoroughly coat the leaves, but do not apply it at an inordinate amount in which the fertilizer drips off the leaf. Instead, apply 2 pounds of urea — a nitrogenous fertilizer — approximately 40 pounds of manure around the tree.

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