A backyard orchard provides fresh and juicy fruit for you to enjoy straight from the tree or to can and use later. Unfortunately, pests such as insects and fungus also enjoy feasting your fruit tree, which can result in foliage and fruit dropping prematurely. Pesticides and fungicides help control these problems, but commercial products can cause more harm than good, killing beneficial insects and wildlife. Instead, use organic pesticides and fungicides to control problems with fruit trees without compromising the crop.
Neem Oil and Jojoba Oil
Derived from the neem tree, neem oil is an all-purpose spray and safe for use in organic gardening. It helps control undesirable insects and fungal diseases that attack fruit trees without harming the fruit or the plant. It is not toxic to mammals in small doses and quickly biodegrades in the environment. Neem oil treats mildews, rusts, leaf spots, leaf curl, blights and various other fungal diseases. It also controls aphids, spider mites, scale insects, earwigs, whiteflies, weevils, stinkbugs and many other garden pests. Jojoba oil is used in the same manner as neem oil and treats and controls most of the same pests and diseases. It comes from the seed of a shrub called the jojoba plant, which is native to California, Arizona and New Mexico.
Horticultural oil generally is derived from highly refined petroleum and helps control most common garden pests and fungal diseases that attack fruit trees. This all-purpose pesticide is safe for use in organic gardening and controls both insects and fungus such as leaf spots, rusts, mildews, black spots, aphids, scales and whiteflies. Horticultural oil has a low toxicity level to birds, bees and humans and but can be toxic to fish and other aquatic wildlife.
Insecticidal soaps are used as both an insecticide and fungicide, treating a wide array of pests that fruit trees can acquire, including sooty mold and scale insects. Insecticidal soaps stop fungal diseases by interfering with the cell membranes. Once the cell membranes have been compromised, the fungal pathogen can no longer grow and attack the fruit tree. Insecticidal soaps kill unwanted bugs by smothering them. Once the liquid has covered the entire insect, it blocks their breathing ability, causing them to smother and die. Insecticidal soaps are safe to use around bees and have a low toxicity level to predatory insects.
Bacillus thuringiensis is essentially a stomach poison that targets specific insects at their larval stage, including leaf-eating caterpillars, loopers, hornworms and leaf rollers. It is non-toxic to fish, humans, birds, bees, pets, wildlife and other beneficial insects. Bacillus thuringiensis is a bacterium that -- when consumed by the targeted pest -- will cause it to stop feeding, which leads to death within two or three days.
Pesticides and fungicides of all types require proper usage to ensure the fruit tree isn’t damaged. Using pesticides correctly also increases their effectiveness. Each brand and type has directions printed on the label that you should follow carefully prevent injury to yourself or the fruit trees. A good rule of thumb is to only apply the pesticide when temperatures fall between 40 and 90 degrees Fahrenheit, on a calm day and when there is no rain in the forecast for at least 24 hours.
- Oregon State University Extension Service: Least Toxic and Organic Pesticides for Gardeners
- Fine Gardening: Control Pests and Diseases Safely with Neem
- University of California Integrated Pest Management Program: Horticultural Oil
- University of California Integrated Pest Management Program: Soap
- Missouri Botanical Garden: Bacillus Thuringiensis (Bt) Kurstaki and Israelensis Strains
- North Coast Gardening: Keeping Honeybees Safe While Using Pesticides
- Missouri Botanical Garden: Oil Sprays
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