Organic Sprays for Fruit Trees

Protect fruit trees organically.

Nearly every gardener must deal with pests and disease, especially if growing fruit trees. Insects love fruit for the same reasons people do: they taste and smell sweet. Under-pruned or infested trees also develop fungi and mildew more easily because they are stressed or lack air flow through the branches. Chemical pesticides kill and repel many insects and diseases, but also pose a threat to animals eating fallen fruit, to the humans eating the harvest, and even to the trees themselves.
Organic fruit tree sprays are a healthier and safer alternative. Gardening stores often stock these sprays for gardeners looking for green alternatives. Some sprays simply consist of household products.

Lime Sulfur

Lime sulfur not only helps kill insects and their eggs, it also repels fungus and mildew. This green, powdery substance usually comes in large bags and is available at garden supply stores.
Downsides to this organic alternative include the sulfur smell and the necessary mixing with horticultural oil before application. Horticultural oil is a thick, organic oil that smothers insects. Gardeners apply the mixed substances with garden sprayers; the process works but leaves a bit of a mess. The mixture works best when applied in windless, sunny conditions and in temperatures between 32 and 70 degrees Fahrenheit.

Seaweed and Molasses

According to My Garden Tips, spraying a mixture of liquid seaweed and blackstrap molasses on fruit trees not only eradicates mildew and fungus, but also feeds the trees. My Garden Tips states that the fluids soak quickly into the leaves, leaving them lush and green. This also eliminates worries about the sweet molasses attracting insects.
Liquid seaweed is what it sounds like: seaweed pureed into a semi-thick liquid. Most garden supply stores sell it by the gallon and almost all grocery stores carry blackstrap molasses. The molasses dissolves into the liquid seaweed if mixed properly and applies easily with a hose-end garden sprayer. The mixture should coat the branches, leaves and trunk evenly.

Vinegar and Murphy Oil Soap

Mixing apple cider vinegar and unscented liquid Murphy Oil Soap is possibly the simplest and least expensive organic spray out there. The apple cider vinegar contains antibacterial and antifungal properties that help clear up mildew and fungus right away. The Murphy Oil Soap traps and smothers pests and their eggs. The mixture made from these two should be semi-thick and applied evenly to the branches and trunk with a garden sprayer. A hose-end sprayer or sprayer with a tank should do fine. This mixture requires more frequent application than others, about once every three days until pests and evidence of them disappear.

References

• My Garden Tips: Organic Fruit Tree Sprays
• Michigan State University Extension: Organic Apple Sprays