Fruit trees can benefit from several kinds of chemicals applied to the foliage, branches and surrounding soil. Various chemical formulations are commonly used to prevent and treat fungal and bacterial infections, dissuade or kill pests, fertilize the soil and to improve the tree's growth and fruiting performance. While many fruit tree species have unique issues that dictate what specific chemicals may be helpful, most fruit trees experience similar enough problems to warrant some type of chemical intervention at some point in their life cycle.
Fertilizers and soil amendments are common chemical treatments for fruit trees. Keeping the tree growing vigorously, flowering and developing fruit in profusion are part and parcel of growing fruit trees. When fruit trees fail to grow or fruit easily, feeding a balanced complete fertilizer with a 10-10-10 guaranteed analysis in the early spring before flowering is warranted. Chemical fertilizers contain synthetic elements of nitrogen, phosphorous and potassium and are dosed by giving 1/10 pound of fertilizer for every year of the tree's age.
Bacterial infections are common on fruit trees and can become active by a wide range of conditions that let the bacteria take hold and multiply in compromised trees. Common bacterial infections in fruit trees include fire blight, bacterial canker and bacterial spot. Bacteriacides for fruit trees often use copper, lime sulfur or sulfur as the active ingredient to kill and contain the bacteria cells. Bacteria treatments are often mixed with fungicides to prevent or treat both issues in a single application. The are most commonly applied in anticipation of a problem and to prevent overdevelopment of bacteria.
Fungicides are used to control fungi plants that colonize on a fruit tree. Some common examples are molds, botryosphaeria, apple scab, bitter rot, brown rot, and black knot. Fungal infections are are commonly treated by spraying the trunk, branches and foliage with chemical formulations that contain one or more of the following active ingredients: Captan, Chlorothalonil, lime-sulfur, Mancozeb, Benomyl, Dodine, Dikar, Glyodex or Polyram.
Pesticides are used to control insect damage to both the fruit tree structure and the fruit itself. Beetles, moths, curculio, mites and aphids are among the many pests attracted to fruit trees. They are treated with chemical formulations sprayed onto the tree during a fixed period from anticipated harvest time, which varies widely by product. Common insecticides use on fruit trees include: Carbaryl, Malathion, Metaldehyde, Azadirachtin, Permethrin and Pyrethrins. Horticultural or dormant oil spray made from paraffin and petroleum products is also used as a preventative treatment that effectively smothers the eggs and insects.