Fruit trees attract a variety of insects that damage fruit, foliage or wood. Gardeners control these pests with chemicals or organic alternatives, also called natural insecticides. The latter method of control is cheaper, environmentally friendly and safer for consumers and wildlife. Home and commercial gardeners should consider using natural insecticide to deter or control pests attracted to their fruit trees.
There are a few different types of natural insecticides, such as insect soaps that destroy the pest's cells after penetrating the coating and oils extracted from these soaps that suffocate adults and prevent oxygen from reaching the eggs. Kaolin clay coats parts of the fruit tree in a protective layer that pests find unappetizing, while neem and other botanical pesticides kill pests through use of plant toxins. Diatomaceous earth cuts through the exoskeleton of a fruit tree's pest and kills it.
Organic insecticides, unlike their chemical alternatives, do not leave any toxic residue on the fruit. The fruit of a tree treated chemically requires thorough scrubbing and washing on the part of the consumer to prevent residual toxin ingestion. According to the Environmental Working Group, the list of five fruit trees with the largest amounts of pesticides includes peach, apple and nectarine. Natural insecticide does not kill pollinators, such as honeybees and parasitic wasps, like some chemical alternatives.
To prevent pest outbreaks, apply the selected natural insecticide in late winter when the fruit tree is dormant. Most pests, such as caterpillars, aphids and mites, lay eggs at this time that hatch and feed on the tree in the growing season, causing severe damage. Application of a natural insecticide at this point kills the eggs and prevents or reduces future outbreaks.
Treat pests that actively feed or damage fruit trees during the growing season with target sprays. For instance, pests such as aphids have several life cycles in a single growing season and require several applications of insecticide for effective control.
According to the Colorado State University Extension, soap detergent sprays injure certain fruit trees such as plums and cherries due to the phytotoxicity, and the susceptibility to damage increases when temperatures rise above 80 degrees Fahrenheit. To reduce plant injury, dilute sprays more than three percent as noted on the product instructions to create a weaker solution, or spray freshwater on the trees two to three hours after spraying.
Although exposure or ingestion of small amounts of natural insecticide residue is considered safe, it still causes skin and lung irritation. The North Dakota State University Extension recommends that gardeners who spray fruit trees wear protective clothing and a face mask during application, and select a nonwindy day to prevent spread. The extension also suggests that gardeners read through label directions for application rates and precautions prior to use.