The peach tree's sweet sap attracts pests.
Gardeners use oils on dormant peach trees to control overwintering pests and to prevent fungal infection. Dormant oils go by many names, including superior oil, mineral oil and horticultural oil, but all prevent pests through physically smothering the egg or insect and by creating a protective film on the tree. According to the Alabama Cooperative Extension, dormant oil treatment is the single best preventive against peach tree disease and death.
Ingredients
Different brands use different oils.
Manufacturers create dormant oil from petroleum oils, vegetable oils or fish oils. Lime, copper or other pesticides may be added. Neem oil, an extract from the neem tree, is a common ingredient and is very effective against pests; however, some products only add a minuscule amount of neem oil for marketing purposes. Read the directions before applying any oil spray.
Control
Severe aphid infestations damage buds and new growth.
Dormant oils are not general insecticides. They control specific pests that overwinter on vulnerable plants and trees and cause problems, such as aphids, mites, whitefly and fungal diseases. The best protection against peach twig borers is a thorough spray of dormant oil before the flower buds open, and small insects have not developed a resistance against it.
Timing
Apply dormant oil before buds open.
Apply dormant oils in the fall, after the trees are hardened for the winter, and before buds open in early spring, to control scale and aphids. Do not use dormant oils when temperatures are below freezing, but they may be used on warm winter days when temperatures will remain above freezing for 10 to 12 hours after the application. Highly refined oils are lighter and do not harm actively growing trees, according to the Texas A&M Extension.
Application
Use one gallon of spray for every five feet of growth, suggests the Colorado State University Extension. A 10-foot-tall peach tree with a 10-foot spread would need two gallons of dormant oil for complete coverage. Mix dormant oil with water according to the label instructions and agitate the sprayer often. Coat the tree completely, including trunks, and add an extra application to any cracks in the bark. Timing is important; dormant oil harms plants in very cold or very hot temperatures.
Safety
Because dormant oils are physical controls, the chemicals are not harmful to humans or animals. The oils break down quickly and do not harm beneficial insects unless gardeners spray the insects directly. However, many products have added pesticides; read the label carefully, take precautions when spraying and wear eye protection.
Tags: buds open, peach tree, against peach, , before buds