Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I apply a dormant spray on my fruit trees?

As the name implies, dormant sprays are applied when plants are dormant, usually in February or early March. They can be used to control certain insects and diseases, depending upon the material used. While dormant sprays are not the solution to all plant pest problems, they are a good choice because by killing overwintering pests you can reduce a major source of infestation and slow development of a disease or insect problem dramatically. Dormant sprays also greatly eliminate the risk of killing pollinating insects, such as, bees, by being applied well before the beneficial pollinating insects are active.

Dormant oil sprays, also referred to as horticultural oils or superior oils, kill overwintering adults or eggs of insects on the tree by suffocation. They are nontoxic to humans and pets. They are best applied at temperatures above freezing. Insects controlled include scale, aphids, leafrollers, tent caterpillars and webworms. Dormant oils are also effective in controlling overwintering spider mites.

Several fungicides can also be used as dormant sprays to control certain diseases. Peach leaf curl is probably the most common. Materials for the control of peach leaf curl include Kocide, Benlate and Bordeaux mixture. Liquid lime sulphur can be used to control both peach leaf curl and scale insects on peach trees.

For more information on fruit spray materials and schedules including dormant sprays, refer to Extension publication number 6010, Home Fruit Spray Schedule, available at the Garden's Kemper Center for Home Gardening.