Sulfur Spray for Apple Trees

Updated February 21, 2017

Whether you're growing a few apple trees or an entire orchard full, a fungicide program will be necessary. For organic gardeners, control of powdery mildew, apple scab and cedar-apple rust may involve using sulphur spray.

Sulphur as a Fungicide

Sulphur has been used as an organic fungicide for centuries, and is sprayed on crops like apples, stone fruits and vegetables, according to the University of California.

Types of Sulfur Spray

West Virginia University notes that there are several types of sulphur sprays for apple trees, including liquid lime-sulphur, dry wettable sulphur and flowable sulphurs. There is a granulated form of sulphur as well, but it is not appropriate for spraying.

When Sulfur Spray is Used

Application of sulphur spray on apple trees takes place beginning when the trees are just starting to leaf out and may continue until harvest or the end of August, according to the Michigan State University Extension.


Even though sulphur sprays are organic, they can still be caustic and irritating to eyes and skin. Inhalation of sulphur mist should be avoided. Read all mixing, spraying and storage instructions carefully, and pay close attention to safety precautions.

Toxicity to Beneficial Insects

Sulphur is toxic to many beneficial insects that are natural predators of insects and mites that can damage apple crops.

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About the Author

Leslie Lane has been writing professionally since 2007. Her areas of expertise include landscape and garden design; trees, shrubs and perennials; plant care; and plant pests and diseases. An education in landscape horticulture from Lansing Community College is paired with several years experience working for one of Michigan's premier wholesale/retail nurseries and growing farms.