Fungicides are pesticides that kill or prevent the growth of fungi and their spores. They can be used to control fungi that damage plants, including rusts, mildews and blights. They might also be used to control mold and mildew in other settings. Fungicides work in a variety of ways, but most of them damage fungal cell membranes or interfere with energy production within fungal cells.

Keep these tips in mind when using fungicides:

• A fungal disease in plants can be misdiagnosed easily. Check with your local county extension office for help identifying plant disease. They may also be able to recommend a treatment strategy for your lawn or garden.
• Often, plant diseases are transmitted when leaves are wet. Ground level watering and good air circulation can be used to keep leaves dry.
• Many fungicides remain on the surface of plant tissues and do not spread throughout the plant. Others penetrate the cuticle and circulate through plant tissues.
• Pruning shears and other tools can carry plant diseases from one plant to another. Learn about garden sanitation to prevent spreading fungal pathogens yourself.
• Although they can slow or stop the development of new symptoms, many fungicides are designed only to prevent disease. These are not highly effective after symptoms have developed.