Fungicides a Part of a Disease Control Program

Fungicides should be only one part of a disease control program. A relatively small proportion of all the diseases plaguing the landscape/gardener can at present be controlled by fungicides.

Other practices such as proper seedbed preparation, fertilization, crop rotation, weed and insect control, use of resistant varieties where adapted and recommended, seed treatment, use of disease-free seeds and transplants are only some of the means of disease control which are important and should not be ignored.

What Fungicides Won’t Do

A protective fungicide applied to the foliage does not generally protect against:

• Disease organisms entering through the roots (nematodes or root-rot and wilt-producing fungi)
• Bacterial diseases (since bacteria often enter through natural openings in the plant or wounds)
• Viruses which are frequently injected into plants by insects.

Protective fungicides kill only the disease organisms which fall on treated plant foliage. They will not destroy established infections.

To be effective, a fungicide must:

• be applied before infection occurs and the disease has become established
• be reapplied periodically since moisture, sunlight and plant growth dilute the chemical leaving plant surfaces unprotected
• be applied thoroughly so that all plant surfaces are covered
• be used according to directions as given by the manufacturer’s label

Fungicides should generally be applied at 7-10 day intervals depending on the weather, and the type and severity of the diseases present.

Fungicides may be needed and applied as often as every 3-5 days during rainy periods and may be omitted during prolonged hot, dry periods. It is better to spray before a rain, because infections occur generally when foliage surfaces are wet.

Your local county agent can usually give you additional information regarding fungicides and their uses in your area.

Most states have bulletins, pamphlets and spray schedules listing the recommended fungicides.

Always read and follow the directions printed on package labels and other literature supplied by the manufacturer. These instructions are printed to ensure your safety. Many of the products listed are poisonous. Be sure to keep all pesticides away from children and pets. All precautions, directions for amounts to use and timing of applications should be carefully followed. Remember! The plants you save will be your own.