Powdery Mildew is a disease that forms patches of white powder on the leaves of many plants. You can rub these patches of white off with your fingers. Lilacs are frequently attacked, as are alpine currants roses, zinnias, garden peas, and sometimes lawns. This disease usually occurs in shady spots or in areas where shrubbery or buildings restrict the flow of air, resulting in moist or humid conditions.

Powdery mildew in lawn can often be controlled by pruning up the shrubs in the area. This allows greater air movement. The disease can be spread around your lawn when you mow the grass. If powdery mildew is serious on your lawn, you may need to use a fungicide in those areas where mildew is developing. Use a combination lawn fungicide to control powdery mildew in you lawn.

Pruning alpine currants and other shrubs infected with powdery mildew can be helpful, if the pruning opens up the plant to more air circulation. When powdery mildew is severe and the attack is early in the season, a fungicide may be needed to help control this disease.  Always read and follow all pesticide directions.

Powdery mildew usually develops late in the season on garden peas. Mildew problems will be reduced somewhat if you use disease free seed and if you don't plant peas in the same area more than once in three years.

This page was last updated May 2007

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