The mint plant is a popular aromatic herb native to Europe and Asia. Mint plants are perennials that often reach heights of up to 3 feet. While the mint plant is an ideal choice for beginning gardeners, it is susceptible to some common diseases that affect plant growth.
Fusarium wilt typically affects basil and members of the mint family. Fusarium wilt is introduced into fields and greenhouses through contaminated seed. Plants with this disease grow normally until they reach heights of 6 to 12 inches, then their growth becomes stunted and they wilt. Symptoms associated with fusarium wilt can include brown streaks on stems, sudden leaf drop, crooked appearance of stems and discolouration of stem tissue. However, according to the North Carolina Cooperative Extension, most mint plants do not exhibit outward symptoms of fusarium wilt but carry over the inoculum each year, resulting in the infection of new plants. Fusarium wilt can persist in the soil for eight to 12 years.
Verticillium wilt is a fungal disease that affects more than 300 species of plants. Plants in the mint family are susceptible to verticillium wilt, states the Missouri Botanical Garden. The symptoms associated with this disease vary according to environmental conditions and plant type, but can include yellowing of foliage, sudden wilting, premature defoliation and stunting of plant growth. Initial symptoms can affect only a part of the plant or the entire plant. Plants can die quickly or can die slowly over the course of years.
Powdery mildew is a serious problem that commonly affects members of the mint family, such as bee balms. Powdery mildew is caused by a fungus, causing a white powder to appear on leaf surfaces and leaves often drop prematurely. Symptoms of this fungal disease are severe in plants that are overcrowded, are stressed by drought and are growing in partial to heavily shaded areas. Planting mildew resistant varieties is the best way to avoid powdery mildew in mint plants. Removing and destroying mint plants that are infected by powdery mildew will reduce the chance of infection the next year.