What is Blight?

Blight is a specific form of damage to the tissue of plants caused by colonization by an infectious organism like a virus or fungus. Blighted plants will develop wilting, withering, and browning, often in addition to lesions on the stems and leaves. Infections that cause blight are often known as blights, and can occur in many different types of plants. There are some steps gardeners can take to reduce the incidence of blight in their gardens and fields.

Plants damaged by blight typically develop spots on their leaves, followed by yellowing, withering, and browning. As the plant starts to die, it can dry up. Parts of the plant may break off or collapse, depending on the source of the infection. Blight can spread from plant to plant, causing an entire crop to become infested and useless or ruining a section of an ornamental garden.

Early blight strikes toward the beginning of the growing season, while plants are developing. Plants may have difficulty sprouting, or sicken and die soon after getting established. Late blights wait until the end of the season and attack when plants are fully mature. For crops, this can mean a complete destruction of a crop, like potatoes, tomatoes, or corn, as the disease spreads through the field. For annuals, removing the plants can address the problem, but with perennials and trees, blights can represent a tremendous loss if mature and established plants must be removed.

There are a number of techniques for dealing with blight. Using clean, healthy soil for planting is often recommended, and soil can also be treated to kill bacteria and molds. At the first sight of blighting, removal of infected plants may be recommended, with the plants being securely disposed of so they cannot infect the rest of the garden. It is also possible to apply topical treatments to infected trees and plants to kill the infectious organisms. Providing supportive care to help the plant recover may allow it to survive the blight.

Gardeners are also usually directed to take care in planting and caring for their gardens. Crowded plants are more at risk of becoming infected, as are plants that are not watered appropriately. Watering late in the day can result in retained moisture and subsequent fungal infection, for instance, while plants with low water needs that are overwatered can become blighted. Monitoring garden health closely for any signs of disease and taking prompt action when disease is identified is critical for preventing the spread of disease.