March 26, 2009

Each growing season, many different diseases threaten Kentucky vegetables. However, by practicing good management techniques before and during planting, home vegetable growers can minimize disease risks, said Kenny Seebold, plant pathologist with the University of Kentucky Cooperative Extension Service.

Diseases usually are caused by fungi, bacteria or viruses. While they can appear anytime during the growing season, many favor wet, cramped conditions for development.

"The longer the leaves stay wet and the more plants that are jammed together in one area, the greater the disease risk," Seebold said.

Growers can lessen risks by making sure there is enough space between plants to promote good air flow. Water management also is critical. Over watering crops can lead to disease development. If possible, growers should water plants near the soil and not on the leaves. Seebold said the best time to water plants is in the morning because the foliage will dry quickly. If gardeners find they have soil drainage problems, they may need to add organic matter to the soil or fill in low spots that collect water.

One of the least expensive ways to control diseases is to plant cultivars that are resistant to certain plant pathogens. Growers should be aware that the availability of these resistant plants varies by crop and disease. While a variety may be resistant to certain pathogens or diseases, it does not mean the plant is immune.

Annually rotating crops can also help gardeners lower disease risks, especially if there were past disease problems in a certain plot. He said growers should rotate crops with others that are not of the same plant family. Crops that are of the same family, such as tomatoes and peppers or cucumbers and squash, could be susceptible to the same diseases.

Controlling insects and weeds can also help reduce the chances of disease. Some insects can carry pathogens that can transmit to crops, and weeds can be safe harbors for pathogens and insects.

Also, the time of planting is key to disease management.

"Planting some crops, like beans and peas, too early could make them more susceptible to disease," Seebold said. "Growers should measure the soil temperature at about a 4-inch depth to determine proper planting time. Ideally, the soil temperature should be at least 65 degrees."

Before planting, it's a good idea to clean any gardening tools and equipment that were used in past years, especially if they were used in an area that had disease problems in the past. Pathogens can overwinter on soil or on plant matter left on tools.

Because of uncontrollable factors such as weather, there is no way to ensure disease-free crops. Seebold said growers should scout their gardens regularly for any signs of disease problems. Catching and managing a disease early can help minimize the number of plants lost. If diseases develop during the growing season, fungicides may be used in small amounts to control the disease. Growers who are unsure of the type of disease their plants have or who have questions on management tactics or proper fungicide use, can visit their county office of the UK Cooperative Extension Service.

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Writer: Katie Pratt, 859-257-8774

UK College of Agriculture, through its land-grant mission, reaches across the commonwealth with teaching, research and extension to enhance the lives of Kentuckians.

 

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