UT Institute of Agriculture Suggests Ways to Prevent Plant Disease


Powdery mildew on Tennessee garden

Downy mildew on cucumbers (shown right) and other vegetables is a common problem for home gardeners in Tennessee. Photo by S. Bost, courtesy UTIA.



Did you know that planting tomatoes deep into the soil, as many gardeners do, can get you into trouble if it is done before the soil warms up? This is just one of many factors that home gardeners should consider when starting their gardens this spring.
"Plant diseases are caused by fungi, bacteria, viruses and nematodes," says Steve Bost, professor of entomology and plant pathology and University of Tennessee Extension specialist. "These pathogens are not harmful to humans, but they can be very damaging to plants." 
To help growers of both organic and non-organic crops, Bost has developed a new publication available through UT Extension that includes instructions on how to apply cultural practices and protection products to grow a healthier garden. His new publication also includes a list of many of the most common plant diseases and offers suggestions on how ways to control them.
Listed below, is a selection of easy-to-follow tips from Bost’s publication:
Garden site selection: Try to plant your garden in an area with good natural drainage and full sunlight. Properly drained soil will help prevent root rot in your garden.
Optimal growing conditionsMake sure your garden has proper soil pH, adequate fertilization, good weed control and that your plants are properly spaced.
Use resistant varieties of plants: Purchase seeds that are already resistant to diseases prevalent in your garden. Be sure to purchase seeds resistant to specific pathogens, and try to avoid the varieties simply listed as "disease resistant."
Disease-free transplants: Buy only locally-grown transplants or grow your own, from disease-free seed. Infected transplants sold by the bedding plant industry are a major source of infestation in Tennessee gardens, and the types of diseases brought in on transplants are difficult to control.
Planting date: Carefully choose the best date to plant your vegetables. Planting in soil that is too cool can result in many diseases like seed rot and stem rot. Crops that are planted for late summer and fall harvest will have more disease problems because pathogens build up during the growing season.
Crop rotation: Plant your crops in different parts of your garden every year. This helps prevent pathogen buildup in the soil. Try to rotate out whole families of crops because pathogens tend to attack all members of a plant family.
Seed disinfestation: Many pathogens that are carried on the seed can be killed outright with either hot water or diluted chlorine bleach. The process must be done precisely so as to avoid damaging the seeds. Consider utilizing these services if your seed company offers them.
Mulch:  This common landscaping material can help reduce fruit rot on many crops by preventing the crop from making direct contact with the soil. 
For more practical tips on how to control diseases in your garden and detailed information about the most common plant diseases for each crop, you can review Bost’s publication "Home Vegetable Garden Disease Control" (Publication Number W 316) online at the UT Extension publications website: extension.tennessee.edu/publications. Search for the title or publication number. You may also contact your local county UT Extension office.

The UT Institute of Agriculture provides instruction, research and outreach through the UT College of Agricultural Sciences and Natural Resources, the UT College of Veterinary Medicine, UT AgResearch, including its system of 10 research and education centers, and UT Extension offices in every county in the state.



Dr. Steve Bost, Professor of Entomology and Plant Pathology, 615-835-4573,