Removing debris from the garden can reduce the amount of pathogens that over-winter to infect plants the following year. Gardeners should prune out diseased plant parts or completely remove diseased plants from the garden; the longer they stay, the more diseases they can pass on to their neighbors. Rotating crops to new spots in the garden each year can also reduce the build-up of pathogens in the soil.
The second side of the triangle is an environment conductive to allowing the disease to grow. We can't control rainfall, but we can make conditions less favorable for diseases to take hold. Adequate spacing between plants improves air flow, reduces the localized humidity and moisture around plants, and keeps airborne pathogens from settling in one space for too long.
Healthy soil reduces the likelihood of diseases. Improving the texture of heavy soils (with which most of West Virginia has been blessed) can keep soil from staying too wet, which causes root damage and allows for root rots and wilts to invade plants.
Increasing the number of good fungi and bacteria in the soil makes it more difficult for the bad guys to take hold, much like the good bacteria (say from yogurt) can help improve health in people. Feeding the good guys with lots of organic matter and using winter cover crops in the vegetable garden are keys in keeping the good guys healthy. Crop rotation will also keep them happy.
The third side of the triangle is the plant itself. The pathogen has to be able to infect it to cause a disease. There are several ways to make sure that the plant and pathogen are not compatible.
Rotating crops will help keep plants and their potential pathogens separated (I see a pattern emerging). Making sure the plant is healthy, with proper fertility, light, etc. goes a long way in helping the plant resist or recover from disease.
But perhaps the best way to make sure that the plant and pathogen are not compatible is to select disease-resistant varieties. While it may be too late to do so this year, doing so next year will help reduce disease instances if there were problems this year.
John Porter is the WVU Extension Service agent for agriculture and natural resources in Kanawha County. He may be reached at john.por...@mail.wvu.edu or at 304-720-9573. Twitter: @WVUgardenguru.