Soilborne diseases, such as common scab and stem canker, can be a problem when growing potatoes, often ruining a potato patch. Recent research has focused on using beneficial microbes and compost as non-chemical alternatives for combating these diseases. The results have been promising.
Researchers at the University of Maine grew potatoes treated with two biological control agents and two types of compost to see if these treatments would significantly reduce the amount of disease on potatoes. The two compost treatments consisted of a conifer-based blend and a hardwood-based blend. The biological treatments included spraying Bacillus subtilis and a hypovirulent strain of Rhizoctonia solani on the patch.
All treatments reduced the incidence of stem canker by 27 to 50 percent compared to the control. The biological treatments and conifer-based compost reduced the incidence of common scab, but the hardwood-based compost increased the amount of the disease. Overall, the potato yield was 30 to 54 percent higher for all the treatments compared to the control plot.
For more information on this research, go to: USDA Agricultural Research Service.