The organic farmer's approach to controlling plant disease is a preventative "wellness regime" for the land. We don't use fumigants, also known as "soil sterilants," to kill soil diseases and weeds; instead, we rely on healthy soil with its natural "immune system" intact.
Using fumigants to prevent disease is like prescribing really strong antibiotics: they kill all the good organisms in the soil along with the bad. In addition, fumigants (such as methyl bromide) may cause serious human health and environmental problems.
How healthy soil keeps diseases in check
One of the biggest rewards of organic farming is healthy soil that's full of beneficial organisms, hard-working bacteria and fungi that break down organic matter into nutrients that can be readily used by plants. Beneficial microorganisms also compete with and/or prey upon disease-causing organisms. These "good" microorganisms function like the white blood cells in our bodies, keeping the harmful bacteria and fungi that cause disease in check.
Chemical fertilizers and pesticides kill the soil's natural immune system, forcing conventional farmers to use large amounts of chemical fungicides and soil sterilizers to protect their crops from disease.
Cover crops can also help protect crops against disease
At Earthbound Farm, we're currently working with cover crops that have soil disease-suppressive qualities. When such a cover crop is tilled into the soil, it releases a natural compound that inhibits the germination of certain fungal spores, protecting the next crop planted in that soil.
Crop rotation prevents pest buildup
Planting the same crop in the same location season after season ("monocropping") encourages the buildup of diseases and pests that plague that particular crop. We're diligent about rotating our crops to avoid such problems.
Next in Organic 101:
Fighting pests with a little help from our friends