Wednesday, November 30, 2016

Fungicides in dispute

 St. Jacobs – The question stumped the speaker at a Healthy Soils workshop here recently: do fungicides kill beneficial fungi?

Christine George
Soil microbiologist Christine George waffled and mug-wumped, replying that some scientists believe they are harmful while others believe they are temporary and do little or no lasting harm.

But she added that repeated year-after-year use of seed-treatment fungicides will probably upset the previous soil balance of microbes.

The farmer who posed the question said he has received conflicting answers from recognized experts in crop and soil management.

What was clear from George’s presentation is that fungi serve a useful purpose by transporting nutrients through their long filaments to the zone right next to roots so plants benefit.

Her workshop presentation outlined how bacteria, fungi, protozoa and nematodes are necessary for good soil health and crop growth.

She emphasized that organic matter is a key to good soil health, improving soil structure, water-holding capacity, water penetration and providing a home and food for bacteria, fungi, protozoa and nematodes.

She said both beneficial and disease-causing organisms are necessary, but also said that it’s good crop management to encourage the beneficial ones so they can out-compete the disease-causing ones.

The workshop was presented by the Grand River Conservation Authority with funding from a number of sources, such as the Ontario Soil and Crop Improvement Association and the federal and provincial agriculture departments.

George, who is a Masters-degree graduate from the University of Guelph, works for the Grand River Conservation Authority.