A small percentage of growers and scientists believe that glyphosate promotes the growth of plant pathogens, such as fusarium.
A 2009 paper by Myriam Fernadez, an organic farming and crop pathologist with Agriculture Canada, found an association with glyphosate use and fusarium in cereal crops.
“(We) established a relationship between previous glyphosate use and increased fusarium infection of spikes and subcrown internodes of wheat and barley, or fusarium colonization of crop residues,” she said in the European Journal of Agronomy.
“However, because of the close association between non-cereal crops, reduced tillage and glyphosate use, it was not possible to completely separate the effects of these factors on fusarium.”
Recently, scientists from the United States Department of Agriculture and the University of Maryland reached a different conclusion. They studied glyphosate use on corn and soybean crops and published a paper in 2018.
“Geography, farming system, and seasonal progression were significant factors determining composition of fungal and bacterial communities,” they wrote in bioRxiv. “Plots treated with or without glyphosate did not differ in overall microbial community composition after controlling for these factors. No differential effect of glyphosate treatment was found in the relative abundance of organisms, such as Fusarium spp. or putative growth-promoting bacteria Pseudomonas spp.”