Based on the results from greenhouse test and field trials, we confirmed that glyphosate application could cause higher SDS severity level in different growth stages, even in the early V-stages. Preliminary data showed reduced soybean root initiation and development after the use of glyphosate, which would probably impair plant resistance and ability of recovery. Nodulation was significantly lower in soybean roots when glyphosate was applied in greenhouse conditions, regardless SDS infection. Extra inoculation of rhizobium seemed to improve plant resistance to SDS. In the field trials, glyphosate caused reduction of canopy density as well, though the weather conditions in 2013 were not favorable for SDS occurrence.

The reduction of canopy density was detectable using aerial remote sensing. Several preliminary tests on toxin production in different liquid media and their pathogenic effects under glyphosate treatment using a detached leaf assay in greenhouse conditions indicated that glyphosate significantly increased symptom expression caused by toxin and also significantly reduces development of new roots on petioles of detached soybean leaves in greenhouse conditions. This result is consistent to the observations from potted plants and indicated that glyphosate affected the whole plant not only the root systems. New greenhouse trials are set up in our greenhouse to further test effects of glyphosate to root systems and fungal infection.