A new farm study by Brazilian researchers shows that glyphosate herbicide applications increased infection with the pathogenic fungus that causes leaf blight and may decrease the yield of GM Roundup Ready soybeans.

Also the percentage of normal seedlings decreased with increased applications of glyphosate.

The authors concluded, "The results indicate that there is potential for damage by glyphosate… which are most likely related to or arise from potential injuries or the deleterious action of glyphosate… Changes in the nutritional balance and physiology of the plant as a whole, as well as in photosynthesis and other biosynthetic processes, can lead to decreased biomass accumulation in the tissues of agronomic interest, with potential negative effects in not only plant development but also the productivity and quality of seed harvested."

The study:
The role of glyphosate in RR soybean production and seed quality
(Glyphosate na produção e qualidade das sementes de soja RR)
ALBRECHT, L.P.; ALBRECHT, A.J.P.; BRACCINI, A.L.; OLIVEIRA JR., R.S.; ZOBIOLE, L.H.S.; ÁVILA, M.R.
Planta Daninha vol.32 no.2 Viçosa Apr./June 2014
http://dx.doi.org/10.1590/S0100-83582014000200018
Full text: http://www.scielo.br/scielo.php?pid=S0100-83582014000200018&script=sci_arttext

(Comment by Claire Robinson)