Glyphosate and Previous Crop Residue Effect on Deleterious and Beneficial Soil-borne Fungi from a Peanut–Corn–Soybean Rotations

Bean seedlings (Phaseolus vulgaris L.) were transplanted to soil with corn previous crop residue, peanut previous crop residue and no agricultural soil, and treated with a range of glyphosate concentrations. Trichoderma, Gliocladium, Fusarium and Pythium soil-borne fungi populations were monitored during 24 days after glyphosate treatment to study the glyphosate and previous crop residue effects on these populations. In addition, those genera of soil-borne fungi were tested to study in vitro toxicity to glyphosate. Independently of glyphosate concentration, the highest population of Trichoderma spp. and Gliocladium spp. were registered on soil with previous corn residue. Fusarium and Pythium populations increased proportionally to the increment of glyphosate concentration. No effect of glyphosate was founded on Trichoderma and Gliocladium populations. The in vitro study results indicated an inhibitory effect of glyphosate on mycelial grown of the most studied soil-borne fungi.