Bento et. al, 2016
Bento CP, Yang X, Gort G, Xue S, van Dam R, Zomer P, Mol HG, Ritsema CJ, Geissen V, “Persistence of glyphosate and aminomethylphosphonic acid in loess soil under different combinations of temperature, soil moisture and light/darkness,” Science of the Total Environment, 2016, DOI: 10.1016/j.scitotenv.2016.07.215.
ABSTRACT:
The dissipation kinetics of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were studied in loess soil, under biotic and abiotic conditions, as affected by temperature, soil moisture (SM) and light/darkness. Nonsterile and sterile soil samples were spiked with 16mgkg-1 of glyphosate, subjected to three SM contents (20% WHC, 60% WHC, saturation), and incubated for 30days at 5°C and 30°C, under dark and light regimes. Glyphosate and AMPA dissipation kinetics were fit to single-first-order (SFO) or first-order-multicompartment (FOMC) models, per treatment combination. AMPA kinetic model included both the formation and decline phases. Glyphosate dissipation kinetics followed SFO at 5°C, but FOMC at 30°C. AMPA followed SFO dissipation kinetics for all treatments. Glyphosate and AMPA dissipation occurred mostly by microbial activity. Abiotic processes played a negligible role for both compounds. Under biotic conditions, glyphosate dissipation and AMPA formation/dissipation were primarily affected by temperature, but also by SM. Light regimes didn’t play a significant role. Glyphosate DT50 varied between 1.5 and 53.5days, while its DT90 varied between 8.0 and 280days, depending on the treatment. AMPA persisted longer in soil than glyphosate, with its DT50 at 30°C ranging between 26.4 and 44.5days, and its DT90 between 87.8 and 148days. The shortest DT50/DT90 values for both compounds occurred at 30°C and under optimal/saturated moisture conditions, while the largest occurred at 5°C and reaching drought stress conditions. Based on these results, we conclude that glyphosate and AMPA dissipate rapidly under warm and rainy climate conditions. However, repeated glyphosate applications in fallows or winter crops in countries where cold and dry winters normally occur could lead to on-site soil pollution, with consequent potential risks to the environment and human health. To our knowledge, this study is the first evaluating the combined effect of temperature, soil moisture and light/dark conditions on AMPA formation/dissipation kinetics and behaviour.
Kaskey and Mulvany, 2016b
Jack Kaskey and Lydia Mulvany, “Creating a Problem- And a Lucrative Solution,” Bloomberg, September 5, 2016.
SUMMARY:
Discusses the herbicide treadmill and how it has sparked the development of, and demand for, dicamba-resistant technology. FULL TEXT
EPA, 2016a
Environmental Protection Agency, “COMPLIANCE ADVISORY: High Number of Complaints Related to Alleged Misuse of Dicamba Raises Concerns,” August 2016.
SUMMARY:
EPA and state agencies have received an unusually high number of reports of crop damage that appear related to misuse of herbicides containing the active ingredient dicamba. Investigations into the alleged misuse are ongoing. This Compliance Advisory is intended to provide information on the agricultural and compliance concerns raised by these incidents. FULL TEXT
USDA, 2014
United States Department of Agriculture, “Monsanto Petitions (10-188-01p and 12-185-01p) for Determinations of Nonregulated Status for Dicamba-Resistant Soybean and Cotton Varieties: Final Environmental Impact Statement,”
December 2014.
SUMMARY:
The U.S. Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS) received two requests (petitions) from Monsanto Company, St. Louis, MO (Monsanto) seeking determinations of nonregulated status for genetically engineered (GE) plant varieties referred to as MON 87708 soybean and MON 88701 cotton, that have been engineered to be resistant to the herbicide dicamba (Monsanto, 2012b; 2012a). These GE plant varieties are currently regulated by APHIS, and Monsanto requests that APHIS grant the petitions (Petition 10-188-01p for MON 87708 soybean and Petition 12-185-01p for MON 88701 cotton), so that these varieties can be grown without any APHIS regulatory oversight. Since these two GE plant varieties are currently under APHIS regulatory oversight, the Agency requires
Monsanto to comply with a full range of safeguarding measures to ensure that these regulated GE plant varieties do not transfer or spread from their APHIS-approved outdoor planting sites. APHIS authorization is also required to move these regulated varieties interstate. Once a developer of a GE plant has obtained sufficient information to conclude that its regulated GE plant is unlikely to cause injury, damage, or disease to plants or plant products (i.e., pose a plant pest risk), it may submit a petition to APHIS to no longer regulate the organism. This is referred to as seeking nonregulated status. If a petition for nonregulated status is approved by APHIS, permits or notifications are no longer required by the Agency to grow or ship the GE plant throughout the United States and its territories. If APHIS determines that nonregulated status is appropriate for one or both the Monsanto GE varieties, they will no longer be subject to any regulations pursuant to Part 340. FULL TEXT
Benbrook Consulting Services, 2016
Benbrook Consulting Services, Use of Dicamba on Crops as Surveyed by the National Agricultural Statistics Services (NASS), 2016.
SUMMARY:
Table detailing NASS reports of dicamba use (percent of total crop) and application rates. FULL TEXT
EPA, 2016c
Environmental Protection Agency, “Dicamba; Pesticide Tolerances,” Federal Register, 40 CFR Part 180, December 8, 2016.
SUMMARY:
This regulation establishes tolerances for residues of dicamba in or on cotton, gin byproducts; cotton, undelinted seed; soybean, forage; and soybean, hay. Monsanto Company requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA). Sets the cRfD at 0.04 mg.kg.day. FULL TEXT
Monsanto, 2005b
Monsanto, “Monsanto, UNL Sign Agreement to Develop Dicamba-Tolerant Crops,” Monsanto Press Release, March 23, 2005.
SUMMARY:
Monsanto press release announcing agreement with University of Nebraska-Lincoln to develop dicamba-resistant crops. FULL TEXT
Monsanto, 2016a
Monsanto, Monsanto Meeting Whistle Stop Tour – Day 1, Monsanto Official Transcript, August 17, 2016.
SUMMARY:
Detailed transcript of Monsanto investor meeting in August 2016 where dicamba and glyphosate investments and projections were discussed. FULL TEXT
BASF, 2016a
BASF, Engenia Herbicide Label, December 20, 2016, EPA Registration Number: 7969-345.
SUMMARY:
EPA label for Engenia Herbicide for dicamba-resistant crops. FULL TEXT
Monsanto, 2016b
Monsanto, XtendiMax With VaporGrip Technology Herbicide Label, November 9, 2016, EPA Registration Number 524-617.
SUMMARY:
Label for XtendiMax with VaporGrip Herbicide for use with dicamba-tolerant crops. FULL TEXT