Pre-harvest use of glyphosate: Recent Austrian decision
Under the provisions of its national plant protection legislation, the Austrian Parliament voted on July 5th 2013 to ban the use of glyphosate-based herbicides as a pre-harvest maturation tool for crops used in food and feed. This decision was cited as an application of the ‘precautionary principle’ and will be revisited when glyphosate’s registration is renewed at EU level in 2015.
Pre-harvest applications - a use defended in the joint EU re-evaluation of glyphosate
In the joint dossier submitted by the Glyphosate Task Force (GTF) for the renewal of approval of glyphosate in the EU, pre-harvest application of glyphosate (both for weed control and harvest aid) was included amongst the representative uses of the herbicide for which the GTF wishes to obtain renewed approval. A full risk assessment submitted with the dossier shows no concerns for consumers (dietary), operators or the environment for pre-harvest uses.
The use of glyphosate as a tool in harvest management and crop maturation and ripening
The promotion of the maturation and senescence of crops and the control of weeds makes harvesting easier by encouraging ripening of the grains and managing the weeds which grow around crops. Application of glyphosate is an efficient tool for achieving more rapid ripening, thereby providing farmers with an effective harvest management treatment.
Wet summers, years with poor weed control or the uneven dispersion of crops throughout fields can mean that crops ripen unevenly and contain considerable amounts of “green crop materials” such as green seeds, stems, secondary tillers (late plants) and weeds.
The presence of green crop materials can make harvesting difficult by putting an extra strain on farm machinery, resulting in increased fuel and labour costs. In addition, high moisture content in grains can lead to problems when storing the harvest including mould growth and condensation. In some cases wet seeds need to be dried artificially, incurring further costs.
Residues related to the pre-harvest use of Glyphosate
The residues related to pre-harvest uses are the basis for the setting maximum residue levels (MRLs) for crops like cereals, pulses and oil seed crops where pre-harvest treatments are recommended. These MRLs are set for the highest recommended doses for weed control. Such MRLs are not to be confused with toxicology thresholds. Exceeding an MRL only provides an indication that recommendations were not respected by the user and does not indicate risk to consumers or livestock.
In addition, as part of the regulatory approval process, MRLs are only established where resultant dietary exposures do not present either acute or long term risks for consumers. The threshold for dietary risk is set with a safety factor of 100, and for glyphosate the sum of all the worst case dietary exposures is well below this threshold.
It should be noted that in official residue monitoring programs of commercial crop commodities only a small fraction of the commodities that could have received a pre-harvest treatment, shows actual detectable residues. For example, the latest (2010) EFSA report on pesticide residues in food focusses on oats and rye, both crops which may be treated pre-harvest. For oats 23.8% of samples showed detects but none exceeded the MRL and all residues were less than 5% of the MRL. There were only 3 detects in rye, all <5%MRL. Combining these EU data with national monitoring programmes for cereals showed no MRL exceedances, and 75 detects/878 samples (8.5%).
Although Austria`s decision was based on the "precautionary principle", the GTF criticizes the ban enacted in Austria. It is considered to be disproportionate and scientifically undifferentiated, it further restricts
Last update: 08 January 2014