Questions on Label Statements
Chris
Boerboom
I had a good question about interpreting a statement on a
Raptor label this week and I thought could try to answer this
and a couple other questions about different types of precaution
and prohibition statements found on labels.
The original question was about the Raptor label where it
states "There should be an interval of at least 20 days between
application of Raptor and cutting or feeding of alfalfa forage
or hay." The question was if you could apply Raptor and harvest
the alfalfa 10 days later and wait another 10 days before
feeding the haylage. This would make a total of 20 days after
the application before feeding.
The answer is that the 20 day "preharvest interval" would not
be met so this could not be done. The "20 days before feeding"
really refers to 20 days before grazing. The reason for
preharvest interval statements on labels is to make sure that
there is enough time for the herbicide to be metabolized in the
plant so little or no herbicide is left in the harvested crop.
The technical term for the maximum amount of herbicide residue
allowed in the crop is called the "tolerance". The tolerance for
a herbicide in a crop might be 0.05 parts per million. The
tolerance will differ between herbicides and crops and is
approved by the EPA. By following the preharvest intervals, we
ensure that unsafe levels of herbicides residues do not end up
in food.
There are other label directions intended to make sure
unapproved herbicides residues do not end up in food or feed.
One example is when a herbicide is not labeled for direct
applications to a certain crop. For example, the Option label
states "is NOT to be used on sweet corn." At this time, Option
probably does not have a tolerance in sweet corn. If sweet corn
was tested and found to have residues of Option without an
approved tolerance, the harvested crop may need to be destroyed.
Another example could be if residues were picked up by a
rotational crop. For instance, alfalfa is not an approved
rotational crop after applications of Harness. If a corn field
was lost to hail and alfalfa was replanted in the summer, the
alfalfa could take up Harness and contain low levels of
residues. This could be illegal if a tolerance for Harness is
not established in alfalfa.
Many of the "Do Not" statements on the label are intended to
protect the environment (ie. do not apply if wind is greater
than 10 mph), prevent illegal levels of residues (ie. do not
make more than to applications), or avoid crop injury. There is
only one type of "do not" statement that I believe the EPA
allows applicators to deviate from. An example is "Do not apply
less than 14 ounces of Basis Gold per acre." EPA allows
applications at rates less than the labeled rates, although
there is no guarantee of performance.
When reading a label, it is important to understand that
there is a difference between "Do not" and "Should not".
Statements with "do not" are very specific prohibitions against
doing something (and the label is a legal document). Other
statements that may contain wording like "should not, is not
recommended, or avoid" are precautions and are generally
intended to protect the manufacturer because there is a risk of
severe crop injury.
The statement "Do not use nitrogen fertilizer as spray
carriers" on the Option label is a very specific prohibition
because of the risk of severe crop injury. However, the
statement "Avoid spraying in gusty conditions" is a very wise
recommendation, but not a prohibition.
Some labels may seem to contradict each other, but they may
be outlining the options available. The Basis Gold label states
that Basis Gold "may cause unacceptable injury" if applied after
a T-band or surface band application of Counter CR on soils with
less than 4% organic matter. This is a recommendation and allows
the practice, but means that DuPont will not be responsible if
injury occurs. In this case, BASF is less concerned about the
injury and produced a supplemental label for Counter CR that
states it is okay to use a banded application of Counter CR and
follow it with Basis Gold on soils with greater than 1.5%
organic matter. There are many other examples where one label
has a precaution and a second label allows the practice (ie.
tank mix, sequential use, etc). These are legal options because
the first label did not prohibit the practice, but merely
recommended against it.
There are certainly many other confusing statements on
labels, but most of them can be understood with little common
sense. If you are stumped by the meaning of an important label
statement, contact the manufacturer for clarification.
June 2002 |
