WEED CONTROL

Herbicide Residue

Finesse (chlorsulfuron + metsulfuron) at 2/10 to 3/10 oz
product/A may carryover in soil for more than three crop years.
Finesse breakdown in the soil is affected soil pH, soil
temperature, soil microorganisms, and soil moisture. Low soil pH,
high soil temperature, and high soil moisture increases Finesse
breakdown in the soil. Of these three factors, only soil pH
remain relatively constant, but can have the greatest effect on
rate of breakdown in the soil. The rate of Finesse breakdown
increases as soil pH decreases. Finesse should not be applied to
soils with a pH above 7.9 because pH over 7.9 can cause
phytotoxic herbicide resisdues for an unacceptable length of
time. Also, Finesse carryover in soils with a pH greater than 7.9
can injure wheat and barley and other crops planted in rotation
can be extremely sensitive to very low concentrations of Finesse. 

Soil temperature, and to a greater extent, soil moisture, can
vary significantly from year to year and from area to area. For
this reason, soil temperature and soil moisture should be
monitored regularly when considering rotating to other crops.
Rotational crop restrictions for Finesse are found on page 64 of
the 1996 North Dakota Weed Control Guide in the table, "Rotation
Restrictions for Crops Grown in North Dakota". A field bioassy
MUST BE completed before rotating to any crop except HRS and
durum wheat, barley, oat, rye, and triticale. A Laboratory Recrop
Bioassay (LRB) service previously offered by DuPont is no longer
available in North Dakota.