WEED CONTROL

Herbicide Residue

Permit (halosulfuron) may have a residue the year following
application to corn. Permit is a medium to long residue
sulfonylurea herbicide (SU) and is affected by many of the same
factors for breakdown as other long residual SU (see Finesse in
this section of the guide), except soil pH. Permit breakdown in
soil increases as soil pH increases (alkaline hydrolysis) while
other SU herbicides degrade more slowly with high pH. However,
Permit is affected to the same degree by soil temperature and
soil moisture as the other long residual SU herbicides.
Rotational crop restrictions for Permit 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 other than those
indicated on the label.