Yellow Nutsedge Control
Carrot Country
Winter 2006
One of the most signifi cant weed issues facing
vegetable crop growers in California’s Antelope Valley is yellow nutsedge.
Yellow nutsedge is a very
prolifi c weed that easily outcompetes onions and carrots and can reduce yields
beyond 70 percent. There are currently no herbicides registered in onions or
carrots
for its control.
Several years back, a trial was conducted to test the effects of four herbicides:
Outlook, Dual Magnum, Basagran and Shark, at different stages of onions growth
to control yellow nutsedge.
On its Web site, the University of California Cooperative Extension reports
that
the best treatment was Outlook applied at the two-leaf onion stage. This treatment
provided at least 80 percent control of yellow nutsedge four to six weeks from
the application time. The treatment did not appear to have any effect on the
onion
growth, however yield still needs to be measured.
Goal 4F - New formulation of Oxyfluorfen
Goal 2XL has traditionally been a major onion herbicide. The active ingredient
of Goal 2XL is oxfl uorfen and is currently only available in an emulsifiable
concentrate form, which causes signifi cant injury to onions if applied before
the two
leaf stage. However, a new formulation of oxyfl uorfen, called Goal 4F, appears
to
cause less injury to the onions and can be applied at the fi rst true leaf
at low rates
while the weeds are small and easier to control. The chemical showed good results
in the fi rst year of trials (2004) in Lancaster and elsewhere in California.
Trials in
Lancaster showed good control of weeds with low onion injury at the four and
six
ounce rates applied at the fi rst true onion leaf stage. Note: Goal 4F is not
registered
for use on onions in California.
© 2006 Columbia Publishing