Vol. 54—2000 - NorthEastern Weed Science Society

WEED CONTROL IN SWEET CORN WITH CARFENTRAZONE
M.J. VanGessel, Q. Johnson, and M. Mahoney'
ABSTRACT
Sweet com (Zea mays) growers could benefit from the availability of a POST herbicide
that improves overall weed control, but not limit crop rotation. The development of
PPO-inhibitors in field corn (Zea mays) may provide some new options for sweet com
as well. There is interest in labeling carfentrazone for use in sweet com. Studies were
conducted to evaluate the potential for carfentrazone use in sweet corn.
Carfentrazone was compared with other PPO-inhibitors, CGA-24B757 and flumiclorac.
Field studies were conducted in 199B and 1999 at the University of Delaware's
Research and Education Center. In 199B, carfentrazone, CGA-24B757, and flumiclorac
were applied alone and in combination with 2,4-0. In 1999, carfentrazone, CGA­
24B757, and flumiclorac were also applied in combination with atrazine. 'Bonus' was
the sweet com variety in 199B. To evaluate crop tolerance, in 1999 four sweet com
varieties were used. 'Bonus' and 'Steriing' are both processing varieties and 'Cotton
Candy' and 'Alpine' are both fresh market varieties. Each variety was planted in
separate rows of four row plots. Treatments were applied at V-5 com stage in 199B
and V-3 stage in 1999.
Injury was more noticeable when carfentrazone, CGA-24B757, and flumiclorac were
tank-mixed with 2,4-0 or carfentrazone was applied with atrazine, compared to these
herbicides applied alone. Weed control was improved when either of the PPOinhibitors
was tank-mixed with 2,4-0 or atrazine compared to these herbicides alone.
Cotton Candy was more tolerant to the PPP-inhibitors than the other varieties.
While carfentrazone or other PPO-inhibitors tested are not broad spectrum enough,
they may have merits to supplement soil-applied herbicides. These herbicides will need
to be used as a planned approach since their effectiveness on weeds 7.5 to 10 em tall
is greatly reduced, with a few exoeptions. Furthermore, the eariy application timing will
improve weed control of those species with marginal tolerance to these herbicides.
'Assoc. Prof., Ext Assoc., University of Delaware, Georgetown, DE; and Tech.
Serv., FMC, Oxford, MD.
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