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Project Leader and Principal UC
Investigators
D.E. Bayer,
UC
Davis
E.
Roncoroni
J.F.
Williams
D.M.
Brandon
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New slow-release granular formulations of Ordram were the most
promising of all new herbicides evaluated this year. These included
three new "non-smelly" starch-xanthide formulations and three others
with new systems of slowing the release of Ordram from granular carriers. All gave excellent watergrass control at only three pounds active
ingredient per acre whether applied before flooding without soil incorporation or eight or 11 days after flooding.
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"New slow-release granular formulations of Ordram were
the most promising of all new herbicides evaluated this
year." |
Granular formulations of Bolero (not yet registered), Drepamon (not
yet registered) and Ordram consistently gave better control of late
watergrass than their liquid formulations after pre- or post-flood applications
at four pounds active ingredient per acre, but these were compared in a field where watergrass
was so dense that none of the treatments gave complete control. The growth of surviving weeds severely
reduced the grain yield of the short-stature, late-maturing M7 rice variety.
Most of the high-rate single and multiple applications of Ordram 10G
that were made in accordance with its new "Special Local Need" label
gave excellent control of early and late watergrasses in a good stand of
M9 rice, and none appeared to cause rice injury or other problems. Split
applications, with one at three or four pounds active ingredient per
acre before flooding and the other at three to five pounds active ingredient per acre after flooding, gave somewhat better control than when
applications were made two weeks apart after flooding. However,
single applications of Ordram 10G at four to five pounds active ingredient per acre were at least as effective as any legal split application.
The new expanded label for Ordram should provide better barnyard-grass control by allowing higher rates and repeated applications.
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"Single applications of Ordram 10G at four to five pounds active ingredient per
acre were at least as effective as any legal split application." |
Water-run applications of Bolero 8E (not yet registered) provided
extraordinary weed control. Compared with water-run Ordram 8E,
which requires continuous flooding to maintain control of watergrass
and bearded sprangletop, water-run Bolero can be followed by drainage
and flush irrigation without losing effectiveness. Water-run Bolero also
effectively controlled other weeds, including roundleaf and Eisen's
waterhyssop, ducksalad, red berry and smallflowered umbrellaplant.
Applications of Basagran when maximum foliage was exposed and
before the plants flowered, provided good control of smallflowered
umbrellaplant arid roughseeded bulrush in other studies.
Du-Ter (not yet registered) showed promise for the control of algae, but
additional research is needed to integrate its use with the use for stem rot
control and for label development and registration.
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