INTERACTIONS BETWEEN SEED DEPTH, THICKNESS OF TRASH BLANKET AND HERBICIDE TREATMENTS ON EMERGENCE OF VINE WEEDS IN SUGARCANE

By A. GAUNGOO, S. SEERUTTUN and C. BARBE 
Mauritius Sugar Industry Research Institute, Réduit, Mauritius
sseeruttun@msiri.intnet.mu

Abstract

VINE weeds are appearing more frequently in sugarcane fields, particularly with the
increasing adoption of green cane trash blanketing (GCTB). Current control measures are not
effectively providing adequate control of these weeds.

A project to develop strategies for managing vine weeds has been initiated and
included three trials studying the factors influencing emergence of three Ipomoeaspecies
sown in trays. In the first trial, seeds of I. trilobaand I. obscurawere found to emerge at
depths beyond 8 cm while germination of I. nilwas reduced at seed depths greater than 4 cm.
In the second trial, emergence of the three vine species was found to be unaffected by
a trash layer of 5 cm whereas a significant reduction was observed as trash thickness was
increased to 10 cm. An interaction between depth of the vine seed and thickness of trash layer
was also noted; i.e. emergence of seeds at depths between 2 and 4 cm was reduced by more
than 75% when covered by a trash layer of 10 cm.

In the third trial, six pre-emergence herbicide treatments namely atrazine, atrazine +
hexazinone, sulfentrazone, amicarbazone, trifloxysulfuron + ametryn, and diclosulam were
tested for their efficacy against I. trilobasown at soil depths of 2, 6 and 10 cm. At 6 weeks
after spraying (WAS), irrespective of seeddepth, all herbicide treatments provided
satisfactory control. The interaction betweenherbicide treatment and seed depth was
significant at 12 WAS; irrespective of sowing depths, only sulfentrazone provided less than
5% germination over a period of 18 WAS.

These results indicate that both thickness of the trash layer and choice of the
herbicide treatment should be taken into consideration in the development of strategies to
control vines in sugarcane under GCTB.

www.issct.org
Agronomy - Proc. Int. Soc. Sugar Cane Technol., Vol. 27, 2010
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