Weed control strategy
Weed control strategy
CONTROL of competitive weeds after maize seedling emergence is crucial for ensuring high yields, according to a three-year study by the Maize Growers Association.
When growers fail to control weeds for the first 40 days post-emergence, trial results show yields can be reduced by an average of 40%, explains Garth Bretherton of chemical suppliers Syngenta.
A 100% control of key maize weeds, including orache, black nightshade, volunteer oilseed rape and nettle, was achieved in MGA trials.
Pre-emergence Gesaprim (atrazine), followed by Jester (prosulfuron and bromoxynil) and Gesaprim at the two to four leaf stage was used.
"This combination provides growers with greater flexibility for tricky field situations, soil types and soil moisture," adds Mr Bretherton.
But maize herbicides must be applied differently to ensure optimum coverage, warns Syngenta application specialist Tom Robinson.
"It is best to use low-drift nozzles producing big droplets, which fall directly to the target, when applying pre-emergence applications to bare ground.
"Once the crop emerges, the broad leaves of maize plants provide emerging weeds with shelter from herbicide applications. Therefore, to ensure good coverage of herbicide, switch to 110í flat fan jet nozzles which will apply a medium to fine spray," advises Mr Robinson. *