Immediately after drilling a pre-emergent herbicide (eg; Nortron) should be applied. Norton should be mixed with glyphosate to remove any already emerged weeds. Nortron will suppress weed germination through the beet germination period reducing the weed pressure through the early crop development stage.
The effect of a Nortron spray miss at the pre-emergence application is clearly obvious in the photo below.
After the crop has emerged the use of post emergence selective herbicides is required to remove germinated weeds and also provide some residual control. Usually two to three post emergence herbicide applications are required through to the crop covering in. Once the crop has covered and reached canopy closure it can outcompete and suppress further weed competition.
Post emergence herbicides in beet are based around Betanal products (eg; Betanal Quattro, Betanal Forte) with further tank mix partners used as required.
Spray Timing is Critical
Ideally start post emergence applications as early as possible. This allows targeting of smaller actively growing weeds (cotyledon – 2 leaves) that are more easily controlled at lower rates. Lower rates are also safer to the beet crop and are less likely to check the growth of the crop. Delaying application, allowing the weeds to become too large will require higher herbicide rates and may result in only partial control. Post emergence applications also need to be timed to critical beet growth stages.