For cost-effective weed control in root crops, the emphasis must be placed on pre-emergence application of herbicides. Every year we receive a large number of calls from concerned growers who have applied no herbicide at all and who are concerned that their root crop is disappearing under a sea of weeds. By this point, it is usually too late to save the crop!
By planning ahead and making weed control decisions when the seed is ordered, it is possible to avoid many of the pitfalls and ensure the crop gets a good, clean start and establishes vigorously.
Residual herbicides cannot be applied to broadcast crops. For reasons of crop safety, the seed must be drilled and covered completely by settled soil. Pre-emergence applications should be made before the crop seed chits, which may occur within 48 hours of drilling, so it is important to have everything ready beforehand.
The table below summarises the products available for pre-emergence application to root crops.