Weed control in potato crops, May 2019

Most weed control is based around conventional chemistry of a basic residual + contact combination.  Products can be mixed and rates matched according to the weed spectrum.
Timing is everything with potato weed control with the aim being to control the weeds before the crop starts to emerge. After the recent wet spell, weeds will germinate rapidly in the warm moist soils. If conditions remain moist soon after the beds have settled then it may be worth applying the residual product while holding back the contact element until just before crop emergence. This would be preferable to allowing the beds to dry up which would reduce the effectiveness of later applied residuals. If the beds remain dry after planting then hold off and hope to apply the whole mix onto a moist bed 2-3 days before crop emergence – this is the ideal. It does mean that regular digs across crops are required to see how close the crop is to emergence.