Early treatment is recommended in cases where leaf stages of the weed are not indicated. Where a range of rates is given, the low rate should be used for weed control on low organic matter soils and sandy soils. Similarly, if a range is given for post-emergence herbicides, the lower rate should be used for light infestations and good growing conditions. Herbigation Herbigation is one method of herbicide application currently used by a limited number of growers in Manitoba. Herbigation is the process of applying a herbicide to the soil or plant surface by injecting the chemical into the irrigation water.
Some herbicides are more effective if applied with irrigation water.
This is especially true for pre-emergence herbicides that require moisture to be activated. Not all herbicides that are registered for use on potatoes are registered for herbigation. Consult the chemical manufacturer or your local agricultural representative before herbigating. The amount of irrigation water required to incorporate the herbicide will depend upon the water holding capacity of the soil, soil moisture status at the time of herbigation and the desired incorporation depth. Always read product labels before applying herbicides.