Growers can protect their crop marketing options and keep markets open for everyone by following the label at all points in the season. Applying crop protection products or desiccants without following label directions may result in unacceptable residue levels that exceed established maximum residue limits (MRLs).

Following the label includes:

  • Using a product only on the crops it is registered for.
  • Correctly timing the application.
  • Strictly adhering to the pre-harvest interval (PHI).

Also known as the spray to swath interval, the PHI outlines the number of days that must pass between the application of any crop protection product and cutting the crop by either swathing or straight-cutting.

PHIs can vary greatly between products – from as little as one day to up to 60 days – so it is important growers are aware of the PHI for each product they intend to spray and understand the implications it has on harvest timing.

Pre-harvest intervals are set to ensure a product’s active ingredient has enough time to break down in the plant and not leave unacceptable residues behind. Because breakdown occurs in the plant only, not in the seed, storage time after cutting the crop will not decrease residue levels.

If a grower’s spray window was condensed due to late planting, or if their crop is facing a late-season threat as cutting approaches, it is crucial growers stick to the PHI to avoid leaving unacceptable residues and keep their crops ready for markets while working to meet harvest goals.

As fields get closer to cutting, pesticide choices become more limited, based on the PHI. To help time applications, canola growers can visit, an interactive interval tracking tool. Growers can enter the product they sprayed to see how many days they must wait to cut after application, or, they can enter a planned cutting date to find a product that is still safe to apply. can also sync with the calendar on a grower’s smartphone so they always have this reference available in the field.