Tip 2: Always Read and Follow the Label

To prevent unacceptable pesticide residues and protect market access, always read and follow the label. Only apply products to approved crops, at the label rate and crop stage and respect the pre-harvest interval (PHI). Improper or off-label use of pesticides is illegal and may result in unacceptable residues, putting market access at risk. Use decision-support tools like the PHI Calculator, review the annual Product Advisory for market risks and contact the manufacturer if any label instruction is unclear before spraying. 

How to read a pesticide label 

Rate 

Always follow the correct application rate listed on the label and do not exceed the maximum number of applications per year. 

• MRLs are calculated using the label rate for each crop type.  

• Exceeding label rates or additional applications increase the likelihood of unacceptable residues.  

• Following the label rate reduces residue risk in harvested grain. 

Timing 
 
Apply crop protection products only at the crop stages specified on the label. 

• Applications made too early or too late can increase the risk of unacceptable residues.  

• Example: Glyphosate for pre‑harvest weed control must only be applied when grain moisture is less than 30% in the least mature areas of the field. 

• Use the Pre‑Harvest Glyphosate Staging Guide for visual confirmation of correct timing. 

Pre-Harvest Interval (PHI) 

The PHI is the minimum number of days required between the last application of a pesticide and swathing or straight‑cutting the crop. 

• PHIs provide growers with the information required to ensure residues in treated grain do not exceed MRLs. 

• PHIs can vary greatly between products, depending on the product and crop.  

• As harvest approaches, pesticide options become more limited, but PHIs must always be respected, even if your crop is facing a late-season threat. 

Before making crop management decisions: 

• Review the Product Advisory to understand market risks associated with specific product–crop combinations.  

• Canola and pulse growers can use the Keep it Clean PHI Calculator to help time applications and choose acceptable products.  

• Talk to your grain buyer to confirm acceptability for both domestic and export markets. 

Common pesticide label terms 

• Active ingredient: The chemical component that controls the pest. 

• MRL (Maximum Residue Limit): The highest level of pesticide residue legally allowed in food or feed, when a pesticide is used according to label directions. 

• Off‑label use: Any application that does not follow label directions; illegal in Canada. 

• Crop stage: The specific growth phase when a product may be applied. 

• Registrant/manufacturer: The company responsible for the product label and regulatory approval. 

Pre-Harvest Glyphosate Staging Guide

An illustrated guide to help manage pre-harvest application of glyphosate and determine when grain moisture content is less than 30% in the least mature part of the field.

Do Not Use Glufosinate-Ammonium on Pulses

There is an elevated risk of maximum residue limit (MRL) related trade disruption if glufosinate is used on pulses due to missing or very low MRLs in export markets.