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Managing the pre-harvest application of glyphosate

Use this handy staging guide to determine when grain moisture is less than 30%.

General Information

  • Where allowed, glyphosate is registered for pre-harvest weed control and is not to be used as a desiccant.
  • Pre-harvest glyphosate may only be applied when grain moisture content is less than 30% in the least mature part of the field. Applying too early can result in unacceptable product residues in the grain.
  • To avoid unacceptable residue levels, always follow the product’s label for application rate, timing and pre-harvest interval (PHI).
  • Never harvest earlier than recommended – this can increase the risk of unacceptable glyphosate residues in harvested grain.
  • When using glyphosate for pre-harvest weed control in a tank mix with other products, such as Saflufenacil (Heat), the products must still be applied when grain moisture content is less than 30% in the least mature part of the field and must also follow the PHI of the most restrictive product label.

Barley (Malt, Food and Feed)

Use the thumbnail test to determine if a kernel is ready for pre-harvest glyphosate application.
  • What To Look For: At less than 30% grain moisture, the kernel is firm and reasonable pressure from your thumbnail leaves a dent (i.e. hard dough stage).
  • Recommended Harvest: 7–14 days after pre-harvest glyphosate application.
  • Do not use: Malt barley will not be accepted by grain buyers if treated with pre-harvest glyphosate.
  • Be informed: Barley may not be accepted if treated with pre-harvest glyphosate – check with your grain buyer before applying. Strictly follow the product label guidelines to minimize scrutiny in the global market place.

Canola

Canola Pods Visual Reference
  • What To Look For: By applying pre-harvest glyphosate at 50-60% seed colour change in the least mature areas of the field, growers can be confident grain moisture will be <30% At this stage, seeds in the main stem will be:
    • Top = green, firm to roll
    • Middle = mostly brown, with some speckling
    • Bottom = completely brown/black
  • Recommended Harvest: 7–14 days after pre-harvest glyphosate application.

Chickpeas

  • What To Look (And Listen) For: Plants are yellowed with mature pods. Seeds have changed colour and detached themselves from their pods; pods rattle when shaken
  • Recommended Harvest: Minimum 7 days after pre-harvest glyphosate application.
  • Be informed: Chickpeas may not be accepted if treated with pre-harvest glyphosate. Check with your grain buyer before applying.

Dry Beans

  • What To Look (And Listen) For: 80–90% of the leaves have dropped and pod colour change (to mature colour) is 80%; upper pods are yellow and seed rattle in the lowest pods. Seeds have lost their green colour when split.
  • Recommended Harvest: Minimum 7 days after pre-harvest glyphosate application.
  • Be informed: Most dry bean dealers do not accept beans treated with pre-harvest glyphosate. Check with your grain buyer before applying.

Faba Beans

Grain moisture is greater than 30%. Leaves and lower pods start to turn yellow. Wait! It’s too early for pre-harvest glyphosate.
Lower pods are dark brown/black. Grain moisture is 30%. All plants in the field must reach this stage before applying pre-harvest glyphosate.
Most pods are dark brown/black and grain moisture is 20% or less.
  • What To Look For: Leaves are drying down and stems are green to brown in colour; lower pods are dark brown/black.
  • Recommended Harvest: Minimum 7 days after pre-harvest glyphosate application.
  • Faba beans may not be accepted if treated with pre-harvest glyphosate. Check with your grain buyer before applying

Lentils

Grain moisture is 40%. Wait! It’s too early for pre-harvest glyphosate. All the normal pods on nodes 10–13 of the main branch completely fill the pod cavity and field remains green.

Grain moisture is 30%.* 80% of the plant is yellow to brown. Seeds from the top third of the plant are fully-formed and firm; seeds from the bottom third are hard and tan-brown; pods rattle when shaken.

*All plants in the field must reach this stage before applying pre-harvest glyphosate.

Grain moisture is 20%. 90% of the pods on the plant are tan-brown.
  • What To Look (And Listen) For: 80% of the plant is yellow to brown. Seeds from the top third of the plant are fully-formed and firm; seeds from the bottom third are hard and tan-brown; pods rattle when shaken.
  • Recommended Harvest: Minimum 7 days after pre-harvest glyphosate application.
  • Be informed: Lentils may not be accepted if treated with pre-harvest glyphosate. Check with your grain buyer before applying

Oats

  • What To Look For: At <30% grain moisture, the kernel is firm and reasonable pressure from your thumbnail leaves a dent (i.e. hard dough stage).
  • Recommended Harvest: 7–14 days after pre-harvest glyphosate application.
  • Be informed: Oats may not be accepted if treated with pre-harvest glyphosate – check with your grain buyer before applying. Strictly follow the product label guidelines to minimize scrutiny in the global market place.
Use the thumbnail test to determine if a kernel is ready for pre-harvest glyphosate application.

Peas

  • What To Look (And Listen) For: Most pods (80%) are yellow/golden brown; seeds in bottom pods are detached and rattle in pod.
  • Recommended Harvest: Minimum 7 days after pre-harvest glyphosate application.
  • Be informed: Peas may not be accepted if treated with pre-harvest glyphosate. Check with your grain buyer before applying

Wheat

Use the thumbnail test to determine if a kernel is ready for pre-harvest glyphosate application.
  • What To Look For: At less than 30% grain moisture, the kernel is firm and reasonable pressure from your thumbnail leaves a dent (i.e. hard dough stage).
  • Recommended Harvest: 7–14 days after pre-harvest glyphosate application.
  • Be informed: Wheat may not be accepted if treated with pre-harvest glyphosate – check with your grain buyer before applying. Strictly follow the product label guidelines to minimize scrutiny in the global market place.

On-farm practices make a difference in protecting Canada’s reputation as a trusted supplier of high-quality canola, cereals and pulses. For current product advisories and more ways to keep your crop ready for market, visit keepitclean.ca/product-advisory.

pdf Download the Pre-Harvest Glyphosate Staging Guide (494 KB) .