ISSUE #439 Last Chance at Weeds and Insects

The month of June provides the last window of opportunity to control weeds and apply insecticides to eliminate competition. Careful consideration of how best to use layby herbicides to maximize weed control and profitability has to be made very soon. Earliest planted fields may already have layby herbicides applied. Contact your agriculturist for assistance with layby use decisions.

Herbicides Registered Are:

Outlook, Dual, Treflan

Treflan Very low cost Beet injury can be severe if prolonged cool, wet weather right after use.
Better weed control spectrum. Needs immediate incorporation.
Outlook Less rain needed for activation than Dual. Needs rain to activate
Longer half-life than Dual May cause beet injury if applied to early
No immediate incorporation needed.  
Less injury potential than Treflan.  
Dual Less injury potential than Treflan. Shorter half-life.
No immediate incorporation needed. May cause beet injury if applied too early.
  Needs more rain than Outlook for activation.


Where Layby Herbicides Most Needed:

  • Fields with poor stands
  • Fields with very high pigweed populations
  • See 2002 photo above

Tips for Layby Product Use:

  • The larger the beet growth stage at application the less the injury risk with Dual and Outlook.
  • Best weed control occurs with rainfall soon after application.
  • Early Dual and Outlook application increases chances for adequate rainfall for activation.
  • Post emergence microrate or conventional rate herbicide applications following layby use almost always improve total weed control (especially if no rain for 1, 2 or 3 weeks after layby use).
  • Very early layby use may result in reduced control of late emerging pigweed species as product degradation occurs.
  • Layby herbicide applications should be delayed until the full 4 to early 6 leaf beet stage - if the beets have had stand loss and injury from a previous soil applied herbicide application.
  • Rotary hoeing or other incorporation may improve Dual and Outlook performance if there is no rainfall for 5-7 days after application.
  • CAUTION: Layby applications DO NOT control emerged weeds.

Level of weed control is very dependent on timely and adequate rainfall for herbicide activation of Dual and Outlook.

Root Maggot Emergence and Control:

Root maggot fly emergence began last week. Peak fly emergence is predicted to be about June 8th by NDSU Entomologists. Mark Boetel, North Dakota State University and Ian McCrae at the University of Minnesota Crookston Research and Outreach Center are monitoring fly emergence and populations again in 2003.

Root Maggot Control:

  • Refer to the Sugarbeet Pocket Production Guide for insecticide recommendations.