Burndown Herbicide Programs and Weed Potential of Cover Crops
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Transcript of Burndown Herbicide Programs and Weed Potential of Cover Crops
Burndown Herbicide Programs and Weed Potential of Cover Crops
Rich HoormannEC Region Agronomist
Cover Crops and Weed Potential
• Rye• Wheat • Oats• Red clover• White clover• Lespedeza• Medics• Crimson clover• Other legumes
• Hairy vetch• Rape• Radish• Turnips• Winter peas• Brassica• Annual ryegrass• Summer annual grasses• Barley
Burndown Recommendations
No-Tillage burndown
HerbicideAnnual
ryewinter wheat Alfalfa
Crimson Clover
Red Clover
Hairy Vetch
Cover Crops
2,4-D 0 0 7 8 8 9
Aim 1 0 - - - -
Aatrex 6 6 4 3 5 7
Balance Pro - - - - - -
Bavnvel/Clarity 0 0 9 8 9 9
Basis - 5 5 5 5 5
Canopy EX - 1 4 5 5 -
Distinct/Status 1 1 8 8 8 8
Glyphosate 9 9 4 3 6 6
Gromoxone Max 7 6 4 9 4 8
Sencor 9 9 4 3 5 5
Septer 4 4 3 2 5 3
Spartan - - - - - -
Valor - - - - - -
Valor XLT - 6 4 4 4 -
Purdue University: Keith D. Johnson Forage Specialist
Annual Ryegrass Control• Tillage very effective• Mowing after
bloom/before complete seed development– Variable success– Some seed may be produced
• Plastic mulch smothered– Smaller easier to control
• Michael Plumer Natural Resources Management
Annual Ryegrass• Annual ryegrass volunteers are particularly undesirable in small grains,
so special care must be taken if they are part of your rotation. It can be controlled with tillage and/or herbicides. When tilling, plow under and disk as soon as conditions permit.
• The timing of herbicide applications is important to control ryegrass. Apply glyphosate at 3 pt/ac when the grass is 6-9 inches tall, day temperatures are > 50 F and the weather is sunny.
• A second or third application may be necessary to burn down ryegrass. • Simazine can be added to the tank mix but requires rain to activate, • Atrazine should not be tank mixed with other herbicides. Apply 14-21
days after the glyphosate. Atrazine also needs rain to activate. Cornell
Annual Ryegrass Control as Influenced by Rate and Application Timing
(graph adapted from Lins et al. 2005)
A. Ryegrass Application Timing
Glyphosate Rate (lb ae/A)
Roundup PowerMax
Rate (fl ozs/A)A. Ryegrass Control (%)*
Late Tiller 0.375 11 400.75 22 591.5 44 75
Second Node 0.375 11 29
0.75 22 461.5 44 66
Boot 0.375 11 430.75 22 671.5 44 86
Early Flower 0.375 11 580.75 22 791.5 44 88
*Results summarized across 6 locations in 3 states
More Thoughts on Annual Ryegrass (Lolium multiflorum) as a Cover Crop
• For control prior to corn, I would prefer to see a burndown herbicide like glyphosate or Gramoxone applied in combination with a photosynthetic inhibitor like Atrazine or Princep
• Annual ryegrass is one of the worst weeds of wheat production in the southeastern and mid-Atlantic states.
• Glyphosate-resistant biotypes of annual ryegrass occur in Mississippi and Oregon (and other countries as well).
Competition of Ryegrass
Michael Plumer Natural Resources Management
Determine Growing Point
Timing of Burndown & Adjuvant
Purdue University: Keith D. Johnson Forage Specialist
Hairy Vetch• WORDS OF CAUTION: Hairy vetch contains many hard
seeds with 15 to 30 percent common. These hard seeds can remain in the soil for several years, then germinate to develop into unwanted plants. Vetch is an especially serious weed plant in wheat. Thus it should never be permitted to mature and set seed.
• Glyphosate alone was relatively ineffective at controlling hairy vetch in corn;
• (1) Paraquat, (2) Paraquat + 2,4-D, (3) Paraquat + dicamba, (4) Glyphosate, (5) Glyphosate + 2,4-D, (6) Glyphosate + dicamba, (7) 2,4-D, (8) Dicamba.
• California Data
Hairy Vetch control
• 2,4-D, Banvel or their mixtures should be used • Note - if hormone sensitive crops are following
the cover crop, apply hormone sprays in the fall to avoid injury. OMAFRA
Rye
• Control on time. Incorporate before seed set. May regrow if tilled before boot stage, typically early May.
• Mow in the spring after all the tillers are past the boot stage but before the plants have headed out.
• For no-till planting, roll at heading.
Wet warm spring weather can cause quick growth and make incorporation difficult. Apply glyphosate at 1 lb/ac ai. for effective control of rye. Cornell
Balance is difficult
Thanks for your time