524 - Weed Control Easier - Pitfalls Remain
The acreage planted to Roundup Ready® sugarbeets in 2009 will exceed 90%. Use of glyphosate resistant beets certainly makes many aspects of weed control in sugarbeets much easier. Delayed planting of all crops this spring will result in need to control weeds in all crops simultaneously increasing demands on grower's time. Many sugarbeet fields were not sprayed on time in 2008 resulting in yield loss due to crop competition.
Avoid Competition with Proper Timing
|Weed Pressure||Recommended Timing|
||2-4 leaf beets
||2 leaf beets
||Cotyledon - 2 leaf beets
Roundup Rate Selection
One rate of glyphosate does not fit all situations. Select rates based on a number of factors including the following considerations:
- Weed species present
- Environmental conditions
- Weed growth stage
- Possible weed tolerance or resistance to glyphosate
|Situation||Rate (4.5 lb/Gal Acid Equiv)|
|Small weeds, very favorable environment
|Less favorable environment or larger weeds
|Unfavorable environment, very large weeds, hard to control weed species, suspected tolerance to glyphosate
Timing the Second Application
- The label states it must be 10 days or more after the first application
- Determine if sufficient weeds have emerged
- Determine when weed size and density justify spraying
- Most second applications will be from 14 to 28 days after the initial application
Tips on Maximizing Weed Control with Roundup
- Weed control is best between 10 a.m. and 4 p.m.
- Add 8.5 to 17 lbs of AMS per 100 gallons of spray solution.
- Weed control is often better with spray volumes at the low end of the range.
- Rain within 6 hours after application may reduce weed control.
- Avoid spraying with dust on plants.
- Avoid spraying with dew on plants.
- Cool weather slows activity and time needed to kill weeds.
- Frost before application will reduce control.
- Drought slows weed growth, reduces Roundup activity.
- Delay cultivation at least 3 days after Roundup use to maximize control.
- Air temperature over 85 F during application can reduce weed control.
- Don't spray after sunset-weed control can be reduced.
Generic Glyphosate Use
Growers can legally use any generic glyphosate product labeled specifically for post emergence use on sugarbeets. If a generic glyphosate is used a grower will no longer qualify for Monsanto's reward program for other Roundup Ready® crops. Be sure to select generic rates carefully. The acid equivalent content can vary from 3.0 to 4.5 lb/gallon.
Dr. Jeff Stachler, NDSU/UM Sugarbeet Weed Specialist has identified the following generic products labeled for sugarbeet.
|3.0 Acid Equivalent||3.7 Lbs Acid Equivalent||4.5 Lbs Acid Equivalent|
|Alecto 41S Bucaneer
Genesis Extra II
Gly Star Original
Gly Star Plus
Grand Slam 4X5
Imitator Plus (MN only)
Mad Dog Plus
Meychem 41% Glyphosate
Nufarm Credit Extra
Wise Up Plus
Alecto 41 UL (MN only)
Strikeout UL (ND only)
Four Power Plus
Extra Credit 5
Duplikator 5.5 Plus (MN only)
Replant and Tech Fees
If replanting occurs contact the seed dealer that supplied the original seed to properly handle any technology fee rebates that might be necessary.
Springtails and Wireworms
Springtail and wireworm infestations have been identified in the RRV. Poncho Beta has proven effective in NDSU trials against these pests.