Posts Tagged ‘small grain weed control’

Small Grain Weed Control

Friday, March 11th, 2011

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Be sure to read the herbicide label carefully because some products can be tankmixed with nitrogen but only if the nitrogen is no more than 50% of the spray solution (nitrogen is mixed 1:1 with water). A few specifics:

● Osprey cannot be applied within 14 days of nitrogen application

● Harmony Extra can be applied with nitrogen, but use of surfactant differs depending on concentration of nitrogen and targeted weed species

● Axial XL and PowerFlex can only be applied with nitrogen if it is mixed 1:1 with water; also PowerFlex cannot be applied with nitrogen if the amount is more than 30 lbs of N/A

Axial XL and PowerFlex are two herbicides that are effective on annual ryegrass. Both of these can be double-cropped with soybeans. However, PowerFlex will injure vegetables planted after harvest.

There are reports of fields with poor chickweed control due to resistance to Harmony, Harmony Extra, or Finesse. If you are in that situation, your alternatives are quite limited. Most other small grain herbicides do not provide acceptable chickweed control. One product to suggest is Starane Ultra (from Dow AgroSciences). This product is labeled for wheat and barley and has good crop safety and fair to good chickweed control. However, it will not control other key species such as wild garlic. Starane Ultra can be tankmixed with Harmony Extra to broaden the spectrum of control. Starane Utra by itself does not need an adjuvant and can be applied in nitrogen. Be sure to read and follow label directions.

Finally, a reminder on timing restrictions for small grain herbicides. The timing restrictions are based on crop safety.

2,4-D – up to jointing stage (pre-jointing)

Banvel/Clarity – up to jointing stage (pre-jointing)

Osprey – up to jointing stage

Buctril – up to boot stage

Harmony Extra or Harmony GT – up to flag stage (pre-flag leaf)

Starane Ultra – up to flag leaf emergence

PowerFlex – jointing

Axial XL – prior to boot

Reducing Weed Seed Production in Harvested Fields and Non-Cropped Areas

Friday, August 20th, 2010

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Many annual and some perennial weeds are beginning to flower now, particularly those that emerged early in the summer. Removing now the flowering portions of the plant or seed heads will prevent most of these plants from producing mature seed. If these plants are mowed off, they are likely to regrow and eventually produce seed, but the quantity of seed produced will be dramatically reduced. Many of these fields will need at least one additional mowing to prevent seed production. However, delaying a mowing for a few weeks will allow a greater proportion of the developing seeds to mature and contribute to the seedbank. Another option is a herbicide treatment, however few herbicides will kill these large weeds. Glyphosate is one option, but be sure to match the herbicide rate with size and stage of the weeds.

Small Grain Weed Control

Thursday, March 4th, 2010

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

The current weather is forcing us to do things different than we normally do. One issue to keep in mind is the herbicide and nitrogen restrictions. Be sure to read the herbicide label carefully because some products can be tankmixed with nitrogen but only if the nitrogen is no more than 50% of the spray solution (nitrogen is mixed 1:1 with water). A few specifics:

  ● Osprey cannot be applied within 14 days of nitrogen application.

  ● Harmony Extra can be applied with nitrogen, but use of surfactant differs depending on concentration of nitrogen and targeted weed species.

  ● Axial XL and PowerFlex can only be applied with nitrogen if it is mixed 1:1 with water; also PowerFlex cannot be applied with nitrogen if the amount is more than 30 lbs of N/A.

Axial XL and PowerFlex are two herbicides that are effective on annual ryegrass. Both of these can be double-cropped with soybeans. However, PowerFlex will injure vegetables planted after harvest.

There are reports of fields with poor chickweed control due to resistance to Harmony, Harmony Extra, or Finesse. If you are in that situation your alternatives are quite limited. Other small grain herbicides that we are familiar with do not provide acceptable chickweed control. One product to suggest is Starane Ultra (from Dow AgroSciences). This product is labeled for wheat and barley and has been used in the western US for control of Group 2 resistant weeds. Local data is limited, but in our trials it has good crop safety and good chickweed control. However, it will not control other key species such as wild garlic. Starane Ultra can be tankmixed with Harmony Extra to broaden the spectrum of control. Starane Utra by itself does not need an adjuvant and can be applied in nitrogen. Be sure to read and follow label directions.

Finally, some reminders on timing restrictions for small grain herbicides — the timing restrictions are based on crop safety.

2,4-D: up to jointing stage (pre-jointing)
Banvel/Clarity: up to jointing stage (pre-jointing)
Osprey: up to jointing stage
Buctril: up to boot stage
Harmony Extra or Harmony GT: up to flag stage (pre-flag leaf)
Starane Ultra: up to flag leaf emergence
PowerFlex: jointing
Axial XL: prior to boot

Preplant Weed Control in No-Till Small Grains

Friday, September 18th, 2009

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

No-till small grains require a weed-free seedbed for best results. A weed-free seedbed results in warmer soils and less early competition for light and nutrients. Non-selective herbicides labeled for this use are glyphosate (various formulations) or Gramoxone Inteon. Apply a non-selective (or “burndown”) herbicide at least 7 to 10 days prior to planting. This is especially important when planting into fields where grassy weeds or perennial weeds are problems. Glyphosate is the preferred product if the field has a history of grassy weeds (annual bluegrass, ryegrass, etc.) or if perennial weeds (horsenettle, yellow nutsedge, hemp dogbane, etc.) are presented.

Additional herbicides for use with Gramoxone Inteon or glyphosate include:

Dicamba (Banvel) can be applied at 2 to 4 oz/A with the burndown. There are no planting restrictions with this low rate of Banvel. Otherwise, the interval is 1.25 days per 1 ounce of product; this is 20 days for 1 pint.

Valor SX has a label for tankmixing with a non-selective herbicide to provide residual weed control. A minimum of 30 days must pass, and 1 inch of rain/irrigation must occur, between Valor application and planting winter wheat. Labeled rate is 1 to 2 oz/A.

2,4-D: most 2,4-D products are not labeled for use prior to planting small grains. So be sure to read the label of the specific 2,4-D product you plan to use.

Concerns with Some Chickweed Populations

Friday, March 6th, 2009

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Scott Hagood, extension weed specialist from VA Tech, has identified four fields from Virginia (across the bay) that had common chickweed that was resistant to Group 2 herbicides (this includes Harmony, Harmony Extra, Finesse, and others). Likewise, we have had reports of fields on Delmarva with chickweed populations not controlled with Finesse or Harmony Extra. We are investigating this in the greenhouse and have no answers yet as to why the chickweed was not controlled.

However, if you have fields with poor chickweed control and do not feel Harmony or Harmony Extra are performing as they should, your alternatives are quite limited. Other small grain herbicides that we are familiar with do not provide acceptable chickweed control. One product to suggest is Starane Ultra (from Dow AgroSciences). This product is labeled for wheat and barley and has been used in the western US for control of Group 2 resistant weeds. Local data is lacking on its performance, but it appears to have good crop safety and good chickweed control. However, it will not control other key species such as wild garlic. Starane Ultra can be tankmixed with Harmony Extra to broaden the spectrum of control. Starane Utra by itself does not need an adjuvant and can be applied in nitrogen. Be sure to read and follow label directions.

Small Grain Weed Control

Friday, March 6th, 2009

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

If you did treat your fields in the fall for weed control, is time to be scouting the crop. Weed control is important to achieve maximum wheat yields. There are a number of good herbicides for small grains, provided they are used at the proper timing. Weeds need to be small (less than 2 inches in height or diameter) and actively growing. This often requires a separate application for herbicides since this often does not coincide with nitrogen applications. Often weeds are not actively growing during the first nitrogen application and then weeds are too large (and wheat interferes with herbicide coverage) at time of the second nitrogen application.

Fields that were no-tilled or where chickweed emerged shortly after planting in the fall are fields to check first for spring treatment. If you have wild garlic or Canada thistle, the time of application should be delayed since you need to spray these weeds when they have fully emerged. Yet, coverage is important for these species; so allow adequate emergence, but do not wait too long. If weed pressure from winter annuals is great, it may not be possible to get control of the winter annuals and perennials with one application. In that case, two applications may be required.

Harmony Extra can be applied with nitrogen. If spraying Harmony Extra with nitrogen, be sure to pre-mix it in water first. If using nitrogen as your carrier, there is no need for a surfactant unless you have wild garlic and it is over 8 inches tall. If applying Harmony Extra in nitrogen diluted with water, use a non-ionic surfactant at ½ to 1 pint/100 gallons of solution. If applying it in water use a non-ionic surfactant at 1 qt/100 gallons.

There are various formulations of Harmony and Harmony Xtra as well as generic brands. Be sure to read the label so you have the correct rate. Also, remember the TotSol Formulation from DuPont requires extensive mixing to fully dissolve the granules.

Grass control in small grains is still challenging, even with a few new products. Hoelon is the only product labeled for grass control in barley, and it will only control annual ryegrass before it is more than 2 tillers. For winter wheat, Osprey is also available. Fall will be a better time for Osprey applications, but it will control annual ryegrass in the early spring. Osprey cannot be applied with nitrogen carrier and the Osprey application and nitrogen application must be made 14 days apart. Spray solution can not be any more than 15% liquid nitrogen. Osprey has activity on small annual bluegrass. If Osprey does not fit into your situation because of the nitrogen applications, Axial XL has shown good results with spring applications. However, Axial XL will not control other grass species.

Finally, the following are the timing limitations for small grain herbicides. The timing restrictions are based on crop safety.

● 2,4-D – up to jointing stage (pre-jointing)
● Banvel/Clarity – up to jointing stage (pre-jointing)
● Osprey – up to jointing stage
● Buctril – up to boot stage
● Harmony Extra or Harmony GT – up to flag stage (pre-flag leaf)

Volunteer Rye Cannot Be Controlled in Small Grains

Friday, September 19th, 2008

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

There have been a considerable number of fields with rye-strips planted for vegetables in some areas, and these fields are very convenient to plant small grains in the fall. However, keep in mind that there is no herbicide available to control volunteer rye in wheat or barley. There are a few herbicides that will control or suppress Italian (or annual) ryegrass in these crops, but they will not control grain rye used for wind breaks. Therefore, if the windbreaks were allowed to produce seed this year, you can expect the rye to act as a competitive weed in your small grains. Rye seeds generally germinate the same year they are produced, so it is not a long-term problem. However, it can be an issue if you planted rye strips last fall and then plant small grains this fall.

Be Sure to Use a Burndown with No-Till Small Grains

Friday, September 19th, 2008

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

More and more fields are being planted as no-till small grains. These fields need a non-selective herbicide prior to emergence (either Gramoxone or glyphosate). Too often, these fields look ‘clean’ at planting time but numerous weeds have emerged and are quite small. These weeds are much easier to control prior to planting than later. Harmony GT or Harmony Extra are not replacements for these non-selective herbicides.

Osprey Winter Wheat – Best Suited for Fall Applications

Friday, September 19th, 2008

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Osprey is registered for grass weeds in winter wheat, including annual ryegrass and annual blue grass. Osprey also controls a number of broadleaf weeds that are common in our area. Osprey is not labeled for barley. Osprey is used at 4.75 oz wt/A. Application timing is emergence to jointing of wheat or 2 leaf to 2-tiller grasses. Osprey requires a non-ionic surfactant plus nitrogen. Fertilizer nitrogen (28 to 32% N solutions) should be used at 1 to 2 qt/A. Ammonium sulfate (AMS) can be used at 1.5 to 3 lb/A. Osprey can be applied with methylated seed oil. Osprey should not be applied with crop oils or silicone based surfactants. Osprey is not labeled for use with liquid fertilizer carriers. The label states that liquid fertilizer solutions should be no more than 15% of the spray carrier volume. Nitrogen fertilizer greater than 15% of the spray volume should not be applied within 14 days of the Osprey application, which makes timing of spring applications difficult. As a result, fall applications are more appropriate than spring. Osprey can be tankmixed with a Harmony GT and Harmony Extra (as well as other herbicides), but tankmixtures with Banvel/Clarity or 2,4-D may reduce grass control. The grasses specifically mentioned on the label that are important in our region are annual ryegrass (it will not control volunteer grain rye), annual bluegrass, and roughstalk bluegrass. The label lists brome species as suppression. Broadleaf activity is good on wild radish and wild mustard plus suppression of henbit and common chickweed. UD has tested Osprey for ryegrass the past two to three years with favorable results. Soybeans can be planted 90 days after treatment and refer to the label for other crops.

New Formulations/Confusion for Small Grain Herbicides

Wednesday, March 26th, 2008

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Remember the good old days when someone said they used “Harmony” on their wheat and you knew exactly what they meant. Then came Harmony Extra, Harmony GT, followed by Harmony Extra XP and Harmony GT XP. Now there is Harmony Extra SG with TotalSol and Harmony SG with TotalSol. These are new soluble granule (SG) formulations with 50% active ingredient. Granules are supposed to fully dissolve and solution will appear relatively clear. It appears to take longer to go into solution than the previous formulations, so if mixing in a 5-gallon bucket before adding to nitrogen carrier, it may take up to 10 minutes of constant stirring if the water is cold. Use patterns have not changed with the new formulation, but the concentration of the product has.

Harmony Extra 50SG with TotalSol is DuPont’s new formulation for the combination of thifensulfuron and tribenuron. The “old” Harmony Extra XP formulation was 75% active ingredient and the new Harmony Extra SG is a 50% active ingredient, so the SG formulation requires more product to get the same active ingredient. (0.6 oz/A Harmony Extra SG TotalSol = 0.4 oz/A Harmony Extra XP). The use pattern has not changed with the SG formulation. (more…)