Valtera - A New Herbicide For Identity Preserved (IP) Soybeans

With IP soybean premiums ranging from $2 to $3/bu, the control of "IP premium killing" weed species is important!

Valtera, a newly registered pre-emergent soybean herbicide manufactured by Valent provides control of:

• Eastern black nightshade, whose poisonous berries stain IP soybean seed, making the crop unmarketable;
• Lambsquarters and pigweed, two abundant weed species that have reduced soybean yields by as much as 40% when herbicide programs have failed
• Herbicide resistant populations of:
  • Eastern black nightshade (resistant to Pursuit),
  • Lambsquarters (resistant to Pursuit, Pinnacle and Sencor),
  • Pigweed (resistant to Pursuit, Pinnacle, Classic, First Rate and Sencor).

Currently Valtera is only registered for use on its own, or as a pre-plant tank-mix with glyphosate. Research conducted by the University of Guelph has shown that for a complete weed management program in IP soybeans, Valtera must be tank-mixed with either Pursuit or Conquest to control both annual grass and broadleaf weeds.

Valtera Strengths

• Eastern black nightshade, lambsquarters, pigweed species

Control of Other Weeds (according to U.S. label)

• Common and Mouse-eared chickweed, Canada fleabane

Valtera Weaknesses

• Annual Grasses (suppression only) and perennial weeds
• Cannot be applied in conventional-till soybean systems.

Mode of Action
Valtera is a group 14 herbicide (same mode of action as Reflex and Blazer).

Application Timing
Valtera must be applied before soybean emergence, either as a pre-plant or pre-emergence herbicide, from 30 days prior to planting up to three days after planting.

Use Rates and Precautions
Valtera (56 g/ac)
Valtera (56 g/ac) + glyphosate (0.67 L/ac or equivalent depending on formulation)

Crop Safety
Soybean tolerance to Valtera is maximized when the herbicide is:

• applied prior to soybean planting,
• applied to medium or heavy textured soils,
• applied to minimum tillage cropping systems.

In 2008 research trials, there was significantly more crop injury when Valtera was applied to conventionally tilled soybeans compared to no-till soybeans (Table 1). Soybean yields were not affected by the increase in observed crop injury.

Table 1. Soybean visual injury 3 weeks after the applications of Pursuit + Valtera* and Cleansweep

Where Does Valtera Have the Greatest Fit?
2008 University of Guelph research trials showed that Valtera improved weed control and soybean yields (Table 2) compared to other standard herbicide programs when the weed populations consisted of herbicide resistant weeds such as:

• Lambsquarters (LQ), Sencor resistant
• Redroot pigweed (RRPW) - Pursuit, Pinnacle, Classic and FirstRate resistant

Experimental tank-mix used and rates included:

• Pursuit (168 ml/ac) + Valtera (56 g/ac)
• Conquest A (230 g/ac) + Conquest B (43 g/ac) + Valtera (56 g/ac)

Table 2. Soybean yield and control of annual grass and herbicide resistant annual broadleaf weeds with Valtera tank-mixes compared to other standard herbicide programs

Woodstock, ON, 2008 (Dr. François Tardif, U of G)
GFT = Green foxtail, HCG = Hairy crab grass
*Experimental treatments - not currently registered

Figure 1. Dual + Sencor (Woodstock, ON - 2008)

Figure 2. Cleansweep (Woodstock, ON - 2008)

Figure 3. Pursuit + Valtera* (Woodstock, ON - 2008)
*Experimental treatment - not currently registered

What About Ragweed?

Valtera alone will only suppress common ragweed and will not control giant ragweed. Valtera tank-mixed with either Pursuit or Conquest will increase the control of common ragweed compared to either one of those herbicides on their own. To put things into perspective, at Ridgetown in 2008, Broadstrike Dual Magnum controlled common ragweed the best (refer to Table 3). Conquest + Valtera gave comparable control. If you have used Broadstrike Dual Magnum in the past and were happy with its control of common ragweed, Conquest + Valtera should offer similar control.

Table 3. Control of common ragweed (% visual control) and soybean yield (bu/ac) in 2008 with different soybean herbicide treatments

Location: Ridgetown, ON, 2008
(Dr. Peter Sikkema, U of G)
*Experimental treatment - not currently registered

For more information:
www.valent.com/canada