Valent USA is promoting Valor for enhanced burn-down of tough broadleaf weeds when applied in a tankmix with glyphosate products prior to planting soybeans. At higher rates, it provides residual control of important broadleaf weeds and suppresses some grasses.

Its utility as a burn-down partner has been recognized by Monsanto, which has included Valor as an approved burn-down tankmix partner with Roundup UltraMax through the Roundup Rewards program, says market segment manager Shinsuke Shojima.

The active ingredient in Valor is flumioxazin, a protoporphyrinogen oxidase (PPO) inhibitor. Valor's residual control takes hold on susceptible weeds shortly after they emerge, when cell membranes are disrupted, resulting in rapid weed death.

Valor can be applied at rates of up to 3 oz./acre. At 1 oz., it enhances burn-down of glyphosate products and provides soil-residual suppression of susceptible weeds. At 2 oz./acre, its residual control spectrum includes seedling dandelion, common lambsquarters, mare's tail, horseweed, eastern black nightshade, pigweeds and shepherd's purse. The 2.5-oz./acre rate adds common ragweed and waterhemp control. Additional weeds that are suppressed at 2.5 to 3 oz./acre include giant ragweed, smartweeds, velvetleaf, large crabgrass, barnyard grass, giant foxtail and fall panicum. Control at specific rates is affected by soil organic matter and texture. “You can expect four to six weeks of residual control of susceptible weeds, depending on soil characteristics and application rates,” Shojima says.

Soybeans can be planted immediately after Valor is applied. The rotation interval for other field crops is a year or less. Alfalfa, canola, oats, sugar beets and other crops not specifically addressed on the label can be planted in 12 months if a soil bioassay is negative.

Valor is formulated as a water-dispersible granule containing 51% active ingredient and is available in 5-lb. packages.

Cost to growers is about $5/oz. for Valor.

Steadfast, from DuPont, offers a one-two contact and residual grass-control punch to control tough grasses such as woolly cupgrass, sandbur, barnyardgrass, quackgrass, shattercane and johnsongrass. It also controls certain broadleaf weeds, including Powell amaranth, jimsonweed, annual morningglory, redroot pigweed, Pennsylvania smartweed, common sunflower and wild mustard. Available in limited quantities in 2001, supplies were concentrated heavily on the northern and western edges of the Corn Belt, where total postemergence weed control programs are strongest. DuPont plans to significantly increase product availability in 2002.

Steadfast's active ingredients — nicosulfuron and rimsulfuron — are among the ingredients in DuPont's Accent Gold and Basis Gold. Steadfast contains a 2:1 ratio of the two actives (compared to a 1:1) to boost its contact power.

The recommended use rate for Steadfast is 3/4 oz./acre and typically costs the grower about $15/acre. To help assure accuracy when mixing, retailers will dispense the herbicide from a highly accurate (± 0.1 oz.) bulk unit into jugs that hold up to 64 oz., enough for 85 acres. Jugs come with measuring cones, or dealers can custom-fill jugs to match growers' needs, says corn product manager Brian Kjergaard.

Steadfast is labeled for tank-mixing with a wide range of broadleaf herbicides, including atrazine, Clarity, Distinct, Hornet and Marksman. Callisto is expected to be on the mix list by the 2002 season, pending EPA approval. DuPont recommends applying Steadfast three to five weeks after planting, when grasses and broadleaf weeds are 1 to 3 in. tall. Controlling grasses early reduces competition for moisture and nutrients. Rainfall to activate the herbicide's residual control is also more likely at that time, Kjergaard says.

Most field crops can be planted the year after Steadfast is applied. However, sugar beets cannot be planted for 18 months. DuPont will market DPX79406, an unnamed, but labeled, herbicide containing the same amount of rimsulfuron, but less nicosulfuron, to growers in rotation-sensitive geographics.

Ponder these stats from Jess Lowenberg-DeBoer, director, site- specific management center, Purdue University.

• In 2000, 38% of all dealers offered soil sampling with GPS, mostly 2.5-acre grids.

• Computer-controlled variable-rate application services were provided by 33%.

• In the Midwest, more than 50% of dealerships offered the above services.

• From fall 1999 to spring 2000 the use of GPS guidance by custom applicators grew from about 5% to more than 24%. Growth was strongest in the Midwest.

• A 2000-acre grain farm purchasing a yield monitor and GPS for $7,000 can pay for it in the first year if the resulting data leads to choosing better corn and soybean varieties that add 1 bushel per acre to overall yield.

• A review of 108 articles in the trade press found that 63% reported profits from using precision agriculture technology. However, when Lowenberg-DeBoer and a colleague reviewed eight studies of variable-rate fertilizer, they found that when benefits were recalculated using standard budget methods, only variable-rate nitrogen on sugar beets consistently showed profits.

To help understand tech terms, he defines site-specific management as doing the right thing at the right place at the right time. Precision agriculture automates site-specific management using computers, sensors and other electronics.

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