YOU WON'T HAVE TO bone up on new chemistries to evaluate new corn and soybean herbicides for 2005. New entrants to the corn and soybean weed-control market are either new combinations of existing active ingredients or new brands of generic herbicides.

Three new corn weed-control products are expected in 2005, plus two soybean-only brands. There also will be three switch-hitters for both corn and soybeans.

Two of the three corn-only herbicides — Lexar and Expert herbicides from Syngenta — are premixes designed for the central and southern Corn Belt. The third, WideMatch from Dow AgroSciences, is a premix niche player for the western Corn Belt.

The soybean-only herbicides — Canopy EX, from DuPont, and Sequence, from Syngenta — are premixes as well.

The three switch-hitters include two new high-load glyphosate products from Dow AgroSciences, Glyphomax XRT and Durango. The other new brand, Parallel herbicide, is a generic metolachlor (with and without a safener) from Makhteshim Agan of North America.

The new premixes are more convenient and cost less than mixing your own, says Dawn Nordby, extension weed specialist at the University of Illinois.

Among the new premixes, Lexar probably offers the biggest weed-control management change. Syngenta is promoting the herbicide, a three-way mix of atrazine, S-metolachlor and mesotrione, as a one-pass preemergence program in a market dominated by sequential treatments.

“Simplicity is the big selling point,” Nordby says. However, she cautions against relying on one-pass programs when weed pressure is heavy. “With low weed pressure it will work great,” she says. “When you have more than moderate pressure from large-seeded broadleaf weeds, control may not be adequate.”

Nordby notes that Expert (glyphosate, atrazine and S-metolachlor) and Sequence (glyphosate plus S-metolachlor), which are designed for glyphosate-resistant crops, provide additional modes of action on weeds, plus soil residual activity. Both can increase weed-control flexibility and held prevent buildup of more tolerant weed species or biotypes.

Nordby says that WideMatch, which contains the active ingredients in Starane and Stinger herbicides, will provide improved control of the troublesome western Corn Belt weed, kochia, as well as Canada thistle and several important large-seeded broadleaf weeds.

Fall-applied Canopy EX, which replaces Canopy XL, controls labeled winter annual and perennial weeds in fields to be planted in soybeans. It will offer improved control of chickweed, Nordby says.

The two new glyphosate products should perform the same as other glyphosates. Similarly, Nordby says, the new generic metolachlor should perform similarly to herbicides that contain the same metolachlor active ingredient.

Here are details on the new corn and soybean herbicides.

Corn herbicides

Over-the-top glyphosate plus Bicep II Magnum

Last year, Syngenta introduced Expert herbicide as a burndown herbicide with residual control for southern Corn Belt no-till acres. This year, the company is refocusing Expert as a one-pass early post herbicide that offers both systemic over-the-top and residual control of weeds in glyphosate-resistant corn.

Expert 4.9SC contains 2.14 lbs. of atrazine, 1.74 lbs. of S-metolachlor, 16 oz. of IPA glyphosate and 0.087 lb. of the safener benoxacor. Given the amount of atrazine in the mix, it is designed primarily for the central and southern Corn Belt.

Syngenta recommends that Expert be applied at 3 qts./acre before weeds become competitive — prior to three weeks after planting. Its soil residual control capabilities should eliminate the need for a second in-crop application of glyphosate, the company says. The burndown rate structure ranges from 2.5 to 3.75 qts./acre, depending on soil type.

Although Syngenta is promoting Expert on glyphosate-resistant corn, the company first recommends considering a weed-control system that includes a preemergence herbicide, such as its Lumax, Lexar, Bicep II Magnum or Dual II Magnum.

“You want to minimize early-season weed competition to optimize yield,” says Corey Huck of Syngenta. Applying a preemergence herbicide reduces the risk of early weed competition, although Expert can provide excellent season-long weed control when applied early.

Expert is formulated as a suspension concentrate (SC). It will be available in 220-gal. mini-bulks and in bulk.

One-pass control for the central Corn Belt

Central and southern Corn Belt corn producers who have been spiking Lumax herbicide with extra atrazine can save themselves time and money with Lexar, a new three-way premix designed for their weed-control challenges.

Lexar, from Syngenta, is a mix of atrazine, S-metolachlor and mesotrione. Lumax contains the same active ingredients but at ratios designed more for the northern Corn Belt. At a typical use rate of 3.5 qts./acre, Lexar contains 1.5 lbs./acre each of atrazine and S-metolachlor (essentially Bicep II Magnum, including the safener), plus 6.3 oz./acre of mesotrione, the active ingredient in Callisto herbicide.

“We found that a lot of our customers were adding atrazine to Lumax to improve preemergence control of giant ragweed, cocklebur, morningglory, wild sunflowers and other tough broadleaf weeds,” says Pat Steiner of Syngenta. Growers were attracted to Lumax because of mesotrione, which improves overall broadleaf control and lengthens soil residual activity, he adds.

The new premix, which provides at least six weeks of residual control, makes one-pass preemergence weed control a possibility on all but the toughest acres, Steiner says. Because it has three modes of action, it is a strong tool for managing herbicide-resistant weeds.

“If you have extremely high giant ragweed pressure, you still may want to use Bicep followed by Callisto over the top,” Steiner adds. Growers should note that the Lexar label prohibits applying Callisto over the top, so Lexar users must choose another post broadleaf product in case of weed breaks.

The optimum application timing for Lexar is preemergence. However, it may be applied from preplant through 12-in.-tall corn. To achieve broad-spectrum control, it must be applied prior to grass weed emergence, since it will not provide consistent control of emerged grasses.

It is approved for tank mixing with glyphosate herbicides, as well as Princep, AAtrex, Accent, Basis Steadfast and Warrior.

Lexar is formulated as a suspension concentrate with consistency and handling properties similar to those of Bicep II Magnum. It will be available in 2.5-gal. jugs, in mini-bulk containers and in bulk. The retail price is expected to be about $25 to $28/acre at typical use rates.

WideMatch designed for western Corn Belt

WideMatch, a premix combination of the active ingredients fluroxypyr (the active ingredient in Starane) and clopyralid (Stinger), is designed to control the calling-card weeds of the western Corn Belt: kochia, Canada thistle and wild buckwheat.

However, the postemergence herbicide also promises control of common ragweed, cocklebur, velvetleaf, wild sunflower, morningglory, venice mallow, devil's claw and marestail, says Brett Oemichen of Dow AgroSciences. The herbicide also is labeled for use in small grains, its primary market.

The herbicide is a 1:1 mix of the active ingredients. It should be applied at 1 to 1⅓ pts./acre from emergence up to and including the V5 corn growth stage.

The mix is primarily a foliar weed killer, but the clopyralid component also offers two to four weeks of residual control on much of the combo's broadleaf weed lineup, except kochia, on which the clopyralid component has no activity.

WideMatch could be a good addition to a glyphosate-resistant corn weed-control program. “There certainly are some warts and freckles in a glyphosate program, including morningglory, wild buckwheat, velvetleaf and kochia,” Oemichen says. “As you look at some of these glyphosate misses, there is a very complementary fit.”

WideMatch is available in 2.5-gal. jugs and in mini-bulk.

Corn/soybean switch-hitters

Dow AgroSciences introduces glyphosate twins

Dow AgroSciences has joined the high-load glyphosate market with the introduction of Glyphomax XRT and Durango.

The herbicides, which are virtually identical, contain 4 lbs. of acid equivalent glyphosate per gallon and have a recommended use rate of 24 oz./acre. They also contain proprietary surfactants, so no additions are necessary (with the exception of ammonium sulfate, as conditions dictate).

“From a handling efficiency standpoint, we have a 25% more concentrated product, so you cover 25% more acres in a mini-bulk,” says Nate Miller of Dow AgroSciences.

The only difference between the brands is that Glyphomax XRT includes an assurance package and Durango doesn't. The brands are priced accordingly.

The two new glyphosate brands will replace Dow AgroSciences' lower-load Glyphomax and Glyphomax Plus brands once supplies are gone. Both brands are labeled for use on glyphosate-resistant soybeans, corn, canola and cotton.

Parallel focuses on glyphosate-resistant corn

Parallel herbicide, which contains metolachlor, the active ingredient in the old Dual herbicide, is being marketed for preemergence grass and small-seeded broadleaf weed control in glyphosate-resistant corn.

Parallel's marketer, Makhteshim Agan of North America (MANA), a U.S. arm of the world's largest manufacturer of generic active ingredients, is targeting glyphosate-resistant corn to take advantage of a growing market, which made up about 18% of corn acres in 2004, says Larry Huff of MANA.

By focusing on sequential treatment programs with glyphosate, MANA also hopes to avoid controversies surrounding weed-control capabilities between generic metolachlor and Syngenta's Dual II Magnum, which contains S-metolachlor. University research shows that the s-variant of the active ingredient may provide more weed-control punch per ounce, especially under adverse environmental conditions and high weed pressures. Syngenta and Sipcam, which markets generic metolachlor, have been embroiled in a lawsuit over weed-control claims.

“University research shows that the way to maximize yield is to not let early grasses compete with corn,” Huff says. “If you know you want six to 10 weeks of grass and small-seeded broadleaf control, then apply Parallel and come back with glyphosate. Our pricing is built around this market.”

In addition to the active ingredient, metolachlor, Parallel contains benoxacor, the same safener used in Dual II Magnum. Other generic metolachlor products use another safener, dichlormid.

Parallel will be available in 2.5-gal. jugs and 220-gal. mini-bulks, as well as in bulk. A version without the safener, Parallel PCS, will be available for use in soybeans, cotton and peanuts.

Soybean herbicides

Winter weed control gets a boost

In recent years, Canopy XL tank mixed with Express herbicide has been one of the most effective fall herbicide programs for fields to be planted with soybeans.

New Canopy EX, which replaces Canopy XL, is a premix that includes tribenuron, the active ingredient in Express, plus chlorimuron, the active ingredient in Classic herbicide, also part of Canopy XL. (The second ingredient in Canopy XL is sulfentrazone, the active ingredient in Authority or Blanket.)

Canopy EX is labeled to control a broad range of winter annual and perennial weeds, including dandelion, deadnettle, henbit, pennycress and shepherd's purse. Fall applications of Canopy EX can be made immediately after harvest until freeze-up. Packaged in 5-lb. bags, it is labeled for application at rates of 1.1 to 3.3 oz./acre. It should be applied at least 45 days before planting to weeds less than 1 to 3 in. tall. For optimum burndown results, 2,4-D (LVE) is recommended.

At press time, state registrations for Canopy EX had been granted in more than 10 states, including Illinois, Indiana, Ohio, Kansas, Michigan, Missouri and Nebraska. Registrations are pending in several other states, including Iowa.

Sequence promises one-pass boost in soybeans

Sequence herbicide from Syngenta promises to turn one-pass weed control into reality for glyphosate-resistant soybeans.

The herbicide, a mix of the active ingredients in Dual Magnum and Touchdown, has been approved for over-the-top use in glyphosate-resistant soybeans for the 2005 season. The premix was approved as a burndown treatment in the spring of 2004 in soybeans.

At the use rate of 2.5 pts./acre, the premix contains .71 lb. acid equivalent glyphosate and .94 lb. of S-metolachlor — a herbicidal dose of both active ingredients. At that rate, the mix provides burndown capabilities as well residual control, says Corey Huck of Syngenta.

Huck notes that last year, for the first time, there were more two-pass programs in glyphosate-resistant soybeans than single-pass programs. “Where growers have been getting by with one shot [of glyphosate] and considering a second, this will fit well,” he adds.

Where pressure is heavy from small-seeded broadleaf weeds, such as waterhemp and lambsquarters, the premix will allow growers to postpone a second glyphosate treatment and help assure season-long weed control.

The 5.25 EW (emulsion in water) formulation contains an emulsion of the oil-based Dual Magnum in a water/glyphosate solution. It handles much like Bicep and will be available in 2.5-gal. jugs, 120-gal. mini-bulks and in bulk.

ASSURANCE PROGRAMS GET MAKEOVER

Competition from generic glyphosates and tough-minded buying habits of cost-conscious growers are shaking up assurance programs offered by premium glyphosate brands — Roundup WeatherMax and Touchdown Total.

After watching industrywide premium-brand sales decline by almost half from 2002 to 2004, Syngenta has pared down the assurance package offered with Touchdown Total and realigned its price, says Corey Huck of Syngenta.

Meanwhile, Monsanto has upgraded the assurance package that comes with Roundup WeatherMax by increasing trait replant and trait crop loss protection and by simplifying volunteer corn and respray elements. It also has added crop loss and replant provisions for Roundup OriginalMax.

In 2004, the two premium brands made up about 45% of total glyphosate volume, a dramatic decline, considering that about four out of five growers used premium brands in 2002. At the same time, sales of low-cost glyphosates nearly doubled.

Dow AgroSciences also is conscious of the cost/value trade-off of assurance programs. Its new high-load glyphosate, Glyphomax XRT, includes an assurance program. But its new Durango herbicide, which is virtually identical to Glyphomax XRT, doesn't.

In the future, Syngenta expects that premium and mainstream brands will merge into a branded segment that will be priced at a modest premium to generics — perhaps just a few dollars per gallon.