Several pre and post products make up the list of new soybean herbicides for 1998, including one with a different mode of action and another targeted for use on transgenic varieties.

Most of the new offerings are truly new - not just premixes of existing weed killers. Some are stand-alone products; others are intended to be tankmixed or used ahead of other herbicides.

Here are a few details on the new herbicides, as provided by chemical marketers.

Authority Broadleaf, from FMC, is a pre-emergence and preplant-incorporated herbicide with a totally new mode of action. It takes out 38 of the toughest broadleaf weeds (including those resistant to ALS inhibitors) with one pass while providing partial control of annual grasses and excellent crop safety.

It's a good partner for Roundup Ready soybeans, providing early residual control of broadleaf weeds such as jimsonweed, kochia, lambsquarters, morningglory, nightshade, nutsedge, pigweed, ragweed and velvetleaf.

Authority Broadleaf uses two chemistries: sulfentrazone and chlorimuron ethyl. Sulfentrazone disrupts the enzyme system necessary for the production of chlorophyll. Chlorimuron ethyl is a sulfonylurea herbicide that broadens the spectrum of pre-emerge activity.

The cost will range from $17-19/acre.

Matador, one of two new postemergent herbicides from FMC, offers fast and effective control of annual and perennial grasses. Controlled weeds include seedling johnsongrass, crowfootgrass, foxtail, sandbur, crabgrass, quackgrass and wirestem muhly.

Matador's active ingredient is quizalofop. The herbicide's per-acre cost: $7-8.

Skirmish, also from FMC, handles a wide assortment of tough-to-control weeds, including cocklebur, jimsonweed, morningglory, mustard, ragweed, smartweed, yellow nutsedge, sunflower and velvetleaf.

The active ingredient, chlorimuron ethyl, controls susceptible weeds by translocating throughout the above-ground plant tissue and underground roots. Leaves of susceptible weeds turn yellow three to five days after application, and complete control occurs between seven to 21 days after treatment.

Skirmish may be tankmixed with postemergent grass herbicides like Matador or Cobra. It's priced at $5/acre.

Raptor is the newest member of the imidazolinone herbicide family. American Cyanamid distributed the new postemergent herbicide in a limited test market in 1997 and now offers full product availability in '98.

"It offers growers outstanding broad-spectrum contact and residual control of over 50 grass and broadleaf weeds," according to George Fennell, product manager.

At a broadcast rate of 5 oz per acre, one quart of Raptor treats 6.4 acres for about $29/acre.

FirstRate, from Dow AgroSciences, is said to be the first broadleaf herbicide to control cocklebur, velvetleaf, morningglory, and common and giant ragweed in beans without concern of crop injury or carryover.

It can be applied surface-preplant, preplant-incorporated or postemergence, in all tillage systems, alone or in a tankmix.

"The beauty of FirstRate is that it has such a flexible fit across the Midwest, either soil- or post-applied," says Brian Barker, product resource manager.

With Roundup Ready soybeans, it can be used in a one-pass, postemergent tankmix treatment with Roundup. Or in a two-pass program, soil-applied FirstRate can be followed by Roundup post-applied.

Its active ingredient, cloransulam-methyl, is an ALS inhibitor absorbed by both roots and foliage, says Barker. Its water-dispersible granules are priced at about $8-10/acre.

Python WDG, also from Dow AgroSciences, gives growers an effective and flexible choice for pre-applied foundation control of small-seeded broadleaf weeds.

"The foundation control that Python WDG provides on lambsquarters, pigweed and velvetleaf differentiates it from other herbicides," says Barker. It's also an excellent foundation for control of waterhemp as part of a planned two-pass program.

The active ingredient, flumetsulam (Broadstrike), is an ALS inhibitor that works by preventing the synthesis of amino acids required for plant growth.

Python WDG can be applied surface-preplant, preplant-incorporated or pre-emergence. It can be tankmixed with a variety of grass and broadleaf herbicides, or be used alone as a foundation application, especially on herbicide-tolerant crops such as Roundup Ready soybeans.

Python WDG costs $7-9/acre.

Frontrow just received EPA registration for use as a postemergent product on soybeans. It controls both teaweed and sicklepod, plus cocklebur, morningglory, velvetleaf, and both common and giant ragweed.

Also from Dow AgroSciences, it can be applied earlier than other options, from the unifoliate to fourth-trifoliate leaf stage. It can be used alone in a total post program, tankmixed with a grass product or applied as a rescue treatment.

Frontrow comes in convenient co-packs. One contains cloransulam-methyl; the other holds flumetsulam.

Liberty, from AgrEvo, is a postemergent soybean herbicide recommended for use only on seed designated as Liberty Link or warranted by AgrEvo as being resistant to Liberty.

"It is most effective on annual weeds with good activity on perennials," says Dale Kinney, director of field development.

The active ingredient, glufosinate-ammonium, works through contact with green tissue, severely limiting photosynthesis. Liberty controls annuals such as foxtail, kochia and lambsquarters, and perennials such as rhizome johnsongrass, quackgrass, Canada thistle and orchardgrass.

It has no residual activity and may be tankmixed with any herbicide registered for postemergent use on soybeans except Classic and Cobra. It's priced at $15.50 for a 20-oz/acre application and $21.50 for 28 oz/acre.

Saber, new from United Agri Products, is a phenoxy postemergent herbicide that controls many susceptible annual weeds and suppresses a number of perennial broadleaf weeds.

"It is a premium dimethylamine formulation of 2,4-D, which gives excellent control of annual broadleaf weeds at lower rates than similar products currently on the market," says Pat McGourty, registration manager.

Depending on application rate, it costs $2-4.25/acre.