The newest version of WeedSOFT, a computer weed-control decision aid, is now available to crop producers. You may recall that we reported the advent of the software program back in March 2001 ("Tough on Weeds").

The updated version includes weed-control decision tools for grain sorghum and wheat, as well as for corn and soybeans. These are new features of the 2003 "Advisor" module of the WeedSOFT program.

"This version of the program helps growers do more than simply choose the best herbicide for the job," said Brent Sellers, University of Missouri weed scientist who helped modify the Nebraska-developed software to fit Missouri conditions. "WeedSOFT 2003 helps you choose the most cost-effective herbicide or tank-mix for the weeds you have in your field. It can also tell you what happens to yields if you choose not to control those weeds."

"WeedSOFT is a good tool; we're using it in our training sessions," said Lyndon Brush, MFA staff agronomist who helped Sellers "road-test" the program. "It's a great tool if you put in accurate information, but it can take a little time."

The off-season may be a good time to key in information for fields you'll be planting next spring, said Sellers. "Winter is a great time to play 'what-if' games with the software and test weed management strategies."

WeedSOFT may be more useful to most corn or sorghum growers than to soybean farmers, because of the popularity of Roundup Ready soybeans, he added.

"If you're growing non-GMO [conventional] soybeans, this summer is a good time to scout and assess the weed problems in your fields," Sellers continued. "Each year is going to be different, but WeedSOFT can be an excellent planner for two-pass weed control systems."

Lyndon Brush agrees: "Good records can help you do a better job of controlling weeds, whether you use a computer software program or not," Brush said. "You should know the five major weeds in each field, and most farmers know which weeds are giving them problems.

"Those late weeds you're seeing now may not hurt yields much this year, but they may be seeding trouble for the next season," he added. "Is your weed strategy reducing the seed bank of the most troublesome weeds? The WeedSOFT program can provide a lot of options and any good plan needs to be flexible. You need to be able to adapt your weed-control plan to meet specific situations."

In WeedSOFT's "Advisor" a grower lists the crop, the weeds to be controlled, weed populations and growth stages, expected yield and other information.

"The software includes standard pricing for herbicides and mixes, but you may want to input the prices from your local supplier," said Sellers. "The software then calculates what a particular weed-control plan would cost, and estimates the yield damage that would occur if weeds are not controlled."

When WeedSOFT was being fine-tuned earlier this year, Sellers and Brush created a fictitious corn field with foxtail, waterhemp and cocklebur. Brush selected a herbicide combination that would control 95 percent or more of broadleaf weeds and 60 percent of the foxtail, if applied when weeds are 2 to 4 inches tall, at a cost of $20.34 per acre. Spraying the weeds in that particular field returned an estimated $16.16 per acre over the cost of herbicide and application.

Waiting until weeds averaged 4 to 8 inches tall changed the economic picture. Broadleaf weed control dropped to about 75 percent, with 47 percent of the foxtail grass controlled. Net returns dropped to $14.41 per acre.

"There was still a benefit to applying the herbicide, but we missed some weeds that had begun to take a toll on yields and may add to the weed seed bank in the soil in future seasons," said Sellers.

"WeedSOFT provides a great many herbicide selections--perhaps too many for some growers," said Brush. "The program has a lot of potential, although not every farmer may decide to use it."

"WeedSOFT is a support system; just one tool in helping you make weed-control decisions," Sellers agreed. "It's not foolproof and it shouldn't be the only basis for making a decision during the season. But it can let you sort through a lot of options and help you decide which one may be best for your situation."

WeedSOFT versions are available for Illinois, Indiana, Kansas, Missouri, Nebraska and Wisconsin. WeedSOFT 2003 costs $195 and works only on computers with Windows 95 or newer operating programs with a CD-ROM drive. Order the software from Bulletins, P. O. Box 830918, Lincoln, NE 68583-0918. You need to specify which state version you need and include your e-mail address to receive software updates.

"We'll add new herbicides, new tank mixes and update label changes periodically," said Sellers.