Selecting a cheap herbicide-control program this year could turn into an expensive decision. If rescue treatments are needed, costs can soar. But a dim outlook for commodity prices practically demands that corn and soybean growers identify ways to reduce their herbicide investment in 2000 - without cutting corners so tightly that weeds flourish and yields suffer.

"It's like walking a tightrope," acknowledges Mike White, Iowa State University field crops specialist in Warren County.

Here are 10 practical ideas that may help you with your herbicide cost-reduction efforts. Some of the ideas are suited to specific tillage practices. Others impact purchasing decisions. However, all will require an increase in your time and management efforts and careful evaluation to succeed.1. Match specific herbicides to specific weed problemsFarmers must know what weeds are present across their total crop acreage, identify problem areas and prepare to use a wide range of herbicide solutions, says Jeff Stachler, extension weed associate for Ohio State University. He believes that a targeted approach to weed control is most effective and helps hold down expenses.

"Don't buy the same product for all acres," he says. "That'll cost you more in the long run."

Make herbicide decisions as early as possible

2. Early decisions require advance planning, but they can result in significant savings. Retail herbicide prices in January are typically 10 to 15% less than they are in June.

3. Check each nozzle individually Calibrate sprayers correctly and change any nozzles that vary more than plus or minus 10% the difference from the correct nozzle rate.

Typically, growers calibrate by applying the correct gallons per acre, says White. Instead, he advises checking each nozzle individually. This approach still takes little time, results in accurate application amounts per square foot and provides the best herbicide coverage for a given rate. In addition, extension specialists encourage growers and custom applicators to consider the new anti-drift technology now available, which improves herbicide placement.

Of course, all this assumes that growers are making their own applications, which White encourages. "It can mean $4.50 to $5 an acre in out-of-pocket near-term savings," he says.

4. Put some steel in the field If tillage is an option, consider using a rotary hoe between three and five days after planting when weeds are in the white stage - just prior to emergence. A follow-up cultivation pass may then eliminate the need for a postemergence herbicide treatment in many fields.

A second option is to band herbicides over the row and cultivate between rows. White says this practice can reduce herbicide costs between 30 and 50%. However, be aware that most herbicide labels advise against cultivating seven to 10 days prior to or after the application.

"Stressed weeds, with their roots damaged from a cultivator, don't take up a herbicide as efficiently as healthy weeds," White explains.

5. Consider applying less than the labeled herbicide rate The emphasis here is on the word "consider." Reduced rates don't work for everyone or under every condition, and weed-control experts vary on their opinions of this idea. Tom Bauman, extension weed specialist at Purdue, is reluctant to encourage Indiana growers to adopt this practice. He says variable soils and an extended weed-emergence time frame pose challenges to reduced rates. The result is that difficult-to-control weeds tend to escape.

"There are simply some weeds, like velvetleaf, that probably need a full herbicide rate for control," he explains.

In Iowa, White offers a different perspective. He says experienced applicators often can reduce their postemergence application rates between 10 and 30% and still achieve good results. Their success depends upon spraying at the correct weed stage and during good environmental conditions. Because Mother Nature impacts both, a backup plan is needed.

In Ohio, Stachler recommends what he calls a planned two-pass program, consisting of a reduced rate of a preemergence herbicide followed by a full rate of a postemergence herbicide. He says farmers there can achieve good weed control in corn and soybeans for between $18 and $25/acre, excluding the application cost and adjuvants.

"You have to plan this," Stachler notes. "It doesn't just happen. What you want to avoid is using an unplanned, full-rate two-pass program. That's when you see costs reaching $50 to $60 an acre."

Dave Bowlin, south regional manager for Heartland Coop, uses Stachler's approach with his customers in Iowa. He estimates that a complete herbicide program in his region ranges between $20 and $30 for soybeans and $30 to $35 for corn. "One guy last year only had $10 an acre in his chemicals," he says. "The conditions were perfect, but that's not the norm."

Farmers do need to evaluate the potential negative consequences before applying reduced rates. Any liability falls on the grower's shoulders if the weed-control results are poor. "You assume the responsibility of the performance," Bauman says. "I can't stress that enough."

6. Scout fields and map weeds White advises growers to walk fields until lay-by to identify various weed species and their height, location and density. For thorough results, some extension specialists encourage growers to walk their fields using a Z-pattern approach in each one. "Windshield scouting doesn't count," White notes. "You need to actually walk, motorcycle or four-wheel through the field."

In the process, record the results. A pocket-size notebook works well for this part of the job. The information can then be transferred to a field map (available free of charge at most local Farm Service Agency offices). Growers can either write directly on these maps or trace their field boundaries on white paper and then record their notes on the paper. The more years a grower scouts and maps fields, the better acquainted he'll be with his weed species and the approach needed to control them. "A good map may allow you to spot treat a field as opposed to making a blanket application," White says.

7. Differentiate between economic weed problems and cosmetic concerns This option most impacts the number of post applications needed. Some weeds do little damage to yield potential once the crop is up and actively growing. Weed species, growth stage, weather, soil conditions and planting time help determine how competitive a weed is with the crop. Notes Mike White: "Recent research studies at Iowa State and other Midwest universities have shown no economic yield loss from light to moderate infestations germinating five weeks after the corn or soybeans have emerged."

However, some weeds just shouldn't be tolerated, extension specialists agree. These weeds may be extremely competitive with the crop or cause another problem that's difficult to solve. Such weeds may include black nightshade, Canada thistle, woolly cupgrass and giant ragweed.

Landlords also often impact farmers' decisions on whether to spray. Bowlin tells his customers to discuss with landlords the economic implications of multiple post applications. "When you explain the costs involved and that there may be little or no economic benefit, the issue often resolves itself," he says.

8. Tailor seed selection and planting practices to fields Bowlin encourages growers to tailor their seed selections to fit individual fields. A crop planted in correct populations - that germinates well and develops a uniform stand - tends to canopy quickly and minimize sunlight-to-soil contact. This reduces the opportunity for weeds to gain a strong foothold. "That can make our herbicide applications more effective," Bowlin says, "and we may be able to use less product."

9. Time herbicide applications for best results In conventional tillage, soil-applied applications made as close to planting as possible usually work best and cost less. Any available residual will help prevent weeds from emerging later in the season. White says that higher rates are often needed with fall or early spring soil-applied herbicides to offset their early application. The reason is because the earlier the herbicides are applied, the sooner they lose their effectiveness.

For best control results in no-till corn and soybeans, Stachler encourages growers to invest well in their burn-down treatment. The tendency, he says, is for farmers to skimp on the burn-down application because of its cost. The result then is usually less-than-stellar weed control that requires a rescue treatment. His advice: "Invest in a good burn down, and it will save you money later in the season."

For post applications, focus on small weeds. White emphasizes that growers need to apply post products when weeds are 3 to 4 in. tall. Applications then provide the best control results and minimize yield losses most effectively. He says alight to moderate infestation after the early post application will not reduce yields economically. "Most farmers push their post-emergence applications to the 6- to 10-in. weed size [five to six weeks after planting] to reduce the chance of more weeds emerging late in the season," he explains. "However, this later application tends to require a higher application rate and, by then, considerable yield loss has probably already occurred."

Del Johnson has reduced his herbicide investment by using a combination of more tillage and closely timed applications. The Warren County, IA, grower makes one tillage pass before planting soybeans. He scouts fields and, depending upon the results, usually makes one herbicide application between 21 and 28 days after planting. This approach allows him to save about $10/acre over the program he traditionally used.

In corn, Johnson sprays a preplant product two weeks ahead of planting. He makes a second tillage trip across fields, just ahead of the planter, to take out any germinating weeds. This program runs about $20/acre, he says, but it's not fail-proof. "We had a 10-acre field in the bottoms last year where the germination was off. We had to go in there with a rescue," he acknowledges. "You always need a backup plan, just in case."

10. Build a strong relationship with weed-control experts Local extension weed specialists, ag chem dealers and seed representatives have the ability to help growers save money and make sound investments. Early pay discounts, bulk discounts, sequential application program discounts and seed/herbicide combinations are just some of the options that they can help growers identify and tailor to best fit their needs. Later in the growing season, these same people scout fields, troubleshoot problems and, when needed, often offer a morale boost - sometimes the most valuable service of all.

"These people deserve a lot of the credit for our success," Johnson says. "Good relationships with them are more valuable to us than saving 50 cents per acre in chemical costs."

Bowlin agrees and shares his perspective: "This year might be the worst time in the world to price shop."