OPINION

Editor's Note: The following six essays are the result of a contest held for North Dakota State University students enrolled in PlSc 323: Principles of Weed Science. Seventy-five students took Assistant Professor Shane Friesen's Principles of Weed Science course during the spring semester in Fargo. As part of the course, students were asked to write an essay on a weed science topic of their choice, with the best ones sent to Agweek for judging and a chance of publication.

Holding pattern: As world begins to embrace other GMO crops, Roundup Ready wheat still getting cold shoulder

By Thomas Ritteman

FARGO, N.D. -- With the rapid growth in biotechnology in the past 10 years, the agricultural industry has seen changes in technology that farmers 50 years ago never would have even dreamed of.

A large portion of biotechnology in agriculture has been aimed at creating pesticide-resistant crops through the use of a process known as genetic engineering. This topic has created a lot of controversy in the past 15 to 20 years, not only in the United States, but also globally. Many consumers -- both foreign and domestic -- think that genetically engineered crops are unsafe for human consumption.

Recently, a controversy over genetically engineered wheat -- more specifically Monsanto's Roundup Ready wheat -- has erupted. This was caused by the public's perception that genetically engineered wheat is not safe since wheat is directly used to make food products such as flour.

Genetic engineering refers to a process that involves the direct manipulation of an organism's genes. Genetic engineering is different from traditional breeding, which is the manipulation of an organism's genes indirectly. Traditional plant breeding has resulted in many crop varieties that are commercially available today such as the Glenn hard red spring wheat variety, which was developed at North Dakota State University in Fargo.

Traditional plant breeding is a widely accepted practice and is used to produce more effective crop varieties every year. However, genetic engineering in ag crops also has resulted in designing crops with more effective characteristics and certain GE crops such as Roundup Ready soybeans or corn have been widely accepted throughout the U.S. Roundup Ready corn is simply herbicide-resistant corn that can be sprayed with harmful herbicides and still be able to tolerate them and survive, whereas conventional corn wouldn't survive.

GE wheat differs from GE corn or soybeans because it is used to make flour, which is directly consumed, whereas corn and soybeans go through a processor and are used indirectly to make cooking oils and sweeteners. The only question that remains is whether consumers ever will be able to feel comfortable with eating food that contains GE wheat.

Current GM crops

Consumers never will be willing to accept genetically modified crops if they think the food products produced by them are unsafe. U.S. consumers have accepted GM food, but in many other parts of the world such as in Europe, Japan and Australia, consumers demand labeling so they can choose between foods that contain either a conventional or a genetically modified origin. A large majority of all consumers -- foreign and domestic -- still view genetically modified foods as unsafe for human consumption.

The crop seed for producing GM foods was developed and released commercially by Monsanto, one of the largest chemical and seed companies in existence today. It is responsible for the commercial release of Roundup Ready crops such as soybean and corn, which are resistant to their glyphosate-based herbicide: Roundup.

According to NDSU professor Burton Johnson, "Roundup Ready corn and soybeans weren't really debated over like wheat was because they were not as big of an issue as compared to wheat since they aren't directly used to make food products."

While soybean and corn are both processed and used for oil, meal and starches, wheat is used directly for making: flour for bread, pasta, cakes and other pastries, Johnson says.

Though Roundup Ready soybeans are gaining acceptance by consumers all over the world, the same cannot be said for Roundup Ready wheat.

Monsanto has been working on transgenic wheat since it purchased the breeding programs of two established wheat development companies back in 1982. North Dakota State University's hard red spring wheat breeder Mohamed Mergoum indicats that the university's hard red spring wheat breeding program and other state universities received the Roundup Ready gene from Monsanto in 2001 so it could be inserted into conventional wheat. Mergoum says that the Roundup Ready wheat project was shelved in 2004 and the work and research done with Roundup Ready wheat was put to a halt.

According to Johnson, the Roundup Ready wheat project was stopped because of resistance from within the entire wheat industry, which is made up of the certified wheat seed producers, wheat processors and rural wheat producers. Johnson says the wheat industry thought it was in its best interest not to have Roundup Ready wheat at this time mainly because of the public's perception, which still has not changed today.

Impact on the U.S.

The current situation today with Roundup Ready wheat comes down to three things: its advantages, its disadvantages and the views of the consumers. Some key advantages of GE wheat are that it increases crop yields by allowing for more effective pest management and that it can reduce pesticide use and, ultimately, pesticide costs. Monsanto's Roundup Ready wheat is resistant to the herbicide of the same name and it allows farmers to spray Roundup on their wheat crop to kill weeds without killing the crop. This can save on the amount of other chemical used, too, consequently reducing pesticide costs by allowing for only one herbicide to be applied instead of several applied numerously throughout the crop year.

A key disadvantage is that Roundup Ready wheat would increase the risk of the development of weeds resistant to the herbicide, creating "super-weeds," which may be exceptionally difficult to control because glyphosate no longer would be effective.

Another disadvantage is that Roundup Ready wheat is a serious threat to the U.S. wheat export market because foreign countries don't want to buy it. The U.S. is the world's leading wheat exporter, and if it switched to GM wheat, it could lose millions of dollars in exports per year. Consumers also are resisting the use of food products created by GE wheat because they think GM foods are harmful to both their health and to the health of the ecosystem.

NDSU's Johnson thinks the wheat industry will remain without GE wheat for several years to come because there are so many other tools available to control weeds in wheat that we don't necessarily need Roundup Ready wheat right now.

Though Roundup Ready wheat never has been commercially released, that doesn't mean researchers have stopped working with transgenic wheat. According to Mergoum, the NDSU wheat breeding program currently is working on two different types of transgenic wheat. That means GE wheat is going to continue to be a major issue in the future.

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Weed resistance on the rise: But steps can be taken now to slow the rate of herbicide resistance

By Jonathan Tupa

FARGO, N.D. -- With the release of Roundup Ready crops in the 1990s, the number of acres treated with Roundup increased exponentially, which has led to an exponential increase in the number of weeds that have been exposed to the chemical. As a result, glyphosate resistance has become a significant concern.

Glyphosate is a nonselective systemic herbicide, absorbed through the leaves, used to kill weeds. It can be used as a nonselective, pre-emergence, pre- and post-emergence and selective herbicide in Roundup Ready crops. It first was released as an herbicide in the 1970s and has been used as a "cure-all" for weed control ever since. Glyphosate is well liked by the farming industry because it offers impeccable weed control, is less toxic than many other herbicides and is easy to use. Its relatively cheap price also makes it very attractive. It is effective in controlling grasses, broadleaf and woody plants.

Current status

Herbicide resistance is the inherited ability of a plant to survive and reproduce after exposure to a dose of herbicide normally lethal to the wild type. Today, there are more than 68 different glyphosate-resistant weed biotypes that have been identified worldwide.

One of the first documented glyphosate-resistant weeds in the U.S. is horseweed (marestail). Since first being documented in 2000 in Delaware, there now are more than 500,000 acres with resistant horseweed in several states in the central United States and it is spreading to other parts of the U.S.

Horseweed has been a fast-moving resistant weed and is mostly a problem in minimal to no-till operations. Waterhemp and Palmer amaranth are a couple of the other weeds getting recognition for their resistance to glyphosate. Other common weeds that also have shown resistance to glyphosate are ryegrass, common ragweed, common lambsquarters and giant ragweed. Not all of these weeds have been discovered in North Dakota, but it is only a matter of time before they are.

Potential impact on N.D.

Farmers widely have adopted the use of Roundup Ready crops because of their high weed-control efficiency and ease of use. Historically, glyphosate has been cheap to purchase and has different variations of the chemical from different companies. More than 80 percent of today's soybeans are Roundup Ready and are being treated more than once. Roundup Ready corn acres are increasing every year along with soybeans. With this enormous number of acres being treated with glyphosate -- some at low rates, which helps promote resistance, to save money -- more weeds are coming in contact with the chemical.

Glyphosate is the most widely used chemical in North Dakota, treating almost 25 percent of all acres sprayed, which is almost 2.5 times as many acres as the next chemical.

With the different types of crops that you can grow with the Roundup Ready gene increasing, the worry of strong resistance in many common weeds likewise is increasing. Some farmers are going with a completely Roundup Ready rotation (corn, soybeans and now sugar beets). This eases short-term production issues but could create more issues in the future. Rotating Roundup Ready crops with LibertyLink and nongenetically modified crops is the best way to reduce the chance of glyphosate resistance.

Preventative measures

What can be done? There are several ways that we can help slow the resistance:

•  Tillage: Controlling weeds through cultivation of soil will eliminate most of the weeds before the application of glyphosate is needed.

•  Crop rotation: Rotate crops that are not Roundup Ready so you are spraying different chemicals on the weeds in your fields. When rotating the crops, rotate crops with different lifecycles, different lifecycles will confuse the weeds in the field. With crop rotation, you also can confuse the weeds; some weeds don't like to grow with certain crops.

•  Rotate your herbicide use with different modes of action.

•  If you have weeds that you think may be developing resistance or have escaped the glyphosate treatment, you should eliminate them through hand weeding. This will stop them from producing resistance seeds and slow future problems.

•  Scout your fields, find out what weeds are out there and make your spray mixes according to those specific weeds.

•  When spraying glyphosate, do not skimp on chemical; use a high rate, but never exceed the labeled rate. By using a higher rate, you are eliminating some of the chance of escapees. Don't exceed the labeled rate; it is illegal and you could face criminal penalties.

•  Scout your fields regularly to identify weed escapees from the herbicide treatment.

If historic use trends continue, glyphosate resistance will be inevitable in North Dakota -- and the world. Without the release of a new herbicide that has the same effectiveness as glyphosate, with a different mode of action that could be alternated with glyphosate, we will just see an increase in the resistance of weeds.
Overall, glyphosate has been a highly sustainable herbicide with resistance evolving much slower than other common chemistries such as ALS inhibitors. For it to be used as a sustainable herbicide alternative in the future, good IPM strategies will need to be instituted and followed by America's farmers.

Herbicide resistance cannot be prevented, but it can be slowed. As a current farmer and a farmer of the future, I hope that we can figure out a way to completely avoid weed resistance.

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Waiting game: What have we learned from the Roundup Ready debacle?

By Dan Aichele

FARGO, N.D. -- In this day and age of agriculture, reaching maximum yield potentials as efficiently as possible is a top priority for farmers. Biotech companies and seed companies have been working with numerous different traits and varieties to help farmers reach their goals. In the last few years, Roundup Ready crops have been a leading development. But as we have seen, there are certain groups that have presented resistance to the marketing of this new technology, holding the product back through the judicial system.

In 2005, Roundup Ready alfalfa was deregulated by the U.S. Department of Agriculture and was released commercially through a joint venture between Monsanto and Forage Genetics International that August. In 2006, a lawsuit against USDA was filed by a few different entities most notably, the Center for Food Safety.

Judge Charles Breyer of the federal court in San Francisco ruled that Roundup Ready alfalfa must be taken off the commercial market and regulated again. Breyer stated that the Animal and Plant Health Inspection Service did not take "a 'hard look' at the potential environmental impacts of its deregulation decision."

The main concern is that the Roundup Ready gene might spread into organic or other types of alfalfa. This is possible because alfalfa reproduces through cross-pollination. Other concerns included issues of weed resistance and weed shifts. To meet Breyer's expectations, the APHIS needs to complete an environmental impact study.

Forage Genetics Inc. released a statement saying that the 18- to 24-month study likely would not be completed before the latter half of 2009 before which no new planting of Roundup Ready alfalfa is allowed without proper authorization.

Objections

Weed resistance is a problem faced by nearly all herbicides as they become more widely used. There are methods to counter herbicide resistance by using mechanical means and effective crop rotations. "Roundup Ready Alfalfa: An Emerging Technology," a report by researchers at the University of California-Davis, cites this as essential when dealing with volunteer growth of previous herbicide-resistant crops.

Weed shifts occur because some weed species are more resistant to certain herbicides than others. Over the years, these more resistant weeds tend to concentrate in an area if the same herbicide always is used. For example, weeds such as cheeseweed (common lambsquarters), burning nettle, filaree (storksbill) and common purslane are not always effectively stopped with Roundup. To avoid this problem, variance in herbicides should be used as well as effective crop rotations.

Questions also were raised about how to remove alfalfa stands after their useful lives are past. Typically, a glyphosate like Roundup is used to kill the remaining plants, but this would not work for a crop that is genetically designed to be resistant to Roundup. A 2004 article in the Western Farm Press explains that other herbicides such as 2,4-D and Dicamba are effective killers of Roundup Ready alfalfa.

There apparently was no concern about the human or animal consumption of Roundup Ready alfalfa as the judge allowed any Roundup Ready alfalfa planted before March 30, 2007, to be harvested for hay or seed. Most of the alfalfa crop for the year in California already had been planted, but in North Dakota and other Great Plains states, alfalfa planting had not yet begun. According to the UC-Davis report, "the gene introduced in RR alfalfa is the same gene used to create other RR crops such as corn, soybeans, oilseed rape, and cotton." So this gene already is a familiar player on the U.S. Department of Agriculture's crop scene. Studies still are evaluating the effects of Roundup Ready alfalfa when fed to livestock.

Is Roundup Ready alfalfa coming back?

Amid all the flak received by Roundup Ready alfalfa, farmers are rising up and speaking out in favor of the genetically enhanced crop. Fields with few weeds definitely are appealing to producers, especially considering the high quality demanded from alfalfa harvests. The presence of weeds in alfalfa hay significantly reduces its forage quality. This in turn reduces the quality of milk production in dairy operations.

Horses are another type of livestock that is touchy about its feed quality. With the increased effectiveness of weed control using Roundup Ready technology, producers can be pleased with the quality of their forage crop.

"As a producer, I am concerned about where this lawsuit goes and the impact it might have on advancing agricultural technology," Mark Watte, a farmer in California's San Joaquin Valley says in the Western Farm Press article. "It is basically a sham by the same environmental groups who want to stop any application of new technology in agriculture."

Besides the Center for Food Safety, co-plaintiffs in the lawsuit include Western Organization of Resource Councils, National Family Farm Coalition, Sierra Club, Beyond Pesticides, Cornucopia Institute, Dakota Resource Council, Trask Family Seeds and Geertson Seed Farms. The senior attorney on this case for the Center of Food Safety, Will Restov, called the decision "another nail in the coffin for USDA's hands-off approach to regulations on these risky engineered crops," which are being grown on 123 million acres in the United States alone.

The U.S. Environmental Protection Agency, the U.S. Food and Drug Administration and USDA all have done work with Roundup Ready alfalfa, and Monsanto claims Roundup Ready Alfalfa "has met every safety prerequisite for commercial use."

The Western Farm Press article states that the Center for Food Safety said in its case that Japan would "discontinue imports of U.S. alfalfa if a GE variety is grown in this country." The article also says "Japan has approved importing hay from RR alfalfa fields."

Because the Animal and Plant Health Inspection Service did an "environmental assessment" instead of an "environmental impact study," Breyer ordered a halt on all sales of Roundup Ready alfalfa until the study is done and Roundup Ready alfalfa has "passed the test." The judge's major concern was not for the safety of humans or animals because he allowed people who already had planted the crop at the time to continue to harvest it. The worry was that cross-pollinated Roundup Ready alfalfa would spread the Roundup Ready gene to organic and conventional variety.

Forage quality always is a major concern for dairy farmers and horse producers. Alfalfa is an important livestock feed, and Roundup Ready alfalfa is a valuable tool for keeping weeds out of the stand, which vastly improves forage quality for more sensitive eaters such as horses and dairy cattle. One also must remember that this is not only an important decision for alfalfa producers, but also is critical in that it will set a precedent for other court decisions that may arise concerning other Roundup Ready crops such as sugar beets. Now farmers can only wait for the Animal and Plant Health Inspection Service to finish its work and report back.

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Weed wars: Integrated weed management strategy should yield best results in leafy spurge battle

By Jacob Ell

FARGO, N.D. -- Leafy spurge (Euphorbia esula), an herbaceous perennial weed, is listed as a noxious weed in North Dakota. It is a deep-rooted plant that can reproduce by both vegetative buds and by seed. This plant generally stands 1.5 to 2.5 feet tall, having roots as deep as 29.5 feet.

It is native to Eurasia. Although leafy spurge is not native to North America, there are many other spurge species that can hybridize with leafy spurge, such as E. esula and E. waldsteinii, creating tremendous genetic diversity. This diversity helps to make the plant adaptable. Because of genetic diversity, this plant's recalcitrance, the ability to reproduce both sexually and asexually combined with a deep root system, adaptability to many soil types and conditions and the native populations of spurge species, effective conventional and biological control can be difficult.

Economic impact

With an estimated $23.3 million annual economic loss in North Dakota alone, it is clear that this weed is a significant burden on North Dakota. This cost is composed of several major factors: The high cost of controlling leafy spurge and the loss of production from infested land. Leafy spurge can out-compete many grasses, and cattle tend to avoid areas that are heavily infested. This can reduce cattle carrying capacity from 50 percent to 70 percent and, in severe cases, completely devastate rangeland, according to www.invasive.org .

Leafy spurge has a long history, but it was not always the major problem it is today. Leafy spurge first was documented in Massachusetts in 1827. It first was labeled as a weed in 1921. Effective herbicides became available in the 1940s, and efforts to manage leafy spurge with biological control began in the 1960s. The first leafy spurge symposium was held in 1979. By 1997, leafy spurge was present in 35 states and all but one Canadian province. And by 1999, North Dakota estimated its leafy spurge infestation to be 450,000 hectares.

Range animal control

Sheep and goats are the only two known range animals for which leafy spurge is palatable. Studies in Idaho showed that goats are a better biological control of leafy spurge than sheep in most circumstances. However, palatability of leafy spurge is different from state to state. This was demonstrated by Scott L. Kronberg and John W. Walker in experiments that showed sheep preferred leafy spurge from soils with relatively high fertility and avoided the plant from relatively less-fertile soil. Goats grazed leafy spurge regardless of soil conditions. Sheep preferred leafy spurge from North Dakota over leafy spurge from Idaho, so sheep may be a better biological control agent in North Dakota, while goats may be more useful in Idaho.

Preference for leafy spurge also can vary depending on what other plants are available in the landscape. If more palatable plants are available, then both sheep and goats may not provide good control.

Plant stress at the site also can affect the palatability of leafy spurge. More stressful environments low moisture, shade and low nutrient content in soil will increase a plant's natural defenses. In leafy spurge, these natural defenses are adverse phytochemicals. These defensive phytochemicals cause negative post ingestion problems which are severe in cattle and can be moderate in sheep. These problems can create a learned avoidance of leafy spurge. However, goats do not seem to be negatively affected by these defensive phytochemicals.

Insect control

Insects are another biological control. Efforts to control leafy spurge with biological control agents began in the 1960s with the release of the Hyles hawk moth in 1964. As of December 2002, North Dakota State University research shows that only eight of the 12 species of insects released in North Dakota have become successfully established.

Different insect species attack leafy spurge in different ways. Some, such as leafy spurge hawk moth (Hyles euphorbiae), feed on the leaves and flowers. Others, such as like the leafy spurge flea beetles in the genus Aphthona. A. lacertosa and A. nigriscutis, feed on the roots and have been the most successful biocontrol agents used in North Dakota, and by 1996, have become established in every county.

Release on south-facing slopes is most successful. The site conditions play a major role in the establishment of a stable control population. A. lacertosa and A. nigriscutis tend to do better in different sites. To determine which Aphthona species is best suited for a particular area, it is necessary to release both species, NDSU research shows. Once established, a healthy population of either species potentially can have a dramatic effect on leafy spurge. Leafy spurge foliar cover can be reduced by A. nigriscutis and A. czwalinae/ A. lacertosa an average of 38.2 percent during a three-year period.

Over time, weeds can become resistant to herbicides, which are not always the best option. Therefore, effective biological control is becoming increasingly important. Because biological control is unpredictable and difficult to manage, an integrated weed management strategy will produce the best results. Combining herbicides with biological control agents can be a very effective strategy. Also, a combination of insects and sheep or goats is possible. And this method produces very good results.

The control methods used are site specific, so any weed management program needs to be custom made for the site. A control burn also can be utilized with insects provided that it is done late enough in the season that eggs have been laid. Insects are available for distribution through the county weed control agent for a specific area and generally can be obtained in midsummer, when populations are at their peak.

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Glyphosate: The ultimate herbicide - n Proper management by herbicide users will ensure its continued availability

By Charles Elhard

FARGO, N.D. -- Glyphosate has become one of the world's most popular herbicides because of its remarkable ability to kill nearly any unwanted plant. But how long can we continue to use it? Won't weed resistance become a widespread problem?

When introduced in the 1970s as Roundup by Monsanto, glyphosate was thought to be the "silver bullet" of herbicides. This would seem logical with its nonselective, systemic properties, ease of use, low cost and immediate inactivation once in the soil. It quickly became widely used not only in the United States but also worldwide. In fact, in the United States alone, Monsanto netted $2.4 billion from Roundup in 2001.

One of the reasons for its success is that Roundup still is popular with conservation farmers. It is used for weed control instead of tilling the soil, reducing the possibility of erosion by wind and water.

Monsanto's development of glyphosate-resistant crops such as canola, corn, soybeans, cotton and recently alfalfa and sugar beets (with wheat currently being developed) has added to the demand for the herbicide. With an herbicide as popular as glyphosate, shouldn't there be some concern about safety, overuse and development of natural resistance by plants?

Many studies have been done to test the safety of glyphosate, and most of these studies have shown glyphosate to be safe. For example, chronic tests done with glyphosate were completed on rats, mice, rabbits and dogs in studies that lasted from one month to two years. No observed effects were shown by any of the animals, even at high doses. This is because glyphosate is poorly absorbed by the digestive tract and nearly all of the herbicide is removed from the body without harm. No carcinogenic effects were seen, and glyphosate was not found to cause skin irritation. Eye irritation, however, was found to occur.

Glyphosate resistance

Glyphosate resistance in weeds is probably the single most important concern faced by the herbicide industry today. Glyphosate-resistant weeds have begun popping up all over the world, including the United States, where several weeds have been found to be resistant to glyphosate.

Rigid ryegrass was the first weed to show resistance to glyphosate in 1996 in Australia. It showed up in 1998 in California. Common and giant ragweeds have become resistant in seven states, including Minnesota. Horseweed has become the most common glyphosate-resistant weed in the United States. Since 2000, horseweed resistance has been found in 17. As glypho-

sate use increases, chances are more resistance to the herbicide will be observed.

Why have these weeds become resistant? The most widely accepted reason is overuse. The growing of glyphosate-resistant crops has become popular with farmers and an increasing number of acres of these crops are being planted every year. For example, use of Roundup Ready soybeans has increased from about 2 million acres in 1996 to more than 70 million acres today. Roundup Ready corn acreage also has increased. Almost no acres were planted in 1998, compared with more than 35 million acres today. Intense use of glyphosate on the same field year after year without an alternate herbicide greatly increases the probability that resistant weeds will arise and multiply. This overuse allows weeds that have genetic traits endowing glyphosate resistance to survive and thrive.

The resistance gene can be passed on from one plant to another through pollen so cross-pollination is another way of resistant weed development. This potentially could create huge populations of resistant weeds, especially with plants that are prolific seed producers.

There also is some concern that the rate of glyphosate used could contribute to resistant weeds. Several weeds have been shown to survive up to eight times the recommended use rate. It still is unknown, however, if rate changes have contributed to the glyphosate-resistant weeds, so farmers are being told to stick to the recommended labeled rates.

Resistance prevention

As important as glyphosate is to the farmer, it needs to be used in ways that will prevent future outbreaks of weed-resistance. One way to do this is by rotating glyphosate-resistant crops with other conventional crops, which will reduce the overuse of glyphosate on one field. Another potential preventative practice would be to rotate glyphosate with other herbicides, especially those with different modes of action. Other possible preventative practices include mixing glyphosate with another herbicide to make sure possibly tolerant weeds are exposed to a herbicide other than glyphosate. Glyphosate should not be a cure-all.

Cultivation techniques still should be implemented as much as possible to reduce the possibility of resistance because of overuse of glyphosate. As always, read the label thoroughly, follow labeled rates, and scout fields for resistant weeds regularly. Monsanto recently released an educational weed resistance management Web site for its customers. This site provides information and recommendations on weed control strategies to minimize risk of resistance. The site, www.weedresistancemanagement.com , offers insight from a wide range of experts including weed scientists, crop advisers, experienced growers and leaders in retail and industry.

Glyphosate is an important herbicide, from the home gardener all the way to the farmer and likely will continue to be widely used for many years to come. Therefore, preventative action needs to be taken by its users to prevent excessive use of glyphosate and, most importantly, glyphosate-resistant weeds. If everyone implements proper management steps, glyphosate will be available for use in the future.

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High-priced weeds: Taking action against weeds can keep more money in farmers' pockets

By Jonathan Anderson

FARGO, N.D. -- If at this time last year a "marketing psychic" walked up to you and told you what prices were going to be today, what would you do differently on your farm? If you knew about $6-per-bushel corn, $15-per-bushel soybeans and $18-per-bushel spring wheat, what would you do to squeeze every last bushel out of your land?

With low commodity prices, losing a bushel here or gaining a bushel there is not a huge concern for most farmers. A typical comment at the local elevator might be: "We got 52 bushels an acre on the back 40, 57 on the front. Only a five-bushel difference, no big deal."

No big deal? Two years ago, it was no big deal. Today, five extra bushels of corn, soybeans or spring wheat could result in an additional $30, $75 and $90 profit per acre. Growers tend to disregard a few bushels when making decisions on their farm. While this may have been fine in the past, an extra bushel or two is significant revenue with today's prices.

"Over the years, I have worked really hard on weed control and here in 2006, survey results indicated that 59 percent of the growers said weeds are their worst problem," says Dr. Alan Dexter of North Dakota State University in Fargo.

Weeds are a large, if not the biggest, contributing factor to reduced yields. They are harmful enough that civil and criminal penalties are given to those who fail to comply with noxious weed and noxious weed seed laws.

Any farmer can tell you that weeds cause yield loss, harvest difficulties and make you look bad compared with neighboring growers. Even after harvest, weeds can cost the farmer via dockage and cleaning losses.

What some farmers do not take into consideration is just how much yield and quality are hindered. Weeds compete for light, water, nutrients and space and also may have toxic effects on crops. Even if not very large, weeds will take their share of all those components. Growers know weeds are not good, but some do not consider how bad weeds really are.

First, instead of trying to add revenue per acre, think of the weeds as taking away from your income. People may be more likely to take action when something is being taken from them. Many growers are not aware of what they have to start with. Underestimating the land you cultivate is a common mistake in agriculture, according to Kevin Johnson of CHS Ag Services in Grand Forks, N.D. Growers tend to set their yield standards lower than they should. Some have the attitude that a 60-bushel soybean yield is an unrealistic goal for the upcoming year. If you do not plan for 60 bushels, of course you are not going to get 60 bushels an acre.

Once you have set a high goal, you may have to invest a higher amount to achieve it, but you will reap the benefits later, Johnson says. When proper fertilizer and seed are established, weed management is the next most important concept under your control.

"We can't allow the weeds to survive out there," Dexter says. "If you need to go out and spray three or four times to get those weeds, then do that. Don't try to save 50 cents an acre by cutting rates."

The same principle is valid for a variety of crops. Compare the cost of applying to the cost of not applying instead of the amount you are saving. For example, you go out in your soybean field and find 10 common lambsquarters plants, 10 redroot pigweed plants, four cocklebur plants and maybe one volunteer corn plant per 100-foot row. You conclude the weeds in the field are not too serious yet, so you will spray in a few days. That seemingly insignificant amount of small weeds has the potential to reduce your 60-bushel-per-acre goal by nine bushels, or 15 percent, according to David R. Pike in his research "Economic Threshold for Weeds." That $10-per-acre herbicide looks pretty good when compared with the loss of $115 to $120 potential profit per acre, even if multiple applications are needed. USDA data show that only four years ago, nine bushels would only raise the farmer's profit $36 to $40 per acre when the market was hanging around $5. The economic gain by controlling weeds may play a giant role in maximizing farm revenue.

Taking control

Farmers have relied on herbicides since the early 1950s as their primary method of controlling weeds. While this approach toward continued use of farm practices may have worked in the past, it will not maximize yields any longer. Weeds have altered their ways of growing, and farmers must adapt accordingly. Using different, integrated management practices may be the only way to get weeds under the growers' control. Getting these weeds under control is the only economical choice. It will take time and effort to clean up the field, but in the long run, your benefits will be greater than the costs.

Let's pretend you have a 40-acre chunk that has been extremely weedy in the past. These weeds may be resistant to some herbicides now. Over the years, the weeds have produced seeds that lay dormant in the soil, which may make control seemingly impossible. The out-of-control weeds continue to rob those ever-so-pricey bushels year after year. Turning the land into fallow to eradicate weeds would be too large of a sacrifice for many growers to swallow. Alternatively, the growers can attack the weeds in multiple ways to regain control. If fallow is an unacceptable choice on your farm, try different row spacing, rotations, biological control, resistant varieties or others. New integrated pest management products and methods are being developed to help producers maximize yields.

By looking at historical data, we can observe that these high prices are unlikely to continue. On the other hand, input prices, unlike commodity prices, are not as volatile. Expenses such as equipment, pesticides, fungicides, storage, transportation and labor have risen in price as well. Montana Sen. Jon Tester says "when commodity prices fall, input prices usually stay high, hurting farmers." A prime example is fuel. Although relatively unrelated to agriculture prices, the same principle applies. Today, we are comfortable -- almost happy -- paying $3 to $4 per gallon, a price range that was thought absurd only a few years ago.

An extra bushel today means a lot more than it has in the past. Taking a chance today means putting more on the line. Taking care of those troublesome weeds never has been more economical. Next time you're debating whether to control weeds, take out your calculator and the choice will be obvious.