When Weeds Become Monsters
D. Hunter Reardon
AUBURN, Ala.–Evolution is turning modern weeds into monsters, as a phenomenon–– herbicide resistance–– makes control increasingly difficult for farmers. Dr. Steve Li, Alabama Extension weed scientist, called the development a “Pandora’s box” that cannot be closed. Li offered a nuanced but grim outlook on the subject.
“In the beginning, glyphosate killed almost everything out there. It’s cheap, and it doesn’t last long in the soil. It was almost the perfect herbicide,” he said. “Unfortunately, the good days didn’t last long.”
Glyphosate, the active ingredient in RoundUp™ and similar herbicides, was first released in 1974. Its utility in the world of agriculture took off in 1996 with the introduction of “RoundUp ready” crops, which withstood glyphosate. These crops were the first genetically modified organisms–– commonly referred to as GMOs–– on the market.
Now, farmers could grow crops resistant to the herbicide and spray their entire field with glyphosate. Weeds withered while their crops remained unscathed. It seemed too good to be true–– and it was.
“Some people in the field originally thought that no weeds would develop resistance to glyphosate,” Li said. “That didn’t last long, either.”
Eight years after the advent of glyphosate-resistant crops, extension agents at the University of Georgia first identified glyphosate resistance in pigweed. These hardier pigweeds spread to neighboring states, costing hundreds of million dollars in lost profit. Not only is pigweed a strong competitor against crops, it is also a prolific producer that can generate up to 100,000 seeds per plant.
Now, many pigweed populations are completely resistant to glyphosate. In 2016, a test of 58 locations in Alabama found only one field free from glyphosate-resistant pigweed, compared to 57 infected fields. Resistance to other herbicides, including PPO-inhibitors, is also on the rise. Other weeds, meanwhile, have acquired resistance to glyphosate, including horseweed, ragweed, and rye grass.
How did this happen?
Acquiring resistance is a long but simple task for a species. Even the most thorough herbicides can’t exterminate 100 percent of the population, and a tiny fraction always survives. The few weeds that made it through the glyphosate fallout of 1996 likely did so because of an oddball mutation that resisted the herbicidal mode of action. Those weeds reproduced with one another, and their offspring inherited the same mutation. Over the course of the following decade, the weeds with the gene for resistance had a monopoly on survival. It’s no surprise that this led to evolution in overdrive.
Li cautioned against blaming the problem entirely on genetically modified crops. “One of the myths is that this is a GMO problem,” he said. “We had weed resistance issues way before GMOs were released.” Indeed, the natural path of evolution indicates that glyphosate resistance would have increased no matter what. GMOs did not create the problem, Li explained–– they only accelerated it.
Li also blamed regulatory pressure on chemical companies for causing a lack of incentive to find solutions. “Let’s say there is a new chemical out there like glyphosate,” he said. “As of now, chemical companies don’t have enough incentives to discover and commercialize it. The way the patent law is, there’s not enough time to make a good profit.” Besides, he added, most of the easy targets for herbicides–– including enzyme inhibitors and hormone mimics–– are already on the market.
Of course, searching for a new chemical is a cat-and-mouse game. As with glyphosate, resistance will always develop over time.
What options do farmers have?
Li offered some solutions to the epidemic, though most came with a qualifier. “You can use alternative strategies, but keep in mind, everybody does this to make money,” he said. “You don’t have an unlimited budget.”
Specialty and vegetable crop farmers may have the money to send their labor force out to hand-pull weeds. Because of low commodity prices, row crop farmers don’t have this option. Cover crops in the winter help, as can crop and herbicide rotation. “You just don’t have that many chemistries to rotate,” said Li, “and you don’t always have that many crops to rotate, either.”
Using residual herbicides, cover crops and preventing resistant weeds from producing seeds will alleviate weed resistance problems. However, it is unlikely these tactics will resolve the issue in a long run.
“It’s a very difficult question to answer. There’s no easy solution. If there were, we’d know it already.”
What has the impact been on Alabama?
Alabama Extension agricultural economist Max Runge emphasized that the monetary impact on Alabama has been negligible. “It has affected profit margins,” he said, “but we’ve been fortunate in Alabama that it’s not a tremendous issue so far for most farmers.
“However, some areas have more problems than others, and it’s not likely to go away.”
Though Li noted the limits of crop rotation, Runge said that it still gives Alabama an advantage over the Midwest. “We can rotate corn, soybeans, and cotton in the north, and throw in peanuts down south. You use different chemicals for different crops, and that helps prevent resistance,” he said. “In the Midwest, they’re just growing corn and soybeans.”
Rotating herbicides–– using glyphosate or glufosinate one year and a PPO-inhibitor based chemical the next, for example–– prevents any single resistant mutation from gaining dominance in the gene pool. Crop rotation makes this a realistic solution for the time being.
Runge also praised the extension program in Alabama for educating farmers about weed resistance. He said that farmers in less affected regions are diligent in stemming the flow of resistant weed seeds. “Farmers are careful to clean equipment brought in from out of state and wash off residual seeds,” Runge said. “Education is just another factor helping our state.”
Published Sept. 19, 2017 at http://news.aces.edu/blog/2017/09/19/roundup-ready-crops-battle-roundup-ready-weeds/
Pod Blasting Makes Peanut Farmers’ Lives Easier
D. Hunter Reardon
AUBURN, Ala.–Rapid technological advancement has become a staple in the field of agriculture. For decades, complex scientific discoveries have been the driving force behind ever-increasing yields. However, not all innovation stems from a chemical breakthrough. Pod blasting, a 20-year-old method to measure peanut maturity, is a simple process that requires nothing more than a pressure washer and a picker basket.
Kris Balkcom, Alabama Extension research associate and peanut specialist, recently walked through the process, offering both information and tips on the subject. For starters, pod blasting comes with some big advantages. “It’s a lot faster and easier,” Balkcom said. “You get a better idea of maturity from a higher percentage of the crop.”
The quickest way to determine if a peanut crop is mature enough for harvest is to check the color of the pods. The darker the pods are, the closer they are to maturity. Farmers must remove the exocarp, or the outer shell, in order to find the color and measure maturity.
“We used to hull-scrape with a knife,” Balkcom explained. “When you do that, you’re looking at a handful of peanuts.” Additionally, removing each exocarp by hand was a tedious process. “Now, with pod blasting, we’re looking at 200 peanut pods at a time, easily.”
A breakdown of the pod blasting process
- The farmer gathers a representative sample of peanuts from the field, including at least five or six plants.
- The farmer removes the pods by hand from the plants. Also, no pods should be left in the ground. This collection process garners about 200 pods.
- All 200 pods are poured into a picker basket, and the basket is placed in a five-gallon bucket.
- The pods are sprayed with a lightweight pressure washer at 1300-1600 PSI. The sprayer should hold the pressure washer about a meter away from the pods to avoid destroying the pods. This ensures that the exocarps are removed without damaging the fruit.
- The naked pods are measured against a maturity board. The color coded board shows the farmer how many days remain until optimum harvest time. The darker the pods, the closer they are to maturity.
The main purpose of pod blasting is to invert peanuts at the best possible time. About 140 days after planting, the farmer turns over the peanuts in the field and leaves them to dry. If done before or after optimum maturity, farmers risk losing a significant portion of their crop. Jimmy Jones, Alabama extension agent, helped to quantify the advantages of pod blasting.
“If the farmer inverts their field a week early, they’ll lose 300-500 pounds of their crop,” Jones said. “If they’re a week late, they’ll lose at least 500 pounds, and probably more.”
This has some big financial implications. Peanuts can go for about 425 dollars a ton, and the higher the quality, the higher the price. “We have a 100-point grading system based on peanut quality,” Jones said, “and with pod blasting, we can gain the farmers about 3 points on the scale. The price rises about 8 dollars a point.” Furthermore, inverting at the right time ensures that the vines retain their vigor, which helps the peanuts into the machine.
Jones is the county extension coordinator in Henry County, and holds pod blasting workshops at the Wiregrass Research and Extension Center. From 8 am to 12 pm on Tuesdays and Fridays in September and October, he pod blasts peanut samples for farmers in the region. An extension agent for 29 years, he remembers the days before producers began using pod blasting
“We were still scraping the peanuts on the tailgate with the farmers back then,” Jones said. The hull-scraping process, he explained, took all day. In the early days of pod blasting, it would take 30 minutes just to run the sample.
“Now it takes me three minutes,” he said. “We can run as many as 50 farmers in a day.”
The main thing he emphasized with pod blasting was making sure that farmers hit the optimum harvest date. “If you miss, you should miss early,” he advised. “If you miss the date completely, it starts getting pretty drastic.” Harvesting before maturity can result in losses up to 500 pounds, but harvesting late will result in even greater losses. Of course, with pod blasting, farmers can now pinpoint their optimum harvest date within three to five days.
What can be done?
The first round of pod blasting should begin about 125 days after planting. This year in Alabama, that date is about a week away. “You can look at the plants and tell–– when peanuts near maturity, they go from lush green to a more bronze color,” Balkcom said. “You should always pod-blast at least ten days before harvest time to make sure you aren’t overshooting.”
Balkcom also recommended checking different spots in the field, as well as pod blasting multiple times. Not all the peanuts have to be mature at the optimum inversion time, either–– sometimes, farmers have to invert their field while some of the pods are still growing, rather than risk losing a crop of already-mature peanuts. “You play the hand you’re dealt,” Balkcom said. Fortunately, the advent of pod blasting has made the process that much easier for peanut farmers throughout the state.
There is some new technology on the horizon. Jones said that he can envision a day when peanut farmers don’t have to sample at all. Already, cotton farmers check their optimum harvest date with a smartphone app by inputting conditions and crop variety, and there’s been some experimentation with this concept for peanuts.
For the time being, pod blasting remains the best way to maximize yields. “It’s a tried and true method,” said Jones, “and that’s what we’re going to continue to do.”
Published Sept. 14, 2017 at http://news.aces.edu/blog/2017/09/14/pod-blasting-helps-peanut-farmers-determine-optimum-maturity/
Soybean Rust Spreading Across Alabama
D. Hunter Reardon
AUBURN, Ala.–After a few weeks of consistently wet weather, soybean rust is making its annual march from the Gulf Coast to north Alabama. Spurred on by wet leaves and strong winds, the fungal disease popped up in 33 of Alabama’s 67 counties. Alabama Extension specialist Dr. Dennis Delaney weighed in on the development and offered advice to soybean farmers across the state.
“Some fields look great, and some look terrible. It’s all over the board,” Delaney said. “This bout of rust is about average, but with wet weather, it’s spreading more quickly than usual.”
Delaney explained that each year rust sweeps from the more humid coast to the northern part of the state. “Soybean rust is an annual issue,” he said. “It’s a matter of when it moves in. If it moves in during early fall, most soybeans are already out of danger.”
Soybean rust affects the leaves of the plants, which provide nutrients for the developing soybean pods. If the plants are beyond the R5 growth stage–– past the point of seed development–– soybean rust is harmless, and dies when cold weather arrives later in the year. If it arrives in the late summer, it can present problems. Farmers have some ways to fight back, but they must act quickly.
What can be done?
“The only really good controls we have for soybean rust are fungicides,” Delaney said. “They are mainly preventative, and if you hear there is rust in your area, you often need to spray your fields.” Once the soybean rust has developed, it is much harder to control.
Many farmers in north Alabama do not spray their fields for soybean rust annually, he said. On the coast, meanwhile, it’s usually a good idea to spray most summers. Most fungicides control a variety of fungal diseases, and soybean rust is usually among them. Delaney stressed that farmers must consider economics when choosing whether or not to spray.
“Farmers must decide if their yield projections are high enough for fungicide to be an economical choice,” he said. “There are no forecasts for damage out yet, but soybean rust can often result in a 30 percent yield loss. For most farmers, spraying is going to be an economical choice this year, but it is always case-by-case.”
Dr. Ed Sikora, an Alabama Extension plant pathologist, also advised spraying for soybean rust. “Growers should be advised to consider a fungicide application this year, particularly a product with both protective and curative activity,” he said. Using a curative fungicide could help farmers who are already seeing rust in their fields.
Another solution is planting early. If farmers plant soybeans in the early part of the season, they will often mature before the wave of soybean rust can reach them.
Published August 31, 2017 at http://news.aces.edu/blog/2017/08/31/soybean-rust-spreading-across-alabama/
Alabama Peanuts Benefiting from Wet Summer
D. Hunter Reardon
AUBURN, Ala.–One year removed from a drought of epic proportions, Alabama peanut farmers are happy with the rainier summer of 2017. Though wet conditions can cause a separate set of issues, peanuts are looking very strong thus far.
According to the National Agricultural Statistics Service in Alabama, 91 percent of peanuts had reached the pegging stage by Aug. 7, compared with 85 percent at the same time last year. In addition, a full 80 percent of peanut crops were rated as “good” or “excellent” by the NASS.
Dr. Austin Hagan, an Alabama Extension plant pathologist, recently gave his take on the status of peanuts statewide. “Anytime it rains, that’s good,” Hagan said. “And we’ve had rain all year.”
The steady rainfall has presented some problems, like standing water, slowed emergence and an uptick in leaf spot. But Hagan said these are minor issues, preferable to those presented by a prolonged drought. He also noted that the overall health of the crop is in good shape.
“We don’t have any dry areas, so we don’t have some of these situations that were holding back yields last year,” Hagan said. “Even if it stops raining next week and doesn’t rain for the rest of the year, we’ll still have a good-sized crop.”
Effects of steady rain
One pesky peanut disease–– white mold–– has been all but vanquished by the rain. “We’re not seeing a lot of white mold this year, whether the farmers sprayed for it or not,” said Hagan. “White mold is a very aerobic fungus that likes a lot of oxygen.” Wet conditions, he continued, have basically drowned out the disease.
On the other hand, there has been an increase in leaf spot, a fungus that prefers wet weather. However, Hagan explained that advances in technology have helped with resistance. “To be honest, a lot of the varieties we have today hold up a lot better than the varieties from 30 years ago,” he said. “With these kinds of foliar diseases, you don’t see pod-shedding, and the plants can withstand a little leaf-shed.”
Still, farmers may want to tackle the leaf spot they see this year, if only because the crop is looking so strong. “If you do see disease, you might want to shorten up intervals on fungicide sprays or switch to premium fungicide,” Hagan said. “Yields are looking good enough this year that farmers should switch, as they will see a payout from this investment.”
Published August 18, 2017 at http://news.aces.edu/blog/2017/08/18/alabama-peanuts-benefit-wet-summer/