Superweeds

MplsGopher

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Nothing political about this, so this is the appropriate forum. Just thought it was very scientifically interesting.

Monsanto first rolled out Roundup Ready soybeans in 1996. Farmers rushed to adopt the paired products: By 2011, according to the Department of Agriculture’s Economic Research Service, about 94 percent of all soybean acres in the United States were planted with seeds engineered to resist herbicides. Cotton and corn followed similar trajectories. Between 1990 and 2014, the volume of U.S. glyphosate use increased more than 30-fold. “It was just so cheap and effective that that’s all people used for almost 20 years,” says Stephen Duke, a former researcher at the Department of Agriculture.

It turns out that Palmer amaranth was perfectly adapted to evolve resistance and to do so quickly. The plant is native to the Southwest, and its leaves were once baked and eaten by people among the Cocopah and Pima tribes; the Navajo ground the seeds into meal. But as the pigweed spread eastward, the plants began competing with cotton in the South, emerging as a serious threat to the crops by the mid-1990s.

Whereas cash crops are virtually identical — farmers purchase new genetically engineered seeds containing the glyphosate-tolerance trait every year — Palmer amaranth benefits from incredible genetic diversity. It mates sexually (obligate outcrossing, in biology-speak), and female plants produce hundreds of thousands of seeds each year. The plants that sprouted with random mutations that inadvertently equipped them to survive showers of herbicide lived to reproduce with one another. Then, once applications of Roundup annihilated all the weeds in a field except the resistant Palmer amaranth, the pigweed could spread without competition. In one study, researchers planted a single Roundup-resistant Palmer amaranth plant in each of four fields of genetically modified cotton. In three years, the weeds choked out the cotton, and the crop failed.

A weed killer like glyphosate does its damage by striking a specific target within a plant. When Roundup is sprayed on a leaf, it enters the plant’s cells and binds to an enzyme that helps produce amino acids necessary for survival. Glyphosate disables that enzyme; when the plant can’t synthesize those building blocks, it dies. Other weed killers target different compounds: Atrazine, for example, binds to a molecule that carries electrons during photosynthesis, the process by which plants make food from sunlight. With the electron-carrying compound out of commission, the plant can’t make food, and it starves.

The trouble with these weapons is that they work only as long as their targets stay the same. If a weed killer is like a key and its target like a lock, a change of the locks can render the herbicide useless. Many species evolve resistance in this way: A single mutation or set of mutations can change the shape of the target site, leaving the would-be lethal substance with nowhere to bind. With glyphosate, Palmer amaranth doesn’t change the locks; it simply replicates them. The weed killer still disables the enzymes it reaches, but the plant produces extra enzymes. Imagine a door with a thousand locks — and glyphosate can bring only a hundred keys to open it.

Even more concerning, weeds are evolving resistance mechanisms that can defend against multiple different herbicides aimed at multiple different target sites — to belabor the metaphor, an entire key ring. Enzymes in a plant cell can act like a vigilant doorman, stopping different weed killers near the entrance and neutralizing them before they ever reach their destination. Scientists hypothesize that these doormen-enzymes are active to some extent even in the tiniest seedlings: A baby Palmer amaranth plant may be able to disable herbicides that were sprayed before it emerged from the soil.

Ultimately, Roundup was no match for the pigweed’s evolutionary vitality. Roundup-resistant Palmer amaranth populations quickly spread through the South, then moved north, hidden at times in cottonseed hulls used for animal feed. Once consumed, the tiny seeds passed intact through the digestive systems of the cows that ate them. Farmers who sprayed the contaminated cow manure on their fields — a common practice, as a cheap form of fertilizer — unwittingly assisted the weed’s spread. Palmer amaranth, the ultimate opportunist, now grows in at least 39 states.

It’s not as if no one saw this coming. Globally, 263 species in some 71 countries are known to have evolved resistance to herbicides, encompassing nearly every major class of weed killer on the market. In the 1970s, a decade after Rachel Carson published her landmark exposé, “Silent Spring,” the entomologist Robert van den Bosch coined the term “pesticide treadmill,” a concept referring to the slow escalation in the potency of the chemicals needed to control pests and maintain crop yield. (Resistance problems are not confined to weeds: Last fall, the E.P.A. proposed phasing out certain species of corn that are genetically modified to kill insects after tolerance was reported.)

Already, Hartzler says, herbicide costs have more than doubled for most U.S. farmers over the last 10 or 15 years, as the treadmill slowly speeds up, and they’re forced to buy more and more chemicals. This is a relatively recent reversal: For decades, weed killers got better and better as old technologies fell by the wayside. “You burn out one product, but what you replace it with is better than what you were using before,” he says. “And that’s basically how it was from the 1950s until the turn of the century. In ’96, we had Roundup Ready. And that was the top of the mountain.”
 

short ornery norwegian

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Weed resistance is getting to be a bigger issue every year. Certain weeds develop a resistance if the same herbicides are used every year, forcing the suppliers to come up with new formulations.

Then you get situations like the dicamba mess, where it turned out that dicamba products caused damage to other crops, resulting in a lot of legal action.

Farming just never seems to get any easier. plant diseases, insect problems, weeds, cost of inputs, drought, hail - and if you avoid all of that, just maybe you can turn a profit if the grain markets turn your way.
 


MplsGopher

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Weed resistance is getting to be a bigger issue every year. Certain weeds develop a resistance if the same herbicides are used every year, forcing the suppliers to come up with new formulations.

Then you get situations like the dicamba mess, where it turned out that dicamba products caused damage to other crops, resulting in a lot of legal action.

Farming just never seems to get any easier. plant diseases, insect problems, weeds, cost of inputs, drought, hail - and if you avoid all of that, just maybe you can turn a profit if the grain markets turn your way.
It does seem like a tough job!
 

Gopher_In_NYC

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Nothing political about this, so this is the appropriate forum. Just thought it was very scientifically interesting.

Monsanto first rolled out Roundup Ready soybeans in 1996. Farmers rushed to adopt the paired products: By 2011, according to the Department of Agriculture’s Economic Research Service, about 94 percent of all soybean acres in the United States were planted with seeds engineered to resist herbicides. Cotton and corn followed similar trajectories. Between 1990 and 2014, the volume of U.S. glyphosate use increased more than 30-fold. “It was just so cheap and effective that that’s all people used for almost 20 years,” says Stephen Duke, a former researcher at the Department of Agriculture.

It turns out that Palmer amaranth was perfectly adapted to evolve resistance and to do so quickly. The plant is native to the Southwest, and its leaves were once baked and eaten by people among the Cocopah and Pima tribes; the Navajo ground the seeds into meal. But as the pigweed spread eastward, the plants began competing with cotton in the South, emerging as a serious threat to the crops by the mid-1990s.

Whereas cash crops are virtually identical — farmers purchase new genetically engineered seeds containing the glyphosate-tolerance trait every year — Palmer amaranth benefits from incredible genetic diversity. It mates sexually (obligate outcrossing, in biology-speak), and female plants produce hundreds of thousands of seeds each year. The plants that sprouted with random mutations that inadvertently equipped them to survive showers of herbicide lived to reproduce with one another. Then, once applications of Roundup annihilated all the weeds in a field except the resistant Palmer amaranth, the pigweed could spread without competition. In one study, researchers planted a single Roundup-resistant Palmer amaranth plant in each of four fields of genetically modified cotton. In three years, the weeds choked out the cotton, and the crop failed.

A weed killer like glyphosate does its damage by striking a specific target within a plant. When Roundup is sprayed on a leaf, it enters the plant’s cells and binds to an enzyme that helps produce amino acids necessary for survival. Glyphosate disables that enzyme; when the plant can’t synthesize those building blocks, it dies. Other weed killers target different compounds: Atrazine, for example, binds to a molecule that carries electrons during photosynthesis, the process by which plants make food from sunlight. With the electron-carrying compound out of commission, the plant can’t make food, and it starves.

The trouble with these weapons is that they work only as long as their targets stay the same. If a weed killer is like a key and its target like a lock, a change of the locks can render the herbicide useless. Many species evolve resistance in this way: A single mutation or set of mutations can change the shape of the target site, leaving the would-be lethal substance with nowhere to bind. With glyphosate, Palmer amaranth doesn’t change the locks; it simply replicates them. The weed killer still disables the enzymes it reaches, but the plant produces extra enzymes. Imagine a door with a thousand locks — and glyphosate can bring only a hundred keys to open it.

Even more concerning, weeds are evolving resistance mechanisms that can defend against multiple different herbicides aimed at multiple different target sites — to belabor the metaphor, an entire key ring. Enzymes in a plant cell can act like a vigilant doorman, stopping different weed killers near the entrance and neutralizing them before they ever reach their destination. Scientists hypothesize that these doormen-enzymes are active to some extent even in the tiniest seedlings: A baby Palmer amaranth plant may be able to disable herbicides that were sprayed before it emerged from the soil.

Ultimately, Roundup was no match for the pigweed’s evolutionary vitality. Roundup-resistant Palmer amaranth populations quickly spread through the South, then moved north, hidden at times in cottonseed hulls used for animal feed. Once consumed, the tiny seeds passed intact through the digestive systems of the cows that ate them. Farmers who sprayed the contaminated cow manure on their fields — a common practice, as a cheap form of fertilizer — unwittingly assisted the weed’s spread. Palmer amaranth, the ultimate opportunist, now grows in at least 39 states.

It’s not as if no one saw this coming. Globally, 263 species in some 71 countries are known to have evolved resistance to herbicides, encompassing nearly every major class of weed killer on the market. In the 1970s, a decade after Rachel Carson published her landmark exposé, “Silent Spring,” the entomologist Robert van den Bosch coined the term “pesticide treadmill,” a concept referring to the slow escalation in the potency of the chemicals needed to control pests and maintain crop yield. (Resistance problems are not confined to weeds: Last fall, the E.P.A. proposed phasing out certain species of corn that are genetically modified to kill insects after tolerance was reported.)

Already, Hartzler says, herbicide costs have more than doubled for most U.S. farmers over the last 10 or 15 years, as the treadmill slowly speeds up, and they’re forced to buy more and more chemicals. This is a relatively recent reversal: For decades, weed killers got better and better as old technologies fell by the wayside. “You burn out one product, but what you replace it with is better than what you were using before,” he says. “And that’s basically how it was from the 1950s until the turn of the century. In ’96, we had Roundup Ready. And that was the top of the mountain.”
So not this type of weed?

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short ornery norwegian

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if pot was legalized, I think a lot of people would be eager to get in on the opportunity to be a licensed grower. there is a lot of money to be made from legal pot - and none of the risks of trying to do it illegally.

and your kids would automatically become the most popular kids in school. "What does your dad do? Oh, he grows pot."

either that, or move to Montana and raise Dental Floss.
 

Gopher_In_NYC

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if pot was legalized, I think a lot of people would be eager to get in on the opportunity to be a licensed grower. there is a lot of money to be made from legal pot - and none of the risks of trying to do it illegally.

and your kids would automatically become the most popular kids in school. "What does your dad do? Oh, he grows pot."

either that, or move to Montana and raise Dental Floss.
Passed here and IIRC goes into effect next year with an extra $600 million in tax revenue by year three.
 

Wally

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if pot was legalized, I think a lot of people would be eager to get in on the opportunity to be a licensed grower. there is a lot of money to be made from legal pot - and none of the risks of trying to do it illegally.

and your kids would automatically become the most popular kids in school. "What does your dad do? Oh, he grows pot."

either that, or move to Montana and raise Dental Floss.
Its not that easy and you would have to compete with well funded large scale producers.

The vast majority of marijuana should be grown outside in warm climates. There is no need to waste electricity on indoor growing.
 




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