Different Weed Control Strategies

Glyphosate Alternatives for Weed Control in Winegrape Vineyards

By Tim Hammerich, with the Ag Information Network

For years, glyphosate has been a tool many grape growers have relied on to help manage weeds. What can managers do when glyphosate isn’t an option, such as when a winery doesn’t want to buy grapes where glyphosate was used for weed control. UC Cooperative Extension Advisor for Napa County, John Roncoroni, says growers have options.

“I know a lot of growers, once we found that we weren’t going to use glyphosate. Well their first thought was to just use different herbicides,” he said. “And it’s like, well, you can do that. But one of the other things is we really need to look at different strategies when we may not have, what I’ve called glyphosate the hammer.”

“If the hammer cannot be used anymore, you have to know which weeds you have. You want to get to them early, they’re much easier to control, but you also need to identify weeds at an early stage,” he noted. “And you can use a bunch of different kinds of techniques. Where you get in early with cultivation when the weather conditions are right. Or you use a flamer. Flamers are pretty efficient tools as long as the weeds aren’t big.”

Roncoroni said in addition to these techniques, cover crops can also be helpful.

“One of the old-is-new techniques, again, is looking at under-vine cover crops. Using something that won’t attract gophers, hopefully. But when we’re looking at something like that an annual reseeding crop such as Zorro fescue, which grows to be maybe eight to ten inches, will re-seed itself, and then you can cultivate,” noted Roncoroni. “It takes two or three years to establish, so you have to be able to stick with it for a couple of years, but it competes with the weeds as it’s growing. It then leaves a dry duff, which does not need water once it goes dormant in the springtime, so it won’t interfere with irrigation.”

Contact your county extension agent for more information about integrated pest management practices.

California Ag Today2020-02-19T19:35:49-08:00February 27th, 2020|

Preemergent Herbicides Pay off

Preemergent Herbicides will Insure Clean Berm This Spring

By Patrick Cavanaugh, Editor

While the tree crops are completing their harvest, it will be time on preemergent weed control. Kurt Hembree is a UCANR Weed Management Farm Advisor in Fresno County.

“For nut crop growers particularly, as the rains may approach, this is an opportunity to make sure your spray rig in in operation at its strongest point Make sure there are no leaks and that it has been calibrated,” Hembree said. “Pay attention to the spray nozzles. Have your guys check them and replace them if they are worn. If they are damaged, they do not do you any good on the spray rig.”

Good maintenance will help not only in the coverage standpoint, trying to get the herbicides to the ground to weeds where they need it. It will also reduce some of the drift potential.

Hembree also recommended the appropriate combination of herbicides. “It needs to include two different chemistries and modes of action in the tank. This will help starve off weed resistance on some of the tough weeds. And you tend to get more weed when you have more modes of action in the tank,” he said.

“If you need a postemergent herbicides at the time the preemergents go out then it must go into the tank this time of year as we go into winter,” Hembree said.

If growers want a clean berm come springtime, you need to start it out clean by getting the appropriate mixes in the tank. “Growers should target the toughest weeds that you know you have to battle,” noted Hembree.

California Ag Today2021-05-12T11:01:45-07:00October 22nd, 2019|

Field Bindweed is A Struggle to Control

Field Bindweed Difficult to Manage

By Jessica Theisman, Associate Editor

Field Bindweed is a struggle in the summer months. Scott Stoddard, UCANR Cooperative Extension Farm Advisor, Merced County, discussed with California Ag Today how to manage the weed during the summer in annual crops.

“Field Bindweed is predominantly a summer weed, so we are trying to manage it more in our summer annual crops such as cotton, corn, melons, and tomatoes,” Stoddard said.

This weed has been documented back 100 years but only recently has become more of a problem for farmers.

“It did not seem to be as universally impacting people as much as it does now,” Stoddard said.

Farmers are asking themselves what they are doing irrigation-wise that impacts the weeds.

“Does drip irrigation favor this weed? Does conservation tillage favor this weed? There are all kinds of unknowns,” Stoddard explained.

Stacking herbicides can help and control the Field Bindweed.

“Herbicides in the annual crop systems are marginal and you have to stack them. You have to combine the Roundup with something like a Treflan and then combine that maybe with some applications of other herbicides,” Stoddard said.

Even with stacking the herbicides, they are still marginal. On the herbicide angle, this is one of the things that makes weeds so challenging.

California Ag Today2021-05-12T11:01:46-07:00July 26th, 2019|

Monsanto: Jury Got it Wrong on Glyphosate

A Statement from Monsanto Following San Francisco Verdict

No Evidence that Glyphosate Causes Cancer

By Scott Partridge, Monsanto Vice President

Like everyone else following the Dewayne Johnson v. Monsanto Co. trial, my colleagues and I have deep sympathy for Mr. Johnson’s plight. Our hearts go out to the Johnson family, and we understand their desire for answers. Glyphosate is not the answer. Glyphosate does not cause cancer. The jury got it wrong. We will appeal the jury’s opinion and continue to vigorously defend glyphosate, which is an essential tool for farmers and others. We are confident science will prevail upon appeal.

The jury’s opinion does not change the science. Glyphosate has a more than 40-year history of safe use. Over those four decades, researchers have conducted more than 800 scientific studies and reviews that prove glyphosate does not cause cancer.

The National Institutes of Health (NIH) and the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) both recently reaffirmed glyphosate does not cause cancer. The U.S. Environmental Protection Agency (EPA) and other regulatory authorities in Europe, Canada, Japan, Australia, Korea, and elsewhere routinely review all approved pesticide products and have consistently reaffirmed that glyphosate does not cause cancer.

Rather than arguing the science, the plaintiff’s lawyers repeatedly crossed the line, distorted the facts and used baseless and egregious emotional appeals to inflame the jury. We are deeply troubled by the conduct of the plaintiff’s lawyers in this case. The judge admonished this conduct on several occasions and instructed the jury to ignore these statements. However, we are concerned that this conduct unduly influenced the jury’s deliberations, and we will be raising this issue in our appeal.

The plaintiff’s lawyers know they cannot win on the science. This lawsuit is based solely on the opinion of one organization called IARC. IARC is not a regulatory authority and did no independent studies. IARC is the same organization that determined beer, meat, cell phones, and coffee cause cancer. Investigative reports by Reuters and the Times of London have uncovered that IARC members reviewing glyphosate concealed important scientific data, edited out the conclusions of key studies, and were closely aligned with U.S. trial lawyers.

After IARC’s opinion was announced in 2015, U.S. trial lawyers started running advertising campaigns to recruit people for their lawsuits against Monsanto. There were no lawsuits blaming glyphosate for cancer until after IARC’s opinion. A federal judge overseeing some of these lawsuits recently stated that plaintiffs’ evidence is “shaky” and any lawyer faces a “daunting challenge” in bringing a case to trial based on IARC’s opinion.

Our next step is to file post-trial motions with the Court. Following the Court’s ruling on the motions, we will file our appeal with the California Court of Appeals if needed. We are fully confident that science will prevail in the end. Glyphosate-based herbicides are too important to farmers and others for these baseless lawsuits to go unchallenged.

California Ag Today2021-05-12T11:05:09-07:00August 14th, 2018|

Herbicide Limits Plantings Following Cilantro

Caparol Label Change Sought To Reduce Plant-Back Restrictions Following Cilantro

By Patrick Cavanaugh, Editor

Cilantro production is important in California and more growers are planting it. However, an herbicide used in cilantro has plant-back restrictions to other crops.

It’s easy to grow and works well as a rotation crop, explained Oleg Daugovish, a UCANR Cooperative Extension Strawberry and Vegetable Crop Advisor serving Ventura County.

“It’s an easy fit in our production systems. You can fit it between many crops,” Daugovish said. “It’s a quick crop and can be planted in a small planting window.”

To help minimize weeds, Caparol herbicide is labeled for use on cilantro. “It works very well and it’s all we need to control weeds in cilantro,” Daugovish explained.

“But the problem is that we have some plant-back restrictions. Some of the crops, we obviously have to rotate your cilantro with something,” Daugovish said. “You have to have a label that allows you to go back to the field with other crops such as peppers, lettuce, Brussel sprouts or spinach.”

That’s the biggest problem for growers, as they like how it works on cilantro, but need an allowance to go back in with different crops without worry.

Under the IR-4 program, Daugovish conducted research to see if other crops could safely be planted after a cilantro crop. The research indicated that crops following cilantro within the plant-back restrictions were safe for the most part.

“They treatments were similar to the untreated,” said Daugovish. “We are putting some numbers together and running statistics in different locations such as Salinas, Santa Paula, and Ventura.”

Daugovish said it appears that it is safe to follow cilantro without waiting for plant-back restrictions, and he plans to submit the data to the IR-4 program who can get it to the registrant who can amend the label.

“We need to make the change on the label so growers can use it without the plant-back restrictions,” said Daugovish. “We expect to have the data sets to support a label change so that growers can use it.”

“As far as herbicides, we may not have another option for a while, but if growers can use is safely with peace of mind it will be a major benefit,” he said.

California Ag Today2021-05-12T11:05:13-07:00March 21st, 2018|

Glyphosate Does Not Cause Cancer, Study Finds

Glyphosate Cancer Study Turns up Nothing

By Patrick Cavanaugh, Farm News Director

With all the clamor that glyphosate herbicide is a cancer causing material, let the facts tell the real story.

Liza Dunn is an emergency medical doctor and also a medical toxicologist on the faculty at Washington University in St. Louis. And she’s also been working with Monsanto on anything that could show that glyphosate herbicide could not be safe when used correctly.

She discussed a robust study showing no evidence that glyphosate is cancer causing. None!

“The Ag Health Study is a study of more than 57,000 farmers with their pesticide applicators, and they had followed them since the mid ’90s to look at effects of pesticides exposure. And one of the pesticides that they’ve looked at is glyphosate,” Dunn explained.

“In 2005, there was even a journal article that demonstrated that there was no association between glyphosate in any kind of cancer whatsoever. That data was refreshed in 2013, and once again, the data demonstrated unequivocally that there was no association between glyphosate and any kind of cancer,” she said.

However, that second set of data was never published.

“Which is just incredible because the person who had that data said that it would have changed the outcome of the France-based International Agency for Research on Cancer (IARC) decision.”

“That was in 2015, and why the research was not published is beyond me,” Dunn said.

According to her, IARC is going completely in the wrong direction.

“The IARC have gotten much more involved in looking at things that are not carcinogens, and out of abundance of caution, I guess – I’m not sure what their motivation is – they’ve decided to classify them as carcinogens anyway,” Dunn said.

California Ag Today2017-11-08T20:26:58-08:00November 6th, 2017|

Weed Control in Rice Fields

Controlling Herbicide-Resistant Weeds in California Rice Fields

By Emily McKay Johnson, Associate Editor

Whitney Brim-DeForest, UC ANR Cooperative Extension rice farm advisor for Sutter, Yuba, Placer and Sacramento Counties in California, currently works in all rice production areas across the state to identify problematic weeds in rice fields.

Given her background in weed science, Brim-DeForest explained California rice growers flood their fields for weed suppression, as well as use herbicides for weed control and management. “I’d say that we do have quite a few herbicides right now. As we continue to get new herbicide resistant weeds every year,” said Brim-DeForest, “we are starting to run out of options, especially for some growers who encounter herbicide resistance.”

Brim-DeForest believes herbicide resistance was first discovered in the early 1990’s, but “has become significantly problematic for growers within the last 20 years. Because of the herbicides we use and the limited number that we have, we have ended up with an increasing number of weeds that are herbicide resistant every year. Since about 2000, we’ve had a new species or herbicide that encounters resistance every year,” she stated.

Brim-DeForest treats a multitude of weed species in her line of work. “I would say the watergrass species is our biggest problem,” she noted. “We also have a weedy red rice that was discovered in the early 2000s. It is not widespread, but we do have a few fields with it,” she explained.

Featured Photo: Whitney Brim-DeForest, UC ANR Cooperative Extension rice farm advisor.

California Ag Today2021-05-12T11:03:00-07:00July 11th, 2016|