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Bibliography Tag: dicamba watch

Zhang et al., 2019b

Zhang, J., Huang, Y., Reddy, K. N., & Wang, B.; “Assessing crop damage from dicamba on non-dicamba-tolerant soybean by hyperspectral imaging through machine learning;” Pest Management Science, 2019, 75(12), 3260-3272; DOI: 10.1002/ps.5448.


BACKGROUND: Dicamba effectively controls several broadleaf weeds. The off-target drift of dicamba spray or vapor drift can cause severe injury to susceptible crops, including non-dicamba-tolerant crops. In a field experiment, advanced hyperspectral imaging (HSI) was used to study the spectral response of soybean plants to different dicamba rates, and appropriate spectral features and models for assessing the crop damage from dicamba were developed.

RESULTS: In an experiment with six different dicamba rates, an ordinal spectral variation pattern was observed at both 1 week after treatment (WAT) and 3 WAT. The soybean receiving a dicamba rate >/=0.2X exhibited unrecoverable damage. Two recoverability spectral indices (HDRI and HDNI) were developed based on three optimal wavebands. Based on the Jeffries-Matusita distance metric, Spearman correlation analysis and independent t-test for sensitivity to dicamba spray rates, a number of wavebands and classic spectral features were extracted. The models for quantifying dicamba spray levels were established using the machine learning algorithms of naive Bayes, random forest and support vector machine.

CONCLUSIONS: The spectral response of soybean injury caused by dicamba sprays can be clearly captured by HSI. The recoverability spectral indices developed were able to accurately differentiate the recoverable and unrecoverable damage, with an overall accuracy (OA) higher than 90%. The optimal spectral feature sets were identified for characterizing dicamba spray rates under recoverable and unrecoverable situations. The spectral features plus plant height can yield relatively high accuracy under the recoverable situation (OA = 94%). These results can be of practical importance in weed management. (c) 2019 Society of Chemical Industry.


Gullickson, 2018

Gil Gullickson, “Minnesota Dicamba Temperature, Cutoff Dates Credited for Less Off-Target Movement,”  Successful Farming, Published Online September 27, 2018.


Looks at upcoming re-registration decision on dicamba by EPA.  Reports that “in 2017, inquiries regarding off-target dicamba in the Roundup Ready 2 Xtend system tallied 99 inquires per 1 million acres. This year, it’s down to 13 per 1 million acres, and most revolved around weed-control issues, says Brett Begemann, Bayer Crop Science chief operating officer. Xtend soybean acreage is up, though, having doubled from last year’s 25 million acres to this year’s nearly 50 million acres.” Fact that 100,000 farmers and applicators attended dicamba training made a big difference. On Minnesota restrictions: “Compared with states that did not have cutoff dates, Minnesota had limited complaints of off-site dicamba movement in 2018, says Gunsolus. In 2017, there were over 250 reports of dicamba damage, he says. In 2018, MDA has so far fielded 52 reports of dicamba damage covering 1,850 acres, says Joshua Stamper, director of the pesticide and fertilizer management division for the MDA.” FULL TEXT

Neff, 2018

Lisa Neff, “Farmers, conservationists challenge Trump’s EPA, Monsanto over crop-damaging pesticide,” The Wisconsin Gazette, February 13, 2018.


Wisconsin Gazette describes the suit against the EPA and Monsanto, which was initiated by five agricultural and environmental watchdog organizations: the Center for Biological Diversity, Center for Food Safety, Earthjustice, National Family Farm Coalition, and Pesticide Action Network.  The lawsuit alleges that many critics warned that dicamba was likely to drift when applied during the hot summer months, but did little to address these concerns, instead bowing to pressure from Monsanto to conditionally approve the new formulations. Court documents also claim that EPA recognized the potential negative impact from dicamba to hundreds of endangered species that would be exposed, but did not follow Endangered Species Act requirements to seek guidance on protective measures from the appropriate federal wildlife agencies. “That the EPA would indulge in this kind of recklessness and junk science to appease Monsanto is shocking,” said Paul Achitoff, attorney with Earthjustice, in a statement. FULL TEXT

Hettinger, 2018

Johnathan Hettinger, “EPA eased herbicide regulations following Monsanto research, records show,” St. Louis Post-Dispatch, March 1, 2018.


Reports on a document review investigation that reveals that Monsanto’s own science played a key role in how the use restrictions for the new dicamba formulations for use with Xtend crops were set. EPA had originally proposed a larger, more comprehensive, all-direction buffer for all of the new dicamba formulations, the first to be approved for post-emergent use over growing crops.  Then, Monsanto submitted updated research on dicamba drift that, according to the company, demonstrated little to no volatility. EPA was apparently convinced, since it reduced the buffer to just 110 ft on the downwind side of fields on which the herbicide is applied — a big difference. This story reports that Monsanto research used to justify this was conducted in Georgia and Texas, two states that have had only modest problems with dicamba drift and crop damage, likely due to local weather conditions. FULL TEXT

Bradley, 2018a

Kevin Bradley, “July 15 Dicamba injury update. Different Year, same questions,” Integrated Pest Management, University of Missouri, July 19, 2018.


latest drift-damage estimates from 2018 have been released by Dr. Kevin Bradley, University of Missouri Division of Plant Sciences. Bradley has been compiling national numbers since the crisis began and is one of the most respected, independent weed scientists trying to help farmers, the ag industry, and regulators find a less costly way to deal with the spread of glyphosate-resistant weeds.

Source: University of Missouri

The map above summarizes the latest data.  An estimated 1.1 million acres of soybeans alone have already been damaged by drifting dicamba.  Illinois, Arkansas, and Missouri are by far the hardest hit by this crisis, now in it’s third year. FULL TEXT

Beck, 2018

Madelyn Beck, “Federal Suit Alleges Companies Knew Dicamba Would Drift, Monsanto Created Monopoly,” KUNC Radio, August 8, 2018.


Describes court documents filed August 2018  on two “master complaints” in the dicamba drift Multi District Litigation (MDL) pending in federal court.  The first complaint is a crop damage class action, and the second alleges antitrust violations.  Lawyers representing the plaintiffs allege that defendants Monsanto and BASF are “commercializing a product that literally destroys its competition.”  FULL TEXT

Kennedy, 2018

Merritt Kennedy, “West Texas Vineyards Blasted By Herbicide Drift From Nearby Cotton Fields,” NPR, August 21, 2018.


Reports on vineyards in Texas damaged by dicmaba drift from Xtend cotton plantings.  Grapes are particularly sensitive to dicamba, and can take years to recover.  Radio portion includes interviews with farmers on both sides of the issue.  Dicamba injury was recorded on 90-95% of vineyards in some parts of Texas.  FULL TEXT

Polansek, 2018

Tom Polansek, “U.S. seed sellers push for limits on Monsanto, BASF weed killer,” Reuters, August 16, 2018.


Reports on the 2018 dicamba drift crisis and the decision by two large U.S. seed sellers to urge EPA to ban dicamba use overtop of growing resistant crops.   Harry Stine, CEO of Stine Seeds, says : ““I’ve been doing this for 50 years and we’ve never had anything be as damaging as this dicamba situation. In this case, Monsanto made an error.”  FULL TEXT

Chow, 2018

Lorraine Chow, “Top Seed Companies Urge EPA to Limit Dicamba,” EcoWatch, August 17, 2018.


Reports on comments by top seed companies in U.S. to EPA urging they ban dicamba use in summer and fall.  Includes a statement by Beck’s Hybrids, the largest seed company in the U.S.. FULL TEXT

Steckel, 2018

Larry Steckel, “Dicamba drift problems not an aberration,” Delta Farm Press, August 8, 2018.


Veteran Tennessee extension weed scientist Larry Steckel writes about the ongoing drift crisis.  He estimates that only 100,000 acres of non-Xtend soybeans remain in the state, and 40% of those are showing injury from dicamba.  He stand by efforts of applicators to follow the complicated label instructions, and proposes that volatility and temperature inversions are the cause.  FULL TEXT

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