Dicamba - HH-RA.org

Bibliography Tag: dicamba

Christensen et al., 2016

Christensen, C. H., Barry, K. H., Andreotti, G., Alavanja, M. C., Cook, M. B., Kelly, S. P., Burdett, L. A., Yeager, M., Beane Freeman, L. E., Berndt, S. I., & Koutros, S.; “Sex Steroid Hormone Single-Nucleotide Polymorphisms, Pesticide Use, and the Risk of Prostate Cancer: A Nested Case-Control Study within the Agricultural Health Study;” Frontiers in Oncology, 2016, 6, 237; DOI: 10.3389/fonc.2016.00237.

ABSTRACT:

Experimental and epidemiologic investigations suggest that certain pesticides may alter sex steroid hormone synthesis, metabolism or regulation, and the risk of hormone-related cancers. Here, we evaluated whether single-nucleotide polymorphisms (SNPs) involved in hormone homeostasis alter the effect of pesticide exposure on prostate cancer risk. We evaluated pesticide-SNP interactions between 39 pesticides and SNPs with respect to prostate cancer among 776 cases and 1,444 controls nested in the Agricultural Health Study cohort. In these interactions, we included candidate SNPs involved in hormone synthesis, metabolism or regulation (N = 1,100), as well as SNPs associated with circulating sex steroid concentrations, as identified by genome-wide association studies (N = 17). Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Multiplicative SNP-pesticide interactions were calculated using a likelihood ratio test. We translated p-values for interaction into q-values, which reflected the false discovery rate, to account for multiple comparisons. We observed a significant interaction, which was robust to multiple comparison testing, between the herbicide dicamba and rs8192166 in the testosterone metabolizing gene SRD5A1 (p-interaction = 4.0 x 10(-5); q-value = 0.03), such that men with two copies of the wild-type genotype CC had a reduced risk of prostate cancer associated with low use of dicamba (OR = 0.62 95% CI: 0.41, 0.93) and high use of dicamba (OR = 0.44, 95% CI: 0.29, 0.68), compared to those who reported no use of dicamba; in contrast, there was no significant association between dicamba and prostate cancer among those carrying one or two copies of the variant T allele at rs8192166. In addition, interactions between two organophosphate insecticides and SNPs related to estradiol metabolism were observed to result in an increased risk of prostate cancer. While replication is needed, these data suggest both agonistic and antagonistic effects on circulating hormones, due to the combination of exposure to pesticides and genetic susceptibility, may impact prostate cancer risk. FULL TEXT

Lerro et al., 2020

Lerro, C. C., Hofmann, J. N., Andreotti, G., Koutros, S., Parks, C. G., Blair, A., Albert, P. S., Lubin, J. H., Sandler, D. P., & Beane Freeman, L. E.; “Dicamba use and cancer incidence in the agricultural health study: an updated analysis;” International Journal of Epidemiology, 2020; DOI: 10.1093/ije/dyaa066.

ABSTRACT:

BACKGROUND: The herbicide dicamba has been commonly used agriculturally and residentially. Recent approval of genetically engineered dicamba-resistant crops is expected to lead to increased dicamba use, and there has been growing interest in potential human health effects. A prior analysis in the Agricultural Health Study (AHS) suggested associations between dicamba and colon and lung cancer. We re-evaluated dicamba use in the AHS, including an additional 12 years and 2702 exposed cancers.

METHODS: The AHS is a prospective cohort of pesticide applicators in Iowa and North Carolina. At enrollment (1993–1997) and follow-up (1999–2005), participants reported dicamba use. Exposure was characterized by cumulative intensity-weighted lifetime days, including exposure lags of up to 20 years. We estimated relative risks (RR) and 95% confidence intervals (CI) using multivariable Poisson regression for incident cancers diagnosed from enrollment through 2014/2015.

RESULTS: Among 49 922 applicators, 26 412 (52.9%) used dicamba. Compared with applicators reporting no dicamba use, those in the highest quartile of exposure had elevated risk of liver and intrahepatic bile duct cancer (nexposed = 28, RRQ4 = 1.80, CI: 1.26–2.56, Ptrend < 0.001) and chronic lymphocytic leukaemia (CLL, nexposed = 93, RRQ4 = 1.20, CI: 0.96–1.50, Ptrend = 0.01) and decreased risk of myeloid leukaemia (nexposed = 55, RRQ4 = 0.73, CI: 0.51–1.03, Ptrend = 0.01). The associations for liver cancer and myeloid leukaemia remained after lagging exposure of up to 20 years.

CONCLUSIONS: With additional follow-up and exposure information, associations with lung and colon cancer were no longer apparent. In this first evaluation of liver and intrahepatic bile duct cancer, there was an association with increasing use of dicamba that persisted across lags of up to 20 years. FULL TEXT

Gage et al., 2019

Gage, Karla L., Krausz, Ronald F., & Walters, S. Alan; “Emerging Challenges for Weed Management in Herbicide-Resistant Crops;” Agriculture, 2019, 9(8); DOI: 10.3390/agriculture9080180.

ABSTRACT:

Since weed management is such a critical component of agronomic crop production systems, herbicides are widely used to provide weed control to ensure that yields are maximized. In the last few years, herbicide-resistant (HR) crops, particularly those that are glyphosate-resistant, and more recently, those with dicamba (3,6-dichloro-2-methoxybenzoic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) resistance are changing the way many growers manage weeds. However, past reliance on glyphosate and mistakes made in stewardship of the glyphosate-resistant cropping systemhave directly led to the current weed resistance problems that now occur in many agronomic cropping systems, and new technologies must be well-stewarded. New herbicide-resistant trait technologies in soybean, such as dicamba-, 2,4-D-, and isoxaflutole- ((5-cyclopropyl-4-isoxazolyl)[2-(methylsulfonyl)-4-(trifluoromethyl)phenyl]methanone) resistance, are being combined with glyphosate- and glufosinate-resistance traits to manage herbicide-resistant weed populations. In cropping systems with glyphosate-resistant weed species, these new trait options may provide effective weed management tools, although there may be increased risk of off-target movement and susceptible plant damage with the use of some of these technologies. The use of diverse weed management practices to reduce the selection pressure for herbicide-resistant weed evolution is essential to preserve the utility of new traits. The use of herbicides with differing sites of action (SOAs), ideally in combination as mixtures, but also in rotation as part of a weed management program may slow the evolution of resistance in some cases. Increased selection pressure from the effects of some herbicide mixtures may lead to more cases of metabolic herbicide resistance. The most effective long-term approach for weed resistance management is the use of Integrated Weed Management (IWM) which may build the ecological complexity of the cropping system. Given the challenges in management of herbicide-resistant weeds, IWM will likely play a critical role in enhancing future food security for a growing global population. FULL TEXT

Dellaferrera et al., 2018

Dellaferrera, Ignacio, Cortés, Eduardo, Panigo, Elisa, De Prado, Rafael, Christoffoleti, Pedro, & Perreta, Mariel, “First Report of Amaranthus hybridus with Multiple Resistance to 2,4-D, Dicamba, and Glyphosate,” Agronomy, 2018, 8(8). DOI: 10.3390/agronomy8080140.

ABSTRACT:

In many countries, Amaranthus hybridus is a widespread weed in agricultural systems. The high prolificacy and invasive capacity as well as the resistance of some biotypes to herbicides are among the complications of handling this weed. This paper reports on the first A. hybridus biotypes with resistance to auxinic herbicides and multiple resistance to auxinic herbicides and the EPSPs inhibitor, glyphosate. Several dose response assays were carried out to determine and compare sensitivity of six population of A. hybridus to glyphosate, 2,4-D, and dicamba. In addition, shikimic acid accumulation and piperonil butoxide effects on 2,4-D and dicamba metabolism were tested in the same populations. The results showed four populations were resistant to dicamba and three of these were also resistant to 2,4-D, while only one population was resistant to glyphosate. The glyphosate-resistant population also showed multiple resistance to auxinic herbicides. Pretreatment with piperonil butoxide (PBO) followed by 2,4-D or dicamba resulted in the death of all individual weeds independent of herbicide or population. FULL TEXT

Gullickson, 2018

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

SUMMARY:

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.

SUMMARY:

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.

SUMMARY:

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.

SUMMARY:

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.

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.

SUMMARY:

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.

SUMMARY:

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

Bibliography Index