13
Sep
Herbicide Drift from Agricultural Use Found to Harm Bird Habitat
(Beyond Pesticides, September 13, 2019) A study on the use of the herbicide dicamba’s off-target effects finds broad impacts, in both geographic spread and the variety of affected species, with use of the weed killer on Arkansas cropland putting birds at risk in agricultural landscapes. Audubon of Arkansas is reporting results of its community science dicamba monitoring project, conducted under the direction of Bird Conservation Director Dan Scheiman, PhD, and launched in late spring 2019. The project monitored dicamba symptomology in species on municipal, state, and federal lands, where dicamba was not applied, but where its impacts were nonetheless detected. Arkansas Audubon “predicts that in a landscape full of GMO crops [genetically modified organisms] (on which dicamba is typically used), the atmospheric loading of volatile dicamba could be enough to cause landscape scale damage to our state natural areas, wildlife management areas, national wildlife refuges, family farms, and the wildlife they harbor.”
Dicamba herbicides are volatile compounds used to control broadleaf weeds — especially on fields of GMO soybean and cotton crops that have been genetically engineered for resistance to dicamba. These herbicides damage non-GMO crops and native plants well beyond intended application areas. (In 2017, more than 3 million acres of soybeans and other crops suffered damage from the chemical.) In addition, warm temperatures during and after application increase the odds of a state change of the liquid herbicide to a gas, which can then rise and drift for miles in any direction. Thus, dicamba herbicides can move significantly off the intended targets, affecting acreage far beyond the bounds of application sites — damaging as much as half again the amount of acreage on which it is applied.
Community scientists were trained by Audubon to detect such typical dicamba symptoms as leaf cupping (just as it sounds, the leaf takes on a concave shape), epinasty (a distorted leaf growth pattern), and chlorosis (yellowed leaves because of insufficient chlorophyll), and to look for multiple symptoms on one plant, uniform symptoms throughout a plant, and instances of numerous plants in an area exhibiting symptoms. Species found to be affected include oak, redbud, and sycamore trees, and muscadine and trumpet vine plants. From June through August, project staff and volunteers amassed nearly 250 observations of dicamba symptomology across 17 Arkansas counties.
Symptoms were observed in plant species growing on public lands, such as parks, cemeteries, university research farms, church properties, and wildlife management areas, as well as along many state and county roadways. In February 2019, the Arkansas state Plant Board moved the dicamba application cutoff date deeper into the growing season (to May 25) for this year, and changed some regulations to try to limit impacts of the chemical on non-target species. Yet the community science monitoring project found 13 occurrences of dicamba symptoms “within two miles of where [state] Plant Board inspectors collected pigweed tissue samples that tested positive for dicamba. This and the 198 dicamba misuse complaints received by the Plant Board . . . are evidence that dicamba use was widespread this summer despite the May 25 cutoff.”
Dr. Scheiman comments, on the Audubon of Arkansas website, “Spraying Dicamba on millions of acres of soybean and cotton is an uncontrolled experiment that puts sensitive habitats at unacceptable risk. In a landscape full of GMO crops, the atmospheric build-up of volatized dicamba may result in significant damage to our state natural areas, wildlife management areas, national wildlife refuges, family farms, and the wildlife they harbor.”
Complicating the picture of dicamba damage is the increasingly common practice of using both it and glyphosate on GE soy and cotton crops — as glyphosate has become more ineffective, given the development of some weeds’ resistance to the compound. In 2015, Monsanto began selling another iteration of its genetically engineered (GE) soybean seed, which is tolerant of both compounds.
But this seed-plus-double-herbicide protocol has exacerbated the drift problem and resultant plant damage, whether to crops, or to trees and landscapes on nearby private or public lands. Parcels affected have included university research test fields in Missouri, Kansas, Nebraska, and Arkansas, which have reported the same kinds of dicamba symptoms in their test plots from drift (which is a significant problem for their experimental work), and in parks and along public ways in Aberdeen, South Dakota. Recent research shows that the addition of glyphosate to dicamba herbicides increased concentrations of dicamba in the air by as much as nine times those of dicamba alone.
As Beyond Pesticides noted in its July coverage of that research, “exposure to either herbicide poses . . . health risk[s,] and both have been linked to diseases such as cancer. These herbicides also pose a threat to pollinators, especially when drift occurs. Increasing the volatility of dicamba with the addition of summer heat and glyphosate will only increase the spread of the herbicide, resulting in more crop damage, pollinator deaths, and human health concerns. While risks to public health and the environment increase, these new formulations are certain to fail as weeds will, as they have in the past, adapt.”
A number of lawsuits have been brought over this issue of dicamba drift and its resultant harms, including a class action suit. In 2017, the U.S. Environmental Protection Agency (EPA) announced label changes (to “restricted use”) for dicamba products, which aimed to reduce the huge drift issue that causes such damage to contiguous land and crops. In January 2018, following on a huge grassroots effort by Beyond Pesticides and other advocates, the Arkansas state Plant Board instituted a temporary ban on agricultural use of dicamba in agriculture from mid-April through late October of that year. The Arkansas Legislative Council (which by statute acts as a state decision-making body when the legislature is not in session), went on to make that ban official. The moves were attempts to rein in the rampant level of drift, crop damage, and health impacts Arkansans had experienced from the herbicide. Monsanto sued in Arkansas State Circuit Court in 2018 to stop the ban, but lost in that effort.
Then in late 2018 — in apparent obeisance to the agrochemical industry — EPA approved continued use of dicamba. Beyond Pesticides reported at the time: “On October 31, EPA announced changes to dicamba’s registration. Rather than respond to the results of a study performed in coordination with Bayer’s Monsanto, and agreed upon by officials within the agency, Acting EPA Administrator Wheeler decided to ignore adverse impacts to farmers and nontarget species, in favor of the chemical industry. . . . This decision raises a litany of [concerns about] structural problems within the pesticide registration process. Mixtures and synergy are not adequately tested. Inert ingredients are not disclosed. As exemplified in this instance, pesticide producers submit their own studies to EPA in order to support the registration of a product [in] which they have a vested economic interest. Many pesticides, including GE dicamba products . . . are registered conditionally without required health and environmental safety information. . . . Advocates see this action by top-level officials in the Trump Administration as political meddling with a scientific process already structurally deficient, seriously jeopardizing the health and well-being of U.S. residents and the environment. This action is part of a pattern of the Trump administration’s EPA head ignoring the agency’s science.”
As Trump EPA officials continue to roll back and subvert regulations designed to protect the public and the environment, and to work with industry to subvert the agency’s own scientific findings, greater numbers of consumers are changing their purchasing decisions to buy organic foods and other organic products. Marketplace choices signal to producers what the public is willing to purchase, so these choices are an immediate way for the public to protect itself from the risks imposed by regulators’ failures and to give producers feedback. In addition, upset about the way the pesticide industry and EPA collude to manipulate or ignore science in the pesticide review process can be transformed into action. One place to begin is at the local level to eliminate toxic pesticides from your community.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
