(Beyond Pesticides, November 21, 2016) The potential benefits of “weeds” have long been ignored, but a new study attempts to quantify the benefits of all species within an agricultural system, including the undesirable ones. The study, Integrating Insect, Resistance, and Floral Resource Management in Weed Control Decision-Making, by Cornell University scientists, assesses and updates holistic integrated pest management practices. In a discussion with the Cornell Chronicle, lead author of the study, Antonio DiTommaso, Ph.D., states, “Managing crop pests without fully understanding the impacts of tactics —related to resistance and nontarget plants or insects— costs producers money.” The authors introduced a weed management decision framework that accounts for weed benefits and illustrates that by allowing low levels of weeds in a cropping system, a farmer can increase crop yields and provide numerous ecosystem services.
In a case study of an herbicide-tolerant corn cropping system, which had been controlled primarily with glyphosate, the authors demonstrated that the European corn borer (ECB) could be reduced through holistic management decision making. The data suggest that, “Milkweed plants harboring aphids provide a food source (honeydew) for parasitoid wasps, which attack ECB eggs.” By maintaining low densities of milkweed in the corn field, farmers allow beneficial pest populations to flourish, thereby improving the likelihood of controlling the non-beneficial pests. They found that having low milkweed densities in the field was especially effective at reducing yield losses when there were high pest densities of the ECB. In addition to these benefits, milkweed, a plant species that has been disappearing from the landscape due to chemical-intensive, mono-cropped agriculture, is a much-needed plant host for the monarch butterfly. This pollinator species has been declining in numbers over the past few decades due to the loss of milkweed, destruction of habitat, and sublethal effects from pesticides.
Researchers have found that a failure to consider the full costs and benefits of weed management leads to long-term negative externalities, such as wide-scale pesticide resistance and declining non-target organisms that offer ecosystem services. According to the authors, it is vital to fully integrate all of the costs and benefits of weed management to sustain profitability, while minimizing harmful environmental impacts.
This holistic weed management system described in the Cornell study builds upon the foundation of Integrated Pest Management (IPM). While not adopting the systems approach utilized in certified organic production, well-defined IPM is a program based on prevention, monitoring, and control which offers the opportunity to eliminate or drastically reduce the use of pesticides, and to minimize the toxicity of and exposure to any products which are used. IPM does this by utilizing a variety of methods and techniques, including cultural, biological and structural strategies to control a multitude of pest problems. Those who argue that IPM requires the ability to spray any pesticides, or “judicious use of pesticides,” after identifying a pest problem are not embracing an organic systems approach to soil fertility management that nurtures biological life in the soil and only compatible inputs (substances) that do not harm the ecosystem. Chemical-intensive pest control tends to ignore the causes of pest infestations and instead rely on routine, scheduled pesticide applications, which creates a pesticide treadmill with increasing dependency and insect and weed resistance over time. Pesticides are temporary fixes and are ineffective over the long-term.
A large shift in agricultural practices is necessary to ensure protection of human health and the environment over the long-term, according to a wide-ranging report authored by the International Panel of Experts on Sustainable Food Systems (IPES) earlier this year. According to the report, diversified agroecology focuses on maintaining multiple sources of food production, and farming by applying ecological concepts and principles to the design and management of food systems. Industrial agriculture, on the other hand, requires highly-specialized production of a single food crop, and, through scale and task separation, focuses on increasing productivity through intensification. Despite the call for a shift to agroecological farming systems, Beyond Pesticides points out that there is neither a legal nor standardized definition of agroecology or sustainable agriculture. Certified organic systems are accountable to a public rulemaking process and defined by law, the Organic Foods Production Act, which requires an “organic systems plan” that incorporates many of the prongs of agroecology, with efforts underway to add a social justice component.
Ecological pest management strategies, organic practices, and solutions that are not chemical-intensive are the most appropriate and long-term solution to managing unwanted plants and insects. Beyond Pesticides is working to strengthen organic farming systems by encouraging biodiversity and holistic management practices, and upholding the spirit and values on which the organic law was founded. Underpinning the success of organic in the U.S. are small-scale producers who focus on fostering biodiversity, limiting external inputs, improving soil health, sequestering carbon, and using integrated holistic approaches to managing pests, weeds, and disease. As a 2014 University of California Berkeley study determined that diversified organic agriculture can and must be the approach used to feed the world into the future. An October report in The New York Times shows that genetically engineered crops failed to increase yields or reduce pesticide use.
Take action to end the pesticide treadmill by commenting on EPA’s proposal to expand the registration of the toxic pesticide, Enlist Duo. EPA is proposing that its registration to amended to include use on GE cotton and in 19 additional states. Write a comment to EPA telling them that you do not support this expansion for Enlist Duo, as it is not consistent with a transition to organic and holistic management systems. Public comments must be submitted by December 1, 2016 to EPA docket #EPA-HQ-OPP-2016-0594.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Cornell Chronicle