2019 Open House Report: Part l

Beyond Herbicides and Hubris:
Why Butterflies, Birds, Beetles and Babies Need Weeds


Dr. John Losey

In his talk, Dr. John E. Losey* integrated the perspectives of scientists from two different disciplines both focused on the agricultural status of Common Milkweed, a perennial native plant. Weed scientists had traditionally advocated eliminating Milkweed plants along with other unwanted vegetation from farm fields, to prevent their reaching levels that could reduce crop yields. The entomologists’ perspective, by comparison, focused on Milkweed plants providing biodiversity, contributing to pest control and helping restore populations of an iconic insect.

Common Milkweed

The Collaboration consisted of Cornell scientists working to determine the optimum quantity of Milkweed plants per acre needed to support effective natural pest control (involving Milkweed aphids and beneficial predator wasps) while minimizing the Milkweed plants’ negative impact on crop yields.

How this Cornell Collaboration pertained to certain major crops is discussed below — as well as in the widely read scientific publication, “Integrating Insect Resistance, and Floral Resource Management in Weed Control Decision-Making,” (by Antonio Di Tommaso, John E. Losey et al, Weed Science 2016, 64, 743-756)


The weed scientists’ traditional perspective has influenced our nation’s agricultural trend of weed elimination and facilitated development of the Genetically Modified Organism/GMO growing system. This trend has resulted in the transformation of DNA from two major US cash crops, corn and cotton, providing them with the means to tolerate high levels of the herbicide RoundUp® (active ingredient glyphosate). Under this GMO growing system, regular RoundUp applications allow farmers to keep Milkweeds and other plants out of their fields without appearing to harm their transgenic crops. Cultivation of corn and cotton as transgenic/Genetically Modified Organisms (GMOs) in the U.S began in the mid to late 1990s — RoundUp was introduced in the 1970s. Note: At one time more than 90% of the seeds for corn and cotton had been converted into “RoundUp Ready” GMOs (tolerant of the herbicide glyphosate). In conjunction with the growing of these transgenic crops, in the U.S. alone, over 100 million acres were treated with RoundUp to remove all weeds (including Milkweed). At RoundUp’s peak use, nearly 300 million pounds were applied every year (a great increase over the pre-GMO use).

Dr. Losey noted that after farmers adopted glyphosate-tolerant (RoundUp-Ready GMO) seeds for corn and cotton, their fields — treated frequently with RoundUp — came to resemble a “moonscape,” barren of plant life, except for the crop.

Milkweed Aphids

Cornell scientists established that Milkweed plants by acting as hosts for Milkweed aphids — insects that suck plant juice and furnish a sweet by-product honeydew could be part of a natural pest control service for farmers growing corn and cotton. Note: Honeydew is produced by various insects including aphids by sucking sap from the phloem tubes of plants. Phloem sap caries sugar and nutrients produced by the leaves down to the stems and roots. This material becomes honeydew in the aphid’s body and passes out. “Many insects [such as wasps and bees] and even some people include this abundant substance in their diets”. (p. 144, Waldbauer, G., What Good Are Bugs?: Insects in the Web of Life, 2003, Harvard U. Press). Aphids on certain plants such as roses are considered pests.

European Corn Borer

This honeydew is a favorite food of a tiny beneficial wasp that kills a top pest of corn, the European corn borer (another similar wasp provides natural control for a major insect pest of cotton). Greater numbers of these beneficial wasps are linked to higher yields in both crops.

Monarch butterfly

The pre-GMO corn fields of the US South and Midwest where Milkweed flourished, had provided habitat for the Monarch butterfly as the species migrated from Mexico to summer ranges in North America. The Monarch butterfly (perhaps the most popular insect in North America) was named the national insect of the United States in 1990. Note: The Monarch butterfly is being considered as Endangered or Threatened under the Endangered Species Act. In 2014 the US Fish and Wildlife Service found sufficient evidence to classify the Monarch butterfly for protection under the Endangered Species Act. However, the final ruling has not yet been made. If the Monarch becomes listed as Endangered or Threatened, then anyone degrading the Monarch’s critical habitat could face fines up to $50,000 and up to one year in prison.

Milkweed leaves serve as the essential food for Monarch caterpillars and Milkweed blooms are a source of nectar for adult Monarchs as well as for pollinators (bees, butterflies and other insects). Milkweed plants once abundant, are no longer widely distributed throughout the South and Midwest.

Scientists have linked the recently observed decline of Monarch butterflies to loss of Milkweed plants in the Midwest US following widespread applications of RoundUp (as well as to other factors). Beneficial insects (especially bees) have been declining recently, as well. Insect declines can adversely impact birds, fish and other wildlife in a wide variety of food chains.

Current Problems With GMO Crops, and Glyphosate (active ingredient in Roundup)

  • Dr. Losey reported that recently some 20 weed plants have shown resistance to glyphosate (active ingredient in RoundUp), resulting in GMO growers being required to buy a new type of transgenic corn and cotton seeds genetically transformed to tolerate a second more effective herbicide (in addition to glyphosate). In conjunction with planting new transgenic seeds, these farmers now must apply glyphosate and a different herbicide to eliminate all weeds from their GMO fields. The active ingredient in the additional chemical herbicide, dicamba, is difficult to control. After spraying It can volatilize and drift to neighboring farm fields, seriously damaging any unprotected plants. Non-GMO farmers in the Midwest and the South have organized protests against dicamba’s destruction of various crops being grown conventionally or organically. Some states have temporarily banned use of dicamba in response to urging by non-GMO farmers.
  • Recently, GMO seeds have become more expensive. Some farmers have opted to use less expensive non-GMO seeds to avoid the higher costs.
  • Consumers are increasingly demanding non-GMO foods.
  • Although not emphasized by Dr. Losey, the herbicide glyphosate (active ingredient in RoundUp) has been linked to human health hazards. People increasingly exposed to levels of glyphosate in their water and food have called for government action to reverse this trend (Nossiter, A., “The Mayor Who Banned Pesticides and Became a Hero,” The NYT, 9-19-19), (The Cornucopia Institute—on-line). In 2015 the World Health Organization categorized glyphosate as probably carcinogenic to humans. (The Cornucopia Institute—on-line). Researchers have linked glyphosate to disruption of gut bacteria and to autism in children. In combination with aluminum, glyphosate is linked to a synergistic adverse effect on the pineal gland, located in the brain. (Seneff, S., et al, “Aluminum and Glyphosate Can Synergistically Induce Pineal Gland Pathology: Connection to Gut Dysbiosis and Neurological Disease,” Agricultural Sciences, 2015, 6, 42-70)

Financial Support for Biodiversity

Dr. Losey noted that over the past 5 years, a variety of organizations: government agencies, chemical companies, and NGOs, have contributed financially to support “biodiversity” in agriculture. Of the millions of dollars per year raised for research grants, a substantial amount has been focused on increasing Monarch butterfly populations — in part for an unusual reason:

There is a certain fear that if the Monarch butterfly were to be listed under the Endangered Species Act (ESA), as has been generally expected (unless the numbers increase), then “if you harmed one or damaged its habitat you could be fined $50,000 and even spend time in jail.” Thus it is in the self interest of growers (and those companies supporting them with agricultural chemicals) that the Monarch butterfly not be listed as endangered or threatened (under the ESA).

Further, as Dr. Losey maintained, growers want to be good stewards and they’ll forego some profit to foster biodiversity (including greater numbers of Monarch butterflies).

RCLA Comment — Promise and Peril: Researchers’ Findings and Trump Administration’s Policies

The Hopeful Promise: Dr. Losey presented details about Cornell University scientists’ collaboration that has proposed a way of linking biodiversity and natural pest control to a new holistic and sustainable growing system.

If adopted by commercial growers the result could be reduced use of the herbicides, glyphosate and dicamba as well as curtailing of certain insecticides. Note that high levels of pesticides in food and water are possible threats to human health especially of children. Also, chemical pesticides are considered to pose direct and indirect threats to bees, butterflies, beneficial insects, and birds, all reported as undergoing alarming population declines. This represents a serious loss of biodiversity.

Scientists from around the globe as well as at the UN have called for transformative changes to conserve biodiversity and restore losses. (Plumer, B., “Wildlife Facing Extinction Risk All Over the Globe, U.N. Report Warns,” The NYT, 5-11-19) Freedman, A., “More than 11,000 scientists around the globe declare a `climate emergency,’” The Wash Post, 11-6-19)

Dr. Losey and his Cornell colleagues are to be commended for their collaborative, innovative agricultural research. It speaks to the economic concerns of farmers, to the biodiversity concerns of scientists, and to the human health concerns of health professionals who have linked pesticide exposure to various neurological disorders and cancer.

Certain actions by the Trump Administration, however, could serve as obstacles to a successful implementation of the Cornell Collaboration. Further, sustainable agriculture strategies and protection of endangered species are being put at risk from policies by the current administration.

Possible Peril: Actions by the Trump Administration That Could Adversely Impact Farmers, Monarch Butterflies, and Human Health (A Brief Review):

  • Endangered Species Act (ESA) Enforcement Curtailed: If Monarch butterflies become listed under the Endangered Species Act (ESA) as was projected in 2014, then the threat of fines or even jail time for anyone killing them or destroying their habitat could act as an incentive to protect members of the species. Planting Milkweed in crop fields would help increase the species’ numbers and contribute to reducing the possibility of such a listing.

However, if as indicated recently by the Trump administration, the federal government curtails enforcement of the Endangered Species Act, then this incentive for farmers to help increase Monarch population numbers could be eliminated. (Note: In 2018 the Trump administration proposed regulations that would weaken the ESA. (Brulliard, K., “Court restores protections for Yellowstone-area grizzlies,” The Wash Post, 9-26-18)

  • GMO Crops Bolstered/ Pesticide Use Fostered: Now, at a time when GMO crops are losing favor with consumers and when farmers are switching away from GMO to conventional and organic growing methods for economic reasons, the Trump administration has turned the U.S. government into a propaganda arm of the GMO branch of the biotechnology industry. On June 11, 2019 the Trump administration signed an executive order that requires the government to “facilitate engagement with consumers in order to build public confidence in, and acceptance of biotechnology in agriculture.” (IPM Practitioner XXXVI (11/12) August 2019). This action if successful could ultimately cause financial harm to farmers already stressed by declining sales, and needing to reduce costs by switching away from GMO crops. It could also have a detrimental impact on the iconic Monarch butterfly — by resulting in more “moonscape” farm fields without Milkweed plants. Further, the resulting increase in use of glyphosate and dicamba would lead to greater likelihood of food, water and environmental contamination with these hazardous chemicals.
  • Diminished Appreciation for the Value of Science: The holistic approach to milkweed plants in corn and cotton fields based on the collaboration of weed scientists and entomologists has been a groundbreaking science-based, sustainability approach that needs to be matched for other crops. Under the Trump administration, however, the status of science has been considerably reduced in determining the policies of our federal agencies. (Dennis, B., “EPA pushes ahead with effort to restrict science it uses to craft rules,” The Wash Post, 11-13-19)

How to Help Counter these Projected Perils

You Are Invited to Join with Your Friends at RCLA in Support of Biodiversity, and Sustainable, non-GMO Agricultural Programs

We all need to show greater awareness of and support for biodiversity, natural pest control methods, and the reduced use of chemical pesticides as well as greater understanding of and advocacy for true science for the sake of the prosperity of our farmers, the survival of our wildlife and the health of our children and families.

Contact NGOs urging them to provide education and incentives for ways that farmers can switch from GMO-based cultivation and instead use growing methods that are: regenerative and organic (preferably) or even conventional when incorporating Integrated Pest Management (IPM). And of course we all need to purchase organic food and fiber to the greatest degree possible.

RCLA challenges philanthropists to become involved in supporting research on agricultural strategies that enhance biodiversity and lead to greater emphasis on sustainable agricultural methods.

Finally we need you to donate to RCLA so that we can increase our outreach and activities. Please send checks to:

11701 Berwick Rd.
Silver Spring, MD 20904

Note: RCLA discussed changes to agricultural policy in “The Organic Link to Lower Cancer Risks and Sustainable Agriculture: A Report from RCLA.”

Diana Post
President RCLA, December 2019

*About Dr. John E. Losey

Dr. Losey is a professor in the Department of Entomology at Cornell University, chair of the Ladybird Specialist Group of the IUCN (World Conservation Union), and director of the Lost Ladybug Project, a citizen science program that educates non-specialists on the important role that ladybugs play in the suppression of pests. Dr. Losey has published articles on the impact that transgenic crops have on beneficial insects, the economic value of the ecological services insects provide, the causes and consequences of decline in native lady beetles, and the incorporation of volunteers in research and conservation. He teaches courses on insect conservation biology and integrated pest management.

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