Should the Agricultural Use of Neonicotinoids Be Banned?

by Kathy Keatley Garvey
UC-Davis Dept. of Entomology and Nematology

A team of entomology graduate students from the University of California, Davis, successfully argued at the Entomological Society of America’s recent student debates that a ban on the insecticides in agriculture “will not improve pollinator health or restore populations, based on current science. Neonicotinoids are important for control of many significant agricultural and veterinary pests. Part of the solution is to develop better regulations that will protect the health of pollinators and retain the use of an important IPM tool.”


Photo bt Trav Williams, Broken Banjo Photography:

UC Davis won the debate, defeating Auburn University, Alabama, and then went on to win the overall ESA student debate championship for the second consecutive year.

“Neonicotinoids are important for control of many significant agricultural and veterinary pests,” team captain Mohammad-Amir Aghaee said at the onset. “Part of the solution is to develop better regulations that will protect the health of pollinators and retain the use of an important IPM (integrated pest management) tool.” The team also argued successfully that neonicotinoids (also known as neonics) are not all “created equal.”

The insecticide, chemically similar to nicotine, is implicated in the mass die-off of pollinators.  The European Union recently adopted a proposal to restrict the use of three pesticides belonging to the nenicotinoid family (clothianidin, imidacloprid and thiametoxam) for a period of two years.  In addition, the U.S. Fish and Wildlife Service announced that by January 2016, it will ban the use of seeds treated with neonicotinoid pesticides and the use of crops improved through biotechnology throughout the 150 million acres managed by the National Wildlife Refuge System.

ESA officials chose the debate topic and assigned UC Davis to debate the “con” side and Auburn University, the “pro” side. The Auburn team argued that neonicotinoids are causing the death of bees essential for pollinating our food crops, and that the use of neonicotinoids should end. The debates took place at the ESA’s 62nd annual meeting, held in Portland, Ore.

The UC Davis team included graduate students Mohammad-Amir Aghaee, Margaret “Rei” Scampavia, Ralph Washington Jr., and Daniel Klittich. Michael Parrella, professor and chair of the UC Davis Department of Entomology and Nematology, served as their advisor.

The Auburn roster included captain Olufemi Ajayi, Adekunle Adesanya, Julian Golec, Matt Burrows, Scott Clem and alternate Zi Ye. Associate professor David Held served as their advisor.

ESA sponsors the lively, cross-examination-style student debates as an educational and entertaining component of its annual  meetings. The teams are given eight months to prepare. Team members must be enrolled in an entomology degree program (bachelor, masters or doctorate).   Each debate spans 45 minutes and includes a seven-minute statement by each team; cross-examinations; rebuttals; and questions from the judges and audience.
The UC Davis team cited three main points:

  • Pesticides are IMPORTANT tools used in modern agriculture
  • Neonicotinoids were registered as reduced risk pesticide to replace the organophosphates, carbamates, and pyrethroids
  • Banning neonicotinoids would increase of use of pesticides that have known non-target effects

The UC Davis team agreed that acute and chronic studies “have shown that neonics are toxic to honey bees and bumble bees (Blacquiere et al. 2012)” but argued that “all neonics are not created equal (Brown et al. 2014). They cited “inconsistent results with field-realistic doses (Cresswell et al. 2012)” and noted that “many other factors have been documented as contributing to pollinator decline (Epstein et al. 2012).”

It’s not just insecticides that are killing bees, the UC Davis entomologists said. They listed the varroa mite (Varroa destructor), considered by U.S. beekeepers as Public Enemy No. 1; vectored pathogens, acaricides, antibiotics and fungicides directly added to the colony; pathogens such as American foulbrood and Nosema bombi); inadequate honey bee nutrition; insufficient food substitute: habitat fragmentation; and land-use changes and the increasing demand for pollination changes.

The UC Davis entomologists recommended that

  • Regulatory agencies need to have more thorough registration guidelines that incorporate bee toxicity data for all pesticides (Hopwood et al. 2012). This would encompass chronic toxicity, sublethal effects and synergistic effects.
  • Better management practices be mandated that follow IPM principles that protect bees on crops (Epstein et al. 2012). This would include banning certain application strategies, using less toxic neonicotinoids, and encompass the essential education and communication.

In its summary statement, the UC Davis team said: “There is NO definitive scientific evidence that neonicotinoids are the primary cause of pollinator declines. Neonicotinoids are important reduced risk pesticides for management of some of our most damaging pests. Neonicotinoids should be better regulated, not banned.” They concluded: “Given the current state of knowledge, banning neonicotinoids is a premature and disproportionate response to a complex issue. This requires holistic scientific inquiry and interpretation, and cooperation among stakeholders. Any changes must be based on science rather than opinion, current trends, or fear.”

The Auburn team, or the pro-team, opened the debate with “Neonicotinoids are causing the death of bees essential for pollinating our food crops. The use of neonicotinoids should end.”

Why? They outlined six key points:

  1. Critical time for pollinators in the United States
  2. Lethal and sub-lethal effects
  3. Prevalence and exposure
  4. Effects on other pollinators
  5. Risk-assessment
  6. Food Quality and Protection Act (FQPA) as a precedent

Expanding on the fact that this is “a critical time for pollinators in the United States,” the Auburn team pointed out:

  • Honey bees pollinate $15-20 billion dollars worth of crops in the U.S., and $200 billion worldwide
  • Approximately $3 billion worth of crop pollination services are provided by native bees
  • Colony Collapse Disorder likely has many contributing factors but many of those are enhanced by neonicotinoids
  • The declining honey bee population: the U.S. had 6 million bee colonies in 1947 and now it’s down to 2.5 million

The Auburn team keyed in on lethal and sublethal effects of neonics:  synergistic interactions with other pesticides, including DMI (demethylation inhibitor) fungicides; increased susceptibility to pathogens (Nosema spp.); decrease in foraging success; decrease in overwintering queen survival; learning impairment consequences; and reproductive inhibition.

The Alabama-based team also called attention to prevalence and exposure to neonicotinoids. They discussed the neonicotinoid residues found on bee-pollinated crops and plants by various means of exposure: seed coating; foliar spray, soil drench, trunk injections; length of residue (soil vs. foliage and length of bee exposure); and single exposures resulting in season-long impacts. They also said the multiple means of exposure due to application can lead to multiple routes of exposure within bees: via pollen, nectar, guttation fluid and extrafloral nectaries.

In addition, the Auburn entomologists argued that new and novel modes of action and classes of insecticides are emerging. leading to alternative options, and that the banning of neonics in agriculture won’t destroy agriculture. They also discussed the restriction of organophosphate use with the adoption of FQPA in 1996. If neonics were banned, they said, this could open the door “for stronger and more reliable risk assessment” and potentially, “the adoption of integrated pest management (IPM) tactics.”

In their concluding statement, the Auburn team said that current tools for risk assessment may not be adequate; and that limiting neonicotinoid use will not harm agriculture–“it will open the door for more sustainable agriculture and new insecticides.” They emphasized that we must save our pollinators, especially in the United States. “The United States is a special case–globally there is an increase in bee colonies; however, the United States is at a critical point at which bee pollination services are being threatened irreversibly.”

One of the several swaying arguments that led to UC Davis winning the debate was that not all neonics are created equal, and thus, they should not all be lumped together as “an equal” and all be banned.

The UC Davis team received a $500 cash award, a plaque and a perpetual trophy engraved with UC Davis. ESA president Frank Zalom, a distinguished professor and IPM specialist in the UC Davis Department of Entomology and Nematology, presented the awards. UC Davis team consultants included Extension apiculturist (emeritus) Eric Mussen and Extension entomologist Larry Godfrey, both of the UC Davis Department of Entomology and Nematology; and Dave Fujino, director of the California Center for Urban Horticulture at UC Davis.

Mussen, who retired in June after 38 years of service, met periodically with the UC Davis team at its practices. He’s frequently asked if neonics are the primary cause of CCD.  “Neonics are only one of the classes of pesticide residues that we frequently find in analyses of adult bees, beeswax and stored pollens.  We encounter CCD in colonies in which no neonicotinoid residues can be found, and we find colonies surviving year after year with measurable residues of neonicotinoids in the hives.  Obviously, neonicotinoids do not appear to be ‘the primary’ cause of CCD.”

Prior to the meeting, each team submitted a draft summary of its position (600 words maximum), and no more than 15 references, to the Student Affairs Committee Chair. After the meeting, each team can revise its manuscript before it is submitted for publication to the ESA journal, American Entomologist.