More Bad News for Honeybees
Bayer CropScience just scored a big win on both sides of the Canada/US borders. In January, the U.S. Environmental Protection Agency (EPA) announced it completed the registration of Bayer’s new pesticide, flupyradifurone. The chemical spray can now be marketed as an alternative to neonicotinoid pesticides and “safer for bees.” Health Canada’s Pest Management Regulatory Agency (PMRA), also proposed full registration for the sale and use of flupyradifurone. Good news for the honeybees right? Well, not so much. A closer look reveals the EPA and Health Canada may be misleading the public on the ecological safety of pesticide.
Flupyradifurone (flup) is similar to neonicotinoids (neonics) in that it attacks the nervous system of intended and unintended insects. Like neonics it’s a systemic pesticide and is very persistent in the environment with half-lives in soil ranging from 38-400 days. The major difference is that neonics are lethal to honeybees on contact and toxic when ingested. That’s why the class of pesticides is banned in Europe. Flup is acutely toxic only when ingested. As a systemic pesticide, that thin line of distinction gets lost very quickly in agricultural ecosystems because flup is persist in all the plant tissues, including pollen and nectar for two weeks.
Both agencies note the potential threat to honeybees, birds and other small wild mammals. Health Canada’s solution to minimize risk is to requirement the manufacturer to state the hazards on the label. They also recommend spraying early in the morning or in the evening. The EPA rationalizes that “residues declined in pollen and nectar within a two-week window following treatment.” This means honeybees will be exposed the lethal toxin for at least two weeks. For those adult honeybees that forage on this pollen and nectar during that time, death is imminent. However, using some bazaar reasoning, the EPA believes that while honeybees may touch or tread on flup residues, they’ll be alright as long as they do not ingest the pollen or nectar. You don’t have to be an apiarist to understand this is totally counterintuitive to honeybee behaviour. Honeybees are foragers - they’re not out for a Sunday stroll.
These regulatory reviews raise more questions than answers. Honeybees and native pollinators are essential to agricultural ecosystems. Without their contribution most fruits and vegetables cannot produce. Surely at a time when honeybee populations are in such a steep decline, it seems inappropriate and perhaps even irresponsible for regulators to introduce yet another honeybee toxin to the market. So why is this latest chemical with known risks to honeybees and other wild life even being considered? Both agencies maintain that in spite of the acute oral toxicity, flup has no measurable impact on honeybee colonies, fish or other small mammals based on 38 studies. But who sponsored the studies was unclear.
Another concern is the failure to take into account the cumulative impact of flup and neonics like imidacloprid and clothianidin on honeybees and other non-target insects in the environment. Neonicotinoids, as well as a host of other insecticides are currently used as seed treatment combined with use in other areas of agriculture, the home and gardening sites. Adding flup to the chemical mix already found in the environment will mean that honeybees and other non-target organisms will be exposed to mixtures of chemicals that have yet to be evaluated for their combined or synergistic effects, possibly compounding the already dire plight of pollinators.