The death and disappearance of bees is raising questions and concerns from Northwest neighborhoods all the way up to the White House. Some attribute bee declines to the use of certain pesticides – especially after chemicals killed thousands of bees in Oregon. But as EarthFix reporter Cassandra Profita explains, researchers are still trying to determine how much of the nation’s bee problem stems from pesticide exposure.
Beekeeper George Hansen just got some good news.
Hansen: “So they’ve made some honey here.”
The bee hives he rents to a radish seed farm in Oregon’s Willamette Valley are healthy and full of honey. He shakes one of the combs and a sheet of nectar pours out.
Hansen: “That’s all stuff they collected today. That’s pretty good. Makes the beekeeper feel pretty good.”
Hansen’s commercial beekeeping company leases 5,000 honeybee hives to all kinds of farms around the region. These commercial bees have high-risk jobs. The risks they face are complex. But scientists have determined that monoculture crops limit their nutrition. And that makes the bees more vulnerable to pests and diseases. So does exposure to pesticides.
Hansen: “They’re being exposed to agricultural chemicals just constantly, and it’s a lot harder to keep bees healthy under those circumstances.”
Across the country, beekeepers have reported losing 30 percent of their colonies on average since 2006. About a third of the nation’s food crops rely on beekeepers for pollination. So a lot of people are looking for the culprit.
Sagili: “It’s a complex, multifactorial problem.”
Researcher Ramesh Sagili heads the Oregon State University Honeybee Lab. He says a lack of nutrition, new and voracious pests and diseases as well as exposure to pesticides are all part of the problem for bees.
Sagili: “The consensus among researchers is that these six or seven stress factors are playing a perfect storm role and compromising the immune system of the bees.” But the question remains: How much of a role are pesticides playing in that storm? And is it enough to justify banning certain pesticides?
Mace Vaughan works with the insect conservation group The Xerces Society. He says it’s hard to ignore the fact that the rise in bee losses follows an increase in the use of a type of pesticide known as neonicotinoids – or neo-nics for short.
Vaughan: "They've become the most widely used insecticides in the world."
Vaughan says some research suggests low levels of neonics can disrupt a bee’s ability to navigate and forage for food. That may not kill the bees, but it could have what scientists call a "sub-lethal" effect that raises their risk of getting sick. Vaughan's group argues neo-nics should be banned until a new safety review can be completed.
Vaughan: “We don’t have a smoking gun, but we do have research paper after research paper that indicates that very low doses have these sub-lethal effects.”
But none of the research so far has convinced Scott Dahlman that saving bees requires banning pesticides. Dahlman is the director of Oregonians for Food and Shelter. He represents farmers and the companies that make their pesticides. And he says there's a reason neo-nics are so widely used.
Dahlman: "They are much safer for human health and the environment than the other alternatives we've used in the past."
Dahlman says banning pesticides would result in massive crop losses. And that isn't necessary if farmers follow the labels and avoid spraying when bees are around. He says studies showing sub-lethal effects of pesticides only tested bees in a laboratory.
Dahlman: "That's not what happens in the field. I don't think there's enough out there to truly understand what's going on when it comes to possible sublethal effects. But it is a robust area of research, and we'll continue to watch that."
Researcher Sagili says scientists don’t know whether low levels of pesticide exposure could weaken bees enough to cause colony declines. They also don't know what happens when multiple pesticides are combined in a hive.
Sagili: “Are we done with this one?”
Sagili is working with graduate student Stephanie Perreira on an experiment that could help answer those questions.
Sagili: “OK, about 70 percent bees side A. Seventy-percent honey.”
They’re assessing the health of about 40 bee hives in a field in Corvallis. They’ll feed some of the hives pollen laced with pesticide and fungicide. Then, Perreira says, she’ll run a series of tests to see what effect that has on the bees. The experiment is designed to fill a gap in existing research. It’s testing realistic levels of pesticides on bees in the field.
Perreira: “I would like to say that my hypothesis is that being exposed to these pesticides will decrease their immune abilities and increase rates of disease, but there really isn’t a lot of data on that.”
Sagili says the results could shed some light on the sub-lethal effects of pesticides on bees. But those results won't be out for at least a year.
Copyright 2014 EarthFix