Oh No: ‘Safe’ Pesticides Are Killing Bees, Too

The thing about scholarly research is that the more we learn about something, the more we discover how much more we still have to learn. That’s definitely the case when it comes to bees. Researchers have been trying to pinpoint the cause of devastating incidents of colony collapse disorder (CCD).

For example, researchers have been working hard to find a link between bee deaths and certain types of pesticides. In recent years, scientists have more confidently pointed to neonicotinoids as a major cause of CCD.

Alas, it seems the blame can be spread to other pesticides, too. According to a new study out of the University of Maryland, pesticides that have previously been labeled “safe” for bees by the scientific community seem to actually be contributing to the problem as well.

In particular, the research demonstrated that fungicides, typically the pesticides of choice for farmers and gardeners who want to avoid killing pollinators, were much more harmful to bees than originally expected.

The researchers had looked at over 90 bee colonies and charted what kinds of pesticides the bees had in their system. Most bee studies have attempted to identify specific pesticides, but this research kept tabs on every kind of chemical in the bees.

They noticed a lot of fungicides, particularly in colonies that died off. It turned out that when bees had high enough contact with “safe” pesticides, the chemicals were just as likely to destroy a colony than the better-known toxic ones.

In fact, the researchers found very little neonicotinoid in the systems of the bees, perhaps because farmers are more aware of how harmful they can be. Nevertheless, the bees continued to die, apparently due to the exposure to other pesticides.

“Our results fly in the face of one of the basic tenets of toxicology: that the dose makes the poison,” said Dennis vanEngelsdorp, a professor who worked on this study. “We found that the number of different compounds was highly predictive of colony death, which suggests that the addition of more compounds somehow overwhelms the bees’ ability to detoxify themselves.”

While farmers deserve credit for using pesticides they believed did not pose a threat to bees, “credit” doesn’t actually save the bees’ lives. Knowing which kinds of chemicals – if any – can be used when growing crops without killing the bees is important.

Considering that bees were just included in the Endangered Species Act for the first time in American history, finding out the causes of CCD is especially critical. While it’s true that we still have a lot more to learn about bee deaths, it seems appropriate to err on the side of caution to ensure that these pivotal pollinators can have their numbers revived.

Photo credit: Thinkstock


Sarah Hill
Sarah Hill2 years ago

The worst part is a lot of the time pesticides aren't really needed, it's just precautionary.

Marie W.
Marie W2 years ago

Thank you for sharing.

Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Jen S.
Jen S2 years ago

I should mention that I have two well-populated bat houses, who keep the mosquitoes down.

Jen S.
Jen S2 years ago

I have two hives in my gardens and I use no pesticides at all, not even on my roses. Bees are so important and very sensitive to chemicals, so mine don't get any. My single biggest issues are the local farmers who use pesticides in mass quantities. I have some space and the bees have lots of flowers and plants to eat in in my yard.

Patricia H.
Patricia Harris2 years ago

Jane M., I have an even better idea!! How about, instead of doing more research, how about we just ban the damn chemicals?!

Jane M.
Jane M2 years ago

SO SORRY ! this is terrible!! more studies I GUESS!!!

Loran Watkins
Loran Watkins2 years ago

There's no such thing as a "safe pesticide". Look at the ingredients. All they're doing is saying certain levels of this poison can be tolerated by x-percentage of a certain population. It's the same way they rate chemos and radiation treatment for cancer patients. They know they protocols will kill a certain percentage of people who use it, they just figure the inherent damage is worth the risk. When you hear "LDL" levels attached to something that means "Lethal Dose Level". So when my now ex-husband had radiation with an LDL level of 30 that meant 30% of the people getting that sort of radiation died from a radiation-caused disease. LDL levels of pesticides vary but many are in the 15-20% range, and those numbers are most likely the lower end of the scale so that, if questioned, the public will buy it figuring it's "not so bad".

It's bad.

Wendi M.
Wendi M2 years ago


Anne H.
Past Member 2 years ago

Interesting issue to follow up