Beekeepers struggle to keep crops pollinated after half their colonies died last year

JUANA SUMMERS, HOST:

Across the U.S., beekeepers lost about half of their colonies last year. That's according to a national survey. It's one of the highest death rates on record. Honeybees are crucial to our food supply, and across the country, beekeepers are having to work harder to keep crops pollinated. NPR's Allison Aubrey visited a blueberry farm for a lesson in how it works.

ALLISON AUBREY, BYLINE: If you're up for picking blueberries, Hail Bennett has loads of them. It's peak season at his farm in Frankford, Del.

HAIL BENNETT: I think we've got a good blueberry crop this year. You can tell by the size that they're going to have great flavor.

AUBREY: He says honeybees are the key to a great-tasting berry.

BENNETT: We depend on honeybees for our existence. If it wasn't for bees, the blueberries would be much smaller, and they would not have any flavor.

AUBREY: Each spring, he brings in loads of honeybees. For three weeks, they fly around his many acres of blueberries, moving millions of tiny grains of pollen within and between flowers in order to pollinate the fruit.

BENNETT: It's pretty amazing how much work that the bees have to do, and I don't think a lot of people realize that an acre of blueberries has 2 million flowers, and each flower has to be visited six to eight times by a honeybee in order to be fully pollinated.

AUBREY: He breaks open a berry to inspect the seeds.

BENNETT: Probably 15 to 20 at least, so that tells me that that's a great blueberry. And you want to have at least 15 seeds inside that blueberry fruit, and that tells you that that flower was adequately pollinated in the spring.

AUBREY: He offers me a taste.

BENNETT: I would take that one right there.

AUBREY: This variety is called bluecrop.

BENNETT: I like that balance between the acidity and the sugar.

AUBREY: That one is perfect.

BENNETT: Yeah.

AUBREY: Like, a little tart, but...

BENNETT: This one was a good one right here.

AUBREY: ...Also super sweet.

BENNETT: It tastes like great blueberries. You can't beat anything you get fresh off the plant.

AUBREY: Given the vital service that bees provide, there's been alarm in recent years about the rate at which bee colonies have been dying off. And a new survey that tracks colony deaths shows many beekeepers are still struggling. Dan Aurell of Auburn University is one of the researchers.

DAN AURELL: Over the entire year, beekeepers lost 48.2% of their colonies.

AUBREY: He says bees still face many challenges. This is the second-highest death rate since 2010.

AURELL: This is absolutely a concern. We haven't seen a massive spike, but what our survey is showing is that we're not seeing the kind of improvement that we'd like to see.

AUBREY: The bees that farmer Hail Bennett uses for pollination are brought in each spring by a commercial beekeeper, and these beekeepers are having to work harder to protect their bees. One strategy is to try to fend off parasites like the varroa mite. Here's research scientist and beekeeper Jeff Pettis.

JEFF PETTIS: So certainly, a major concern for bees is the varroa mite. It's a very small parasite that feeds on bees and makes it difficult for them to stay healthy in the summer. But in particular, in the winter, it shortens their lifespan.

AUBREY: Varroa is an invasive species that originated in Asia, and Pettis says he uses an organic acid called formic acid to treat against them, which can help.

PETTIS: It is possible to treat varroa. The organic acids are certainly effective, but they do take time and money.

AUBREY: Other challenges bees face are beyond the control of any one beekeeper. Pettis says they include pesticides, a loss of food sources such as wildflowers...

PETTIS: And then you layer on top of that climate change, the big, broad issues of climate change, and bees are really struggling to survive.

AUBREY: For now, blueberry farmer Hail Bennett says he's trying to be a good steward of the land. He invited a hobbyist beekeeper to set up on his farm so people can better understand this connection.

BENNETT: It's important for people to understand that and remember where their food comes from. And, you know, we depend on honeybees for our existence.

AUBREY: Bottom line, he says, no bees, no berries.

Allison Aubrey, NPR News.

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