New research from Ohio State entomologists has uncovered the reason honeybee populations are dying in California almond fields. Credit: Courtesy of the Department of Entomology.

New research from Ohio State entomologists has uncovered the reason honeybee populations are dying in California almond fields.

The study found that bee larvae were failing to become adult drones, primarily due to the different insecticides and fungicides used to protect the almond fields.

“Bees and almonds have a very special relationship,” Reed Johnson, associate professor of entomology and bee expert, said. “Almond production really requires bee pollination.”

With more than a million acres of almonds grown in California, the state accounts for about 80 percent of the world’s almond industry. Because of this, beekeeping is a lucrative business in California.

Johnson said the recommended number of bees is about two bee colonies per acre of almond bloom, which adds up to about 2 million honeybees. Johnson said the problem with this recommended number is that the United States only has about 2.5 million colonies at any given time, and a large portion have already experienced severe colony deaths on the West Coast.

Johnson said that although the use of the synergistic combination of insecticides and fungicides saved almond growers a trip through the field, it took a toll on the resident honeybee population. He said that when the local population takes a hit, bees need to come from other locations.

“The result is bees from Ohio and really all over the country get loaded up on flatbed trucks and sent to California to do almond pollination,” Johnson said.

But bees that are supposed to come back to states like Ohio and pollinate fruit trees, flowers and other important crops are dying off in alarming numbers, Johnson said.

Colin Kurkul, a third-year in microbiology, raised honeybees and worked to identify which combination of insecticides and fungicides were deadly to their larvae.

“Personally, I don’t want the bees to die,” Kurkul said. “I absolutely love working with them, and the way they interact with each other and just their hive mentality is important to agriculture as well.”

Johnson’s research and subsequent recommendations for preventing bee deaths were recently published in the journal, Insects.

Since 2014, the study has seen over a 50 percent reduction in insecticide application, making headway in a decade-long rise in bee deaths.

Johnson said that creating an impact like that is one of the most satisfying parts for him as a researcher.

“We kind of have all our eggs in one basket there during almond pollination, “ Johnson said. “So if something bad happens out there, it’s going to have nationwide effects.”