New species adds to fly problem

Long before the cherry harvest begins, fruit flies have moved in. 

Chris Beason knows that better than anyone. 

The flies usually emerge in June, and won’t stop being an issue until late September. This year the fruit flies were out a little early — just like the cherries that they feed on. 

Beason, a teacher in Minnesota, comes to Montana in the summers to be the cherry pest field inspector for Lake and Flathead Counties.

As he checked his fly traps last Tuesday, Beason pointed out the Western cherry fruit fly. A native species to Montana, the fly has black stripes on its wings.

“It’s pretty easy for me to identify them now,” Beason said as he examined the yellow sticky paper, which was covered in various types of insects.

In 2005, the Flathead Cherry fruit fly pest management area was established. It covers all land within two miles of the lake. By law, all of the cherry tree owners in the area are required to control the flies.

Now another species of fly has moved into the area. The spotted winged drosophila joined the Western fly a few years ago, causing more problems for orchard owners.

There are many sprays, organic and non-organic, that can help control the insects. That’s where Beason comes in. He travels to over 100 orchards around the lake, checking his traps for fruit flies. If there are more than two or three on a trap, he notifies the orchard owners they need to spray.

It’s not always easy to get people to do it.

“About 20 percent of the time I have to play the bad cop,” he said.

If the owners don’t follow the rules, eventually the county will hire people to spray, then charge the bill to the owners.

Even after the harvest, Beason said it is important to spray. 

“The flies will go for the rotten fruit on the ground,” he said. He added that it is important for cherry tree owners to clean up the rotten fruit from the ground after they are done harvesting or it will cause problems the following year.

“Its not a total eradication process like some people think,” Beason said. “Even if an orchard has been spraying for 30 years, they are still going to have flies if they don’t spray.”

When the weather gets cold enough, the larvae from the flies burrow into the ground. There they can lay dormant for up to three years before emerging.

Some people live off the income from their orchards or do it as a hobby, while others use their orchard as a tax break because the land is taxed as agricultural instead of residential. Of the people using the orchards as a tax break, there are those who take care of the cherries, and those who forget about them. Those are some of the people who Beason has trouble getting to spray.

“They buy the property and get their tax break, and within a few years they forget all about it,” he said.

While the flies usually only travel about 50 feet, Beason said he has seen cherry orchard owners get upset at each other about their neighbor’s lack of spraying. An infestation can spread to other orchards nearby, causing hard feelings.

One can understand why people may get upset when one larva in a cherry can ruin an entire crop. A man lost his entire harvest after a processing plant refused his fly-infeststed crop Beason said.