Invasive pest puts local berry farmers on the defensive

Jul 23, 2018

Berry harvest is underway in northern Michigan, and this season’s crop forecasts are rosy. But getting those crops harvested is requiring heavier use of insecticides because of an invasive pest that’s on the rise. The situation is taking a toll on the region’s farms and orchards.


Rick and Karen Cross stand next to a pile of dead Saskatoon bushes.
Credit Marla Camp

This story begins with a Facebook post announcing, “We are unwilling to spray as much as needed to eliminate this pest. Therefore we have taken out our Saskatoons.” 

Rick and Karen Cross pulled up over 300 Saskatoon berry bushes this spring and shuttered their farm near Northport. Where there were once densely packed rows of white-blossomed bushes, there is now an empty field.

"Well at first it was terrible,” says Karen. “Because of how much of your heart and soul you invested into these absolutely gorgeous shrubs and then all of a sudden ‘poof’ — gone."

 

Saskatoons are a relatively new fruit crop in northern Michigan.

Rick and Karen were leading a group of growers trying to build an industry for these deep purple berries that have the crunch of an apple, but taste like wild berries and almonds. However, Saskatoons, along with cherries and blueberries, are among the soft fruits that are susceptible to a new pest — spotted wing drosophila. 

Saskatoons, along with cherries and blueberries, are among the soft fruits that are susceptible to a new pest — spotted wing drosophila.
Credit Rick Cross

"First, I asked my neighbor, 'well what are you doing?'" Rick remembers. "When he told me how much he was spraying — there was no way I was going to spray that much and kill every bee. We had bees dying all around us and that ended the game for me."

Growers would prefer to spray minimally in combination with other, less toxic solutions. Now, some are spraying from just after bloom time all the way to just a few days before harvest.

Nikki Rothwell is the Northwest Michigan Horticulture Research Center coordinator. She says it causes stress out in the fields.

"I had a grower who had a young son and he’s just like, 'I didn’t even feel like I saw him this summer because I was just so worried and so busy' — and he had infested fruit," Nikki says. "That, to me, is just heartbreaking."

Spotted wing drosophila, or SWD, is an invasive fruit fly that multiples rapidly within only five to seven days. Plus, unlike other pests, it infests fruit before it ripens. Since fruit buyers have zero tolerance for pests in fruit, growers must spray continuously to keep their crop marketable.

Rothwell says they are working hard on finding more holistic management programs, but there are few options at this time. It’s costly and she says it’s driven a few growers out of business. It’s particularly hit organic growers hard.

Rick Cross chose to pull up all his Saskatoon bushes (pictured), rather than keep spraying for spotted wing drosophila.
Credit Rick Cross

"The other thing I see too, is just people who are just not going to plant anymore," she explains. "Just because they feel that they just can’t get through their acreage or they can’t get their cherries to the processor in a timely manner. So there are smaller ways we are seeing tart cherries come out because they just can’t manage them because of SWD."

There are other concerns besides cost and stress. The most recommended pesticides being used to fight SWD in Michigan contain a class of chemicals called pyrethroids — and the labels warn that they are highly toxic to bees. But the cherry growers relying on these pesticides insist heavier use is not harming the ecosystem. And Nikki Rothwell agrees.

"We’ve been part of a five-year project that was conducted nationally, looking at pollinators in tart cherries, watermelons, blueberries," she says. "We have not seen the wild pollinators drop off in tart cherry systems because of potential sprays for SWD."

But the reason Rick and Karen Cross were unwilling to spray their Saskatoon berries was because of the effect they’ve seen it have on bees in their fields. Rick says not spraying isn’t an option for him either, not with cherry orchards next door.

"I have neighbors," he says. "So if I have this heavily infested area that I’m not treating, it’s not fair to them. And so to me whether or not it was going to put me out of business if I didn’t spray, I wasn’t willing to wait to find out."

So what’s next for Cross Farms? For now, Rick is waiting for his cover crops of field peas and oats to germinate. He’ll plow them under this fall. They’re thinking about maybe growing native trees next —something like basswood. Rick says basswood’s a very good pollinator, and that has Karen excited.

"I think it would be really wonderful, actually, because I like the idea of planting something that’s going to give back," says Karen. "So, you know the trees are on our mind."