It's no secret that the blueberries crop has skyrocketed around the world, and the United States is no exception. In 2019, the most recent data available from the USDA's National Agricultural Statistics Service, 41,500 hectares were harvested in the United States, up 15% in just one year. Production used totalled more than 300,000 tonnes, jumping 21% from 2018, showing at least in part how much more efficient growers are becoming with improved varieties. In 2009, the total area was just 26,000 hectares, meaning that in just one decade, the area harvested in the US has increased by 60%.
Of the total used production in 2019, the quantities destined for the fresh market and processing were quite similar: 170,000 tonnes (57%) for the fresh market and 136,000 tonnes (43%) for processing. But prices were very different, with fresh market berries fetching four times as much: Eur 3.70/kg (USD 2.03 per pound), compared to a price for the processing product of only Eur 0.90/kg (USD 0.50 per pound).
With such an obvious incentive to grow for the fresh market, it's no surprise that growers who have traditionally grown for processing are increasingly looking to grow for the fresh market, says Lisa DeVetter, associate professor at Washington State University, Berry Crops. But one obvious problem is that growing for the fresh market obviously requires higher quality fruit, and has traditionally been hand-picked.
In the Pacific Northwest, where the harvest has boomed in recent years, this would mean an extraordinary effort. Even then, with the decline in available farm labour in the Pacific Northwest - just as growers feel elsewhere - it would be difficult. "If you had to hand-pick all that (fresh market) fruit," she says, "you would struggle to do it."
THE AGE OF AUTOMATION
If there are not enough hands, it means that you have to harvest by machine, and the share of growers who harvest blueberries by machine for the fresh market continues to grow.
"It's increasing rapidly," says DeVetter. "It was 10-20% about 20 years ago. Then, when labour costs started to rise, growers got motivated. In 2016, about 33% of fresh market fruit was machine-picked, according to national surveys.
IN THIS TIME OF COVID THE MECHANICAL HARVESTING OF BLUEBERRY COULD APPROACH 40-50% OF THE PRODUCT FOR THE FRESH MARKET.
Lisa DeVetter Associate Professor, Washington State University
"The share of blueberries mechanically harvested for the fresh market will be much higher by 2025".
This huge growth has come about because of improvements in harvesting machines that make it possible to harvest quality product for the fresh market, a movement that had a new vitality in 2013, he says. The following year, University of Georgia engineering professor Charlie Li, a sensor technology expert launched a USDA specialty crop research initiative. Oxbo International Corp. of Lynden, WA, which manufactures mechanical harvesters for a variety of crops, was involved in the project from the beginning, says Kathryn Van Weerdhuizen, Global Market Manager, Fruit at Oxbo Corp.
"The key to the project was the Berry Impact Recording Device (BIRD)," says Kathryn Van Weerdhuizen. The size of a blueberry, the BIRD could go through the harvesting process and help researchers understand the exact force that blueberries encounters.
"We could then determine a G-force safety zone for blueberries. The first fall is the worst because the fruit falls from the plant to the picker. It is a key step where the berry can bruise," he says.

Unfortunately, that height turned out to be rather small. The G-force experienced by a blueberry dropped on a hard surface results in adent once the height exceeds 30 centimetres, and blueberry plants can be 180 cm high. The machines have gone through several generations, he says, and researchers have tried all kinds of surfaces in search of the right material. In 2018, the second generation of machines was developed. These first soft-surface machines used neoprene, which worked well but was too susceptible to wear and tear.
"The problem was to find a material for the backing plate, which until then was made of Lexan, that was soft enough but also resisted wear and tear," Van Weerdhuizen says of all the lab tests. "People have tried to glue all kinds of soft surfaces onto hard surfaces, but it didn't work."
The Oxbo 7440 harvester is equipped with SoftSurface, which comprises pick-up plates modified with a food-safe elastomeric polymer and soft intermediate pick-up frames suspended above the pick-up plates and conveyor belts.