Without the use of an abscission agent, recovery rates for commercial harvesting machines—75 percent to 80 percent—aren’t yet optimal. “That much [loss] we can’t ignore,” Roka says.
The best gleaning crews can bring that figure up to about 98 percent of the crop, close to hand-picking rates while costing 20 to 30 cents per box less, he says.
Abscission’s potential to reduce the amount of gleaning necessary could alter that equation.
Changes in tree and grove architecture as well as machine improvements could help raise recovery rates, Roka says.
“It’s all about capacity and improving the total boxes harvested per season,” he says. “Anything that increases capacity will drive down the unit cost.”
“If there are no major changes to the machines, growers or harvest contractors might be reluctant to invest in a harvester,” Burns says.
“We’ve stagnated on the efficiency of the machines,” Roka says. “There haven’t been improvements in seven or eight years.”
Also ripe for improvement is debris reduction. The force now needed to shake off fruit brings down leaves and branches in amounts that draw processor complaints. Applying an abscission agent could cut debris loads through reduced shaking force, he says.
Machinery trends in blueberries
Southern blueberry growers are seeing a flurry of new and improved harvesting machines, but fresh-market fruit prices and concerns about fruit quality mean many still stick with hand-picking.
Breeding programs focus on southern highbush varieties with firmer flesh that bruises less easily, says Gerard Krewer, small-fruit specialist at the University of Georgia in Tifton.