Bud counting benefits growers, but not enough growers have adopted the practice, Michigan State University Extension educator Phil Schwallier said.
As trees continue to get smaller, however, more growers see the need to count buds — and to prune based on those counts — as part of a growing movement toward precision cropping that includes trunk and limb cross-sectional area measurement practices, he said.
Michigan grower Bridget Engelsma described her family farm’s pruning-to-bud-count trial during the International Fruit Tree Association’s 63rd annual conference in Grand Rapids, Michigan, in February. Engelsma spoke during a panel about grower experiences with precision cropping, which included talks from Ontario’s Tom Ferri about the fruitlet growth model, New York’s Jill MacKenzie about her method for counting clusters, and Washington’s Suzanne Bishop about artificial spur extinction.
The Engelsma family grows 65 acres of high-density fruit near Grand Rapids. They’d heard about pruning to bud count on IFTA tours, and Schwallier had been encouraging them to try the technique, so they decided to set up a trial last year, Engelsma said.
Bud load pruning gets growers to think about thinning their crop earlier and with more precision by pruning off excess fruit buds and leaving only an adequate number to set a target crop, Schwallier said.
“We are able to prune poor buds off and leave higher-quality buds,” he said. “This is the beginning of reducing crop load to the desired target level. It reduces the early competition between flower clusters and fruitlets, maximizing potential fruit size and quality.”
The Engelsmas’ pruning-to-bud-count trial consisted of 6-year-old Gale Gala trees on Budagovsky 9 rootstocks. The spacing was 12 feet by 3 feet, for about 1,200 trees per acre. They wanted to reach a specific bud count of 90 apples per tree, with the goal of getting 50 bins to the acre of 80-count Galas, Engelsma said.
In winter 2018–19, Engelsma and her pruning crew trimmed the entire block down to 145 buds per tree. After the initial bud count, they took out two large limbs per tree on the first pass. After a second count, they realized there were still too many buds, so they went through again and took out another big limb from each tree. They ended up counting buds three times that winter. But if they hadn’t counted so thoroughly, they wouldn’t have realized they had too many buds — and wouldn’t have had a clear idea how much thinning they would need to do later in the season.
It seems to have worked. After pruning, they did very little chemical thinning and no hand thinning, she said.
Counting buds is tedious, Engelsma said, but the pruning-to-bud-count technique resulted in “outstanding” fruit size and color.
“We are implementing the practice of pruning to bud count throughout the whole orchard,” she said. •
—by Matt Milkovich