Fruit growers across the country should have adequate supplies of the growth regulator Apogee ((prohexadione calcium)) this season. There had been rumors that it would be in short supply. The product controls vegetative growth in apple trees and, in the Eastern United States, is used to reduce susceptibility to fireblight.

Rumors of a shortage apparently arose in the Pacific Northwest, where an increase in demand of more than 50 percent was fueled by growth in acreage devoted to bluegrass seed production. Apogee is used on three crops—grass for seed, apples, and peanuts.

But the rumors are not true, according to a representative of BASF, the chemical company that manufactures the product. Brian Mueller, a BASF representative on Fruit Ridge near Grand Rapids, Michigan, admitted to having some nervous moments when product demand in the West greatly increased at the same time spring was arriving in the East a month early.

But, he said, he expected new shipments to arrive—just in time for spraying to begin. Good weather and proper timing for Apogee sprays were expected to occur in Michigan’s apple orchards about April 21, when king bloom petal fall was expected to begin.

Mueller said “a real scramble” began when BASF realized demand for Apogee by grass seed growers was going to be high, so it geared up rapidly to produce more.

But record warm March temperatures across the Great Lakes and Mid-Atlantic region greatly advanced bloom in the apple crop, where Michigan is nearly a month ahead of normal. That added to the urgency to get more product quickly.

Phil Schwallier, a Michigan State University Extension fruit educator, said king bloom petal fall was expected about April 20, almost a month ahead of normal and five days ahead of New York. Schwallier, as well as Extension educators in New York and Pennsylvania, recommends use of Apogee on most apples almost every year to reduce vegetative growth and reduce the incidence of fireblight shoot strikes.

In Michigan, the general recommendation is for growers to use two 10-ounce applications two weeks apart, with the first at king bloom petal fall. Rates need to be adjusted for tree size and vigor. Research has shown Apogee will reduce shoot growth about 35 percent and cut the number of fireblight shoot strikes by about 50 percent, Schwallier said.


In Washington, no shortages were reported. Nate Squires at the orchard supply company Northwest Wholesale, Inc., in Wenatchee, said he’d been told he could expect to have roughly the same amount to sell this year as in 2011. “I’m not sure exactly how much we’re going to have,” he said. “We’re just waiting to see what happens.”

Squires said Apogee is more important to some growers than others. Many of the large, corporate growers with extensive plantings of high-density apples depend on it to control vegetative growth, while some other growers don’t use it at all.

Dan Flick, agricultural products manager at Wilbur-Ellis Company in Wenatchee, said he heard last winter that there would be a shortage, but that hasn’t materialized yet. In fact, another orchard supply company offered to sell Wilbur-Ellis some.

“We feel pretty comfortable with what we’ve got,” he said. “That rumor was going around, especially in February, but it seemed to get better since then.”

Apogee was first used in 2001. In apples, Apogee inhibits the production of gibberellin that causes shoot elongation. It reduces fireblight, it is thought, by thickening cell walls in new tissue, thus inhibiting invasion by the fireblight-causing bacteria Erwinia amylovora. It must be applied at least 10 days ahead of expected appearance of fireblight symptoms.

Reducing shoot growth helps control tree size, reduces the need for summer and dormant pruning, and opens trees to better light and air penetration. It may reduce the effectiveness of fruit thinners and require using higher rates of them. It can also cause lenticel spots and cracking on the Empire variety.

The use on peanuts is to control canopy spread, Mueller said. On grass, it shortens and stiffens the stalk to reduce lodging.