Wenatchee, Wash. — Some East Coast and Midwest apple growers think their apples don't look knobby enough. Now, thanks to chemistry, they can buy a spray that helps turn around, stubby-looking apples into more slender products with the distinctive knobs at one end, the trademark of the Washington State Red Delicious apple.
Commonly called "the apple stretcher," the chemical, promalin, was discovered by scientists at the US Department of Agriculture research station at Wenatchee and developed commercially by Abbott Laboratories of North Chicago.
So far this year, the company has sold approximately $500,000 worth of the spray to growers, mostly in the East and Midwest, who want to produce fruit that looks like the classic Northwest apple.
All this tends to amuse the man who, most acknowledge, is the father of promalin, researcher Max Williams of the Wenatchee research station.
The spray isn't entirely what it's cracked up to be he says. Published accounts would lead one to believe that promalin gives the grower maximum "lobiness." But "some growers would be happy if they got any lobiness at all," he says.
Mr. Williams and his colleagues at the station discovered the principle behind the apple stretcher while trying to find a substance that would improve the apple "set" or the amount of fruit on a tree.
They noted an interesting side effect. The chemical tended to make the fruit longer, and they published the fact in 1970.
A few years later, Abbott Laboratories picked up the idea and carried the research further. For the past two years it has been marketing the product commercially.
Promalin basically is made up of the naturally occurring hormones that are responsible for producing the elongated effect and knobs of the Washington Red Delicious apple.
But it just so happens that in most growing areas of the country the warm nights tend to kill this substance, resulting in rounder, squatter looking apples, Williams says.
Few areas outside of central Washington are blessed with the consistently cool nights at blossom time that spur hormone production and the natural occurrence of the knobs.
Northwest apple growers aren't going into a panic over the apple stretcher. In fact, a fair number of Northwest growers have been using it themselves because there are pockets in the Northwest where the nights are warmer and where farmers have a harder time producing apples with distinctive shape.
But another reason for using the chemical is that it increases the length of the apple without cutting its width, in effect increasing yields by as much as 2 to 3 percent.
In some cases the grower can cover the expense of spraying, which at about $ 80 an acre can be pretty expensive, says Cal Bosch, who edits the "Good Fruit Grower," a publication of the Washington Fruit Commission.
Mr. Bosch says he has been running articles about promalin for the past few years and says it is used throughout the region, mostly to increase yield.
Bosch adds he doubts that it will become a secret weapon for Eastern growers.
"Outsiders want the Red Delicious shape, but what they get is what ours look like without promalin. With promalin we get an even more striking product," he says.