By Sharon Omahen
University of Georgia
A University of Georgia researcher is using cable ties to help peach trees make sweeter, larger peaches.
UGA stone-fruit horticulturist Kathy Taylor developed a method that uses cable ties, or strips of plastic like those used to bind computer cables, to control the sugar level in peach trees.
The process, called girdling, isn't new. But using cable ties is.
Keeping the sugar at the top
"Girdling is normally done by using a knife to cut away a strip of the tree's bark," Taylor said. "The sugars that are produced by the tree can't flow below the strip. But this damages the tree and increases the likelihood of insect and disease damage, too."
Taylor says some growers believe the traditional girdling method shortens the life of the tree.
For the past three years, Taylor has used cable ties to girdle peach trees on test plots in middle Georgia, where 95 percent of the state's peach crop grows.
She straps the cable tie to the tree in the winter. In the spring, when the tree grows its peaches, the cable ties restrict the flow of sugars but don't permanently damage the tree.
"You remove the girdle after harvest, and the tree recovers," she said. "And you can do it again the next winter."
Peach trees create sugars by photosynthesis and move them down into the roots for storage. Girdling holds the sugars in the upper part of the tree, Taylor said, moving them up the tree and into the fruit instead.
Larger, sweeter peaches
The increase in sugar draws more water into the fruit. The result is a sweeter, larger peach.
"At the end of the fruiting season, we remove the girdle and allow the sugars to flow back to the roots," she said.
Girdling peach trees with cable ties results in earlier peaches, too, she said.
"Earlier peaches translate into increased profits for the growers," Taylor said. "They'll be able to harvest three to five days earlier than they normally would. And the earlier you can get a crop to market, the greater the return."
Taylor said one large grower adopted the new girdling method last season and had a 5 percent increase in his highest-quality fruit category.
"We've made a lot of progress for middle and late-season peach varieties, but we don't have the technique really optimized for our earlier-season varieties," she said.
Growers as far away as New Jersey and California have shown interest in the cable tie girdling method. "We had a grower in South Carolina try it on about 200 acres with very good results," she said.
Taylor believes the method can be applied easily to fruit crops like apples and plums with similar results. It's available now, but growers haven't widely adopted it yet.
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)