New Technique Thins Excess Blossoms and Boosts Tree
November 23, 2007
Too many flowers on peach and apple
trees are not necessarily a good thing. If all of the flowers that formed in
springtime were allowed to become fruit, the resulting crop may be large, but
the fruit would be excessively small and unmarketable. Larger fruit commands a
higher market price.
Today, U.S. fruit growers are spending up to $500 per acre to hand-remove
excess blossoms, at a total annual cost of more than $156 million. It's a
tedious and time-consuming processoften used in peach productionand
it, like chemical fruit thinning, may be ineffective as well as expensive.
That's why Agricultural Research Service (ARS) scientists have been working on a more
efficient way to reduce the number of blossoms on a tree to promote more
profitable fruit. ARS is the U.S. Department of
Agriculture's chief scientific research agency.
Appalachian Fruit Research Laboratory in Kearneysville, W.Va., plant
Tworkoski and horticulturist
Miller have experimented with using an essential oil plant extract to
reduce the number of blossoms on a tree, allowing more profitable fruit to
grow. Adopting such an environmentally sound approach to blossom thinning would
prevent limb breakage from excess fruit weight, while yielding the larger fruit
many consumers prefer.
The new method involves spraying fruit trees with the natural plant product
while the tree is in bloom. The plant extract damages the blossoms'
reproductive tissues and prevents pollination and fertilization. Flowers are
sufficiently affected shortly after treatment. The concentration of essential
oil plant extract determines the degree of blossom fall. Tworkoski and Miller
are fine-tuning the timing of application with the bloom cycles of various
fruit trees including apples, peaches, pears and other high-value fruit trees.
Not only can this method meet the tree fruit industry's needs for reliable
blossom thinners that are safe and environment-friendly, it may also be
acceptable for use in organic fruit production. A patent application has been
submitted for this technology, and ARS is looking for cooperative research
partners to assist with small field trials.