From: The Great Lakes Fruit Growers News
THINNING GUIDE
New Thinning Guide Available for Apple Growers
The first new thinning manual published in nearly two decades for commercial
apple growers in the Midwest and Eastern United States is now available.
The Apple Thinning Guide is authored by Phil Schwallier, Michigan State
University district horticulture marketing agent. His district includes
the
"Ridge" fruit growing area north of Grand Rapids that produces
over 40% of
Michigan's apple crop.
"I felt that thinning is very complicated and a confusing necessary
practice
that growers were always unsure of what to do," said Mr. Schwallier.
"Much of
the confusion was over all the factors that influence fruit set and thinning.
I've tried to condense the thought process into steps that need to be
considered by growers before, during and after thinning."
The recent release of some new thinning materials including Sevin XLR and
Accel have further confused the issue. Mr. Schwallier reviews how these
materials and the older materials work to help growers understand the
thinning response to them when used alone or in tandem.
"Understanding what thinning materials are available and how they work
will
help growers make decisions on which ones to use and when to use them,"
Mr.
Schwallier said. "Knowing the responses that can be expected from different
varieties will greatly increase the success of thinning."
The in-depth book looks at the factors that involve fruit set and thinning,
and reviews variety sensitivity to help serve as a guide to thinning
decisions with an eye on thinning that will help growers meet the needs
of
today's marketplace.
"The current thinking is to thin earlier and more aggressively starting
at
petal fall," Mr. Schwallier said. "The manual encourages growers
to thin
earlier for successful thinning and return bloom and aggressively for larger
fruit size."
To make the subject easier to understand there are many colorful graphics,
tables, charts and check off lists.
Sections of the book include an introduction, thinning windows, thinning
factors, weather factors, apple thinning rates and timing, and thinning
materials.
The tables cover thinning and fruit set factors, and varieties and thinning
rates. The charts include fruit set and thinning planner, the fruit set
evaluation checkoff and a final pre-spray checkoff.
The fruit set and thinning planner combine the factors that influence fruit
set and response to thinning, including predicted set, bloom factors, weather
conditions, pollination factors, grower management factors and tree and
orchard factors.
The final pre-spray checkoff is designed to be used by growers just before
making any thinning applications and considers weather conditions for the
next five days, predicts thinning response and makes recommendations on
the
thinning action.
"This is something all apple growers will find useful during this important
decision time," Mr. Schwallier said. "This manual will help growers
thin
aggressively and early to provide the best success of annual fruit production
and fruit quality."
The Apple Thinning Manual is available from The Great Lakes Publishing
Company, P.O. Box 128, Sparta, Michigan 49345. Cost is $10 plus $1.50 for
postage and handling for each book. For more information call (616) 887-9008.
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