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color development and made possible the harvest of the
entire crop in one picking.  It has been used on Julyred,
Raritan, Jerseymac, Britemac, Paulared, Opalescent,
Wealthy, Mollie's Delicious and McIntosh.
[!]The use of ethephon on summer-ripening
apples may be confined mainly to fruit to be sold
at retail markets within a week or two after
harvest. Storage holding beyond 2 weeks is not
recommended. For summer varieties, 0.5 to 1.0
pint in 100 gallons of water is recommended.
[!]Wet fruit by applying ethephon at 0.5 pint
in 100 gallons of dilute spray. The 0.5-pint rate
is recommended for the summer-ripening
varieties and McIntosh to reduce the possibility
of overmaturity.
[!]Begin spraying 2 to 3 weeks before the
normal harvest period and about 1 to 2 weeks
before desired harvest date.
[!]Watch maturity closely. Fruit maturity
changes rapidly, especially in hot weather. Fruit
intended for fresh market must be checked for
quality and maturity and not just color. Harvest
the fruit a day earlier rather than a day too late.
[!]Do not apply Ethephon to more trees than
can be harvested in 2 days. A 1-day delay in
harvest can result in fruit drop and loss of fruit
quality.
[!]Move fruit into storage rapidly into market
after harvest.
[!]McIntosh has not responded consistently
well to ethephon sprays. In some instances red
color has been slow to develop, and fruit drop
has been excessive with NAA. In general,
ethephon has produced excellent color with little
fruit drop, and apples have been harvested in fine
condition. In some instances, drop has been
excessive.
An Ethephon response on many Red Delicious
varieties has been good. Application should be made 3
weeks before normal first picking. Ethephon should be
used at 0.75 to 1 pint per 100 gallons of water, and NAA
at 15 ppm is recommended in the same spray. It is
necessary to apply a second spray of NAA after 5 to 7
days. An increase in red color may begin to appear 3 or 4
days after application.
Fruit must be checked for quality and maturity and
not just color. As with the summer-ripening varieties,
watch maturity as evidenced by flesh pressure has dropped
to 16 to 18 pounds. At 14 pounds pressure, the fruit
should move for consumption.
The response in Stayman has been much the same as
Delicious but the use of ethephon probably will not be as
extensive as with Delicious because immediate fresh
market sale of Stayman is not as great as Delicious.
Ethephon is most effective at temperatures between 60
and 85oF. Color improvement may be minimal when
high temperatures prevail.
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An application of naphthaleneacetic acid (NAA) at 3
to 4 ppm about 1 month after full bloom has increased the
amount of return bloom the following year. No thinning
occurs but there is an increase in fruit-bud development
from the hormonal effect of the NAA.
Promalin is a growth regulator that has been used to
increase the length of Delicious fruit. Research results
from different areas are variable, and unwanted fruit
thinning may occur if the material is misused.
Suggestions are listed below for the use of Promalin.
[!]Apply 1 pint Promalin per 100 gallons (do
not apply more than 1.5 pints per acre).
[!]Use of 100 to 200 gallons of water per acre
is recommended.
[!]Overapplication or application when
temperatures exceed 85oF may result in
excessive fruit thinning.
[!]Apply Promalin while king blossoms are
open.
[!]Adding surfactants increase the effects on
fruit shape and fruit thinning.
[!]To determine if Promalin has any effect on
fruit shape or thinning, be sure to leave a few
trees untreated for comparison.
Tre-Hold Sprout Inhibitor A112 is registered for
bearing and nonbearing apple and pear trees to control
watersprouts and root suckers.
[!]Add 0.67 pint Tre-Hold to a mixture of
water and interior-grade latex paint to make a
volume of 1 gallon. Use at least 2 quarts of
paint per gallon of solution.
[!]Prune watersprouts and suckers during the
dormant season and then paint or spray-cut
surfaces with the Tre-Hold solution.
[!]Effective control of root suckers can also be
obtained when Tre-Hold is applied in the spring.
Thoroughly spray new shoots from suckers when
they are 6 to 12 inches high.
Preharvest Fruit Cracking Suppression
on Stayman Apple
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