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21 days. When conditions favor heavy cracking,
better results are obtained by using a greater
number of applications and closer spray intervals.
Research in Virginia has shown 6 applications at
14 day intervals to provide the best crack
suppression.
 Do not use a surfactant. Where Captan is
not being used, oils at the rate of 1 quart per 100
gallons improves penetration of ProVide.
A water bath developed by Dr. Ross Byers
of Virginia Tech, is very effective in testing the
crack potential of Stayman fruit. The following
is the procedure:
a) Sample 5 noncracked fruit from around 4
trees per block;
b) Submerge the 20-fruit sample in a 5-
gallon pail containing a solution of 1 fluid
ounce of X-77 surfactant;
c) Count the cracked fruit after one and three
days;
d) If half the fruit cracks, then fruit on the
trees will likely crack when exposed to the
proper weather conditions and preventative
treat-ment should be applied;
e) Since the cracking potential of fruit changes
throughout the season, the test should be
repeated every two weeks.
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preharvestdrop on McIntosh from 10-20%. Dr. Ed
Stover, Cornell University, Hudson Valley Lab, says
"McIntosh apples typically grow about 1% per day during
the few weeks around harvest. If we can delay harvest, we
can take advantage of additional fruit growth to produce a
significantly higher proportion of 100 count fruit."
For varieties with narrow harvest windows like the
scab resistant variety Liberty, ReTain allows growers to
delay harvest up to two weeks and pick larger, more
highly colored fruit that is firmer than untreated fruit.
Research in 1996 showed ReTain was also effective in
reducing stem cracking in Gala. This may be an added
benefit. In Washington State growers are excited about
ReTain because of its ability to enhance the storage
quality of Red Delicious. In a 4000 bin pooled
experiment, 2000 treated with ReTain and 2000
untreated, ReTain treated fruit treated was 2 lbs. firmer
allowing it to make export grade. NJ grown apples in
regular cold storage will see the same firmness
enhancement with ReTain treated fruit.
Important considerations to follow with ReTain
applications in New Jersey:
[!]Use the full rate of ReTain, 1 pouch or 333
grams/Acre of formulated product with an
organosilcone surfactant at 0.10 % (v/v)
[!]ONLY use one of the following
organosilcone surfactant at surfactants:
Silwet L77 at 13 fluid ounces per 100 gallons
Sylgard 309 at 13 fluid ounces per 100 gallons
[!]Apply 4 weeks before anticipated harvest (28
day PHI), it is better to apply slightly earlier
rather than later
[!]Water Volume- ReTain should be applied
with a sufficient amount of water to ensure
thorough wetting of the fruit while avoiding
spray run-off. Adjust water volume based on tree
size and spacing
[!]For optimum results apply during periods of
slow drying weather conditions.
[!]Do not tank mix ReTain with other
agricultural products
[!]Do not apply NAA or ethephon products to
ReTain treated blocks
For Pears: Contact your Area Fruit Extension Agent
for specific information regarding the use of ReTain on
pears.
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ReTain is a new harvest management tool labeled for
both apples and/or pears. It has received a full federal label
for use in 1997. ReTain was evaluated in eight grower
orchards and at the Rutgers Snyder Research and
Extension Farm on McIntosh, Cortland, Liberty,
MaCoun, Stayman, Mutsu and Empire cultivars during
the past three years in New Jersey under and an EPA-
approved experimental use program
ReTain works as a stop drop material, and is as good
or better than NAA, holding drop prone varieties on the
tree. It delays maturity on average from 7-10 days. Fruit
treated with ReTain can be picked during the normal
harvest period for enhanced retention of firmness in
storage, or harvest may be delayed, allowing the fruit to
continue to grow and develop red color for an extended
time.
Our experience in NJ is that ReTain reduces
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