Prior to the application of the bloom treatments, the treatment trees were properly selected and
randomized. After the trees were randomized, three representative limbs per tree were selected,
marked, and their circumference was measured at the limbs point of initiation off the central leader.
After the limbs were selected and marked bloom counts were made (5 May), so the thinning effect of
the treatments could be quantified.
No other materials with known thinning characteristics, or Plant Growth Regulators were
applied to the trial other than a uniform application of ReTain[TM](4 weeks pre-harvest) during the 1999
growing season. All treatments were applied with the spreader/activator Regulaid®(Kalo, Inc.) at 8
The only fungicides applied to this block in 1999, were for summer diseases, and were the
protectant type fungicides of Captan 50WP, Ziram 76DF, Topsin®-M WSB, and Benlate®50WP, in
combinations. Insecticide sprays were maintained with the Rutgers IPM pest control schedule as
determined by weekly scouting, on-site weather and Skybit®predictions.
Applications for two of the treatments commenced on 6 May, which correlated to full bloom.
The first application for the other two treatments began 6 days later at petal fall. Tree row volume
(TRV) was established at 250 gallons per acre dilute (5). The treatments were applied at 1.5x
concentrate (165.3 gpa) using a 400 gallon Rears model Pull-Blast airblast sprayer retrofitted with a
10' tower, that utilized 15 nozzles per side, to apply the treatments. Ceramic TeeJet D2 and D4 disks
with size 25 cores were alternated along the spray manifold to produce a uniform spray pattern from
top to bottom. The sprayer is equipped with a constant velocity centrifugal pump that operates at 170
psi. Output of the nozzles at this constant pressure was calibrated to 0.712 gpm per nozzle for the
D4/25's and 0.395 gpm per nozzle for the D2/25's. Forward ground speed of the tractor was
calibrated to 2.56 mph, and the travel time for each tree was 3.2 seconds per side, for a total of 6.4
seconds/tree per application. High operating pressures and ball valves in the nozzle bodies assured
proper nozzle shut-off, which prevented possible, overspray contamination between treatments.
Treatments were applied at their scheduled intervals throughout the cell division period.
One of the principal objectives of this trial was to evaluate Accel's®ability to increase fruit size
that was due to its promotion of cell division in a fashion that is independent of its thinning properties.
The best method to do this, it was determined, was to analyze and record the remaining crop load after
June Drop had been completed, then thin each tree evenly, down to one fruit per cluster. A further
analysis of this method indicates it making good horticultural and scientific sense. After cell division is
complete and final fruit size has been physiologically determined, as long as all treatments are treated
equally for the remainder of the trial (ie. irrigation, fertilizer, etc.), the absence of hand thinning to
equally adjust the crop load of all treatments would administer varying crop loads between treatments.
This crop variation would continue to put uneven stress on trees, and give us results that were as much
dependent on tree stress (due to overcropping) as they were from treatment variation. Hand thinning
ensured the authenticity of data analyzing Accel's®ability to increase fruit size was due to its promotion
of cell division in a fashion that is independent of its thinning properties.
In cooperation with this determination, hand thinning was done in July (after June Drop), after
fruit counts were completed (19 July) to thin fruit clusters down to 1 per spur. This thinning was done
to assure uniformity in final crop load between all treatments, which will show accurate results when
comparing treatment effect and final fruit size.
After the roller coaster spring, we then experienced a season long drought, which became the
second driest summer in recorded history. Due to this drought, season long irrigation was utilized on a
weekly schedule throughout the growing season, beginning on 18 May.