Research conducted by BASF Corporation and the Northeast Plant Growth Regulator Working
Group over the past several years have focused on optimum rates and timing of Apogee[TM]for optimum
growth control. The research has indicated that rates and number of applications will vary and depend
highly on orchard location, vigor of cultivar and length of growing season. Research has also
confirmed that the timing of the first application is critical to the success of the product.
A ten year old block of 'Freedom' apples on M26 trained to a central leader system was used to
conduct this experiment at the Rutgers University, Snyder Research and Extension Farm in Franklin
Township, Hunterdon County during the 1999 growing season. This trial was conducted in a
randomized complete block design containing six replications with double tree treatments. A guard tree
separated the two treatments within each replication. The cultivar 'Freedom' was selected due to its
inherent highly vigorous nature and the light crop expected for the 1999-growing season. These
factors together would allow for a definitive analysis of the efficacy of Apogee[TM]. Although the use of
Apogee[TM]may effect and alter many facets of a trees physiological and cultural aspects, only the
reduction of vegetative growth as it correlates to vegetative shoot reduction was analyzed in this trial.
Extremely mild temperatures during February and into the month of March caused the trees to
break bud about two weeks early this spring. Below average temperatures were then experienced
during most of the month of April and May, which slowed bud advancement, and allowed bloom to
settle into the traditional window for our region. Bloom was moderate to light on Freedom in 1999,
due partially to an excessive crop load in 1998. A sufficient bloom period (+7 days) produced only 1
day of adequate sunlight (75% full) containing warm temperatures (+65ºF).
Prior to the initial application of the Apogee[TM]treatment, treatment trees were properly selected and
randomized. After randomization, five representative shoots per tree were selected, marked, and their
length was measured at the shoot initiation point (14 May). Bourse shoots and other reproductive
wood was avoided, as only those shoots in the vegetative mode were the ones targeted for control.
A single application of Sevin®XLR Plus (Carbaryl, Rhone-Poulenc) at 1 qt/a combined with
Accel®(N-1H-purine-6-amine + Gibberellins A4A7, Abbott Labs.) at 20 gm(ai)/a during the early fruit
set stage (6-10 mm) was the only thinning spray applied to this trial. Other than the single application
of Accel®, no other plant growth regulating materials were applied to the trial during the 1999-growing
The entire block was treated uniformly regarding standard commercial production practices. Spray
schedules for insect and disease pressure was maintained via the Rutgers IPM monitoring schedule as
determined by weekly scouting, on-site weather and Skybit®predictions. Irrigation was utilized on a
weekly schedule throughout the growing season, beginning on 18 May. All trees were pruned during
the 1998-99 dormant season and managed in a uniform manner.
Table 1: Treatments_____________________________________________________
TREATMENT #1 - Untreated control
TREATMENT #2 -Apogee[TM](6 oz / 100 dilute equivalent based on TRV)