EFFECTS OF PACLOBUTRAZOL ON PEACHES

1. 1.6 g a.i. per tree applied in solution to 4m² under the tree canopy.

2. 1.6 g a.i. in 1 litre of solution applied at one point under the tree canopy to simulate application by drip irrigation.

3. 1 litre of 2000 ppm foliar spray (about 2 g a.i. per tree).

Untreated trees served as controls.

In the year of application shoot length was reduced slightly by the foliar spray applications, but the most dramatic effect was a considerable reduction in lateral shoots as a result of all treatments.

In the following year (1983) treatments a) and b) resulted in reduced tree height, shoot length and trunk diameter increase and the trees showed a weeping growth habit.
The foliar spray application caused little effect.
On trees showing reduction of growth, leaf size was smaller and specific leaf weight was greater.
Leaf nitrogen content and chlorophyll content were also increased compared to the untreated controls.

In 1984 fruit set and fruit size were not affected by the 1982 treatments.
Vegetative extension continued in the weeping fashion until mid-July, when numerous upright shoots of normal growth developed in the tops of the trees.

Foliar applications of 1000 and 2000 ppm applied when ovule length had reached 11.1 mm or 14.7 mm were not effective for fruit thinning.
These applications resulted in a weeping growth habit and less vegetative extension than in unsprayed trees.