The effect of N-dimethyl amino succinamic acid (Alar) on six-year-old Gravenstein apples

Abstract

Applications of N-dimethyl amino succinamic acid to the foliage on six-year-old Gravenstein apples restricted the extension growth. The reduced growth was characterized by shorter internode length giving the trees a more compact appearance. The number of leaves was also reduced although not to the same extent as extension growth. The leaf size was not affected. Two successive applications of 1,000 p.p.m. or a single spray of 2,000 p.p.m. applied early in the growing season resulted in highly significant increase of bloom in the following year. Yields were doubled by both treatments.

Immediate and Residual Effects of Succinic Acid, 2,2-Dimethyl Hydrazide (Alar) on Young ‘Delicious’ Apple Trees1

“…Our 1967 yield data (Table 3) demonstrate that Alar can be a useful tool for bringing vigorous young apple trees into commercial production. These yield increases are similar to those obtained by Veinbrants (20) in young 'Gravenstein' apple trees induced to flower by postbloom Alar sprays. Significantly, both of these instances of yield responses to Alar sprays occurred in young trees which otherwise would have had a very sparse bloom.…”

“…S uccinic acid, 2, 2-dimethyl hydrazide (Alar) sprays cause numerous responses in the apple tree. Some of the most notable of these are a retardation of internode elongation (2,5,7,8,14) and an increase in fruit bud formation, particularly when Alar is applied shortly after bloom (2,10,14,20). Some reports (2,5,15) also indicate that Alar sprays delay the opening of flowers the follow ing spring, a response probably related to the persistence of Alar in the tree (11,12,13,16).…”