TRANSITORY CONTROL OF VEGETATIVE GROWTH OF POME AND STONE FRUIT TREES WITH LESS PERSISTENT TRIAZOLE DERIVATIVES

Paclobutrazol, triapenthenol (RSW0411), and BAS111 were applied to the lower trunks of ‘Red-Gold’ nectarine and ‘Perfection’ apricot trees in November 1986 and in April and May 1987 using an organic solvent as a carrier.
Generally, paclobutrazol or RSWO411 applied in November or April before commencement of shoot growth, controlled vegetative growth more than applications in May after shoots had started growing.

In foliar trials, formulations containing 250 mg/l of the above mentioned triazoles were applied to young ‘Delicious’ apple trees.
Treatments were made when shoot length was about 15 cm and every 10 days thereafter for a total of 4 applications.
Two or more applications of paclobutrazol reduced growth to 58% of controls.
With RSWO411, 3 and 4 applications reduced growth to 74% and 45% of controls.
Four applications of BAS111 reduced growth to 84% of controls.

The efficacy of the three compounds was generally as follows: paclobutrazol > RSWO411 > BAS111. Apples and nectarines treated with either RSWO411 or BAS111 showed regrowth later in the season, whereas those treated with paclobutrazol showed very little.
The year after foliar treatment with paclobutrazol apples showed a dose dependant growth reduction whereas there was no effect from either RSWO411 or BAS111. Trees receiving trunk paints in 1987 continued to show effects in 1988.

VI International Symposium on Growth Regulators in Fruit Production

Eric A. Curry, A.N. Reed, M.W. Williams

https://doi.org/10.17660/ActaHortic.1989.239.31