EVALUATION OF TWO PROMISING PEACH CHEMICAL THINNERS IN CHILE

Hand thinning is one of the major labour input growing in Chile.
Therefore, during the last five years chemical thinning has been tested.
Ralex^R (Abbott Laboratories) and Armothin^R (Akzo-Nobel) were tested for 5 and 3 seasons, respectively.
Results are so promising that some growers are including the application of these chemicals in their commercial orchard management.
Ralex^R is a gibberellic compound which, if sprayed in spring and summer, not only modify fruit quality, improving fruit firmness, delaying harvest time by 2 to 3 days, but also reduce flower induction for the following season.
Armothin^R, a surfactant, kills late flowers, reducing the amount of fruit setting.
Both chemicals have not presented any phytotoxic effect on foliage or fruits.
Hand thinning requirements were reduced by 40 to 70%. Best results with both chemicals, were obtained when applied on mid-season or late peach varieties such as ‘O’Henry’ and ‘Elegant Lady’; and ‘August Red’ nectarine.
Ralex^R can be applied from mid November through December.
Application rates evaluated ranged from 20 to 40 ppm.
Best results were obtained with the lower concentration.
Armothin^R must be applied when 30 to 60% anthesis is reached.
Doses tested varied from 1 to 4%, with 1 to 2% performing better than higher concentrations.
For both chemicals, repeated application was a better alternative when variety had a profuse or prolonged flowering period.
Our trials demonstrate a good potential of these products for chemical thinning in peaches.

IV International Peach Symposium

G. Lemus

thinning, chemical thinners, gibberellic compounds, surfactants

https://doi.org/10.17660/ActaHortic.1998.465.83