Articles
DORMANT APPLICATIONS OF A SOYBEAN OIL ADJUVANT PLUS ETHEPHON REDUCE PEACH FLOWER BUD SURVIVAL
Article number
884_83
Pages
629 – 634
Language
English
Abstract
Early removal of flower buds, flowers or small fruitlets increases peach fruit size and commercial value.
Due to the lack of labeled or consistent thinning chemicals, peach growers usually wait ~30 days after bloom before hand-thinning fruit, which decreases fruit growth potential.
Experiments were conducted near Seneca, South Carolina to determine the efficacy of combining Vegetoil® (VO), an emulsified soybean oil adjuvant (93% soybean oil), with Ethrel® (E) (a.i. 21.7% Ethephon) for pre-bloom killing of peach flower buds. Contender, Cresthaven and Rubyprince peach trees were sprayed once in January 2008 with 10% VO containing Ethephon concentrations of 25 (only Rubyprince), 50 or 75 ppm.
Dormant oil (DO) at 3% and VO at 10% were the control treatments.
In 2009, 10% VO with 75 ppm Ethephon was sprayed on Cresthaven and Rubyprince trees on either 1 of 5 different dates ranging from 12 January to 16 February.
In 2008, Vegetoil® reduced Contender, Cresthaven and Rubyprince flower bud survival by 10, 20 and 30%, respectively compared to the DO control and by 20-25, 50-60, and 45-55%, respectively when VO was combined with different Ethephon concentrations.
The VO plus E treatments reduced fruit yield by 25-35% in Cresthaven and 45-60% in Rubyprince compared to the DO control. Rubyprince yield was also significantly affected (i.e., reduced) because of a late spring freeze. Contender fruit yield was only slightly reduced by the Vegetoil® plus Ethephon treatments.
Mean fruit size increased 10-15% with the VO and E treatments.
The 2009 flower bud survival, fruit set and yield were significantly reduced by the VO plus E treatments for all application times.
The earliest application date was the most effective in thinning flower buds for both cultivars.
Due to the lack of labeled or consistent thinning chemicals, peach growers usually wait ~30 days after bloom before hand-thinning fruit, which decreases fruit growth potential.
Experiments were conducted near Seneca, South Carolina to determine the efficacy of combining Vegetoil® (VO), an emulsified soybean oil adjuvant (93% soybean oil), with Ethrel® (E) (a.i. 21.7% Ethephon) for pre-bloom killing of peach flower buds. Contender, Cresthaven and Rubyprince peach trees were sprayed once in January 2008 with 10% VO containing Ethephon concentrations of 25 (only Rubyprince), 50 or 75 ppm.
Dormant oil (DO) at 3% and VO at 10% were the control treatments.
In 2009, 10% VO with 75 ppm Ethephon was sprayed on Cresthaven and Rubyprince trees on either 1 of 5 different dates ranging from 12 January to 16 February.
In 2008, Vegetoil® reduced Contender, Cresthaven and Rubyprince flower bud survival by 10, 20 and 30%, respectively compared to the DO control and by 20-25, 50-60, and 45-55%, respectively when VO was combined with different Ethephon concentrations.
The VO plus E treatments reduced fruit yield by 25-35% in Cresthaven and 45-60% in Rubyprince compared to the DO control. Rubyprince yield was also significantly affected (i.e., reduced) because of a late spring freeze. Contender fruit yield was only slightly reduced by the Vegetoil® plus Ethephon treatments.
Mean fruit size increased 10-15% with the VO and E treatments.
The 2009 flower bud survival, fruit set and yield were significantly reduced by the VO plus E treatments for all application times.
The earliest application date was the most effective in thinning flower buds for both cultivars.
Authors
G.L. Reighard, D. Ouellette, K. Brock
Keywords
Vegetoil®, Ethrel®, chemical thinning, Prunus persica, crop load management
Online Articles (103)