Articles
PEAR RUSSET CONTROL WITH GIBBERELLINS AND OTHER PRODUCTS, IN CV. PACKHAM’S TRIUMPH
Article number
475_36
Pages
303 – 310
Language
Abstract
This study was conducted on adult pear trees (Packham’s Triumph) during 1993/1994 season.
Different chemicals with different dosages and number of sprays were evaluated for russet control.
A method of inducing the russet was tested, covering the fruits with plastic bags, demonstrating the important role of humidity on the appearance of this problem.
At harvest, 40 fruits were collected from the inside and outside of 8 trees.
Results indicated that most exposed fruit showed highest russet incidence.
Appearance of russet in the fruit was observed as early as seven days after full bloom, which indicates that applications should be made earlier, to cover the fruit for the longest period possible, from petal fall up to approximately 30 days afterwards.
Since russet is an irreversible phenomena, it is necessary to have preventive applications with adequate products; it has been found that application of gibberellins (GA 4+7; commercial name Provide, Abbott) 3 sprays every 10 days at 10ppm, resulted in the highest percentage of healthy fruit in comparison to untreated control.
However, the flowering of pears was inhibited in the following season.
GA 4+7 sprays act only by reducing the russet caused by weather factors during early development of fruit.
In orchards where weather is the main factor inducing russet, there is the alternative of using the mixture of Mancozeb+Sulphur, in dose of 200g + 200g/100 lt. (4 sprays every 10 days) which results in a high percentage of fruit without russet as related to unsprayed control plants.
Different chemicals with different dosages and number of sprays were evaluated for russet control.
A method of inducing the russet was tested, covering the fruits with plastic bags, demonstrating the important role of humidity on the appearance of this problem.
At harvest, 40 fruits were collected from the inside and outside of 8 trees.
Results indicated that most exposed fruit showed highest russet incidence.
Appearance of russet in the fruit was observed as early as seven days after full bloom, which indicates that applications should be made earlier, to cover the fruit for the longest period possible, from petal fall up to approximately 30 days afterwards.
Since russet is an irreversible phenomena, it is necessary to have preventive applications with adequate products; it has been found that application of gibberellins (GA 4+7; commercial name Provide, Abbott) 3 sprays every 10 days at 10ppm, resulted in the highest percentage of healthy fruit in comparison to untreated control.
However, the flowering of pears was inhibited in the following season.
GA 4+7 sprays act only by reducing the russet caused by weather factors during early development of fruit.
In orchards where weather is the main factor inducing russet, there is the alternative of using the mixture of Mancozeb+Sulphur, in dose of 200g + 200g/100 lt. (4 sprays every 10 days) which results in a high percentage of fruit without russet as related to unsprayed control plants.
Publication
Authors
J.A. Yuri, R. Castelli
Keywords
Pyrus communis, growth regulators, pear disorders, return bloom
Online Articles (74)