Articles
EFFECT OF THINNER AND TIME OF SHADING ON FRUIT SET OF ‘MCINTOSH’ APPLES
Article number
884_64
Pages
505 – 510
Language
English
Abstract
It is well documented that weather conditions play a dominant role in determining the effectiveness of a thinner.
Temperature has emerged was one of the most important of the weather factors.
Less information is available about the influence that light plays in thinner response.
An experiment was initiated to determine if the time at which a tree is shaded (exposed to cloudy conditions) relative to chemical thinner application ultimately influences thinner efficacy and final fruit set.
Mature Pioneer McIntosh/M.9 apple trees were selected for this experiment.
Carbaryl at 1000 mg.L-1 plus NAA 7 mg.L-1 was applied as a dilute handgun application when fruit size averaged 11.9 mm.
An 80% shade cloth was placed over whole trees at two time periods for 4 days.
The time periods for shading were 4 days before thinner application (24 to 28 May) and 6 days after thinner application.
There were 8 treatments with an untreated control, a shade treatment, a thinning treatment and a shade plus thinner treatment for each shade period.
Administering a shading treatment for 4 days prior to thinner application had no influence on altering the thinner response on fruit set.
However, if the shade was administered immediately following thinner application, trees were nearly defruited.
Fruit growth rate was followed on tagged fruit.
Shading did reduce fruit growth rate, but the greatest reduction in fruit growth was associated with shade being administered immediately following thinner application.
Temperature has emerged was one of the most important of the weather factors.
Less information is available about the influence that light plays in thinner response.
An experiment was initiated to determine if the time at which a tree is shaded (exposed to cloudy conditions) relative to chemical thinner application ultimately influences thinner efficacy and final fruit set.
Mature Pioneer McIntosh/M.9 apple trees were selected for this experiment.
Carbaryl at 1000 mg.L-1 plus NAA 7 mg.L-1 was applied as a dilute handgun application when fruit size averaged 11.9 mm.
An 80% shade cloth was placed over whole trees at two time periods for 4 days.
The time periods for shading were 4 days before thinner application (24 to 28 May) and 6 days after thinner application.
There were 8 treatments with an untreated control, a shade treatment, a thinning treatment and a shade plus thinner treatment for each shade period.
Administering a shading treatment for 4 days prior to thinner application had no influence on altering the thinner response on fruit set.
However, if the shade was administered immediately following thinner application, trees were nearly defruited.
Fruit growth rate was followed on tagged fruit.
Shading did reduce fruit growth rate, but the greatest reduction in fruit growth was associated with shade being administered immediately following thinner application.
Authors
D.W. Greene, P. Groome
Keywords
Malus × domestica, naphthaleneacetic acid, NAA, carbaryl, chemical thinner, fruit growth
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