Hand thinning and chemical thinning in the apple varieties Gala, Goldon Delicious and Fuji

Abstract

Due to the high demand for labour necessary for hand thinning of apple trees the present trial was carried out to analyse the practicability of chemical thinning from technical and economic points of view. The experiments were conducted in commercial apple orchards with the varieties Gala, Golden Delicious and Fuji at Fraiburgo, SC, Southern Brazil. The thinning agent naphthaleneacetic acid (NAA) was applied with an emulsifiable mineral oil as adjuvant by an airblast sprayer with a spray volume of 1000 to 1200 l/ha at five to eight days following full bloom. Hand thinning was carried out at 30 days following full bloom. In all varieties chemical thinning proved to be practicable, being economically superior to hand thinning carried out at adequate thinning intensity.