Biennial bearing of the Granny Smith apple and its control by chemical thinning

Abstract

Evidence is presented to demonstrate that with the Granny Smith apple regularity of cropping is influenced by the thinning spray selected, the concentration utilized and the quantity applied. Time of application was found to be of lesser importance. In addition, experimental records suggest that biennial cropping of this variety is not only attributable to lack of 'off' year blossom, but that poor fruit set is also implicated. A long term experiment, showed that biennial application of naphthalene acetamide gave uniform cropping, but more drastic 'on' year crop reduction may have economic advantages.