Evaluation of 6-benzyladenine (BA) and naphthylacetamide (NAD) as post-bloom thinning compounds for 'Early Bon Chrétien' pear
Pear trees often set an excessive number of fruit and therefore require fruit thinning early in the season to improve fruit size at harvest and return bloom the following season. Experiments were conducted in the 2004-2005 and 2006-2007 seasons in the Western Cape, South Africa to evaluate the efficacy of 6-benzyladenine (BA) and naphthylacetamide (NAD) applied at 8 to 12 mm fruit size, on fruit set, fruit size at harvest and return bloom of 'Early Bon Chrétien' (EBC) pear. The treatments, BA (50, 100 and 150 ml L -1) and NAD (30 or 40 mg L -1) were compared to hand thinned/unsprayed controls. BA proved to be the most efficient chemical thinner of EBC when used at rates of 100 or 150 ml L -1, fruit set was significantly reduced compared to the control. BA generally decreased fruit set and yield while fruit size increased with an increase in rate. The 150 ml L -1 BA rate was the most effective treatment. 100 and 150 ml L -1 BA significantly improved return bloom compared to 30 and 40 mg L -1 NAD and the control.