The 2009 ASHS Annual Conference

Excessive fruit-drop limits profitability of certain pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars.   The present study examined the efficacy of ReTain^®, a natural ethylene inhibitor, for reducing fruit-drop.  Four years of field studies on ‘Desirable’ pecan trees found that ReTain^® can substantially reduce fruit-drop; thus, increasing crop-load over non-treated trees by as much as 16-38%, with the percentage retention being greatest in trees with a relatively heavy crop load and minimal in trees with a light crop load.  The efficacy of ReTain^® for reducing fruit-drop increases with crop load.  Efficacy is also greatest when applied soon after the termination of stigma receptivity.  Two post-bloom applications of ReTain^® increased fruit-set in an “on-phase” commercial orchard with an moderately heavy crop by 38%, while not reducing in-shell yield or kernel quality the following year when ReTain^® was not used and the orchard possessed a light to moderate crop-load.  Proper usage of ReTain^® appears to offer commercial producers of ‘Desirable’ nutmeats a practical tool for reducing fruit-drop and managing crop-load.