Individual Shoot Defoliation Minimally Affects Pecan Return Bloom

Abstract

<jats:p>Alternate bearing of pecan [<jats:italic>Carya illinoinensis</jats:italic> (Wangenh.) K. Koch] remains the leading problem of the industry. Several cultural practices have been developed or improved to mitigate alternate bearing. Premature defoliation was one problem identified that substantially decreased return bloom. The objective of this study was to determine the response of individual shoots exposed to various defoliation treatments. In one study, individual vegetative or bearing shoots were hand-defoliated in mid-September. Defoliation was the basal one-half, distal one-half, entire shoot, or not defoliated. Another study applied the same defoliation treatments to bearing shoots in July, August, or September. Defoliation had minimal effects on return bloom and rarely affected the percentage of current-season shoots fruiting the next year. Defoliation date also had little effect on return bloom. These data indicate that individual shoot response to defoliation was not autonomous and has implications for determining crop overload and needed mechanical fruit thinning.</jats:p>