Growth Suppression as a Control for Nectarine Pox

A 2-year study was designed to test the effect of four growth-suppressing treatments on the incidence of nectarine [Prunus persica (L.) Batsch] pox, nectarine fruit quality, and the growth and nutritional status of nectarine trees. Root pruning was the only treatment that significantly reduced the incidence of nectarine pox. The percentage of red surface was increased by root pruning, foliar-applied paclobutrazol, and girdling. Root pruning and paclobutrazol suppressed extension shoot growth. Root pruning decreased fruit N, P, K, Mg, Mu, Fe, B, and Zn levels and increased fruit Ca. Results of the study support earlier observations that nectarine pox is associated with excessive shoot growth, excessive levels of fruit N and K, and low levels of fruit Ca. Chemical name used: Beta-[(4-chlorophenyl) methyl] -alpha-(1,1-dimethylethyl)-l- H-1,2,4 -triazole-l-ethanol (paclobutrazol).