Peach tree short life (PTSL) is associated with the presence of ring nematode, Mesocriconema xenoplax, and poor orchard management practices. The ability of postplant nickel (Ni) foliar application to suppress M. xenoplax population density and thereby prolong survival of peach trees on a PTSL site infested with M. xenoplax was investigated from 2004 to 2011. For this study, the site was divided into plots, which received the following treatments: 1) Ni (foliar-applied); 2) methyl bromide fumigation (MBr); and 3) an untreated control. Peach trees were planted into all plots in Mar. 2005 and the foliar Ni treatment was applied three times in 2005 and 2006. Nickel did not detectably suppress M. xenoplax populations as compared with M Br fumigation. The protective effect of MBr fumigation in suppressing M. xenoplax population density persisted for 27 months after orchard establishment. Trees receiving multiple foliar Ni applications at 0.45 g.L-1 over 2 years, while exposed to M. xenoplax, exhibited greater PTSL mortality than trees growing in untreated or MBr-fumigated plots. These results suggest that foliar applications of Ni to peach trees, growing on a PTSL site, should be used with caution in commercial orchards because these treatments can deleteriously disrupt tree metabolic/physiological processes sufficient to increase the incidence of PTSL tree mortality.
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