Submitted to: Nematologia Brasileira
Publication Type: Abstract Only
Publication Acceptance Date: 4/24/2009
Publication Date: 10/9/2009
Citation: Nyczepir, A.P. 2009. Current management strategies for nematodes in Prunus: Mesocriconema xenoplax and Pratylenchus vulnus [abstract]. In: 2nd International Congress of Tropical Nematology Meeting Program, October 4-9, 2009, Maceio, Brazil. p. 7. Interpretive Summary: Peach tree short life (PTSL) is a disease complex that occurs in all the major peach growing regions in the southeastern United States. In South Carolina alone, it has been estimated that a monetary loss of greater than $6 million occurs annually if PTSL is not managed. The ring nematode (Mesocriconema xenoplax) is known to be intimately associated with the incidence of PTSL and in part, this conclusion is supported by the fact that the incidence of PTSL is dramatically reduced when ring nematode populations are suppressed following the application of nematicides. Root-knot and root-lesion nematodes are also pathogens to peach trees, but do not predispose trees to PTSL. A summary of current research advances in managing ring nematode and PTSL will be presented in a symposium in Brazil. A comprehensive review of current research is undertaken to present new knowledge pertaining to alternatives to chemical control of ring nematode and PTSL disease complex. Advances in ring nematode and PTSL management include: rootstock resistance, cultural practices, biological control, and soil solarization. This comprehensive review provides useful insights for scientists, extension personnel, and growers throughout the world with the most current information and recommendation practices available as it pertains to management of ring nematode and PTSL in the southeastern United States.
Technical Abstract: In the southeastern USA, the productive life span of peach trees has declined and does not exceed 6-10 years in some orchards. One cause of early tree death is a disease complex known as peach tree short life (PTSL). Trees affected by PTSL are usually 3-6 years of age and die before the orchard reaches full productivity. The ring nematode, Mesocriconema xenoplax, is the major biotic factor responsible for increasing susceptibility to bacterial canker (Pseudomonas syringae) and/or cold injury, which are the final agents of tree death in this disease complex. Two other damaging nematodes of peach trees are Meloidogyne incognita and Pratylenchus vulnus, which cause growth suppression but do not predispose trees to PTSL. In South Carolina alone, it has been estimated that a monetary loss of greater than $6 million occurs annually if PTSL is not managed. In recent years, disease management strategies of PTSL have been based on nonchemical approaches, including host resistance, biological control, soil solarization, and cultural practices for suppression of M. xenoplax. Advances in managing PTSL have resulted in the release of Guardian rootstock, which provides greater tree survival on PTSL sites. Since 2007, 75% of peach trees delivered to commercial growers in the southeastern USA have been propagated on Guardian, displacing the standard commercial rootstocks previously used by this industry. Guardian also has demonstrated resistance to some Meloidogyne spp., but not P. vulnus. Rotating land with wheat for 3 years prior to establishing a peach orchard is a cultural recommendation that is as effective as pre-plant methyl bromide fumigation in suppressing M. xenoplax. Investigations on the effect of a biological control cocktail (comprised of five Pseudomonas bacteria) and/or solarization to suppress M. xenoplax are in progress. Preliminary results indicate that solarization is a more promising approach than the biocontrol agents in reducing PTSL tree death.