Submitted to: Journal of Nematology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/20/2004
Publication Date: 6/1/2004
Citation: Nyczepir, A.P., Shapiro Ilan, D.I., Lewis, E.E., Handoo, Z.A. 2004. Effect of entomopathogenic nematodes on mesocriconema xenoplax populations in peach and pecan. Journal of Nematology. 36:181-185. Interpretive Summary: Ring nematodes are widely distributed throughout the world with certain species considered to be economically important to the stone fruit industry. Probably the most studied ring nematode species on Prunus is Mesocriconema xenoplax. It has also been found on pecan in Georgia. This ring nematode is the only plant-parasitic nematode that has been associated with the peach tree short life (PTSL) disease complex in the southeastern United States. Tree loss due to PTSL in South Carolina alone has been estimated at over $6 million per year. New alternatives to chemical control that are less hazardous to man and also more environmentally safe must be found to protect peach trees from this ring nematode. Entomopathogenic nematodes have been reported to suppress the populations of certain root-knot and ring nematode species. However, nothing is known about the efficacy of these nematodes on the ring nematode that attacks peach. In greenhouse and microplot studies, two entomopatholgenic nematodes were evaluated for their potential effect on lowering the population density of the ring nematode on peach and pecan over time. In both studies, the ring nematode population was not suppressed in the presence of both entomopathogenic nematodes. These date provide useful insights into the use of entomopathogenic nematodes as an alternative to chemical control of the ring nematode on PTSL sites in the Southeast.
Technical Abstract: The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm-3 soil to soil surface of each pot, 50 infective juveniles/cm-2 soil surface of either S. riobrave or H. bacteriophora was applied. Another entomopathogenic nematode application of the same density was administered three months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed in the presence of either S. riobrave or H. bacteriophora 180 days following ring nematode inoculation. On pecan, 200 S. riobrave infective stage juveniles/cm-2 were applied to the soil surface of 2-year old established M. xenoplax populations in field microplots. Additional applications of S. riobrave were administered two and four months later. This study was terminated 150 days following the initial application of S. riobrave. Populations of M. xenoplax were not suppressed in the presence of S. riobrave.