Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 16, 2003
Publication Date: November 3, 2003
Citation: Nyczepir, A.P. 2003. Field evaluation of nonchemical alternatives for control of ring nematode on peach. Proceedings of International Research Conference on Methyl Bromide Alternatives. p.119. 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. This ring nematode is the only plant-parasitic nematode that has been associated with peach tree short life (PTSL) disease complex in the southeastern United States. Tree loss due to PTSL in South Carolina alone is estimated at over $5 million per year. New preplant alternatives to chemical control (i.e., nematode suppressive ground covers) that are less hazardous to man and also more environmentally safe must be found to protect peach trees from this ring nematode. Selected crop rotations in conjunction with Guardian rootstock were evaluated from 1996-2003, as a potential preplant ground cover management strategy in suppressing the ring nematode population density and to determine the influence long-term preplant crop rotations have on peach tree growth and incidence of PTSL. Results indicate that nematode populations were greater on Nemaguard than for Guardian rootstock on all sampling dates (2000-2003), indicating that Nemaguard was a better host for the nematode. Preplanting 3-continuous years of canola/sorghum was more effective than preplant methyl bromide fumigation in increasing tree survival from PTSL 26 months after establishing the orchard. These data provide useful insights into the use of canola/sorghum in conjunction with Guardian rootstock as a pre- and postplant alternative to chemical control of the ring nematode on PTSL sites in the Southeast.
Technical Abstract: The effects of 5 different preplant rotations in conjunction with the improved Guardian peach rootstock are being compared for their effectiveness in suppressing the ring nematode and incidence of PTSL tree death from 1996-2003. In the initial phase of the study, 5 different preplant crop rotations and continuous peach plots [i) 1-yr wheat/sorghum; ii) 3-continuous yrs wheat/sorghum; iii) 3-continuous yrs fallow/sorghum; iv) 1-yr canola/sorghum; v) 3-continuous yrs canola/sorghum and vi) 3-continuous yrs peach] were established. After crop rotation sequence establishment in 1999, all trees were removed from the continuous peach plots and one half the number of these plots were then preplant fumigated with methyl bromide, resulting in 7 main plot treatments. In 2000, all plots were planted to either Redhaven peach on Nemaguard or Guardian rootstock. Nematode population density and percentage of PTSL tree survival were recorded over time. Twenty-six months after replanting peach, only the 3-continuous yrs wheat/sorghum (16%), fallow/sorghum (18%) and canola/sorghum (4%) plots had fewer dead trees than the unfuminated (34%). Preplant canola/sorghum (4%) was more effective than preplant methyl bromide fumigation (24%) in increasing tree survival from PTSL. Furthermore, more trees on Nemaguard rootstock (65%) developed PTSL symptoms and died than on Guardian rootstock (2%) to date.