Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2011
Publication Date: 12/1/2011
Citation: Nyczepir, A.P., Cook, J. 2011. Managing root-knot nematodes: A case for cover crops in establishing peach orchards. Journal of Nematology. 43:267. Interpretive Summary: Root-knot nematodes are an important pathogen of peach in the U.S. Several Meloidogyne spp. have been reported to cause damage to stone fruits, but the Southern root-knot nematode is generally the predominant species found on peach. Peach growers in the Southeast have been faced with economic hardships in recent years and are finding it more difficult to afford the costs associated with chemical nematicides. Finding an alternative to chemical control of root-knot nematodes is necessary. In a greenhouse study, penetration, development, and reproduction of root-knot nematode in Jesup (Max-Q) and Rutgers (susceptible) tomato seedlings were studied. Results indicated that infective-stage juveniles ( J2) penetrated tall fescue roots, but that the majority of the nematodes failed to mature and reproduce. In 2005, a field study was initiated at the USDA-ARS laboratory in Byron, Georgia, to determine if 1- and 2-year preplant tall fescue grass rotations were comparable to preplant Telone II fumigation. Results indicate that both fescue rotations and fumigation lowered the population density of the root-knot nematode in soil compared with nonfumigated plots prior to planting peach trees. In 2011 tree growth was greatest in fumigated and 2-yr fescue rotation plots and lowest in nonfumigated plots. These data provide useful insights into the potential use of tall fescue grass as an alternative to preplant chemical control of root-knot nematode prior to peach orchard establishment in the Southeast.
Technical Abstract: Root-knot nematodes (Meloidogyne spp.) are an important pathogen of peach in the United States. Several Meloidogyne spp. have been reported to cause damage to stone fruits, but M. incognita and M. javanica are the predominant species on peach. Preplant fumigant nematicides have traditionally been used to control Meloidogyne spp. in peach in the southeastern United States. In recent years growers have faced economic hardships, making it difficult to afford costs associated with these chemicals that can be hazardous to humans and the environment. Finding an alternative to chemical control of root-knot nematode is warranted. Previous greenhouse studies indicated Jesup (Max-Q) tall fescue grass to be a nonhost for M. incognita and a poor host for M. javanica. In another greenhouse study, penetration, development, and reproduction of M. incognita in Jesup (Max-Q) and Rutgers (susceptible) tomato seedlings were also studied. Each seedling was inoculated with approximately 5,000 eggs per pot. Seven days later the entire seedling was bare-rooted and transplanted into a new pot. Seedlings were harvested at 7, 14, 21, and 28 days after transplanting. The root systems were stained and then evaluated for numbers of J2 in roots and stage of development on each harvest date. Results indicated that M. incognita J2 penetrated tall fescue roots, but that the majority of the nematodes failed to mature and reproduce. In 2005, a field experiment in Georgia was initiated to study the effects of 1- and 2-yr tall fescue preplant rotations for the management of M. incognita. Both tall fescue rotations and preplant Telone II® fumigation suppressed (P = 0.05) population densities of M. incognita J2 in soil compared with nonfumigated plots prior to orchard establishment in 2009. In 2011, tree growth was greatest in fumigated and 2-yr tall fescue rotation plots, intermediate in 1-yr tall fescue rotation plots and lowest in nonfumigated plots. These results provide insights into the possible use of tall fescue as an alternative to preplant chemical control of M. incognita in peach.