Tall Fescue ‘Jesup (Max-Q)’: Meloidogyne incognita Development in Roots and Nematotoxicity

Published in Agron. J. 105:755–763 (2013) doi:10.2134/agronj2012.0374 Available freely online through the author-supported open access option. Copyright © 2013 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Tall fescue [Schedonorus arundinaceus (Schreb.) Dumont. = Lolium arundinaceum (Schreb.) Darbysh., formerly Festuca arundinacea Schreb.] cultivar Jesup (Max-Q), was recently recommended as a preplant ground cover for suppression of the root-lesion nematode Pratylenchus vulnus and two species of RKN on peach in the southeastern United States (Nyczepir and Brannen, 2012). There were multiple reasons for proposing this management strategy. Tall fescue, a forage and turf grass, is grown in many areas in the United States and can be used as a postplant ground cover to reduce soil erosion, is vigorous under poor soil conditions, withstands drought, and is resistant to various pests, including some nematodes (Ball et al., 1993; Bouton, 2002). A symbiotic relationship between tall fescue and the fungus Neotyphodium coenophialum [(Morgan-Jones & W. Gams) Glenn, C. W. Bacon, & Hanlin] can confer enhanced benefits on the grass, including increased competitiveness, growth, survival, and ability to survive drought (Ball et al., 1993; Bouton et al., 2001). However, some strains of N. coenophialum produce ergot alkaloids that cause fescue toxicosis in grazing animals (Bacon et al., 1977; Lyons et al., 1986). Jesup (Max-Q) has the advantage of being an “endophyte-friendly” tall fescue; it is associated with a strain of N. coenophialum that is beneficial to the plant but does not produce the ergot alkaloids (Bouton, 2002; Phillips and Aiken, 2009). When tested with the primary nematode pathogens that attack peach trees in the Southeast, Jesup (Max-Q) was a nonhost or poor host for several species ABSTRACT Tall fescue [Schedonorus arundinaceus (Schreb.) Dumont. cv. Jesup (Max-Q)] was recently recommended as a preplant ground cover for managing plant–parasitic nematodes on peach trees [Prunus persica (L.) Batsch] in the southeastern United States. Jesup (Max-Q) is associated with a strain of the endosymbiotic fungus Neotyphodium coenophialum that does not produce ergot alkaloids that cause fescue toxicosis. To optimize use of this tall fescue for lowering populations of the root-knot nematode Meloidogyne incognita, greenhouse and laboratory studies were conducted on selected factors potentially contributing to suppression. Tall fescue–derived extracts and exudates were tested for nematotoxicity, and M. incognita life cycle development was compared between susceptible tomato (Solanum esculentum Mill.) and Jesup (Max-Q) roots. The highest tested root and shoot extract concentrations inhibited M. incognita hatch up to 46% compared with controls, and were nematotoxic to the infective second-stage juveniles (J2; up to 66% decrease in viability). Root exudates were nematotoxic to J2 (up to 27% mortality), and inhibited hatch up to 48%. Roots of susceptible tomato plants (controls) had approximately 3 to 7 times more infective J2 than tall fescue roots, 40 to 80 times more females and egg masses, >1800 times more eggs/plant, and 10 to 83 times more galls/ plant. The nature of Jesup (Max-Q) suppression of M. incognita included low J2 penetration rate and failure of infective J2 to complete their life cycle in this cultivar. Compounds derived from Jesup (Max-Q) tall fescue decreased nematode viability, also contributing to M. incognita suppression by this plant.