Location: Fruit and Nut ResearchTitle: Assessment of selected pecan and peach rootstocks for resistance to Meloidogyne partityla) Author
Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2012
Publication Date: 12/1/2012
Publication URL: http://handle.nal.usda.gov/10113/56077
Citation: Nyczepir, A.P., Wood, B.W. 2012. Assessment of selected pecan and peach rootstocks for resistance to Meloidogyne partityla. Nematropica. 42:281-286. Interpretive Summary: The pecan root-knot nematode (PRKN) is associated with stressed trees exhibiting dead branches in the upper canopy and/or typical Mouse-ear associated foliar symptoms. In GA, it is not uncommon for peach growers to interplant pecans within a peach orchard so that when orchard productivity declined, the grower pushes out the peach trees and continue using that site for pecan production. Currently, there are no recommended resistant pecan rootstocks available for managing this nematode pathogen on pecan and its host susceptibilty to peach is unknown. Evaluating peach and open-pollinated pecan seedlings for nematode resistance is warranted. Greenhouse studies were initiated to determine the host susceptibilty of selected pecan and peach rootstocks for resistance to the PRKN. Results indicate that all pecan rootstocks supported nematode reproduction and were rated as good hosts, whereas all commercial peach rootstocks were rated as highly resistant to this nematode. These data provide useful insights into the need to further explore the development of IPM management strategies (i.e., resistance & biological control) for control of PRKN on pecan and their affect on orchard profitability.
Technical Abstract: Open pollinated pecan seedling rootstocks were evaluated for susceptibility to Meloidogyne partityla, M. arenaria, and M. incognita in the greenhouse. Cultivars tested included seed from ‘Apache’, ‘Caddo’, ‘Curtis’, ‘Moneymaker’, ‘Pawnee’, ‘Schley’, ‘Stuart’, and ‘Wichita’ parent trees. ‘Elliott’ was included as a control. All open pollinated pecan rootstocks supported nematode reproduction as indicated by number of egg masses per plant, number of eggs per plant, and number of eggs per gram dry root, regardless of nematode species. Reproduction by M. partityla was greater (P < 0.05) on all pecan rootstocks than M. incognita and M. arenaria; indicating that pecan is a better host for M. partityla. All pecan seed sources were rated as good hosts (susceptible) to M. partityla infection and as poor hosts (resistant) to M. incognita and M. arenaria. In another greenhouse study, open pollinated ‘Elliott’ seedlings supported greater (P < 0.01) reproduction of M. partityla than Guardian®, Lovell, Halford, Flordaguard and Nemaguard peach cultivars. All peach cultivars were rated as nonhosts (highly resistant) to M. partityla infection. Interplanting pecan and peach trees in a commercial orchard environment does not appear to exacerbate the M. partityla population density between the two perennial crops in the southeastern United States.