Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2003
Publication Date: 6/1/2003
Citation: Nyczepir, A.P., Wood, B.W., Reilly, C.C. 2003. Evaluation of selected pecan (carya illinoensis) rootstocks for resistance to meloidogyne partityla. Phytopathology. 93(6):566. Abstract. Interpretive Summary: Pecan is an important nut crop throughout much of the southern United States with Georgia being ranked as the leading producer. Root-knot nematodes, Meloidogyne spp., are recognized as pests of pecan. In 2002, M. partityla was first reported on pecan in Georgia and was associated with stressed trees exhibiting dead branches in the upper canopy. Ideally, long-term control of this potential nematode pest on pecan could be achieved with host resistance. However, no data are available on pecan resistance to M. partityla. Evaluating known rootstock cultivars of pecan for resistance to this nematode needs to be investigated. In 2002, nine pecan rootstocks were evaluated for susceptibility to this root-knot nematode under greenhouse conditions. Plants were planted singly in plastic pots and the soil infested with 1,400 root-knot nematode eggs. The study was terminated after 230 days following inoculation and at which time the i) number of egg masses and root galls per root system, ii) number of eggs per root system, and iii) dry root weight were recorded. Results indicate that all rootstocks tested were good hosts to M. partityla. These data provide useful insights into the utilization of commercial pecan rootstocks established in orchards infested with this root-knot nematode in the Southeast. Additionally, this data was necessary for providing a better understanding for the need to 1) further evaluate additional pecan germplasm for useful sources of resistance and 2) determine this nematode's distribution in the major pecan producing regions of the Southeast.
Technical Abstract: Pecan is an important nut crop throughout much of the southern U.S, with GA being ranked as the leading producer. Meloidogyne incognita and M. arenaria are known to attack pecan. In 2002, M. partityla was first reported on pecan in GA and was associated with stressed trees exhibiting dead branches in the upper canopy. Host resistance is an effective nonchemical management strategy, however, no data are available on pecan resistance to M. partityla. Nine pecan rootstocks were evaluated for susceptibility to this nematode. Stocks included seedlings of Apache, Caddo, Curtis, Elliot, Moneymaker, Pawnee, Schley, Stuart, and Wichita cultivars. Seedlings were planted singly in pots and the soil infested with 1,400 eggs. The number of egg masses and root galls per root system, number of eggs per root system, and dry root weight were recorded after 230 days. Resistance rating was based on inhibition of nematode reproduction relative to that on a standard stock (Elliot). Results indicate that all stocks were good hosts to M. partityla. Further evaluation of pecan germplasm for useful sources of resistance is warranted.