Submitted to: Phytopathology
Publication Type: Abstract only
Publication Acceptance Date: 5/18/2006
Publication Date: 6/1/2006
Citation: Nyczepir, A.P., Wood, B.W., Reilly, C.C. 2006. Impact of Meloidogyne partityla on mouse-ear and nickel deficiency of pecan in Georgia [abstract]. Phytopathology. 96:S86. 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, the pecan root-knot nematode, M. partityla, was first reported on pecan in Georgia and was associated with stressed trees exhibiting typical Mouse-ear (ME) symptoms and dead branches in the upper canopy. Both the ME and replant disorders have recently been found to be due to a nickel (Ni) deficiency, with timely foliar application of Ni correcting both disorders. Determining the interrelationship among root parasitism by M. partityla, Ni deficiency, and severity of ME symptoms in pecan in Georgia needs to be investigated. In 2002-05, a field microplot study was conducted to determine the association of the pecan root-knot nematode and ring nematode with nickel deficiency and Mouse-ear of pecan. Results indicate that nickel deficiency, and thus ME symptom, in pecan trees can be triggered and enhanced by M. partityla colonization of roots. These data provide useful insights into the interrelationship between pecan root-knot nematode and severity of ME symptoms in pecan in Georgia and establishes the need to further investigate potential management strategies of this root-knot nematode pest on pecan.
Technical Abstract: The Mouse-ear (ME) malady of pecan is a nickel (Ni) deficiency that has most recently become an orchard replant disorder. Mouse-ear has been associated with nematode parasitism in some commercial pecan orchards in Georgia. A field microplot study of pecan seedlings treated with either Meloidogyne partityla or Criconemoides xenoplax or both found that parasitism by M. partityla can increase severity of ME symptoms. Furthermore, severity of ME symptoms was inversely proportional (P < 0.05) to Ni concentration in the pecan leaflets, thus supporting previous findings that ME severity is due to a physiological Ni deficiency. Results also indicate that parasitism by C. xenoplax appears to have little or no influence on ME severity or Ni nutrition of pecan. These results provide useful insights into the interrelationship among the pecan root-knot nematode, severity of ME symptoms, and Ni deficiency in pecan. The need to further investigate potential management strategies of M. partityla on pecan is warranted.