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Daucus carota (carrot) infected with Meloidogyne javanica. Note root galling and bifurcation induced by this nematode.
Photograph courtesy of Jeffrey W. Lotz and Janete A. Brito, DPI.

Alpinia zerumbet (shell ginger) flowers.
Photograph courtesy of University of British Columbia Botanical Garden [accessed 25 May 2010]

Luffa acutangula (ridged gourd, loofah)
Photograph courtesy of Top Tropicals [accessed 25 May 2010]

Cissus verticillata (possum grape or seasonvine) heavily galled and necrotic due to the infection of Meloidogyne mayaguensis.
Photograph courtesy of Mariana P. Beckman and Janete A. Brito, DPI.

Nematology Section

Compiled by Janete A. Brito, Ph.D., Maria L. Mendes, Ph.D., Ramandeep Kaur, Ph.D., and Jason D. Stanley, M.S.

This section analyzes soil and plant samples for nematodes, conducts pest detection surveys and provides diagnosis of plant problems, in addition to completing identification of plant parasitic nematodes involved in regulatory and certification programs. State of Florida statutes and rules mandate the principal part of the regulatory activity of the section. Analyses of plant and soil samples include those from in-state programs, plant shipments originating in Florida destined for other states and countries, as well as samples intercepted in Florida from outside the United States.

Nematodes of Special Interest

Nematodes of special interest detected and/or identified in March – April 2010

Meloidogyne javanica (Treub, 1885) Chitwood, 1949 (the Javanese root-knot nematode) was found infecting the roots of Daucus carota (carrot). Root-knot nematodes are a limiting factor in carrot production in several areas of the world and have required extensive use of pesticides. Symptoms of Meloidogyne spp. infection include poor plant growth, yellowing of leaves, and root galling and deformation of tuber crops. Infections in carrots cause short, stubby, forked taproots and lead to severe losses in quality and marketability. (Marion County; N10-00498; Drs. Donald W. Dickson and Maria de Lourdes Mendes, University of Florida; 14 April 2010.)

Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 (the peanut root-knot nematode) was found infecting the roots of Carica papaya (papaya). Roots were galled and necrotic as a consequence of the nematode infection. Two other species of root-knot nematodes, M. incognita and M. javanica, have been found associated with papaya in several countries. (Miami-Dade County; N10-00326; Ana L. Ochoa; 10 March 2010.)

Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 (the peanut root-knot nematode) was found infecting the roots of an ornamental plant, Duranta erecta (golden dew drop). This nematode species induced small root galls on the flowering shrub. Nematode egg masses were clearly visible outside the roots. Several ornamental plants have been found to be susceptible to this nematode species in Florida. (Palm Beach County; N10-00276; Frank A. Burgos; 1 March 2010).

Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 (southern root-knot nematode) was found infecting the roots of an ornamental plant, Alpinia zerumbet (shell ginger). This nematode species has a wide host range and has been found to reproduce on agronomic and horticultural crops as well as weeds in Florida. (Palm Beach County; N10-00276; Frank A. Burgos; 01 March 2010.)

Meloidogyne mayaguensis Rammah & Hirschmann, 1988 (the guava root-knot nematode), a new Host record, was found infecting the root system of the vine, Luffa acutangula (ridged gourd, loofah or plant sponge). Immature fruits of this cucumber relative are eaten as a vegetable in some parts of the world, while the dried and bleached vascular systems of mature fruits can be used as a sponge. Fruits are cylindrical or club-shaped, usually 30-40 cm long and are easily seen hanging from trellises on which the plant grows. (Miami-Dade County; N10-00250; Ana L. Ochoa; 14 February 2010.)

Meloidogyne mayaguensis Rammah & Hirschmann, 1988 (the guava root-knot nematode), a new Host record, was found infecting the root system of a weedy Florida native plant, Cissus verticillata (possum grape or seasonvine). Roots were heavily galled and necrotic as a consequence of the nematode infection. Several weed species in Florida are good hosts of root-knot nematodes, including M. mayaguensis. Weeds hosting root-knot nematodes are of particular importance because they allow for nematode survival even in the absence of a crop. Infected weeds provide a source of nematode infestation for the following season and create a major problem for nematode management in infested areas. (Miami-Dade County; N10-00182; Ana L. Ochoa; 10 February 2010.)

Collectors submitting five or more samples that were processed for nematological analysis in March - April 2010

References

Brito, J. A., R. Kaur, R. Cetintas, J. D. Stanley, M. L. Mendes, E. J. McAvoy, T. O. Powers and D. W. Dickson. 2008. Identification and isozyme characterization of Meloidogyne spp. infecting horticultural and agronomic crops and weed plants in Florida. Nematology 10:757-766.

Kaur, R., J. A. Brito and J. R. Rich. 2007. Host suitability of selected weed species to five Meloidogyne species. Nematropica 37: 107-120.

McSorley, R. 1981. Plant-parasitic nematodes associated with tropical and subtropical fruits. Agricultural Experiment Station, Institute of Food and Agricultural Science, University of Florida, Gainesville, Florida, Bulletin 823.

Rich, J. R., J. A. Brito, R. Kaur and J.A. Ferrell. 2009. Weed species as hosts of Meloidogyne: a review. Nematropica 39: 157-185. http://www.ontaweb.org/. [Accessed: March 10, 2010]