Meloidogyne exigua

 

Contents

 

Rev 12/11/2019

  Classification Hosts
Morphology and Anatomy Life Cycle
Return to Meloidogyne Menu Economic Importance Damage
Distribution Management
Return to Heteroderidae Menu Feeding  References
    Go to Nemaplex Main Menu   Go to Dictionary of Terminology

Classification:

      Tylenchida
       Tylenchina
        Tylenchoidea
         Heteroderidae
          Meloidogyninae

           Meloidogyne exigua Goeldi, 1887

Meloidogyne exigua was the first root-knot species described under this genus name.  It was described by Göldi (sometimes Goeldi) in 1887 having first been reported by Jobert in 1878 on coffee in Brazil.

Some history....(adapted from an article by Luiz Carlos Ferraz in Nematology Newsletter 54(2):8.)

Emil August Goeldi (1859-1917), a naturalist from Switzerland, was invited by the government of Brazil to investigate the decline of coffee trees growing in the Província of Rio de Janeiro during 1886 and 1887.

Local coffee producers had alerted the Emperor to their problem several years earlier and Clément Jobert, a French researcher, had already published (1878) a brief note speculating that the causal agent was a nematode of the genus Anguillula.

In 1897, Goeldi published a 120-page illustrated document, "Relatório sobre a moléstia do cafeeiro na Província do Rio de Janeiro". Eggs, juveniles and male/female adults of Meloidogyne exigua were illustrated and some basic measurements included. This was the first description of a root-knot nematode and Meloidogyne exigua is thus the type species of the genus. Some of the control measures suggested by Göldi are still practiced by growers in Brazil.

 

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Morphology and Anatomy:

 

 


Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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Distribution:

Coffee-producing areas of Central and South America and southern India, China, and some southern European countries (Elling, 2013).

Meloidogyne exigua is present in 22% of the coffee plantations and 95% of the districts in southern Minas Gerais State in Brazil; that region accounts for nearly half of Brazil's coffee production (Elling, 2013).

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Economic Importance:

C-rated pests in California. 

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Feeding:

Feeding site establishment and development typical of genus.

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Hosts:

Coffee, banana, watermelon, pepper, tomato, onion, sugarcane, citrus, rice, rubber tree, and weeds (e.g., Taraxacum officinale, Amaranthus deflexus, and Poinsetta heterophylla).

 All themain coffee cultivars grown are susceptible to M. exigua nematode and germplasm screens have failed to identify resistance in Coffea arabica (Elling, 2013).

For an extensive host range list for this species, click

 

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Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters

 

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Damage:

Feeding causes yellowing of leaves, leaf fall, destruction of root hairs and rootlets, root lesions, small root galls, vascular disruption, and secondary invasion.   Yields of non-infested plants may be twice as high as those infested with M. exigua (Lordello, 1986).

Coffee yield losses estimated at 10-20% in Costa Rica and 45% in Brazil.

Root necrosis and defoliation are greater when roots are infected by both M. exigua and Rhizoctonia solani than by either organism alone.
Meloidogyne exigua typically induces round galls on coffee roots with egg masses within the galls (Humphreys=Pereira et al., 2014).

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Management:

Treatment of seedbeds with nematicides is effective; however, use of nematicides on established coffee plants is not feasible due to phytotoxicity and expense. 

Produce coffee seedlings in nurseries where soil has been disinfested.

In Minas Gerais,  Brazil, the best time to implement chemical control measures against M. exigua is November, which coincides with renewed plant root growth, a high level of lipid reserves
in J2, high nematode population density, and high infectivity (Elling, 2013).

Host Plant Resistance, Non-hosts and Crop Rotation alternatives:

For plants reported to have some level of resistance to this species, click

Although there is no known resistance in Coffea arabica, resistant rootstocks are available, but yield is lower. Coffeae canephora cv robusta is highly resistant to M. exigua.

One year fallow period recommended before replanting an infested coffee plantation in Brazil.

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References:

Elling, A.A. 2013. Major Emerging Problems with Minor Meloidogyne Species. Phytopathology 103:1092-1102.

Goeldi, E.A. 1887. Relatorio sobre a molestia do cafeeiro na provincia do Rio de Janeiro.  Archivos do Museo Nacional 8:7-123 (1892)

Humphreys-Pereira, D.A., Flores-Chavez, L., Gomez, M., Salazar, L. Gomez-Alpizar, L.E., Elling, A.A. 2014. Meloidogyne lopezi n.sp. (Nematode: Meloidogynidae, a new root-knot nematode�.. Nematology 16:643-661.

Lordello, L.G.E. 1986  Plant-parasitic nematodes that attack coffee. Pp 33-41 in Anon.  Plant-parasitic nematodes of bananas, citrus, coffee, grapes and tobacco. Union Carbide Corp.

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Copyright © 1999 by Howard Ferris.
Revised: December 11, 2019.