Meloidogyne exigua

Meloidogyne exigua	Contents	Rev 10/14/2008
	Classification	Hosts
	Morphology and Anatomy	Life Cycle
Return to Meloidogyne Menu	Economic Importance	Damage
	Distribution	Management
Return to Heteroderidae Menu	Feeding	References
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Classification:

      Tylenchida
       Tylenchina
        Tylenchoidea
         Heteroderidae
          Meloidogyninae
           Meloidogyne exigua Goeldi

Meloidogyne exigua was the first root-knot species described under this genus name. It was described by Göldi (sometimes Goeldi) in 1892 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 Göldi (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, Göldi 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:

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Distribution:

Coffee-producing areas of Central and South America and southern India.

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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, and others.

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Life Cycle:

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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).

Root necrosis and defoliation are greater when roots are infected by both M. exigua and Rhizoctonia solani than by either organism alone.

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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.

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.