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Gracilacus hamicaudata Cid & Maggenti, 1988
Posterior end of female (SEM).
Photograph: I. Cid del Prado
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Feeds in colonies under the root cortex and apparently anchored to enlarged
feeding site cells in the phloem parenchyma of secondary roots. The
nematode bodies are not exposed to the root surface. Feeding induces cell wall
thickening. Giant cell feeding sites are formed in the parenchyma tissue of
the vascular cylinder associated with aggregations of nematodes.
At the feeding site, pericycle cells increase in number then collapse and die
(Cid del Prado and Maggenti, 1988)
Type host: Redwood: Sequoia sempervirens
Female attaches to feeding sites in vascular parenchyma by the stylet. Female body swells as gonads
mature. Eggs are deposited in a gelatinous matrix which surrounds the female,
eggs and and newly hatched J2s under the root cortex (Cid del Prado and Maggenti,
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Cid del Prado Vera & Maggenti, A. 1988. Description of Gracilacus
hamicaudata sp. n. (Nemata: Criconematidae) with biological and
histopathological observations. Revue de Nematologie 11:29-33.
Raski, D.J. 1976. Revision of the Genus Paratylenchus Micoletzky, 1922
and Descriptions of New Species. Part III of Three parts--Gracilacus. J.