Hirschmanniella imamuri




Rev 01/09/2024

Classification Hosts
Morphology and Anatomy Life Cycle

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Economic Importance Damage
Distribution Management
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           Hirschmanniella imamuri Sher, 1968


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Morphology and Anatomy:




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





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Hirschmanniella imamuri, like H. diversa, an important pest of lotus in Japan.

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Economic Importance:

Important pest in lotus (Nelumbo nucfiera) cultivation in Japan (Takagi et al., 2023).

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Migratory endoparasite of roots.  Juveniles and adults enter at root tip  of rhizomes.. 


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For an extensive host range list for this species, click

 Besides parasitizing Indian lotus, Hirshcmanniells imamuri also parasitizes rice grown in flooded fields.

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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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Hirshcmanniells diversa and H, imamuri are considered causal agents of blackening disease or browning tuber disease "Renkon Kurokawa-Senchu-Byo" in Indian lotus (Nelumbo nucifera). Lotus cultivars include flowering forms with high value as ornamentals end edible forms with the rhizome as the edible portion. (Uematsu et al., 2020). Hirschmannielaa imamuri, like H. oryzae, is also a pasraite of rice; both cause root-rot in rice roots..

Lotus is an aquastic plant grown and cultivated in ponds or flooded fields. Edible lotus rhizomes are an important food source in Japan.

The nematodes are attracted to to young root tips of  rhizomes and create narrow cavities as they invade over a period of 4-5 hours. Host cells adjacent to the cavitis are destroyed during the during infestation. Following contact with the nematodes, host cell walls and cellular contents became electron-dense and less defined, likely due to digestive enzymes secreted by the invading nematodes. Nematodes invade to a depth of about 1mm in 24 hr \ but apparently does not penetrate deeper into the rhizome (Uematsu et al., 2020)..  The infection results in blackish-brown blothces as the rhizome matures.

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

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


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Sher, S. A. 1968. Revision of the genus Hirschmanniella Luc & Goodey, 1963 (Nematoda: Tylenchoidea). Nematologica 14:243-275.

Takagi, M., Sekimoto, S., Mizukubu, T., Wari, D., Akiba, M., Perry, R.N., Toyota, K. 2023. Geographical distribution and phylogenic relationships of Hirschmanniella diversa Sher (Nematoda: Pratylenchidae) in Japan. Nematology 55:45-58.

Uematsu, S., Yabu, T., Yao, M., Kurihara, T., Koga, H. 2020. Ultrastructure of Hirschmanniella diversa early-stage infection in browning rhizomes of Indian lotus. J. Nematology 52: | DOI: 10.21307/jofnem-2020-055
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Copyright © 1999 by Howard Ferris.
Revised: January 09, 2024.