Plant parasitic nematodes associated with Indian Pennywort Centella asiatica(L.) Urban in Manipur

N. Romabati Devi

Department of Zoology, Modern College, Imphal, Manipur, India

Date of publication (online): 26 December 2009

Date of publication (print): 26 December 2009

ISSN 0974-7907 (online) | 0974-7893 (print)

Editor: Anwar L. Bilgrami

Manuscript details:

Ms # o2111

Received 23 December 2008

Final received 28 October 2009

Finally accepted 30 October 2009

Citation: Devi, N.R. (2009). Plant parasitic nematodes associated with Indian Pennywort Centella asiatica (L.) Urban in Manipur. Journal of Threatened Taxa 1(12): 617-618.

Copyright: © N. Romabati Devi 2009. Creative Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium for non-profit purposes, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Acknowledgments:The author is grateful to Principal, Modern College, Imphal for providing necessary laboratory facilities.

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The most common nematode species associated with medicinal plants have been recorded from the Silviculture Farm at Kalinga in the district of Phulbani, Orissa (Routaray & Das 1982), southern Districts (Madurai, Ramanathapuram, Tirunelveliand Kanyakumari) of Tamil Nadu (Samathanam& Chawla 1982), and ImphalDistrict, Manipur (Romabati et. al. 1992). This study reports plant parasitic nematode species associated with Centella asiatica (L.) Urban in Manipur. Their absolute and relative frequencies and absolute and relative densities are also reported.

Methods: Seventy soil samples including a portion of root-system were collected from the rhizosphereof C. asiatica from different localities of Manipur. The nematodes were isolated from the soil using Cobb’s (1918) sieving and decanting methods and Baermann’s funnel technique (Thorne 1961). The nematodes thus, collected were killed and fixed in warm formalin – glacial acetic acid [F: A (4:1)]. The nematodes were identified up to species level and their populations were counted with the help of a Syracuse counting disc. The roots were examined for gall formation by root-knot nematodes. The number of adult root knot nematode females and larvae were counted. Absolute and relative frequencies,and absolute and relative densities of each nematode species was calculated (Norton 1978).

Results: Twenty-one nematode species belonging to 12 genera were identified. Commonly encountered nematode species were Basiria varians, B. graminophila, Tylenchorhynchus mashhoodi, Aphelenchus avenae, T. leviterminalis, Helicotylenchus dihystera, H. exallus, H. rotundicauda, Cephalenchus lobus and H. digonicus. The most prevalent species of plant parasitic nematodes associated with C. asiatica were T.mashhoodi, A. avenae andH. dihystera with absolute densities 498, 382,338 per 500g soil respectively. Basiria varians had highest absolute (100.00%) and relative frequencies (7.36%). However, its density was low as compared to its frequency (Table 1).

The absolute and relative frequencies Scutellonema brachyurus, Psilenchus elegans, Pratylenchus thornei and Basiria assarensis were 57.14% and 4.21% respectively. The frequency of occurrence of Coslenchus bisuxualis, C. tausifi, Criconemellaoblongata, C. ornata, C. serrata and Hirschmanneilla oryzae was less as compared to other nematode species. M. incognita was recorded only in 5 samples with very high population.

The relative densities of T. mashhoodi, A. avenae and H. dihysterawere 10.82, 8.30 and 7.34% respectively. The frequencyof B. graminophila Cephalenchus lobus, H. digonicus, Pratylenchus thornei and B. assarensiswas high but their populations were very low. Other nematode species Coslenchus bisexualis, C. tausifi, Criconemella serrata, C. ornata and Hirschmanneilla oryzae were also recorded at low densities.

Discussion: Samathanam & Chawla(1982) reported that Helicotylenchus sp. and Meloidogyne sp. were most prevalent nematode genera associated with field crops, medicinal plants and trees in the hilly areas of a southern Districts (Madurai, Ramanathapuram,Tirunelveli and Kanyakumari) of Tamil Nadu. Helicotylenchus abunaamai was most common nematode species associated with a number of medicinal plants grown in a SilvicultureFarm at Kalinga in the district of Phulbani, Orissa (Routaray & Das 1982). The most prevalent and commonly occurring plant parasitic nematodes associated with certain medicinal plants in Imphal were Helicotylenchus sp. and Tylenchorhynchus sp. (Romabati et al. 1992). These results also show species belonging to Helicotylenchus,Meloidogyne and Tylenchorhynchus were prevalent and commonly associated with medicinal plants. Based on the above findings, the most abundantly found nematode species associated with Centella asiaticawere Tylenchorhynchus mashhoodi,Aphelenchus avenae, and Helicotylenchus dihysterawhile Basiria vaianswas found to be highest in terms of absolute frequency.

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