Foliar nematode (Aphelenchoides besseyi) in tuberose (Polianthes tuberosa) in West BengalM. R. KhanE-mail: mrkhanbckv@ rediffmail.com
Foliar nematode, Aphelenchoides besseyi emerged as a serious problem in tuberose in West Bengal, India. This nematode was first time reported from the Hawaii Islands (Holtzmann, 1968) from the leaves of tuberose and subsequently from Ranaghat areas of Nadia district of West Bengal (Chakraborti & Ghosh, 1993). This nematode is widespread in Eastern and Southern India particularly in rice causing 'white tip disease' and estimated to cause yield loss 20 to 30% in rice (Prasad et al., 1986). The nematode has recently got spread to Orissa presumably through bulbs. A. besseyi is nowadays a major limiting factor for cultivation of tuberose in Ranaghat, Haringhata and Panskura areas of West Bengal. The infestation of this nematode in rice also has been encountered in Nadia, Hooghly, Malda, Burdwan, Midnapore, Uttar Dinajpur, Coochbehar districts of West Bengal. The 'Calcutta single' cultivar of tuberose is more vulnerable to A. besseyi than the 'Calcutta double' cultivar. Research results confirmed that A. besseyi is the primary causal agent for malformed flowers and population of A. besseyi causing white tip disease in rice is the same population infecting tuberose causing floral disease (Khan, 2001). The nematode species is widespread in rice in West Bengal (Das & Khan, 2007).
Infected flower stalk initially appears rough, stalk becomes crinkled, stunted and finally distorted and in severe cases flower buds failed to bloom. Brown streaks appear on leaf bracts and petals and subsequently develop into rusty brown spots. The severely infected flower stalk becomes rotten and brittle over drying, even gets blind and the number of flowers per stalk is also reduced. The nematode forms 'nematode wool' on dark brown spots. The ovary contains large number of nematodes. This nematode is generally more serious during rainy season generally from June to September and cent per cent loss of the second year crop of the 'Calcutta single' cultivar of tuberose was encountered. However, in 'Calcutta double' cultivar 30% to 40% flower stalk renders unsaleable and individual flower stalk harbours up to 45,000 nematodes (Khan & Pal, 2001). In Calcutta single, the yield loss may occur to the extent of 59% (Pathak & Khan, 2008) and the presence of nematode species in the cut flower stalk is one of the main constraint to export the flower in the other countries of world.
Infested bulbs harbour nematode in coiled anhydrobiotic condition (quiescent pre-adult and adult stages) in the scaly leaves outside the bulbs. The nematode can also survive in the dried scaly leaves, stems and flowers more than 25 months; however, they cannot survive in soil for long time (Khan, 2004; 2006a&b).Nematode management approaches:
- Presoaking of tuberose bulbs in plain water or in neem-seed-kernel-extract (NSKE 4%) for overnight followed by dipping in monocrotophos 36SL at 500-700ppm for 4-6 hours.
- After sprouting, three to four sprayings with monocrotophos 36SL at 500ppm at 15 to 20 days interval is needed.
- In the second and third year crop, same spraying for 3-4 times with monocrotophos 36SL at 500ppm at 15 to 20 days interval should start from April-May onward to reduce the nematode infestation.
- Field sanitation is most essential for reducing infestation. Infested plant parts should be burnt or buried into the soil.
- Grow nematode tolerant tuberose cultivars, Prajwal and Shringar(Khan & Ghosh, 2007)
- Growing tuberose away from rice field is encouraged to avoid contamination of tuberose field.
For further reading:
Chakraborti, H. S & Ghosh, S. C. (1993). Studies on the floral malady of Polianthes tuberosa L. in West Bengal. J. Mycopath. Res. 31(2): 109-115.
Das, T.K. and Khan, M.R. (2007). Occurrence and distribution of white tip nematode, Aphelenchoides besseyi in West Bengal, India. Indian J. Nematol. 37(1): 94-97.
Khan, M. R. & Feza Ahmad, M. (2002). Managing nematode menace in flower crops. Indian Horticulture, 47 (2): 28-29.
Khan, M. R. (2001). White-tip nematode, Aphelenchoides besseyi in rice-tuberose cropping system. In: Proc. National Seminar on Frontiers of Crop Management (S. K. Mukhopadhyay, D .C. Ghosh and G. C. De eds.) February 1-3, 2001, Visva-Bharati; Sriniketan, India. pp. 142-144.
Khan, M. R. (2004). Observation on foliar nematode, Aphelenchoides besseyi in tuberose (Polianthes tuberosa L.) in West Bengal. Ann. Pl. Protec. Sci. 12 (1): 106-109.
Khan, M. R. Shit, S., Pal, A. K. & Biswas, B. (2006). Management of foliar nematode, Aphelenchoides besseyi infecting tuberose in West Bengal, India. Indian J. Nematol. 36 (1): 44-47.
Khan, M.R., Shit, S., Pal, A.K. & Biswas, B. (2005). Integrated approach for management of foliar nematode, Aphelenchoides besseyi infecting tuberose in West Bengal, India. Intl. J. Nematol. 15(1):30-34.
Khan, M.R. & Pal, A. K. (2001). Plant parasitic nematodes associated with tuberose (Polianthes tuberosa L.) in West Bengal. Ann. Pl. Protec. Sci. 9 (2): 357-359.
Khan, M.R.(2006a). Managing foliar nematode- a threat for tuberose cultivation. Indian Horticulture 51(1):17.
Khan, M.R. (2006b). Current options for managing nematode pest of crops in India, pp: 16-50. In: Plant Nematology in India (N. Mohilal and R. K. Gambhir, eds.), Parasitology Lab., Department of Life Sciences, Manipur University, India, p.178.
Pathak, B. & Khan, M. R. (2008). Yield loss potential of foliar nematode, Aphelenchoides besseyi in tuberose. Indian J. Nematol. 39(1): In press
Khan, M.R. Pathak, B. & Ghosh Dostidar, K. (2008). Management approaches of tuberose foliar nematode, Aphelenchoides besseyi in West Bengal, India. Indian J. Nematol. 38(1): 25-29.
Khan, M.R. & Ghosh, S. (2007). Evaluation of tuberose cultivars against foliar nematode, Aphelenchoides besseyi, In: National Symposium on Nematology in 21 Century: Emerging paradigms, Nov, 22-23, 2007, Nematological Society of India, held at Assam, India, pp.77.