Susceptibility of three Eco-races of tropical Tasar silkworm to Antheraea mylitta cytoplasmic polyhedrosis virus (AmCPV)

Pathogenic infection in tasar silkworm, Antheraea mylitta Drury. is common and there is a breed specific response regarding tolerance. Observations reveal the possibility of differential response by haemocytes to microbial infection in different breeds. Hence, the susceptibility of three eco-races of tasar silkworm viz. Daba, Sarihan and Raily to Antheraea mylitta Cytoplasmic Polyhedrosis Virus (AmCPV) infection and difference in total haemocyte counts were tested. The survival of Daba, Sarihan and Raily eco-races was significantly different (p < ۰.۰۵) when challenged with the same concentration (۱ x ۱۰۵ polyhedra/ml) of AmCPV. Daba eco-race was more tolerant to the AmCPV infection having higher survival (۶۶.۷%) and LC۵۰ values (۱۰۰۰۸۹۳.۱۷۹۶ polyhedra/ml) of AmCPV followed by Sarihan eco-race (۵۰.۷% survival and LC۵۰ value of AmCPV ۱۸۷۲۰۳.۶۱۶۸ polyhedra/ml.) and Raily eco-race (۲۵.۳% survival and LC۵۰ value of AmCPV ۵۱۷۶.۳۷ polyhedra/ml.). Difference in total haemocyte count i.e. higher in tolerant (Daba) and lower in susceptible (Raily) eco-race may be in response to difference to their susceptibility to AmCPV infection.     REFERENCES Aizawa, K. (۱۹۷۱) Structure of polyhedra and virus particles of cytoplasmic polyhedrosis, In the cytoplasmic polyhedrosis of the silkworm (Eds: Aruga, H. and Tanada, Y.) Univ. Tokyo press, Tokyo, pp. ۲۳-۳۶. Aratake, Y. (۱۹۷۳) Strain difference in the silkworm, Bombyx mori L. in the resistance to a nuclear polyhedrosis virus. J. Seric. Sci. Jpn. ۴۲, ۲۳۰-۲۳۸. Balavenkatasubbaiah, M. Nataraju, B., Thiagrajan, V. and Datta R. K. (۲۰۰۱). Haemocyte counts in different breeds of silkworm, Bombyx mori L and their changes during the progressive infection of BmNPV. Indian J. Seric. ۴۰, ۱۵۸-۱۶۲. Butt, M. and Shields S.K. (۱۹۹۶) The structure and behaviour of gypsy moth (Lymantria dispar) haemocytes. J. Inverteb. Pathol. ۶۸, ۱- ۱۴. Ennesser, A.C. and Nappi, A.J. (۱۹۸۴). Ultrastructural study of the encapsulation response of the American cockroach Periplanata americana. J. Ultrastruct. Res., ۸۷, ۳۱-۴۵. Gupta, A.P. (۱۹۸۶) Arthropod immunocytes: Identification, structure, functions and analogies to the functions of vertebrate B – and T- lymphocytes. In: Hemocytic and Humoral Immunity in arthropods, A. P. Gupta (Ed.), John Wiley, New York, pp. ۳- ۵۹. Gupta, A.P. and Han, S.S. (۱۹۸۸) Arthropod immune system. III. Septate junction in the Singh et al., ۱۶۵ haemocytic capsule of the German cockroach, Blettella germanica. Tissue & Cell, ۲۰, ۶۲۹-۶۳۴. Jonesh, J.C. (۱۹۶۲) Current concepts concerning insect hemocytes Am. Zool. ۲, ۲۰۹-۲۴۶. Kawakami, K. (۱۹۶۵) Phagocytosis in muscardine diseased larvae of the silkworm, Bombyx mori (Linnaeus). J. Invertebr. Pathol. ۷, ۲۰۳:۲۰۸۸. Ratnasen, Ahsan, M.M. and Datta, R.K. (۱۹۹۹) Induction of resistance to BmDNV into a susceptible bivoltine silkworm breed. Indian J. of Seric. ۳۸(۲), ۱۰۷ – ۱۱۲. Sahay, D.N., Roy, D.K. and Sahay Alok (۲۰۰۰) Diseases of tropical tasar silkworm, Antheraea mylitta D., Symptoms and control measures, In: Lessons on Tropical Tasar. Ed. By K. Thangavelu, Central Tasar Research and Training Institute, Piska Nagri, Ranchi, ۱۰۴ p. Singh, G.P., Selvakumar, T., Sharma, S.D., Nataraju, B. and Datta, R.K. (۲۰۰۳) Susceptibility of CSR hybrids of silkworm, Bombyx mori L to two species of Aspergillus fungi. Sericologia. ۴۳, ۳۱۹-۳۲۳. Singh, G.P., Mengkui, Xu, Yuyin Chen and Datta, R.K. (۲۰۰۳) Development of Resistance to Bombyx mori Densonucleosis Virus into a susceptible silkworm breed. Int. J. Indust. Entomol. ۶, ۱۴۵-۱۴۹. Snedecor, G.W. and Cochran W.E. (۱۹۹۵) Statistical Methods. Oxford IHB Publishing Co. New Delhi. pp. ۳۳۹ – ۳۶۱. Tauber, O.E. and Yeager, J.E. (۱۹۳۵) On the total blood counts of insects. I. Orthoptera, Odonata, Hemiptera and Homoptera. Ann. Entomol. Soc. Am. ۲۸, ۲۲۹-۲۴۰. Uzigawa, K. and Aruga H. (۱۹۶۶) On the selection of resistant strains of infectious flecherie virus in the silkworm, Bombyx mori L., J. Seric sci. Jpn. ۳۵,۲۳-۲۶. Watanabe, H. (۱۹۶۷) Development of resistance in silkworm, Bombyx mori to peroral infection of a cytoplasmic polyhedrosis virus. J. Invertibr. Pathol. ۹, ۴۷۴- ۴۷۹.

Keywords:

Antheraea mylitta , Am CPV , Haemocytes , Tolerance