J. BioI. Control. 17(1): 97-98, 2003 Research Note

Nuclear polyhedrosis viruses from blackheaded caterpillar, arenosella Walker and sorghum spotted stern borer, Chilo partellus (Swinhoe)

K. NARAYANAN and K. VEENAKUMARI Project Directorate of Biological Control (leAR) P. B. No. 2491. H. A. Farm post, Bellary road, Hebbal Bangalore 560024, Kranataka, E-mail: [email protected]

A~~TRA CT: Two nuclear polyhedrons viruses from the coconut black headed caterpillar, ?p.sma arenosella Walker and sorghum spotted stem borer, Chilo partelJus (Swinhoe) were Isolated and reported for the first time from India. The pathogenicity of both the NPVs have been tested and proved along with gross pathological symptoms.

KEY WORDS: Chilo partellus. nuclear polyhedrosis virus, Opisina aref/osella

Opisina arenosella is a major of maize at National Dairy Research Institute, coconut, often causing extensive damage in all Bangalore. southern states of India, especially Kamataka and Smears of diseased larvae examined under Tamil Nadu. O. arenosella is subject to attack by phase contrast microscope revealed the polyhedra several indigenous parasitoids and predators (Cock in the nuclei of fat body cells and tracheal matrix. and Perera, 1987). The occurrence of diseased The polyhedra were collected and purified from the larvae with the symptoms characteristic of nuclear diseased caterpillars by differential centrifugation polyhedrosis virus infection was noticed among method. Studies on the pathogenicity of the virus field population of O. arenosella on coconut were conducted with ten and fifteen second instar coIIected from a farmer's field in Mandya. larvae ofO. arenosella and C. partellus inoculated Sorghum is an important grain and fodder at the rate of 1 x 1OS POBs/1arva through surface crop of India. Among the stem borer contamination technique and it resulted in 100 per associated with sorghum in India, the spotted stem cent mortality within 3-5 and 6-8 days, respectively borer, Chilo partellus is the major pest. Incidence days. The polyhedra from the inoculated and ?f stem borer ranges from 10-75 per cent with severe diseased caterpillars were harvested, compared and mfestation that can necessitate resowing of the crop checked with original isolates through electron (Pradhan and Prasad, 1955). The occurrence of microscope and found to be the same. Healthy diseased larvae with the symptoms characteristic larvae of O. arenosella generally green when young of nuclear polyhedrosis virus infection was noticed and tum into brown with reddish stripes dorsally, among field population of C. partellus on fodder when they grow into mature larvae and consytruct NARAYANAN and VEENAKUMARI

galleries in the leaves. In contrast, the diseased REFERENCES larvae are pinkish white and do not construct galleries. In the advance stages of infection, cuticle Cock, M. J. W. and Perera, P. A. C. R. 1987. Biological became very fragile and ruptured at the slightest control of Opisina arenosella Walker (: pressure liberating the liquefied body contents Oecophoridae). Biocontrol News and Information, 8: 283-309. containing polyhedral occlusion bodies. Though the occurrence of NPV has been reported earlier by Odindo, M. 0., Otieno, W. A., 0100, G. W., Kilori, J. Philip et al. (1982) from Kerala; no pathogenicity and Odhiambo, R. C. 1989. Prevalence of testing of NPV in O. arenosella has been proven. microorganisms in field-sampled borers on sorghum, The diseased larvae of C. partellus are white in maize, and cowpea in western Kenya. Journal of colour compared to brown colour in healthy Science and its Application, 10: 225-228 larvae. Martignoni, M. E. and Iwai, P. 1. 1986. A catalogue of The NPV of C. parte/lus has not been included viral diseases of , mites and ticks. USDA in the catalogue on viral disease of insects Forest Service, Pacific North west Research Station, (Martignoni and Iwai, 1986). Though the prevalence General Technical Report. of nuclear polyhedrosis virus has been reported from Kenya (Odindo et al., 1989), there seems to be Philip, B. M., Mathai, S. and Jacob, A. 1982. A nuclear no authentic report on the pathogenicity testing polyhedrosis of the blackhead caterpillar, Opisina earlier. arenosella (Walker). (=Nephantis serinopa Meyrick) (Lepidoptera: Cryptophagidae). Current Science. 51: 611. ACKNOWLEDGEMENT Pradhan, S. and Prasad, S. K. 1955. Correlation between Authors are thankful to the Project Director, the degree ofdamage due to Chilo zonellus (Swinhoe) Project Directorate of Biological Control, Bangalore and the yield of jowar grains. Indian Journal of for providing the facilities. Entomology, 15: 136-137.

98