Department of Entomology, College of Agriculture, Andhra Pradesh Agricultural University, Rajendranagar, Hyderabad-500 030, Andhra Pradesh (India).
The artificial diet formulated by Jayanth and Sudha Nagarkatti for the coconut black headed caterpillar, Opisina arenosella Walker comprised four fractions viz., Fraction ‘A’:kabuligrarn powder 50.0 g, casein 15.0 g, methylparahydroxybenzoate 1.0 g, sorbic acid 0.5 g, salt mixture 1.5 g, yeast tablets (powdered) 8.0 g, distilled water 190.0 ml; Fraction ‘B’: coconut leaf powder 5.0 g, distilled water 50.0 ml; Fraction ‘C’: Agar agar 5.0 g, tap water 175.0 ml; and Fraction: ‘D’:ascorbic acid 1.5 g, cholesterol 0.1 g, streptomycin sulphate 0.15 g, formaldehyde 10% 1.0 ml, multivitamin capsule one, and vitamin E one capsule. Besides using coconut leaf powder of Fraction ‘B’ as a check, leaf powder of eight different hosts were also used as replacements while evaluating artificial diets for mass rearing of O. arenosella. Amongst the different hosts tested, artificial diet incorporating toddy palm leaves powder (B. flabelliformis) was the most preferred and suitable. While rearing the coconut pest on this diet, higher sex ratio (1.72 ), high fecundity (58.33 eggs), and shorter developmental period (69.62 days) were obtaibed. This was followed by diet containing coconut leaf powder (C. nucifera) as evidenced by sex ratio (1.60 ) and 71.88 days developmental period. The artificial diet compounded with bottle palm (O. regia) was least preferred, the developmental period being the longest i.e., 94.34 days and the sex ratio as 1.43 . Artificial diets formulated separately with leaf powders of Bungalow palm (A. cunnighariana), wild date palm (P. silvestris), banana (M. paradasica), and oil palm (E. guineensis) were not suitable for development. The diet based on travellers’ palm (Ravenala sp.) did show promise, but with arecanut (A. catechu) development of O. arenosella did not commence.
