Vol. 24 (1) (March 2021) Insect Environment Incidence of leaf defoliator, Catopsilia pyranthe (Linn.) (Lepidoptera: Pieridae) in Senna Sankarganesh, E and Kusal Roy Department of Agricultural Entomology Bidhan Chandra Krishi Viswavidyalaya (BCKV) Mohanpur-741252, Nadia, West Bengal, India Corresponding author:[email protected] Senna is an economically important crop which is internationally and widely accepted for its medicinal values. Being drought tolerant, Senna is grown over one lakh hectare area in semi- arid regions of the country (Jat, 2015). India is the largest producer and exporter of leaves and pods of this plant which have high demand in the global market for its laxative and other medicinal properties (Sathiyabalan, 2019). Few insects were reported to be the pest of Senna and remain active in late summer months (Veeraragavan, 2018). We encountered the severe incidence of leaf defoliator, Catopsilia pyranthe (Lepidoptera: Pieridae) in Senna sophera (L.) Roxb. and other Senna sp. near C-Block Farm of Bidhan Chandra Krishi Viswavidylaya, Kalyani, West Bengal (22059'31'' N Latitude and 88026'54'' E Longitude) during post-monsoon period of 2020. The plants were raised for the medicinal as well as for the ornamental purpose. The peak activity of the pest was noticed during October and November months with a maximum of three larvae in a plant (Fig. 1) and found infesting leaves, tender shoots, flower buds and flowers (Fig. 2). Adult female butterfly laid eggs singly on both the sides of the leaf. The egg (Fig. 3) is white coloured, erect and spindle-shaped. During the investigation, more than one egg was found on the same leaflet of the plant. There were five larval instars. The newly emerged larva (Fig. 4) was cylindrical with a pale yellowish-green body and a round pale coloured head. The larvae excreted a huge amount of black and granular faeces. The mature larva devours the leaf only keeping the midrib intact (Fig. 5). Soon after completion of the final instar, the caterpillar secreted silken thread to secure itself firmly during pre-pupation stage (Fig. 6) and constructed the pupa, called chrysalis (Fig. 7). The pupae (Fig. 8) had pointed head, pale green body and yellow lateral lines on each side. 104 Vol. 24 (1) (March 2021) Insect Environment The adult (Fig. 9) is popularly known as a mottled emigrant, medium-sized butterfly; wings are greenish-white and forewings have a black apical border. Atluri et al. (2004) reported that C. pyranthe breeds throughout the year and the developmental period from egg to adult requires 22 to 29 days with several overlapping generations in a year. The adults are mostly generalist but the larvae are specialized in different species of Cassia (Kunte, 2006). Being the medicinal and consumable crop, the use of insecticides in Senna is not advisable. However, the release of egg parasitoid Trichogramma chilonis @ 1.5 lakh per hectare per week may check the population and could control the pest effectively. References: Atluri, J.B., Ramana, S.P.V. and Reddi, C.S. 2004. Ecobiology of the tropical pierid butterfly Catopsilia pyranthe. Current Science, 86(3): 2. Jat, R.S., Reddy, R.N., Bansal, R. and Manivel. 2015. Good Agricultural Practices for Senna. Directorate of Medicinal and Aromatic Plants Research, Gujarat. p. 8. Kunte, K. 2006. Additions to known larval host plants of Indian butterflies. Journal of the Bombay Natural History Society, 103(1): 119‐120. Sathiyabalan, G., Kumar, T. V. R., Santharam, B. and Senniappan, P. 2019. Farmers facing problems and commercial opportunities of Tinnevelly Senna in India. European Journal of Pharmaceutical and Medical Research, 6(9): 586-589. Veeraragavan, S., Duraisamy, R. and Mani, S. 2018. Prevalence and seasonality of insect pests in medicinally important plant Senna alata L. under tropical climate in the Coromandel Coast of India. Geology Ecology and Landscapes, 2(3): 177-187. 105 Vol. 24 (1) (March 2021) Insect Environment Fig. 1. Catopsilia pyranthe defoliation on Senna Fig. 2 Infestation of leaves and floral parts of Senna by larvae 106 Vol. 24 (1) (March 2021) Insect Environment Fig. 3. Egg Fig. 4. Early instar larva Fig. 5. Late instar larva Fig. 6. Pre-pupation stage Fig. 7. Newly formed pupa Fig. 8. Mature pupae Fig. 9. Adult butterfly 107 .