ABSTRACT Euschistus servus (Hemiptera: Pentatomidae) are important insect pests of crops. Stink bug feeding reduces yields, lowers crop quality, induces delayed maturity and wounds tissues allowing for pathogen entry. Present investigation showed effective control of brown stink bugs with essential oils as evaluated by GSI parameter. The Cassia fistula leaf and flower essential oils treatment decreases the GSI in male adults of Euschistus servus. The results on the GSI in the present investigation indicate that toxic activity of essential oil was in the order: Cassia fistula leaf > Cassia fistula flower. Keywords: Euschistus servus, Cassia fistula, GSI. REFERENCES Agrawal, S. 2006. Biochemical profile in the gonads and haemolymph of Dysdercus similis induced by some natural plant products. Ph. D. Thesis, Dr. H. S. Gour Univ., Sagar (M. P.), India. British Pharmacopoeia, 11. P. A. HMSO: London (1980). Buntin, G. D. and Greene, J. K. 2004. Abundance and species composition of stink bugs (Heteroptera: Pentatomidae) in Georgia winter wheat. J. Entomol. Sci. 39: 287-290. Chyen, D., Wetzstein, M. E., McPherson, R. M. and Givan, W. D. 1992. An economic evaluation of soybean stink bug control alternatives for the Southeastern United States. Southern J. Agric. Econ. 24: 83-94. Emfinger, K., Leonard, B. R., Gore, J. and Cook, D. 2001. Insecticide toxicity to southern green, Nezara viridula (L.) and brown, Euschistus servus (Say), stink bugs, pp. 1159-1161. In Proceedings, 2001 Beltwide Cotton Conferences, 9-13 January 2001, Anaheim, CA. National Cotton Council, Memphis, TN. McPherson, J. E. 1982. The Pentatomoidea (Hemiptera) of northeastern North America with emphasis on the fauna of Illinois. Southern Illinois Univ. Press, Carbondale and Edwardsville. 240 pp. McPherson, J. E. and McPherson, R. M. 2000. Stink Bugs of Economic Importance in America North of Mexico. CRC Press, Boca Raton, FL. 253 pp. Medrano, E. G., Esquivel, J. F. and Bell, A. A. 2007. Transmission of cotton seed and boll rotting bacteria by the southern green stink bug (Nezara viridula L.). J. Appl. Microbiol., 103: 436-444. Munyaneza, J. and McPherson, J. E. 1993. Comparative study of life histories, laboratory rearing and immature stages of Euschistus servus and Euschistus variolarius (Hemiptera: Pentatomidae). Gt. Lakes Entomol., 26: 263-274. NIST Standard Reference Data. 2014. Available online: http://webbook.nist.gov/chemistry/name-ser.html. Rai, R. 2005. Control of fertility in Bagrada cruciferarum (Kirk) by some plant products. Ph. D. Thesis, Dr. H. S. Gour Univ., Sagar (M. P.), India. Todd, J. W. and Herzog, D. C. 1980. Sampling phytophagous Pentatomidae on soybean, pp. 438-478. In: M. Kogan and D. C. Herzog (eds.), Sampling methods in soybean entomology. Springer-Verlag, N.Y. Tomar, D. 2010. Control of fertility of soybean insect pests by some plant glycosides as an insecticidal agent. Ph. D. Thesis, Dr. H. S. Gour Central University, Sagar (M. P.), India.