Academic Journal of Entomology 8 (1): 24-33, 2015 ISSN 1995-8994 © IDOSI Publications, 2015 DOI: 10.5829/idosi.aje.2015.8.1.9244 Corresponding Author: Kausar Malik, Department of Zoology, Lahore College for Women University Lahore, Jail Road, Lahore, Pakistan. Tel : + 92-345-8764999. 24 Study of Combined Pesticidal Effect of Black Onion Seed ( Nigella sativa) and Bacillus thuringiensis on Red Flour Beetle (Tribolium castaneum) Kausar Malik, Absara Hameed, Hafiza Samra Ambreen and Aisha Choudhry Department of Zoology, Lahore College for Women University Lahore, Jail Road, Lahore, Pakistan Abstract: Bacillus thuringiensis, commonly referred to as B.t. is a gram positive bacterium that produces insecticidal crystal proteins. This bacterium occurs naturally in the environment and has been used as a biological pesticide for more than 50 years. In order to manage the loss of stored grains and other agricultural products from insect infestation, many plant products have been evaluated for their toxic properties against different stored grain pests. In the present study, B.t. isolates from collected samples were grown on T3 (Tryptone, Tryptose, Yeast extract) media. Bio-toxicity was checked individually and by combination of Black onion seed (Nigella sativa) and Bacillus thuringiensis, against Tribolium castaneum. The LC of 50 Black onion seeds powder (N. sativa) was 0.35 g/g against second instar larvae of T. castaneum. Toxicity was increased when this compound was combined with three isolates of B.t. (Shaf1, Sd1 and Sid1).The mortality data of T. castaneum was analysed by applying probit analysis programme, determined that larvae are more susceptible and show significant results as compared to adults. Key words: Isolates Biotoxicity Assays LC 50 INTRODUCTION dependent upon 3 years [10]. Larvae breed well in wheat Our economy is continuously harmed by infestation in entire wheat parts the harm is restricted to the germ of stored products brought by stored grain pests which [11]. There is only chance for survival if appropriate food are responsible for worldwide loss of 10 - 40% annually is promptly accessible. [1]. In tropical nations, humidity and temperature run high Bacillus thuringiensis (B.t.) is a gram positive spore during summer season and these misfortunes reach to forming bacteria which was initially identified in 1901 by 50% [2-4]. In Pakistan, grain storage losses by insects Shigetane Ishiwata [12]. It was rediscovered by Berliner have been evaluated to be 2.5 % in six months storage [5]. [13] and recognized as microbial insecticide after the Liquid and gaseous insecticides are continuously being separation from Anagastakuehniella. This bacterium utilized for the control of stored product insects. These yields insecticidal crystal proteins named -endotoxin insecticides are harmful to mankind as they are disrupting throughout the stationary stage of development and is environment due to the development of insect resistance discharged to the environment afterwards sporulation. [6,7]. Scientists are attempting to find new alternatives B.t. is dispersed worldwide. The soil has remained including many herbs and their extracts possessing the primary living space. It is also being isolated from insecticidal properties. dead insect, stored grains, water etc. Products based on The red flour beetle, Tribolium castaneum (Herbst) business scale are based on strains usually isolated belongs to the order Coleoptera and family Tenebrionidae. from dead insects [14]. Examples are Kurstaki segregated It can be a major pest for stored grain based items. This from A. kuehniella; tenebrionis, separated from beetle might have occurred principally in rotting logs and Tenebrio monitor larvae and israelensis separated under tree husks, feeding on insect eggs, pupae and from mosquitoes [15,16]. This bacterium is also known animal detritus [8] yet milled grain items such as flour as entomopathogenic organism. An entomopathogenic appear to be their preferred food [9]. Lifespan is organism is that which is greatly particular and successful items that have been processed or fine grained however