KHAN ET AL (2011), FUUAST J. BIOL., 1(2): 83-86 CONTROL OF ROOT-KNOT NEMATODES AND AMELIORATION OF EGG PLANT GROWTH BY THE COMBINED USE OF BACILLUS THURINGIENSIS BERLINER AND NEMATICIDES M. QASIM KHAN, M. WASEEM ABBASI, M. JAVED ZAKI AND D. KHAN Department of Botany, University of Karachi, Karachi, Pakistan Abstract Root-knot nematodes are considered to be the most destructive plant parasitic nematodes. The use of nematicides for the control of root-knot nematodes is common practice. The use of biological control agents is, however, considered more effective and environmentally safe replacement of chemical nematicides. In the present study, three Bacillus thuringiensis Berliner isolates viz. B.t.-64, B.t.-16 and B.t.-14 were used with and without nematicides such as Carbofuran and Fertinemakil to control root knot nematode, Meloidogyne javanica associated with egg plant. Nematicides were applied in soil before seedling transplantation and bacterial cell suspension was inoculated around the roots after seedling establishment. The combination of B.t. -64 and Fertinemakil was the most effective treatment in reducing root-knot nematodes and improving the Egg plant growth. It was also effective in enhancing the plant growth and reducing the root-knot nematodes infection in combination with other B.t. isolates (B.t. 16 and B.t. 14). Introduction Bacteria are most abundant and common flora of soil. Most of bacteria associated with roots of plant are characterized as plant growth promoting bacteria (PGPB) and found effective for improvement of plant growth by different direct and indirect mechanisms includes production of plant growth hormones, nitrogen fixing ability, enhancing mineral availability in soil (Saharan and Nehra, 2011). Some bacterial species produce metabolites that act directly against variety of pathogens. Different Bacillus species are characterized as PGPB. There are reports that have suggested nematicidal properties of Bacillus species (Siddiqui, 2002; Li et al., 2005). Bacillus thuringiensis Berliner produces parasporal crystals protein known as delta-endotoxins that are toxic to insect pests (Höfte and Whiteley, 1989). This property of producing delta-endotoxins distinguishes B. thuringiensis from other spore forming bacteria. B. thuringiensis consider as an effective measure for controlling a wide range of insect pests (Nester et al., 2002; Wei et al., 2003). There are reports that B. thuringiensis (B.t.) is capable of infecting protozoa, nematodes, flatworms, mites and insects (Feitelson, 1993). Use of biological control agents alone or in combination with nematicides is an effective practice to control root knot nematodes in crop plants (Stephan et al., 1998; Radwan, 1999; Ameer-Zareen and Zaki, 2002,). Carbofuran is systemic nematicide carbamate and granular form of carbofuran is used. Fertinemakil is an organic nematicide consisting Neem cake and fungicide. In the present study three Bacillus thuringiensis (B.t.) isolates with and without nematicides i.e., Carbofuran and Fertinemakil are evaluated to manage root-knot nematodes infection in egg plant (Solanum melongena L.) and to improvement of growth of the plants. Materials and Methods The experiment was carried out in plastic pots of 8 cm diameter containing 250g soil/pot. The soil was amended with nematicides, Carbofuran and Fertinemakil @ 2g and 4g/250g soil, respectively. After two days of nematicides application three weeks old egg plant seedlings were transplanted in each pot and three days after transplantation rhizosphere soil was drenched with 10 ml suspension of actively growing culture of B.t. isolates. Pots without nematicide amendment and drenched with 10 ml distilled water served as control. Each treatment was replicated thrice. After one week of soil drench the pots were inoculated with around 2000 freshly hatched second stage Juveniles of Meloidogyne javanica obtained from infected egg plant. These pots were kept in randomized way on greenhouse bench. Observations on plant growth parameters and root knot nematode infection were undertaken after 45 days of nematode inoculation. The plant growth was measured as plant length and dry weights of root and shoot.