ORIGINAL ARTICLE Evaluation of fungal culture filtrate containing chitinase as a biocontrol agent against Helicoverpa armigera P. Binod 1 , R.K. Sukumaran 1 , S.V. Shirke 2 , J.C. Rajput 2 and A. Pandey 1 1 Biotechnology Division, National Institute for Interdisciplinary Science and Technology (formerly Regional Research Laboratory), CSIR, Trivandrum, India 2 Nirmal Seeds Pvt. Ltd., Pachora, Jalgaon, India Introduction Cotton bollworm (Helicoverpa armigera Hu ¨bner), com- monly known as ‘Heliothis’ is one of the most serious pests on various crops, including cotton, tomatoes, sun- flower, beans, maize and several cucurbitous and citrous crops. It is a multivoltine species with three to four gen- erations requiring multiple control interventions per year (Xiulian et al. 2004). In central and northern India, it is the major pest affecting cotton. The larvae feed exten- sively on cotton plant parts including the newly emerging bolls causing severe loss of crop. Bollworm are relatively safe from natural enemies because of the cryptic feeding habits of the larvae within cotton bolls and because pupae are protected in the soil. Therefore, large numbers of H. armigera in cotton and other vegetables survive to adults that may disperse widely, producing progeny that damage high-value crops (Cabanillas and Raulston 1995; Michael and Donald 1996). Generally chemical pesticides are used to control the larvae, but the species rapidly attains resistance to many of the common pesticides used, resulting in the requirement of heavier dosages or newer pesticides. The use of chemical pesticides is also of signifi- cant environmental concern. Alternate strategies for con- trol of the pest have also been tried extensively which include pheromone traps, pupa busting and use of plant- derived agents (e.g. extract of neem plant) with limited success. This being the status of efforts in control of Heliothis, it is interesting to study biological agents ⁄ prod- ucts for the control of this pest. Biocontrol agents com- prise an important element of many integrated pest management (IPM) programmes. Biopesticides provide an alternative to synthetic pesticides because of their generally low environmental pollution, low toxicity to humans and other advantages (Liu et al. 2000). Biopesti- cides and predators have positive impacts on bollworm Keywords biological control, biopesticide, chitinase, Helicoverpa armigera, Heliothis, submerged fermentation, Trichoderma harzianum. Correspondence Ashok Pandey, Biotechnology Division, National Institute for Interdisciplinary Science and Technology (formerly Regional Research Laboratory), Trivandrum – 695 019, India. E-mail: pandey@csrrltrd.ren.nic.in 2007 ⁄ 0300: received 26 February 2007, revised 19 March 2007 and accepted 22 March 2007 doi:10.1111/j.1365-2672.2007.03428.x Abstract Aims: To evaluate the biocontrol efficacy of culture filtrate containing chitinase from Trichoderma harzianum against Heliothis. Methods and Results: T. harzianum was cultured by submerged fermentation using colloidal chitin as sole carbon source. The ability of the culture filtrate to hydrolyse colloidal chitin indicated the presence of chitinase as one of its com- ponents. Biocontrol assay on Heliothis showed that the culture filtrate is a potent antifeedant as it reduced the feeding rate and body weight of the larvae. It reduced the successful pupation and increased larval and pupal mortality in a dosage-dependent manner when applied topically. The highest mortalities (70%) were recorded for groups treated with 2000 U ml )1 chitinase activity. The percentage of adult emergence was zero for the highest chitinase concen- tration (2000 U ml )1 ) tried. Conclusions: The studies showed that the culture filtrate containing chitinase from T. harzianum is capable of negatively affecting the growth and metamor- phosis of Heliothis larvae. Significance and Impact of the Study: In view of the need for safer and envi- ronmentally friendly pest management tools, the present study could help in the development of enzyme-based biopesticides against Heliothis. Journal of Applied Microbiology ISSN 1364-5072 ª 2007 The Authors Journal compilation ª 2007 The Society for Applied Microbiology, Journal of Applied Microbiology 103 (2007) 1845–1852 1845