Proceedings

Production of Biocontrol Agents and Transgenics

Critical issues in the production of bioagents and transgenics were the subject of a brainstorming session held at PDBC (the Project Directorate of Biological Control) in Bangalore on 13 May 1999. The outcome of this meeting has now been published as a book of the same name*, and provides a thoughtful summary of important issues in this field.

S. P. Singh highlights in the Introduction the importance of mass production for biocontrol. He notes that although biocontrol has been identified as an important tool in pest management, its uptake in India is constrained by an inadequate mass production capability - although India has a far greater capability than many developed and developing countries. Singh identifies commercial production of reasonably priced bioagents as the great challenge. He argues the need for a code of conduct to help regulate the production of good quality biocontrol agents. He also highlights the importance of generating data for registration of bioagents, particularly pathogens, and identifies other constraints currently faced in culturing and mass production, shipment and marketing.

In the first paper, Chandish R. Ballal & S. P. Singh reiterate the message that progress in biological control depends on the ability to develop successful mass production systems for parasitoids and predators. They argue that the ultimate success of any programme will be dependent on the quality and performance of laboratory reared insects. They identify eight elements in insect rearing system management: objectives for the system, colony establishment, the rearing laboratory, research and development of techniques, resources, quality control, production, and supply. They provide a guide to the kinds of problems that can be encountered, and the questions that need to be answered. They stress the importance of genetic issues that should be tackled to avoid inbreeding and genetic drift. They also make the important point that host plant, host and natural enemy rearing need to be simultaneous, and look at key factors and constraints in each of these.

Next, H. Nagaraja & B. Ramesh look specifically at mass production of trichogrammatids, and discuss host culturing, the importance of the source colony, and mass culturing for field release or commercial sale. In particular, they suggest improved methods for culturing Corcyra cephalonica as a host for both trichogrammatids and other natural enemies. Then K. P. Jayanth discusses critical issues in mass production of insect biocontrol agents for weeds. He discusses ways of tackling problems posed by the necessity of large-scale raising of host plants. He considers redistribution of natural enemies within a specified action plan, and suggests that this could help overcome many problems of laboratory-based mass rearing, He ends by stressing the importance of monitoring results.

S. S. Hussaini tackles a wide range of issues concerning the use of entomopathogenic nematodes in biocontrol. He compares conventional and newer, molecular, methods for identification and selection of suitable nematode strains. Amongst issues in mass production, he tackles pilot scale liquid culture, the economics of product development, formulation and storage, application technology and transport.

R. D. Prasad deals with mass production of microbials. He looks for reasons for the scarcity of commercially available products, despite a preponderance of microbial biocontrol demonstrations at the laboratory level. Amongst pre-production issues, he discusses limitations in screening and strain selection, and strain improvement. He also discusses advantages and disadvantages of solid-state fermentation, and lists the advantages of liquid fermentation. He examines key factors in adopting liquid fermentation for mass production, including the post-production phase.

Finally, there are two interesting papers dealing with transgenic crops. T. M. Manjunath & Farah Deeba argue that transgenic (Bt) cotton could play a major role in combating Helicoverpa armigera in the crop in India. They look at the status of transgenic crops in other countries, and of current research in India, and point to the better suppression of the pest in transgenic crop trials. However, they say that transgenic technology has created new social and regulatory challenges, and they highlight some concerns, including those related to toxicity, cross pollination and sustainability. They discuss the benefits and safety of insect-resistant cotton, and outline measures to limit resistance development. They call for concerns to be addressed openly and debated logically. K. S. Mohan & K. C. Ravi look at factors affecting the performance of Bt cotton in the field. They summarize the ideal situation as proper expression of the transgene to yield a biologically active molecule in the right amount and at the right time. They argue that transgenic crops that are developed and used wisely can be very helpful, and may be essential, to world food and fibre production, agricultural sustainability and preserving the environment. However, they say that the technology is new, and for Bt cotton the relative importance of various factors affecting its performance is still unclear. More research and more data are called for. All these authors are confident that transgenic crops have great promise, but agree that the technology is in its infancy and much more research is needed. They also stress the importance of more openness, better information and greater education for the public to overcome what they describe as `fear of the unknown'.

*Singh, S.P.; Ballal, C.R. (eds) (2000) Critical issues in production of bioagents and transgenics. Bangalore, India;
PDBC, 66 pp.
Contact: Dr S. P. Singh, PDBC,
Post Bag No. 2491, H. A. Farm Post,
Bellary Road, Bangalore 560 024, India
Email:
Fax: +91 80 3411961