Micro-organisms dominate the commercial BCA product portfolio. They are living organisms that are often applied through standard pesticide application equipment. In the ASEAN region, interest in microbials (also alternatively termed ‘microbial control agents’ or MCA) to date has been dominated by bacteria and fungi, although protozoa, nematodes and viruses have also been developed for practical use, for instance by government research programmes in Thailand (25). Historically, microbials have been as much about values as commerce and product development, with needs to be driven by highly motivated scientists and research groups (26). From a commercial point of view, there have been three phases in the development of the now highly successful insecticidal bacterium Bacillus thuringiensis (Bt): with decades passing between early (scientist driven) development and the second stage in the late 1980s, when more optimised products were marketed. Finally in the third phase, the well-known but still controversial technology for expressing truncated forms of Bt genes in crops (27), provides highly targeted delivery of the protein to pests at their most susceptible stage (young larvae). However, genetically-modified microbials will not be covered by the Guidelines. 2.1.1 Bacteria Bacillus thuringiensis (Bt) is by far the most important BCA to date, both globally and in the ASEAN region (where for example, 69 products have been recorded for control of Plutella). Globally, isolates in various sub-species belong to 3 different functional sub-groups, specific to: Lepidoptera (Bt serovar thuringiensis, Bt var morrisoni, Bt var kustaki, Bt var aizawai); Coleoptera (Bt var tenebrionis) and Diptera (Bt var israelensis). In recent years, there has also been considerable interest by industry in other Bacillus species (e.g. B. subtilis, B. pumilus) for disease control. Bacillus spp. are commercially and operationally attractive because they have the advantages of ease of production and stability with storage. However, pests are subject to long-documented insecticide resistance to Bt toxins (28). 18 Table 1: Categories of BCA6 and number of products available in ASEAN (Source: ABC database) 2.1 Microbials 6 ‘plant growth stimulators’/regulators include: auxins, brassinolide, cytokinins, gibberellic acid; ‘others’ include oils etc.
Implementing Biological Control Agents in the ASEAN Region
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