Industrial and international standardization of microbial pesticides — I.Bacillus thuringiensis

Bacillus thuringiensis preparations are standardized by bioassay based on a comparison with a reference standard preparation. By this way the standardization of industrial formulations is satisfactory in order to maintain a constant quality within a given product. International standardization is quite another problem and cannot be achieved by facing only standardized titration methods, since other factors, particularly the used strains, contribute to different host activity. An account is given of the actual situation with historical backgrounds and some suggestions are made to avoid possible pitfall. Essentially it would be most useful to demonstrate the biological activity differences of different products. This work could be done by the different specialized laboratories with the help of internationally distributed standard preparations of each proposed serotype and using various technics and multiple test insects.