In conclusion, the key issue of the controversy seems to be whether septicemia (by B. thuringiensis bacteria and/or commensal gut bacteria) or toxicemia (by the Cry toxins) are the prime killing agents alone or in conjunction. Experiments with GM plants expressing solely activated forms of Cry toxins and none of the other contested components, like B. thuringiensis bacteria, spores or crystals, will add complementary **data** still missing in this contentious debate. Although Mason et al. [21] administered Cry toxins from a commercial formulation of GM Pseudomonas fluorescens bacteria, no studies were carried out to date with Cry toxins produced in GM plants. With GM Bt crops, the role of any B. thuringiensis cells or spores, or those of other GM Bt-expressing microbes (e.g., P. fluorescens, E. coli) is a non-issue, the mode of action of GM plant produced Cry toxins hinges solely on their biochemical characteristics. Any effect of added antibiotics would to a large extent, if not exclusively, be limited to interfering with the commensal gut bacteria in the test species. Using GM plants expressing Cry toxin is also interesting since the biochemical form of Cry toxins produced by GM plants differs significantly from those produced in GM bacteria [7].