GENTECH archive


Re: GE Debate v0.2 archive 2274

>Roberto Verzola:
>Should substantial equivalence (SE) be established on a species by
>species basis? For instance, we know Bt corn is not SE to conventional
>corn as far as butterflies, lace wings, and ladybird beetles are

Actually, there is to my knowledge no such case for ladybirds at all, no case for lacewings in the field, and scant evidence that butterflies are at risk in the field. The Losey paper was about event 176 corn, the one with the most toxic pollen to Monarchs, and yet this accounts for only 3% of the Bt corn in the field. The latest data still shows no effects on Monarchs at greater than 1 meter from the corn crop. About ladybirds, I believe you have confused Bt with non-commercial lectin producing potatoes. There is in fact data (including my own for Bt potatoes) that shows no impact on beetles.

With respect to lacewings, lacewing larvae in the field prefer aphids or caterpillar eggs, so the lab experiments on which claims of harm are based, which gave the lacewings no choice but to feed on Bt treated larvae or other impregnated food, are very artificial. Indeed, even Hilbeck and the other authors of the key paper note that "No conclusions can be drawn as to how results from the laboratory might translate to the field" (Environmental Entomology (27: 485). To the contrary, field experiments conducted previously DID NOT detect an impact on lacewings or any other non-target species (Pilcher et al. Environmental Entomology (1998, 26: 446-454).