> As I mentioned, Bti is specific to Diptera. Caterpillars belong to > Lepidoptra. So Bti won't affect them bu Btk will. I'm sure product marketers and supporters say this and it may be true. I'm not convinced yet. Plain Bt was used to kill catapillars before the new sub strains were developed. I do believe a sub strain of bacteria can have target- specific-action. I'm just not sure Bt substrains are as specific as claimed. Btk seems to have worked to kill my Diptera. I would suppose the theory of target-specific-action should have made my effort unsuccessful? On Wikipedia I see: "There is clear evidence from laboratory settings that Bt toxins can affect non-target organisms. Usually, but not always, affected organisms are closely related to intended targets (reviewed in Lovei and Arpaia 2005 and Hilbeck and Schmidt 2006). Typically, exposure is through the consumption of plant parts such as pollen or plant debris or through Bt ingested by their predatory food choices. Nevertheless, due to significant data gaps, the real- world consequences of Bt transgenics remains unclear." I did not want to comment further on this topic and will try not to do so again. I just could not help respond to what I see as "industry speak" stated as fact. I may have missed seeing well done independent studies that show I am mistaken? I do not know the full truth of this situation. I'm just not yet convinced others do either. Kelly O'Neill http://www.bigbubblers.com/ and Big Bubble Magic(tm) at http://www.wetrock.com/ and Wet Rock Gardens Flower Farm 2877 N 19th Street - Springfield, Oregon 97477 U-Pick and more at the farm (open 9 to 6, Sun, Wed and Fri - from March thru Halloween)