So. How do you keep Cabbage White butterflies off your brassicas without harming the little perishers?
Shaan Hurley decided to employ some state-of-the-art technology.
Having read that they are highly territorial and won't go into a garden area where another is, he decided to print himself a Cabbage White.
He designed a 3D butterfly in AutoCAD and used STLOUT or 3DPRINT command to generate an STL file for use by 3D printers. He then printed it on his MakerBot Replicator and affixed it with fishing line to some 1/8” copper wire.
Voila! No more holes in the cabbage leaves!
I guess you could do the same thing with card or paper or plastic as long as you get the colouration right.
Source: http://www.instructables.com/id/3D-Printing-a-Cabbage-Moth-Butterfly-Decoy-to-Sa/