Just thought I'd share my experience.......last year, I laboriously made realistic looking decoys, put about 12 in a small patch, didn't work.
This year I made strings of very simple decoys as follows - and it's WORKING!!
I used thin fishing line, opaque white shopping bags cut into rectangles roughly 7 cm x 5 cm or 2" x 2 3/4". Cut off about 3M of line, find the middle, tie a slipknot, pinch/scrunch the rectangle in the middle of the long side, put it through the slipknot and secure with another knot, spacing each butterfly about 15- 18 cm or 6-7" apart, continue till you've reached the end and then do the other side of the fishing line. The shorter lengths are easier to pull through when making the second knot and I just tied each run of fishing line together when installing it.
I strung these up all around the outside of the brassica bed and crisscrossed them over the beds using stick/stakes. I used about 50 butterflies per square meter.
The cabbage moths are checking out the bed and then flying off WITHOUT LANDING WOO HOO!! I think because I used so many they are seeing the patch as already having too much competition. I've been observing this for over a week - and they are definitely avoiding that bed!
Cheap, easy and I hope this helps someone else! Cheers
