The previous post about organic woodlice control touched on a couple of elements of pest control: trapping and physical separation of pest and plant. Another strategy that can work quite well is using environmental elements to confuse or deter pests. You can apply the principle to planting technique, by mixing up your plants to confuse pests (they don’t have to be too smart to find an acre of one crop). In this case I wanted to deter white butterflies from laying their eggs on our brassicas.
It turns out, white butterflies are quite territorial (or at least smart enough to know when to cut their losses). If a white butterfly sees other butterflies hovering around a target plant, they will move on to somewhere else to lay their eggs. You can use this behaviour to make decoy butterflies repellent to the real ones. People have used egg shells, white pebbles and even bread tags as decoys with mixed success.
My friend Vik had already created a model of a white butterfly and put it up on Thingiverse. All I had to do was download it and print one out.
While it was still hot from the printer I bent the wings up at a more realistic angle. A spare bit of filament melted and stuck to the bottom made a handy stalk to poke into the garden bed.
I printed a bunch (flock?) of butterflies and gave them some anatomical detail with a vivid marker before deploying them to the garden.
The stalks are quite flexible so the butterflies bob about in the wind. They look pretty realistic to me, but more importantly I’ve seen white butterflies hovering around, then leaving without touching down, all this week. Time will tell if any have the courage to sneak in to lay eggs.
If you don’t have a 3D printer, you could probably cut the same shape out of white plastic containers for much the same effect.