This area will be developed further over the coming months.
Wherever possible we harm minimise for controlling the interactions of insects and other animals with our vegie crops. In our context we don't have poultry or other farmed animals, except for worms and microbes along with the wildlife we nurture.
We try to minimise snail and slug breeding by minimising the areas the like to breed and we go hard at the start of the season to stop them breeding up in the first instance.
For aphids we remove aging brassicas and attempt to keep brix(plant sugars) levels high in our brassica crops, you could also use a spray with microbes and molasses, this will benefit the soil, the plant and the sugars in the molasses make eating impossible for the aphids as they don't have a pancreas.
Slug and snail pellets.
Naturosoap, Spraytech Oil BFA reg input. Agrobest Australia
Also see: Matabi spray packs and cloche