Any tips on getting rid of pieris caterpillars on sprouting broccoli and pak choi other than my thumb and forefinger?
I don't know of one short of manual picking and squishing or the preventative measure of covering the whole bed in mesh before the butterflies come scouting around.
Try spraying with Bacillus thuringiensis
I'm trying self-rising flour sprinkled on leaves. The only problem so far is rain washing it off. I'll report back if this really works on cabbage.