Pest Control, Bt
Bt is the spores of the bacteria Bacillus thurungiensis. It is used to protect plants against caterpillar damage. It works by infecting the caterpillars that ingest it and killing them.
Bt should be sprayed on plants in the evening, as sunshine will deactivate it. Spray when you notice the white butterflies re-appearing or on noticing caterpillar damage. Spray weekly until new growth is healthy and undamaged. Use on brassicas, tomatoes and corn (against tomato fruit worm, fall army worm, white butterfly capterpillars and looper caterpillar), lettuces (diamondback moth caterpillars). Dilution rate 1g per litre. Enough for 25 x 1 litre applications.