The questions I want to know is why do white butterfly attack cabbage, cauliflower and broccoli, but leave lettuce plants alone?
All insects have a preferred host plant they like to devour. In this case the white butterfly adores the brassica family of vegetables which include; broccoli, cabbage, cauliflower, brussell sprouts, among others. Growing healthy strong plants means they will be more resistant to pests and diseases. Soil plays a big part in this, so prepare the soil well that you will grow your vegetables in - enrich and aerate it by digging in plenty of Daltons Compost a week to two weeks before planting. To help keep the plants in optimum health apply a side dressing of Daltons Vegetable Fert every 4-6 weeks throughout the growing period (depending on what you are growing and how often you water your garden).
The most important part of pest management is regularly monitoring your garden. This simple task involves walking through your garden weekly looking for problems. Check the stems of plants and under leaves and remove any offending pests immediately, such as the small green coloured caterpillars which develop into the white butterfly. You can also help deter pests with companion planting. This organic technique means planting specific plants such as marigolds or pyrethrum daisy in your vegetable garden, these flowers have a pungent scent that disguises the smell of the “tasty” plant and dissuades pests like the white butterfly. If things to not improve, you can spray with Neem Oil.