Fighting the cabbage white butterfly

The cabbage white butterfly Pieris brassicae is a very common white butterfly in vegetable gardens from April to October. They are found everywhere, in cities, at high altitudes... Measuring about 6.5 cm in wingspan, the cabbage white butterfly wreaks havoc on cabbages and some other plants such as nasturtium, horseradish... Plants deprived of part of their foliage, develop poorly. What is the lifestyle of the cabbage white butterfly? The female lays between 20 and 50 yellow-orange eggs, most often on the underside of the leaves. About ten days later, the eggs give rise to caterpillars. They form small groups that first attack the surface part of the foliage. Five larval stages can be observed. The caterpillars disperse, grow larger and devour everything, leaving only the veins. When the caterpillars have completed their development, they leave their host plant and transform into chrysalides in any shelter. Pupation lasts about 2 weeks for the summer and autumn generations. The chrysalides that survive the winter will not produce butterflies until the following spring. In France, 2 generations of cabbage whites occur each year, but a third is possible in the south of France. The second generation is the one that wreaks the most havoc on autumn and winter cabbages. How to control the cabbage white butterfly? Sow dill or celery between the rows of cabbages. Their fragrant foliage will repel butterflies. Install an insect net from August to October to protect your crops. Cover the soil with ferns or broom to repel butterflies. Spray tansy extract weekly. Starting in July, check your crops by looking at the underside of the leaves. As soon as you spot eggs or caterpillars, get rid of them! If you have an infestation, spray a biological insecticide based on Bacillus thuringiensis bacteria.