Cruciferae vegetables include: Chinese cabbage, Chinese cabbage, cabbage, broccoli, cauliflower, kale, broccoli, cauliflower, mustard, leaf mustard, stem mustard, kohlrabi, mustard tuber, carrot, white radish, broccoli, rape and so on. Cruciferae plants can synthesize mustard oil with high concentration. Pieris rapae has chemotaxis to mustard oil, so it will lay eggs on the leaves of cruciferous plants, so Pieris rapae is concentrated on the leaves of cruciferous plants.

Classification of Cruciferae Vegetables: 1, Brassicaceae. Plants are glabrous or have simple hairs and bifurcated hairs. The lateral nectaries are slightly annular and connected with the middle nectaries. Stamens beyond sepals and petals; Filaments are forked and thin, and the lower part is slightly widened; Anthers linear or oblong, obtuse or pointed. Pistil has a long handle; Stigma almost sessile, small, concave, slightly lacking, without obvious papillae. Silique is round or flat, with cotyledons leaning back or edge against radicle.

2. Brassica. Plants have simple hairs or no hairs. Lateral nectaries are cubic or prismatic, with truncated tips, sometimes slightly 2-lobed or rounded; The middle nectary is nearly spherical or columnar, and a few are degenerated. Staminal filaments rarely dentate. Stigma capitate or 2-lobed, with a few long downward lobes. Silique (two segments are short pods) has a beak, usually with two different segments, which are not cracked or cracked; Cotyledons are often folded in half).

3, the solo cuisine. Plants have simple hairs, forked hairs or glandular hairs, or are hairless. Lateral nectaries are paired, free or United, sometimes with protrusions, usually without middle nectaries. Staminal filaments toothed or absent, anthers short and obtuse; Stigma capitate, shallowly 2-lobed. The silique (silique) is dehiscent, and a few of them are indehiscent.