The difference between Plutella xylostella and Pieris rapae: Plutella xylostella and Pieris rapae belong to Lepidoptera, and they all have four forms: egg, larva, adult and pupa. Plutella xylostella larvae will eat the mesophyll of leaves on the back of cabbage and other vegetables with their mouthparts, leaving a reticular epidermal wound, while Pieris rapae directly eats leaves, resulting in empty mouths. 1, adult body size, wing color: the adult body of Plutella xylostella is relatively small, almost like a toothpick, can fly, and the color of its wings is gray-black; The adult of Pieris rapae is relatively large, which is about the size of a common butterfly. In fact, it is a butterfly itself, called pink butterfly, with white wings. 2. The size of the larvae is different: the color of the larvae of Plutella xylostella 1-2 years old is mainly light yellow, and the size of the larvae of 3-4 years old gradually becomes larger and the color is light green; The larvae of Pieris rapae are all blue-green, and they have two long yellow spots. The most obvious thing is that the hairy tumors on their bodies are thick and numerous, which can be observed by naked eyes. 3. The color and shape of the pupa are different: the color of the pupa of Plutella xylostella is grayish brown, and it is covered with a layer of white gauze. There are many colors of the pupa of Pieris rapae, such as green, grayish green or grayish yellow. The shape of the pupa is very special, a little hard and relatively large, which can be well observed and distinguished from the pupa of Plutella xylostella.