Spodoptera exigua belongs to the order Lepidoptera and the family Noctuidae. It is widely distributed in my country, and its harm to soybeans has become increasingly serious in the south in recent years. The adult body color and forewings of this insect are grey-brown, and the hind wings are white with a slight pink flash. The body color of the larvae changes greatly, ranging from green, dark green, yellow-brown, black-brown, etc. The young ones are greener, and the older ones are darker. Beet exigua moth feeds on soybean leaves as larvae. In severe cases, it can eat all the leaves, causing serious harm to soybeans.

Spodoptera exigua generally occurs for 5 to 6 generations in the Yangtze River Basin. The 1st to 2nd generation damages weeds, and the 3rd to 4th generation damages summer soybeans. The adults emerge in the soil, hide in weeds and soil crevices during the day, and emerge to cause harm at night. The larvae also feed at night. The first-instar larvae live in groups on the back of the leaves, feeding on the back leaf meat, leaving only the epidermis. After the 3rd age, the harm is dispersed, and after the 4th age, the food intake is large and the harm is serious.

For the control of beet armyworm, please refer to the control methods of Spodoptera litura.