Take you to know the symptoms and life habits of the outbreak armyworm

The armyworm has migratory, fulminant and devastating omnivorous pests. Entering the middle and late July , the increase of rainfall, suitable temperature and climatic conditions in northern China is very suitable for the concentrated migration of armyworms and crops that harm corn. The successive outbreaks of armyworms have a wide area and pose a serious threat to the production safety of autumn grain crops such as corn, millet and rice. According to relevant statistics, the area of ​​second- and third-generation armyworms in the country has accumulated nearly 100 million mu, and the scope of the three-generation armyworms is still expanding.

Armyworm

The armyworm is also called cockroach, night worm, and shaving worm. Below, Xiaobian takes everyone to know the symptom recognition and living habits of the armyworm.

First, the symptom identification:

The larvae of the armyworm are exposed to the surface feeding hazards of the crop. Most of the first and second instar larvae are hidden in the heart or leaf sheath of the crops for feeding around the day and night, but their food intake is very small, and the mesophyll leaves the epidermis, resulting in translucent small streaks. In the 5 to 6 instar larvae, for the binge eating stage, the leaves are eaten and the cobs are eaten.

Like the ground tigers, they belong to the genus Noctuidae. They can also be divided into four stages in the life of the armyworm , adults, eggs, larvae and pupa. In the adult fore wing, it is light yellowish brown, slightly grayish, some wings are covered with many dark brown dots, and there are 2 pale yellow round spots on the near front of the center. There is a round spot on the outside and a small spot on the bottom. White dots and 2 small black dots, one dark slash from the top corner to the trailing edge, and 7 small black dots on the outer edge ; the rear wing ends are grayish brown, the base color is light. The eggs are in the shape of a skull, the longitudinal ridges are irregular, and only the middle is cut off. The larvae are reddish-brown, with dark striated lines and black splayed shapes; the body shape varies greatly, often with dark brown, reddish brown, and white vertical lines.

Second, life habits:

There is no diapause in the armyworm, and it can continue to breed only if the conditions are appropriate. The number of generations and the period of occurrence vary depending on the region and climate. In China from the south to the north, two to eight generations occur in one year . Adults lie in the daytime, and come out to eat, mate and give eggs at night. Adults feed on the nectar of various crops, as well as aphids, scales, honeydew, and succulent juices.