Control methods of soybean yellow-bellied lamp moth

The larva of yellow-bellied lamp moth is called caterpillar and leaf caterpillar, which is one of the main seedling pests of soybean. At the same time, this pest can also harm corn, millet, sunflowers, vegetables, weeds and fruit trees.

1. Morphological characteristics: the adults of Spodoptera litura are white, and there are many black spots on the forewings. The abdomen and back are yellow, with a black spot in the center of each segment, two black spots on each side, black stripes on the feet and yellow on the femoral nodes. The egg is hemispherical, the first birth is milky white, and then becomes grayish yellow; the back and ventral side of the larvae are yellowish brown, with gray or grayish brown longitudinal bands on the back, dense brown to dark brown long hairs; belly feet; pupa is dark brown, thick and short, cocoon yellowish yellow is wrapped with more shedding body hairs of the larvae.

2. Life habits: the yellow-bellied lamp moth occurs one generation a year, overwinters as pupae in the cocoon, and feathers into adults at the beginning of June of the following year. Adults lie dormant during the day and come out at night, hiding in crops or grass during the day, and have phototaxis. After 3-4 days of Eclosion, the eggs were laid on the back of the middle leaves of the crop and hatched into larvae after 5-6 days. The first generation of larvae occurred in mid-late June, which was damaged by the newly hatched larvae. When it is a little older, it will be scattered. The larvae have pseudo-death and are good at crawling. The 3rd and 4th instar can crawl 57.7 meters per minute, and the 6th and 7th instar can crawl 107.14 meters per minute. After being alarmed, the pests immediately went into the cracks in the soil or under the grass to hide.

3. Symptoms of damage: the yellow-bellied lamp moth takes the larvae as the harmful crop leaves, which can eat day and night, and only stop eating for 1-2 hours when it is hot at noon, especially in the morning, evening and night. Generally, the larvae begin to eat the mesophyll just 40-50 minutes after hatching, and the food intake increases sharply after the 5th instar, so that the leaves can be eaten into niches or holes, so that the leaves will show withered and yellow markings, and in serious cases, the leaves will be eaten up, and even the young stems will be eaten completely. then transferred to the nearby soybean field to continue the damage. A larva can eat 28 and 37 soybean leaves in its lifetime, which can cause seed destruction when serious occurrence occurs.

4. Control methods: pay attention to timely chemical control in the larval instar, but the control effect is not good when the larva is too old; it is necessary to spray pesticides when the larvae are active in the morning and evening; to do a good job in joint control, because the pests crawl fast, when it occurs, spraying pesticides at the same time can prevent transfer and achieve better control results. Specific methods: ① installed black light to trap and kill adults. In view of the phototaxis of adult yellow-bellied moth, black light can be installed to trap and kill adults to reduce the number of eggs laid by adults. ② carried out deep autumn ploughing to destroy the overwintering place of the yellow-bellied lamp moth and reduce the insect source. ③ clears the weeds around the damaged field in time, or digs trenches to prevent the transfer, when larvae are found to migrate to the field. Ditches can be dug around the field, and some pesticides can be sprinkled in the ditch to kill the larvae. ④ chemical control, 2.5% trichlorfon powder or 5% carbaryl powder can be sprayed. The dosage is 22.5 to 30 kilograms per hectare, and 50% phoxim EC 800 to 1000 times can also be sprayed. When the larvae are old. 90% crystal trichlorfon can be sprayed with 1, 000-1500 times liquid, 375-450 kg per hectare.