Occurrence characteristics and control measures of main insect pests in soybean

Soybeans encounter various pest and disease problems during the growth process, which seriously affects the quality and yield of soybeans. Therefore, it is necessary to strengthen the prevention and control of soybean pests and diseases. This article gives a detailed introduction to the occurrence characteristics and control measures of major soybean pests for your reference.

1, the ground tiger

Earthworms are polyphagous insects with many species, and such insects have a great impact on agricultural production. Among the pests such as the tiger, the most affected species are the yellow tiger, the small tiger, the white tiger and the earth tiger.

1.1, occurrence characteristics

The ground tiger, as its name implies, is a harmful insect that lives below the surface of the earth. These insects are very common in the process of planting soybeans. The most common type of tiger is the yellow tiger and the small tiger.

Small tiger: The adult size of this type of pest is generally about 16-23 mm, and its wings are 45-54 mm in length. The small tiger has a sharper forefoot and a pair of brown kidney-shaped spots on the wings. The larvae of insects such as the small ground tiger are usually dark brown or yellowish brown. They like to move in moist soil. They usually start to recover during May each year, eat a lot, and treat crops such as soybeans and corn in the farmland. The cockroach is destroyed and the corn or soybean plants are swallowed close to the roots of the earth's surface.

Yellow tiger: The adult size of this type of pest can grow to 14-19 mm, and its wings are about 32-43 mm in length. The front wings also have a yellow-brown and kidney-like pattern, but no black wedge-like lines. The shape of the egg is hemispherical. The egg is about 0.5 mm so far. It is mainly milky white for a period of time after birth. After a period of time, the reddish marking appears gradually. Before the hatching, the whole egg will appear black. Old-fashioned larvae can grow to about 32-45 mm in length, their color is yellowish brown, and the larvae have four similarly sized lobes.

1.2, prevention measures

1.2.1 Agricultural control

Agricultural control mainly eliminates weeds and other deposits on the edge of the field in the early spring, which can effectively eliminate some of the tigers and larvae. In the fall, we can kill a lot of larvae and cockroaches by using the way to turn the ground.

1.2.2 Chemical control

One is to kill larvae and mites by using fresh grass as a bait by using 90% of trichlorfon to form 200 times solution. Then spread it evenly by spraying it onto the freshly chopped grass or leaves, and evenly spreading it on the ditch or ridge in the evening. This method is mainly adapted to the clods where the area is small. The second is to deal with the method of making poisonous soil. This method uses 300% phoxim to prepare 300 times solution, then sprays it on fine soil and stirs it evenly, and then sprinkles it near the seedling eye of the ridge. The third is by spraying, which is made up of 1000 times by using 75% phoxim and then sprayed in the field soil in the evening.

2, 蛴螬

Thistle is the larva of the golden tortoiseshell, also known as the white silkworm or the walnut. As far as the common cockroach analysis is concerned, it can be mainly divided into three types: herbivore, manure and rot. Among them, herbivorous cockroaches are the most common in current agricultural production, which endangers a variety of crops, cash crops and vegetables.

2.1, habits and occurrence characteristics

Earthworm is a relatively common underground pest. In the past years of soybean planting, soybean yield has been reduced due to the impact of cockroaches, and the growth rate has slowed down. The scorpion type is mostly in a hypertrophy state, and it is a white C-shape, and a small amount is a yellow-white color. Most of the larvae or adults in the breeding are wintering in the soil. It is the most important crop in the crop hazard.

2.2, prevention measures

There are many types of cockroaches. In the same area, the same land is often mixed with several cockroaches. The times overlap, and the occurrence and harm are very inconsistent. Therefore, only the species of common cockroaches are based on the species, density, and crops. The method of pulling up the appropriate ground for prevention and control is the only way to achieve the desired control effect. 1 Do a good job in forecasting and forecasting. In the work, we must strictly investigate and master the occurrence and prosperous period of adult insects, and use the corresponding prevention and treatment measures as a basis to develop a reasonable prevention and treatment method. 2 agricultural control. Implement water and dry rotation; timely irrigation during corn growth; no application of unfertilized organic fertilizer; intensive cultivation, timely suppression of soil, removal of field weeds; large area spring and autumn cultivation, and ploughing with pests. In severe areas, the wintering larvae can turn over the winter larvae to the surface to make them air-dried, frozen or preyed by natural enemies, mechanically killing, and effective control. At the same time, the use of unfertilized organic fertilizer should be prevented to prevent the introduction of adults to lay eggs. .

3, soybean heartworm

Soybean heartworm is commonly known as the red worm, which belongs to the family Lepidoptera. The larvae invade the bean pods and eat the bean granules. The light insect feeding rate is 2% to 5%, and the heavy ones are 7% to 10%, which seriously affects the soybean quality and yield.

3.1, morphological characteristics

The adult is a dark brown moth with a body length of 5 to 6 mm and a wingspan of 12 to 14 mm. The front wing is mixed with gray, yellow and brown, and the front edge has more than 10 black and purple short twill. The eggs are oval, slightly flat, and yellowish brown. The hatching larvae were yellowish in color and black in the head; the 2nd instar larvae after entering the pods became milky white; the 4th instar larvae gradually turned bright red; the larvae after depilation into the soil turned from red to yellow.

3.2, living habits

Soybean larvae lived in the soil for 1 year and 1 year, and the larvae overwintered in the soil in the second and middle of July. They migrated to the soybean field in the middle and late July, and they lurked in the morning. After 3 to 4 pm, they were moths on the soybean field. Chasing each other, showing a phenomenon of moths. Eggs are prolific on pods, and 1 pod produces 1 capsule. In mid-August, the larvae crawl on the pods after hatching, biting through the pods on the side edges of the pods, feeding on the fresh beans, until the soybeans mature, the mature larvae From the small hole in the pod, it is drilled into the soil layer for wintering.

3.3, prevention methods

3.3.1 Agricultural measures

a. Long distance rotation. Soybean heartworm is only harmful to soybeans, and its wintering place is bean field. The ability of adults to fly is very weak and cannot fly far away. Planting soybeans 1km away from the former soybean field can reduce the insect feeding rate by about 90%. b. Deeply turn the soil, and carry out autumn turn after the autumn harvest to increase the mortality of the overwintering larvae. c. Use excellent varieties. Since the adults of the heartworm are spawning, the pods of the hairless variety have fewer eggs on the pods of the hairy varieties, and the damage is lighter. Therefore, hairless varieties can be used to reduce the insect pests.

3.3.2 Chemical control

When the field adult worms are in full bloom, the total amount of 100m double moths is more than 100 for 3 consecutive days, or an average of 100 pods and 20 eggs to start prevention. a. Dichlorvos smoked adults. In the prosperous period of August 5th, the method is to break the corn mash into 1 section every 1cm, soak it in dichlorvos crude oil, and then press the corn mash that sucks the liquid solution every 4 times (turn down on page 380) (Continued from page 309) The ridge, the density of each step forward is clamped on the soybean branch. b. Control larvae. In mid-August, use 2.5% enemies to kill emulsifiable concentrate 300ml/hm2, or 30% Taoxiaoling emulsifiable concentrate 400ml/hm2, or 4.5% beta-cypermethrin emulsifiable concentrate 1000-1500ml/hm2, spray once to 150~300kg/hm2 of water. can.

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(Source: Beijing Plant General Hospital)

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