Spodoptera exigua, which is the main pest, what are the dangers of Spodoptera exigua?

Spodoptera exigua belongs to the family Spodoptera exigua. The main hazard is cabbage,. Adults are 15-25 mm long and brown.

The forewings have distinct kidney-shaped striated spots (white inside the spots) and annular striae, and the outer margin of the hindwings has a small black spot. The oval is hemispherical, with a brown papillae at the top, longitudinal ridges and transverse grids on the surface. The eggs are mostly laid on the dorsal surface of the leaves, and the single layer is lumpy.

The mature larvae are 50 mm long, the head is yellow-brown, the ventral surface is pale green, and the back is yellow-green or tan, the brown cabbage armyworm is a polyphagous pest, the host is very extensive, about 45 families and more than 100 kinds of crops are affected by it. Among them, the more serious crops are asparagus, cabbage, cabbage, radish, mustard greens, tobacco, spinach, carrots, sugar beets and beans, and can also harm eggplant, melons and food crops. In North China, it mainly harms autumn cruciferous vegetables, and in the northeast and northwest regions and other sugar beet producing areas, the damage is also very serious.

The brown type has an inverted figure-eight pattern on the back of each section. 1 2nd instar larvae walk like inchworm pupae 20 mm long, brown, with 2 long rump spines, the end is swollen and spherical, like a pin. <>

Spodoptera exigua harms the leaves with larvae, the newly hatched larvae concentrate on the back of the leaf to feed, the residual epidermis, showing a dense "small skylight" shape, the larvae are slightly larger and disperse to feed, creating a gap or hole, the amount of food increases sharply after the 4th instar, feeding day and night, the leaves are eaten into large holes, leaving only leaf veins. The 6th instar larvae latent in the rhizosphere soil during the day and at night. Older larvae can burrow human leaf balls and excrete a large amount of insect droppings, causing rot in the leaf balls due to pollution.

The optimal development temperature of Spodoptera exiguae is 18 25 . September and October are the peak periods. Adults emerge at night and lurk on the back of vegetable leaves or in the shade during the day, and come out at sunset.

Adults are phototaxis, but not strong. It has strong chemotaxis to sweet and sour liquid. Adults mate and lay eggs, which like to be laid on tall and dense plants, generally on the back of the leaves of cabbage and spinach.

Each female can lay 600-800 eggs. The lifespan of adult worms is about 10 days. <

Spodoptera exigua mainly injure the leaves of crops, the larvae of the first hatch are gathered together, on the back of the leaves, do not move during the day, and live at night to eat the leaves, and the remaining epidermis is lurking under the leaves, cabbage and the soil around the surface or roots during the day, and come out at night to form gluttony. It is very harmful to crops.

This organism has a strong influence on the leaves of plants, they feed on mesophyll, and they also excrete in large quantities, causing leaf bulbs to rot, affecting the yield and quality of vegetables.

With the development of society, more and more people choose to grow crops at home. The crops grown by yourself are not only clean and hygienic, but also nutritious. Mustard greens are one of the most popular vegetables, but Spodoptera exigua is a very common pest of mustard greens.

So when you find that the mustard greens you grow are infested by Spodoptera exigua, how should you prevent and control it? <>

First, biological control, if the mustard is in the harvest season, people can carry out autumn or winter ploughing to eliminate pupae. This method is a very effective way to eradicate pests at the root. It is also possible to trap with a black light and then kill the infestation.

Finally, there is the release of the natural predator of the Spodoptera exigua, the red-eyed bee, and when the Spodoptera armyworm encounters the red-eyed wasp, then its number is greatly reduced. The above methods are biological control, which not only ensures the quality of mustard, but also ensures the quantity of mustard. <>

2. Chemical controlWhen they find that they are planting camellia with insect pests, the first method that people think of must be spraying pesticides. Because this method is not only fast and effective, but also can kill insect infestations quickly. Although the use of pesticides may also have a good impact on the crops they grow, it will not have much impact on the crops if people spray them in moderation.

Because pesticides are inherently toxic, people should be mindful of how much they spray when using them. If it is sprayed excessively, it will have an inhibiting effect on the growth of mustard greens. If you really don't know how to spray, you can ask your neighbors for advice, and sometimes asking someone else for help may save you a lot of detours.

3. Physical controlPhysical control is the most easy-to-understand method, and it is also the most direct method to eliminate pests. When you are planting mustard, you can ask a friend or family member to observe the growth of mustard after a period of time to determine whether it is infested by pests. If you find that you are infested by pests, you should take immediate measures to manually kill the pests.

Pesticides should be sprayed in a timely manner, and the right medicine should be prescribed, and water and fertilizer management should also be done, and weeds should be removed regularly, and pest pests should be removed.

Relevant pesticides should be sprayed in advance, and at the same time, the infection of various pests and diseases should be prevented, and attention should be paid to ventilation and management methods.

If you want to control Spodoptera exigua, you should first sprinkle pesticides and pesticides on the ground when planting mustard greens, so that you can avoid this creature from getting close to mustard greens.

It can be controlled with pesticides. Some pesticides can kill these moths.

Spodoptera exigua usually appears in the hot summer months and mainly damages the leaves as a larvae.

The temperature is high, it is easy to appear in dry weather, this bug likes hot weather, and this bug is very fond of eating vegetable leaves.

1.Autumn droughts are frequent, which is conducive to the occurrence of pests. High temperature and drought are conducive to the outbreak of Spodoptera exigua, because the drought in July and August is not conducive to the reproduction of Beauveria bassiana, an important natural enemy of Spodoptera exigua, so the larval survival rate is high and the harm is serious.

2.The use of drugs is illegal. First, the medication is not timely.

The vast number of peasants often do not see the insect and lose the period of insect control. The appropriate period for the control of Spodoptera exigua larvae is the peak period of egg incubation, when the larvae are small, the amount of food is small, and the group is harmful, and there is no eye-catching harm. The prevention and control can not exceed the 3rd instar, and after the 3rd instar, the food damage will be dispersed, the resistance will be enhanced, and the control effect will be very poor.

Second, the amount of medicine is large and the amount of water is small, so it is difficult to spray evenly. Third, there is a lack of effective organization and inconsistent insect control actions. 3.

Increased insect resistance. Long-term irrational drug use has led to a significant increase in the resistance of Spodoptera exigua.

<> Spodoptera exigua is an omnivorous pest belonging to the phylum Arthropods, Insecta, Lepidoptera, and Noctuidae. Spodoptera exigua is mainly a shed to damage the leaf chain of crops with larvae, the larvae at the beginning of hatching will gather together on the back of the leaf to eat, and in severe cases, they can often eat up the mesophyll, leaving only the leaf veins and petioles, and then eat one place and then become a closed group and migrate to another place for damage.

The characteristics are different: the larvae of Spodoptera exigua are black, with coarse hairs on the whole, about 2 mm in length, the adults are grayish-brown, with giant claws at the end of the tibiae of the forefeet, the larvae of Spodoptera exigua are green, with yellowish-white longitudinal stripes on both sides, the adults are grayish-brown, and the outer edge of the forewings consists of a row of small black triangular spots.

The occurrence rules are different: Spodoptera exigua will emerge when the temperature rises to 15-16, and 3-4 generations can occur in 1 year in the northern region, and 5-6 generations can occur in 1 year in the Yangtze River basin, and the more generations occur in the south, the more generations will occur.

First, the characteristics are different

1. Spodoptera exigua: the larvae are slightly dark, all have coarse hairs, the body length is about 2 mm, and the second instar larvae are all green; The adult body and wings are grayish-brown, the compound eyes are blackish-purple, and there are giant claws at the end of the tibia of the forefoot.

2. Spodoptera exigua: the larvae are green or dark green, with yellowish-white longitudinal stripes on both sides, and 1 white markings above the back of the valve; The body color and forewings of adults are grayish-brown, and the outer edge of the forewings is composed of a row of small black triangular spots, and the kidney-shaped and ring-shaped lines are yellowish-brown.

Second, the law of occurrence is different

1. Spodoptera exigua: The pupa overwinters 10 cm below the surface, and the pupa will emerge when the temperature rises to 15-16, and 3-4 generations can occur in 1 year in the northern region. The occurrence time in Liaoning is from mid-May to mid-June, and the occurrence time in Shandong is from early May to early June.

2. Spodoptera exigua: Pupae overwintering in the soil, 5-6 generations can occur in 1 year in the Yangtze River Basin, 7 generations can occur in a few years, the closer to the south, the more generations occur each year, and 10-11 generations can occur in 1 year in Guangdong. There is no overwintering phenomenon in South China, and it can be harmful and multiplying all year round.

Third, the prevention and control methods are different

1. Spodoptera exigua: before the larvae are 3 years old, spray 8000-10000 times of 10% Uranus EC, or 4000-5000 times of 21% killer EC, or 3000 times of 50% pine moth-killing EC, spray 1 time every 10-15 days, and spray 2-3 times in a row.

2. Spodoptera exigua: After the larvae enter the peak hatching period, spray 1000-2000 times of 25% chlorpyramide emulsifiable concentrate at 8 o'clock in the morning or 6 o'clock in the evening, or 1000 times of 5% cypermethrin emulsifiable concentrate 500 times of 5% fipronil dispersible liquid, or 1000 times of cyfluthrin emulsifiable concentrate and 500 times of 5% fipronide emulsifiable concentrate.

The grass-aged larvae of the cabbage moth eat the plant mesophyll, leaving the epidermis and forming transparent spots on the leaves, forming leaf cavities. The 3-4-year-old larvae of moths can eat the leaves as holes and insufficiency, and when it is severe, the front leaves are eaten with a net. Crops often gather in the center of the leaf sea at the seedling stage, which affects sowing.

Diamondback moths can also damage soft stems, pods, and grains. Cauliflower moth losses have peaked significantly twice throughout the year, with the first occurring from mid-May to late June. The second is from late August to late October.

Small moths are small and can survive with only a small amount of food, making them easy to avoid enemy damage. The vegetable moth has strong ecological adaptability, can withstand short-term cold of minus 15 degrees Celsius in winter, and can also carry out feeding activities in the environment. In summer, it can withstand the heat of more than 35 degrees, and only heavy rains in summer can kill a large number of people.

Diamondback moth has strong resistance, long-term use of chemical pesticides, large-scale killing of natural enemies, diamondback moth damage for a day, quickly produce a very high level of resistance to various chemical pesticides, in the 90s, many places are faced with the spread of diamondback moth in a large area, damage for a long time, due to the difficulty of prevention and control, diamondback moth gradually replaced cabbage worm to become the first pest of vegetables. The diamondback moth has a short life cycle, and it only takes 10 days for people who eat kale to complete the generation when the temperature is 28 to 30 degrees. Use small moths to attract luminous habits, and use black lights or other light sources to attract adults at 7 to 11 p.m.

Adults are mainly trapped in April and May or with other light sources.

Release diamondback moth predators and control risks. Among them, the moth cocoon bee, the moth wasp, and the moth wasp can control the number of moths the most. Using Chinensis thuringiensis agent, dilute 8000 IU ml of sugar-free and spray 500 to 1000 times.

The dose should not be too high or too low, and the focus should be on preventing young larvae, especially larvae of 1 to 2 years old. It is best to avoid medication in high temperatures and do it in the afternoon or on a cloudy day. Temperatures below 15 should not be used.

If you want to spray, spray the back of the vegetable leaf. Grass-in-star larvae only eat mesophyll, leaving the epidermis, forming transparent spots on the leaves, often called "skylights", 3 4 instar larvae can eat the leaf rice as a hole and insufficient, and in severe cases, use a net to eat the front leaves, and the seedlings set the center leaves, affecting the heart. The larvae can also grow tender stems, pods, and seeds in vegetables, affecting the fruit.

As long as there are cruciferous vegetables and wild vegetables in the fields, the little moths have a chance to survive. Therefore, in winter, leafy vegetables planted in the open field, planted plants, and planted in protected areas are all overwintering insects**. The number of bugs is relatively concentrated, and the resistance of pests is also the weakest.

After harvesting vegetables or before insect activity in early spring, a thorough removal of dregs, dead branches and fallen leaves from the vegetable garden can remove a large amount of replenishment. 2.Prevention of "leg removal"**:

In summer 6 and 7 months, cruciferous vegetables are planted less, cauliflower, summer radish, pea pods, cabbage, broccoli, summer cabbage and other vegetables are concentrated in the small moth is moving to a large area of autumn planting, catch the small moth on these vegetables, place the summer insect **, not only can kill the small moth in a small area.

When Spodoptera exigua is severe, it can eat up the entire field of vegetables. Spodoptera exigua is a polyphagous pest, mainly harmful to cruciferous vegetables such as cabbage and cabbage, as well as melons, beans, nightshade vegetables and sugar beets, among which cabbage, autumn cabbage and sugar beets are seriously affected. After the 3rd instar, the leaves can be eaten into holes or missing carvings, and after the 4th instar, they are dispersed and feed day and night, and the 6th instar larvae are latent in the rhizosphere soil during the day and come out at night.

Older larvae can burrow into the leaf bulb and excrete a large amount of insect feces, causing rot in the leaf bulb due to pollution, resulting in a serious reduction in yield and loss of commercial value of vegetables. Trapping. Using the tropism of the adults, the adults were trapped, and the eggs with egg masses and predatory leaves were removed by trapping the adults with black light and sweet and sour solution.

According to the habit of concentrated feeding of the hatched larvae, combined with field management, the removal of leaves with egg masses and hatching larvae can eliminate a large number of egg masses and hatching insects and reduce the number of insect sources in the field. Biocontrol. The red-eyed wasp is released at the egg stage, with 25,000 heads per 667m, a total of 2-3 times, and the parasitic rate can reach 70%-80%.