How does the burdock Spodoptera litura insect infestation occur? What are the best ways to prevent i

Spodoptera liturae are mainly harmful to larvae, the number of larvae is huge, they like to gather together to gnaw the young leaves of citrus, they eat a large amount of food, and the feeding speed is fast, and the leaves are eaten in a blink of an eye! The bug usually comes out after day and night to harm fruit trees. It can be concealed during the day, and some curly leaves are hidden inside.

Therefore, it is very difficult to take medication. Without mastering the drug** technique, these little things simply cannot be removed. A group of friends from the three armies said.

This bug is so stubborn, no matter how much you take medicine, you won't die. Three consecutive injections of the drug. Completely lethal.

What a headache! I have tried all kinds of nail rhinitis and chlorpyrifos, and I have been spraying for three days without dying, and these insects have been refined.

Spodoptera litura, which begins to be sprayed prophylactically, is resistant to many insecticides in its early stages, and many insecticides are difficult to control when used alone. The older you are, the more fat you store in your body, and the stronger your ability to break down pesticides, making it difficult to kill. Before the age of 3 years is the best time to get rid of Spodoptera litura.

Spodoptera liturae usually comes out at night to hurt people, so the effect of applying medicine at night will be better, and the effect of spraying in the morning will be greatly reduced. At the same time, when injecting drugs, we should not only spray the fruit trees wetly, but also spray pesticides on the floor to achieve a better preventive effect. The agent should be used alternately to achieve better results.

Spodoptera litura, eggs: steamed bread shape, with horizontal and vertical markings on the surface, shiny, milky white when first produced, gradually turning dark yellow, dozens or even hundreds of grains add up, into 2-3 layers of egg mass. Larvae:

The newly hatched larvae are yellow-green with white spots, grow into old bugs, dark green on the back, light yellow on the ventral back, orange on the back, and the body length of the larvae is usually 30-50 mm. Adults: grayish-brown all over, tactile brown silver, forewings with grayish-white broad yarn, hindwings mostly white, water-red color, adults with wings outstretched, 30-45 mm in length.

Pupa: Pupae are oval, with a short rump and two spines at the end, pupae are usually 18-22 mm in size. Occurrence of Spodoptera litura:

5 9 generations occur a year, the north temperature is low, the logarithm is small, the temperature is high in the south can produce 9 generations, generally with old larvae or pupae in the field weeds for winter, the south basically no overwintering phenomenon. It is usually in July and August in the south and severe in August and September in the north, and the temperature suitable for development is around 30 degrees.

Adults are latent during the day and come out at night. 8:00 p.m. 12:00 p.m

00 activities are the most grand, with strong emergency response capabilities and extensiveness. After hatching, the larvae gnaw on the subcutaneous epidermis around the egg mass, leaving only the epidermis and the membranous material formed by the leaf veins. When the insect grows up, the amount of food increases, the insect body density is large, it can eat leaves, and it has feigned death after the age of 3.

The reason for this is that it is in the process of growing, and then some lesions that occur in the leaves, and the best way to effectively control it is to spray pesticides, spraying twice a day.

It may be because there is more watering, or there is no regular watering and fertilization, and the temperature is relatively high, so some pesticides should be sprayed at this time.

1 Activity Habits Adults lurk in dark places such as the back of leaves or soil crevices during the day, and come out at night. Each female moth can lay 3 5 eggs, each has about 100 200 eggs, the eggs are mostly laid at the leaf vein fork on the back of the leaf, the larvae can hatch after 5-6 days, the back of the leaf is gathered at the beginning of the hatch, after the 4th instar and the adult, hide in the soil surface or soil crevice under the leaf during the day, and climb to the plant to feed on the leaves after evening. 2 Tropism Adults have strong phototaxis and chemotaxis, and the effect of black light is more obvious than that of ordinary lamps, and they are also very sensitive to sugar, vinegar and wine flavors.

1) Agricultural control. Removing weeds, ploughing the soil after harvest, or irrigating to destroy or worsen their pupation sites can help reduce the source of insects. Combine the management of incubated larvae with manual removal of egg masses and cluster damage to reduce the source of worms.

2) Physical control. Light the lamp to lure the moth. Using the phototaxis of adults, black light trapping and sweet and sour trapping are used in the peak period.

Use adult chemotaxis with sweet and sour (sweet and sour wine = 3 4 1 2) plus a small amount of trichlorfon to trap moths. Willow branches are dipped and sprinkled with 500 times trichlorfon to trap moths.

alternate spraying of 6 000 8 000 times of 21% killing EC, or 4 000 6 000 times of 50% fenvalerate EC, or 2 000 3 000 times of 20% cyanoma or chrysanthemum EC;

or 4 000 5 000 times of Kung Fu and Uranus emulsifiable concentrate, or 3 000 times of 20% emulsifiable concentrate, or 80% dichlorvos, or chlorpyramide, or 25% malathion 1 000 times, or 5% of Jam Ke, or 5% Nongmont 2 000 3 000 times of liquid, 2 3 times, once every 7 10 days, spray evenly and spray the feet.

Taking advantage of the phototaxis of adults, the adults are continuously trapped by using a black light. Before the larvae entered the 3rd instar binge feeding stage, the roots were sprayed with 20 billion pib grams of Spodoptera litura, 12000 15000 times of water-dispersible granules, and 800 times of 45% phoxanthion EC were used to irrigate the roots.

(1) Spodoptera liturae is a pest of the family Spodoptera exigua, which is widely distributed. Adults are 14-20 mm long, dark brown, and have a wingspan of 35-40 mm. The forewings are grayish-brown, the hindwings are white, and the forewings are intertwined with several grayish-white diagonal stripes, with annular and renal striae in between.

The insect occurs in North China in 3 or 4 generations a year, in the Yangtze River basin in 5 or 6 generations a year, and in South China it can occur throughout the year. Adults are diurnal and nocturnal, and have a strong tropism to black light and molasses odors. It prefers to lay eggs on the back of the leaves of marginal crops in densely growing fields.

The larvae mostly swarm near the egg masses and feed on the leaves. After the third inage, they are scattered and harmed, and the time of harm is in the evening. The suitable temperature for development is 28-30 , and the main hazards are in summer.

Around the end of August, it feeds on the leaves of strawberries in nurseries, as well as flower buds, flowers and fruits, leaving only bare petioles. If Spodoptera liturae are present in the planting area, the damage will be more severe after warming in the shed in winter. Mature larvae pupate in topsoil at a depth of 1 3 cm.

When the soil is compacted, it can pupate under dead leaves.

2) Control methods: remove weeds in the field and on the ground, artificially kill eggs or kill young larvae. Use honey and black light to trap and kill. The key to control is to poison the 1 2 instar larvae stage.

It can be sprayed with 5% anti-Taibao (fluridinurea) emulsifiable concentrate 2000 times, or 3% emamectin benzoate microemulsion 2000 times, or 1% matrine soluble liquid 800 1200 times. It can also be sprayed with 800 IU Bacillus thuringiensis wettable powder 100 150 g on 40 50 kg of water. The larvae after the 3rd instar should be sprayed in the evening, because the older larvae like to be active at night.

It is best to control young larvae.

Inulinoid insecticides can be used.

or the biopesticide matrine, Spodoptera exigua karyotype polyhedrovirus (Cambon).

Spodoptera liturae mainly harms vegetables, tobacco, etc., and gnaws on leaves. The control of Spodoptera liturae can use yellow plates or Spodoptera litura's trap pheromones, and the goods of Quanzhou Lvpusen are not bad.

Prevention and control points.

Agricultural control: weed removal, combined with field operations can remove egg masses and damaged leaves before larvae spread.

Trapping adult insects: Combined with the control of other vegetable insects, Dongfanghong electronic moth lamp or black light or sexual attractant or sweet and sour liquid can be used to trap and kill.

Chemical control: The 3rd and 5th generations of Spodoptera liturae are the key generations of damage, and the control strategies should be adopted to suppress the insect population of the 3rd generation, control the damage of the 4th generation, and pick the 5th generation. According to the damage habits of larvae, the appropriate period of prevention and control should be mastered before the peak of egg hatching to the dispersion of 3rd instar larvae, generally choose to apply pesticides after the sun goes down in the evening, and spray the leaves and leaf backs evenly with sufficient amount of liquid medicine, so that the agents can be sprayed directly on the insect body and food, and the contact killing, stomach poison and poison go hand in hand, and enhance the poisoning effect, which is the key technical measure to improve the control effect.

In the peak stage of egg incubation, you can choose 2 000 2 500 times of 5% Ka Ke emulsifiable concentrate, and 1 500 2 000 times of Sanling emulsifiable concentrate, or 3 000 5 000 times of 1% Lijijing emulsifiable concentrate, or 3 000 5 000 times of 1% Victor emulsifiable concentrate, or 2 000 2 500 times of 24% satisfactory suspension, or 3 000 3 500 times of 15% Anda suspension, or 2 000 2 500 times of 10% depletion suspension, or 800 1 of Aolv No. 1 suspension 200 times liquid, or 10% annihilated emulsifiable concentrate 1 500 2 000 times, or Tiannuo No. 1 emulsifiable concentrate 2 000 3 000 times, or Holux emulsifiable concentrate 2 000 3 000 times, or Dakang emulsifiable concentrate 2 000 3 000 times, or Tianwang Baishu emulsifiable concentrate 1 000 1 500 times, or moth suspension 800 1 200 times, or 20% Lvdefu microemulsion 600 800 times, or 48% Lesben emulsifiable concentrate 1 000 times, or 40% Xinnongbao emulsifiable concentrate 1 000 times, etc., spray control.

Morphological characteristics. Adults: body length 14-20 mm, wingspan 35-40 mm, dark brown. The forewings are grayish-brown, with a broad white twill band from the base of the anterior margin to the posterior rump angle, with two longitudinal stripes in between, and the white twill is not as pronounced as that of the female. Hindwings grayish-white, without markings.

Eggs: Steamed bread-shaped, the masses lay into 3 or 4 layers of egg masses, the surface is covered with brownish-yellow loose hairs.

Larvae: 6 instars, body color is changeable, from midthoracic to 8th abdominal segment there is 1 pair of nearly triangular black spots, among which the 1st, 7th, and 8th abdominal segments are the largest. Mature larvae are 35-47 mm long.

Pupa: 15 20 mm long, cylindrical, with a small end, russet to dark brown, densely covered with small round notches on the anterior margin of the 4th 7th segment on the dorsal surface of the abdomen, with 1 pair of powerful anal spines.

(1) Habits and hazard characteristics: Spodoptera liturae belongs to the family Spodoptera exigua, which is a gluttonous pest with a very mixed diet. The first hatched larvae were swarmed, and after the 2nd instar, they gradually dispersed and fed on the mesophyll, and after the 4th instar, they entered the overfeeding stage, and the 5 and 6th instar larvae accounted for 90% of the total food consumption.

The larvae bite the leaves, flowers, flower buds and fruits, and the leaves are holes or missing, and in severe cases, they can eat the whole field crops into stalks.

Adults are 14-20 mm long, wingspan 35-40 mm, dark brown with white bush hairs on the back of the thorax and dark brown bush hairs on the sides of the abdomen. Forewings grayish-brown, inner and outer transverse lines grayish-white wavy, with 3 white diagonal stripes in the middle, hindwings white. The eggs are flattened and hemispherical, yellowish-white at first lay, purplish-black before hatching, and covered with grayish-yellow villi.

The mature larvae are 35 to 50 mm long, and the larvae are divided into 6 instars. The head is black-brown, and the color of the thorax and abdomen varies greatly, such as earthy yellow, blue-yellow, gray-brown, etc., and there are a pair of half-moon-shaped or triangular black spots from the middle chest to the dorsal surface of the ninth abdominal segment. Pupae 15-20 mm long, reddish-brown, with a pair of short spines at the end of the tail.

Spodoptera litura, which occurs in 5 6 generations a year in Hainan Province, is a thermophilic pest, with a suitable temperature of 28 30 and a serious damage period of 6 September. Adults are nocturnal and nocturnal, with the most active activity at 8 to 12 o'clock in the evening, with phototaxis, and taxis towards sugar, wine, vinegar and fermented substances. The eggs are mostly laid at the leaf vein bifurcation on the back of the leaves in the middle of the plant, and each female lays 3 5 eggs, each with about 100 more than 100 eggs.

When large occurrences, larvae have the habit of migrating in groups and have the tendency to fake death. After the older larvae enter the gluttony period, they generally hide in the shade or in the soil crevices during the day, and mostly come out after the evening to carry out activities, and the mature larvae pupate in 1 3 cm of topsoil or under dead branches and leaves.

2) Control measures: trapping and killing adult insects. Use the phototaxis and chemotaxis of adults to trap and kill, you can use black light and frequency vibration lamp to trap moths, or you can use sweet and sour liquid or carrot, sweet potato, soybean cake and other fermentation broth, add a little brown sugar, trichlorfon for trapping.

Artificial killing. Taking advantage of the characteristics of adult eggs and clumps and incubated larvae swarming, artificial egg picking and larvae were eliminated in combination with field management. Biocontrol.

In the initial incubation period of larvae, it was sprayed with 1500 times of the compound virus insecticide insect plague No. 1, and the effect was better. Chemical control. Catching the larvae in the stage of cluster damage and spotting before the 3rd instar can be combined with field management for picking, and there is no need to apply pesticides in the whole field.

After the 4th instar of the larvae, due to the diurnal and nocturnal damage, the application should be carried out around the evening. The following agents can be used: 5% anti-Taibao EC 3000 times, insect ba, 5% Ka Ke EC 2000 times, 2000 times 2000 times 20% chrysanthemum EC, 40% cyanochrysanthemum vinegar 5000 times, Uranus EC 3000 times, 48% Lesben EC 1000 times, spray once every 7 10 days, 2 3 times.