What are the larval habits of the rice leaf roller?

In China, 2 9 generations occur in a year, and the number of rice leaf rollers gradually increases from north to south. 2 3 generations in the north of Hebei and Shandong, 7 8 generations in the south of Guangdong, and 8 9 generations in Hainan Island. There are 4 generations of rice longitudinal leaf rollers in Sichuan in one year.

The wintering situation varies from region to region and can be divided into three major regions in China: Anniversary Disaster Zone. The average temperature in January is 16 South of the isotherm, including the south of the first line of the Leizhou Peninsula, there are food conditions such as regenerated rice and fallen rice in winter, which can reproduce all year round without dormancy.

Winter dormant area. South of the isotherm of the average maximum temperature in January, i.e. between the south of latitude 30 north and the southern coastline of the continent, larvae or pupae overwinter. Among them, Guangdong, Guangxi and southern Fujian have higher survival rates for overwintering. In Hunan, Jiangxi and other provinces north of Nanling, although some insect populations overwinter in weeds and rice bushes, the survival rate of overwintering is extremely low.

Winter Death Zone. The average maximum temperature in January is 7 north of the isotherm, including Hubei, northern Anhui, Jiangsu, Henan, Shandong and other provinces, and no insect can safely overwinter.

The adult worm is phototaxis, shade-loving and moisture-loving, and can migrate long distances. During the day, it inhabits shady, high-humidity crop fields. Likes to suck nectar.

2 days after the adult emerges, the eggs are often selected to grow in densely grown paddy fields, which lasts for 3 to 4 days, and the eggs are scattered, and a few 2 5 seeds are connected. The number of eggs laid by each female is 40 50 eggs, with a maximum of more than 150 eggs. The spawning position varies depending on the rice growth period.

The eggs are mostly laid near the midrib of the leaf. The 1st instar larvae crawl into the heart leaf or the inside of the young leaf sheath at the tillering stage to eat. At the booting and heading stage, it climbs to the inside of the old insect bract or young leaf sheath to eat.

The 2nd instar larvae can roll the leaf tips into small insect buds, and then the leaf filaments roll longitudinally to form new insect buds, and the larvae can hide in the insect buds to eat. Before the larvae shed their skin, they are often transferred to new leaves to re-bud. The instar larvae eat about 95% of the total food intake, which is the most harmful.

Each larva can roll 5 6 leaves in its lifetime, and the most can reach 9 10 leaves. The old mature larvae pupate in the yellow leaves at the base of the rice bush or in the young leaf buds of ineffective tillers, some in the rice bushes, and a few in the old insect bracts. The adult insect of rice longitudinal leaf roller borer is not phototaxis, and the eggs are mostly laid on the back of the leaf.

3 5 grains are arranged in the shape of fish scales, and a few are yielding. The larvae are not very active and have very few leaves and buds. Mature larvae pupate in the buds of old insects.

This is my idea, I suggest you ask other teachers again, and praise is welcome.

The newly hatched larvae generally crawl into the heart leaf of rice or the leaf sheath nearby, and some burrow into the old insect bracts to eat the mesophyll; The second instar began to spin silk at the tip of the leaf and roll longitudinally into small insect bracts; After 3 years of instar, it begins to bud and become a pest, and the amount of food in the age increases dramatically, and it can cause damage to 5 7 leaves and as many as 9 10 leaves in a lifetime. The larvae are lively, and when they peel off the curly leaves, they quickly fall backwards. After 1 2 days of pre-pupation stage, the mature larvae pupate into thin cocoons.

<> rice leaf roller, also known as scraping insects, white leaf insects, leaf bracts, etc., is one of the main pests in China's rice producing areas. The history of each instar larvae of rice leaf roller borer is introduced as follows:

The hatchling larvae generally crawl back and forth along the veins from the tip of the leaf, eating the mesophyll, leaving behind small white transparent dots in the shape of pinheads that mimic the shape of a forest. The 2nd instar larvae begin to climb to the tip of the leaf or the middle and upper part of the rice leaf. The 3rd instar larvae are more active and begin to bud into damage.

The 4th instar larvae entered the stage of food growth, and the bud and plant changes frequently, and the older the insect age, the more food they eat. The 5th instar larvae entered the gluttony stage, and the size of the insect bracts was similar to that of the 4th instar insect buds, and there were basically no insects in the bracts.

10% emamectindocarb suspension 20 ml + 48% chlorpyrifos EC 50 ml + essential oil 15 ml. 2-3 buckets of water per mu, each bucket of water uses: 50 ml of 5% avermectin EC + 80 ml of 25% probromixin thion EC + 15 ml of essential oil.

It is not easy to plant rice, and the weeds have not been beaten yet, and the borer and leaf roller borer are coming again.

In the early stage, Guangxi, Guangdong leaf roller borer occurred heavily, and recently Jiangxi, Hunan, Hubei and other places also found that some fields have more leaf rollers, and there are 3-4 instars in the first-season rice fields of broken heading, and there are many leaf rollers.

In recent years, the leaf roller borer has also shown resistance, mostly ** leaf roller borer (Striated rice longitudinal leaf roller borer), its older larvae have yellowish body color, greater appetite, heavier harm, and stronger resistance.

If there are more white leaves or leaf bracts in the field, they should be treated with medicine in time, and serious fields should be sprayed again at an interval of 10-15 days.

In order to avoid serious yield decline, especially at the jointing and heading stage of rice, the whitening of functional leaves will affect photosynthesis and lead to incomplete grain filling and premature senescence.

From the perspective of control, rice leaf roller borer is not easy to control. Because when the insect reaches its second instar, it wraps itself in the leaves. In this way, many contact pesticides cannot hit the insects at all, which leads to the control effect will not be very good.

So there are a couple of caveats for this:

The spraying time is very critical, it is best to spray when the eggs are at their peak and the second instar has not yet rolled into the leaves, so that the result is twice as effective with half the effort.

For prevention and control after leaf rolling, gastric toxicity and fumigation pesticides must be used as the leading drugs, and contact killing and systemic pesticides must be used as auxiliaries.

Synergists such as silicones, essential oils, and barrel mixing additives are added during prevention and control to improve the scalability, permeability and rainwater erosion resistance.

How to control rice leaf roller.

1. In the first prevention and control of resale 7-15 days after transplanting, it is recommended to have 1-2 buckets of water per mu. At this time, the seedlings are relatively small, and the water consumption for control can be less.

However, in the peak tillering period, breaking stage, and heading stage, at least 2 buckets of water are needed for each mu of land, and it is best to get 3 buckets of water. Because the amount of water is large enough, the contact between the liquid medicine and the rice leaves will be more uniform and complete, and the control effect will be better.

Choose one of the three.

2-3 buckets of water per mu, each bucket of water uses: 10% emamectindocarb suspension 20 ml + 48% chlorpyrifos EC 50 ml + essential oil 15 ml.

2-3 buckets of water per mu, each bucket of water uses: 50 ml of 5% avermectin EC + 80 ml of 25% probromixin thion EC + 15 ml of essential oil.

2-3 buckets of water per mu, each bucket of water uses: emamectin flubellamide emulsifiable concentrate 80 ml + 36% cyanofiprohydrazine indocarb 10 grams + essential oil 15 ml.

Summary

The pesticides suitable for the control of leaf roller borer are: chlorantraniliprole (Kangkuan), emamectin benzoate (emamectin), avermectin, indoxacarb, chlorfenapyr, lice urea, ethylspinosamad, emamectin, indocarb, emamectonil, chlorfenapyr, indoxacarb, etc. There are many agents to choose from, and it is recommended to rotate the drugs reasonably to reduce the occurrence of resistance.

Hello, the control methods of the elderly larvae of rice leaf roller borer are as follows: (1) Reasonable fertilization, strengthen field management, and promote the growth of rice to reduce damage. (2) Artificial release of red-eyed bees. From the beginning to the peak of oviposition of the rice round longitudinal leaf roller borer, the bees were released in batches in stages, 3-40,000 heads per 667 square meters, once every 3 days, and 3 times in a row.

3) Spray bacillus borer and green worm fungus, spray 150-200g of bacterial powder containing 10 billion live spores per gram of bacterial powder per 667 square meters, 60-75kg of water, and prepare 300-400 times liquid spray. In order to improve the effect of biological control, laundry detergent with a liquid amount of medicine can be added as a wetting agent. In addition, if you can add 1 5 of the liquid to kill the borer, the effect is better.

4) Master in the larval stage or when there are more than 15 new bunches of leaf buds in the larval stage, spray 35-40g of 80% insecticidal single powder or 60ml of 42% trichlorfon or 600ml of 90% crystal trichlorfon per 667 square meters, and also pour 100ml of 50% pine moth emulsifiable concentrate to 400kg of water. Advocate the application of 5% Ruijin special suspension, and use 20ml of medicine per 667 square meters to spray water with excellent effect. 10-30g of 10% imidacloprid hail wettable powder per 667 square meters, 60kg of water, more than 90% of the control effect for 30 days, and the effective period is 30 days.

In addition, it can also be mixed with 10% imidacloprid 10-20g 667 square meters and 80% insecticidal single 40g 667 square meters at the peak stage of 2-3 instar larvae to prevent rice leaf roller borer and treat rice planthopper.

Agricultural control: Rational fertilization and strengthening field management to promote the growth of rice to reduce damage. Biological control:

Artificial release of red-eyed bees, in the beginning of the oviposition period to the peak period of rice leaf borer, the bees are released in phases and batches, 3-40,000 heads per mu each time, once every 3 days, and 3 times in a row. Chemical control: When the larvae are at the peak of 2-3 instars, spray 35-40g of 80% insecticidal single powder or 60ml of 42% trik emulsifiable concentrate per mu.

The following steps are required to investigate the dense curvature of the population of P. oryzae:

1.Select the time and place of the survey: Usually during the rice planting period, i.e. from June to August, paddy fields or paddy fields are selected for observation.

2.Prepare the survey tool: You can use a simple white strip of cloth, spread it in the rice field, and use the light to attract borers to fly and land on the strip of cloth. Yellow sticky boards, lights, insect traps and other methods can also be used to trap and observe.

3.Conduct surveys: Arrange the survey tools that are ready to be buried in the selected location, and record the number of borers regularly every three days. At the same time, it is also possible to observe the leaves, stems and other parts of the rice to see if there are adults or larvae.

4.Data analysis: Statistical analysis of the obtained data, calculation of mean and standard deviation, judgment of population density, and estimation of the degree of harm they may cause according to the trend of data changes.

In short, conducting this survey requires patient and meticulous observation and recording in order to better understand the population density of the rice leaf roller borer and take corresponding measures.

If we want to adjust the population density of rice longitudinal leaf rolling, we should first consider that the population density of rice longitudinal leaf rolling in different regions is different, so it should be adjusted according to the actual situation in different regions.

Secondly, according to the soil type of different jujubes, it is necessary to choose different population densities of rice longitudinal leaf curls, generally speaking, where the soil is fertile, the population density needs to be relatively low, and where the soil is poor, the population density can be higher.

In addition, when considering the adjustment of the population density of rice longitudinal leaf rolling, the climatic conditions should also be taken into account, if the temperature is high, the population density of rice longitudinal leaf rolling can be lowered, and if the temperature is low, the population density can be appropriately increased.

Finally, the population density of rice longitudinal leaf curling also depends on the variety of rice longitudinal leaf curling of Hetanyuan rice, generally speaking, the population density of rice longitudinal leaf rolling is also different for different varieties, so when adjusting the population density of rice longitudinal leaf curling, it should be adjusted according to the specific planting variety.

To investigate the population density of rice leaf curlers, the following steps are required:

1.Determine the study area: First, to investigate the population density of the rice longitudinal snail, it is necessary to make sure that the study area or extent is not disturbed.

2.Define the sample size: According to the expected results, determine the sample size required for the study, i.e., the number of rice leaf curls in the study area.

3.Sampling method: Determine which sampling method to use, such as fixed-point high-denier sampling, mesh sampling, and so on.

4.Quantity: Using the above sampling method, the number of rice leaf rollers was counted in the study area to obtain information about the population density of rice leaf rollers.

5.Analysis: Based on the data obtained, the population density of rice longitudinal leaf curls in the study area was analyzed to obtain quantitative information.

Adult 7-9 mm long, pale yellowish-brown, with two brown transverse lines on the forewings, one ** between the two lines, and a dark brown band on the outer edge; hindwings with two transverse lines, and broad outer margins; In the middle of the anterior edge of the forewings of male moths, there are shining and concave "eyespots", while female moths have no "eyespots" on their forewings. The eggs are about l mm long, oval, flattened and slightly raised in the middle, white and transparent at first, pale yellow when nearly hatched, and the parasitic eggs are black. The larvae mature 14 to 19 mm long, the young larvae are green, then turn yellow-green, and the mature larvae are orange-red.

Pupae 7-10 mm long, yellow at first, brown later, oblong cylindrical.

In China, 2 9 generations occur in a year, and the number of rice leaf rollers gradually increases from north to south. 2 3 generations in the north of Hebei and Shandong, 7 8 generations in the south of Guangdong, and 8 9 generations in Hainan Island. There are 4 generations of rice longitudinal leaf rollers in Sichuan in one year.

The egg stage is 3-6 days, the larval stage is 15-26 days, a total of 5 instars, and the first instar larvae do not bud; At the second instar, it climbs to the tip of the leaf, and spins the edge of the leaf tip or near the tip of the leaf, that is, the "curly tip stage"; The third-instar larvae roll the leaves longitudinally to form obvious bundle-waisted insect bracts, that is, the "bundle leaf stage"; After the 3rd instar, the food intake increased, the insect bracts swelled, and the bracts frequently turned into pests in the 4-5th instar, and the pest bracts were dry and white, and the whole paddy field was full of white leaves. The larvae are lively, and when they peel off the buds to check the insects, they quickly retreat backwards or roll to the ground. The old mature larvae mostly crawl to the base of the rice bush, spin silk on the small leaves or withered yellow leaves of the ineffective tillers to form tight small bracts, and pupate in the bracts, and the pupae are mostly in the leaf sheath or located in the thin cocoons of dead leaves between plants or on the surface.

The pupal stage is 5-8 days, the female moth lays 3-12 days in the early stage of oviposition, the female moth lives 5-17 days, and the male moth 4-16 days. A total of 40-60 days in a lifetime, the length of time is related to the ambient temperature.