The development period of rice leaf roller borer, and the duration of each instar of rice leaf rolle

<> 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.

Adults are 15-18 mm long and 7-9 mm wide, yellowish-brown and shiny, with a darker anterior thorax and dorsal plate than elytra. The dorsal plate of the prothorax is raised, the sides are arcuate, and the posterior margin is densely covered with fine yellow hairs in front of the small shields. The elytra are long ovate, densely dotted, and each has 3 dark longitudinal streaks.

The large claws of the anterior and middle feet are bifurcated, and the basal, rotatory, and leg segments of the three pairs of feet are pale yellowish-brown and yellowish-brown. The larvae are 25-35 mm long, and the anterior cephalic plexus lacks 5-6 bristles on each side, in a longitudinal row. The rear part of the rainbow belly piece is composed of 2 rows of longitudinal hairs, each row of the front segment is composed of 11-17 short conical hairs, accounting for 3 4 of the length of the whole spiny column, and each row of the posterior segment is composed of 11-13 long needle hairs, which are forked backward in the shape of "eight", accounting for 1 4 of the whole hairy column.

The back of the visceral dorsal piece has a round buttocks plate surrounded by ossification rings (finely ground collapse joints).

Summary of prevention and control measures:

1. Select insect-resistant (tolerant) rice varieties and apply fertilizer reasonably to make the rice grow and develop robustly, and prevent the rapid growth in the early stage and the late maturity in the later stage. Scientifically manage water, appropriately adjust the field shelf time, reduce the field humidity during the larval hatching period, or irrigate deep water for 2-3 days during the peak period of pupation to kill the pupae.

2. Protection and utilization of natural enemies and improvement of natural control ability: there are more than 80 kinds of natural enemies of rice leaf roller borer in China, and natural enemies parasitize or prey at each insect stage. Parasitic natural enemies at the egg stage, such as the red-eyed wasp of the Australian red-eyed bee, the larval stage of the longitudinal leaf roller and the velvet cocoon wasp, and the predatory natural enemies such as spiders and frogs, all have a great control effect on the longitudinal leaf roller.

What is the occurrence period and control measures of rice leaf roller?

Prevention and control measures: 1. Select insect-resistant (tolerant) rice varieties and apply fertilizer reasonably to make rice grow and develop robustly, and prevent rapid growth in the early stage and late maturity in the later stage. Scientifically manage water, appropriately adjust the field shelf time, reduce the field humidity during the larval hatching period, or irrigate deep water for 2-3 days during the peak period of pupation to kill the pupae.

2. Protection and utilization of natural enemies and improvement of natural control ability: there are more than 80 kinds of natural enemies of rice leaf roller borer in China, and natural enemies parasitize or prey at each insect stage. Parasitic natural enemies at the egg stage, such as the red-eyed wasp of the Australian red-eyed bee, the larval stage of the longitudinal leaf roller and the velvet cocoon wasp, and the predatory natural enemies such as spiders and frogs, all have a great control effect on the longitudinal leaf roller.

What time is the outbreak now.

Rice leaf roller borer can occur 2-3 generations a year in the northern rice area, the insect source is mainly from the south, the first migration in early and mid-July, and the peak of adults in late July. In early to mid-August, they moved in again, and the fields were full of leaves. In mid-August, severe leaf rolling is the most harmful to rice.

What is the best pesticide to control, when the larvae are in full bloom, you can spray borericidal bacillus or Bacillus thuringiensis solution for control; 50% phosphine EC, 50% pine mothine EC, 25% Ecumers (silicofon) EC, 90% trichlorfon, 42% Telik EC are commonly used for drug control.

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Rice leaf curling generally occurs in the warm climate, abundant rainfall, and the growth of grass seedlings is tender and green. The prevention and control measures are as follows.

1. It can be considered to use rice resistance, select high-yield varieties resistant to diseases and insects, and combine reasonable fertilization to prevent rice from growing tender and green in the early stage.

Rice leaf curling generally occurs in the warm climate, abundant rainfall, and the growth of grass seedlings is tender and green. The control measures are as follows: 1. It can be considered to use rice resistance, select high-yield varieties resistant to diseases and insects, and combine reasonable fertilization to prevent rice from turning tender and green in the early stage. 2. When there is a peak larval period, you can consider using 25% insecticidal double aqueous spray.

Hello, the control of rice leaf roller borer generally adopts a combination of agricultural control, biological control, and pesticide control. Agricultural control includes the selection of insect-resistant varieties and the strengthening of fertilizer and water management to prevent rice from growing violently in the early stage and greedy for green and late maturing in the later stage. Fields with serious insect infestation can be irrigated with deep water for 2 days at the pupa stage; Biological control mainly uses the natural enemies of rice leaf roller borer in nature, such as red-eyed wasps.

Where conditions permit, red-eyed wasps can be released during the peak period of adult oviposition, and the egg parasitism rate can generally reach more than 70%. When the larvae are in full bloom, bacillus boricide or Bacillus thuringiensis can be sprayed for control; 50% phosphine EC, 50% pine mothine EC, 25% Ecumers (silicofon) EC, 90% trichlorfon, 42% Telik EC are commonly used for drug control.

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.

There will be an impact. If such a disease occurs, it is likely to lead to a decrease in yields, rot, and then also affect the growth and development rate of the plants, as well as the harvest, which will affect the economic benefits of the farmers.

In the process of differentiation, pests and diseases will reduce the yield of rice, and will also affect the sustainable development of agricultural production.

Impactful. This pest and disease will reduce the yield of rice and cause some wilting of rice.

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.