Several common pests in rice farmland and their control measures

As we all know, rice is the main food crop in China. The scientific pest control of rice farmland is of great significance to China's social economy. It is also an urgent need to meet farmers' agricultural production and implement farmland pest control. Below, Weiwei, I will introduce the main pests and control measures of rice farmland one by one.

Rice planthopper

Rice planthoppers are long-distance migrations with explosive and sudden pests. There are many types, mainly white-backed planthoppers and brown planthoppers. The brown planthoppers can be divided into two types: long and short-winged, and white-backed planthoppers are only long-winged.

Rice planthopper

(a) harmful symptoms

Both of the planthoppers sucked the juice at the base of adult and nymphal rice plants, causing the leaves to be yellow. In severe cases, the whole plant died and the phenomenon of "falling nest" appeared, resulting in reduced yield.

(2) Characteristics of occurrence

Rice planthoppers occur 8 generations a year, overlapping generations. Adults have strong phototaxis, and eggs are mostly produced in leaf sheaths; short-winged adults have large egg production, and if the number is large, it is a big sign. Early rice is generally seen in early May, with the third and fourth generations as the main damage generation. The peak period of damage occurs from the end of May to the beginning of June and from the end of June to the beginning of July. The late rice is generally seen in the middle and late August. The sixth and seventh generations were the main generations, and the peaks of the hazards occurred in mid-September and mid-October. The white-backed planthopper is most suitable for feeding in the tillering stage and the large fetus, and the brown planthopper ear is most suitable for feeding. Therefore, the third and sixth generations are dominated by white-backed locusts, and the fourth and seventh generations are dominated by brown planthoppers. The warm and humid climate is conducive to the breeding hazards of rice planthoppers. Generally, the rainy summer and the summer drought are prone to cause white-backed locusts to occur; summer and autumn are rainy, summer is not hot, and late autumn is warm, which is conducive to the occurrence of brown planthopper. In the late stage of rice, the greedy youth, the shade of the field, and the high humidity are very beneficial to the occurrence and reproduction of brown planthopper.

There are many kinds of natural enemies of rice planthopper. Among them, parasitic eggs and predators mainly include rice bran and black-shouldered green-streaked owls. The natural enemies of nymphs are mainly stag bees, nematodes, spiders and parasites. The occurrence has different degrees of control.

(3) Main prevention methods

(1) Agricultural control. To achieve scientific water, shallow water and dip, timely exposure to the field, rational fertilization, to avoid the long-term greed of the seedlings, to inhibit the growth and reproduction of rice planthoppers.

(2) Protect the use of natural enemies. Such as the use of pesticides such as methamidophos and other highly toxic and killing effects on natural enemies, the use of selective agents, adjust the time of medication, reduce the number of medications, to avoid a large number of killing natural enemies, play the role of natural enemies.

(3) Chemical control. At the peak of the young nymphs, 3% 奇巧乳 1500~2000 times liquid, the early rice invading the third generation, and the late rice in the sixth generation, can basically control the damage of the rice planthopper in the whole season.

2. Rice leaf roller

(a) harmful symptoms

The larvae threshed the leaves into tube-shaped worms, and the mesophyll in the scorpion left the epidermis into white streaks. In severe cases, the whole field was white, affecting the growth of the rice plants, and the fruiting was not full.

(2) Characteristics of occurrence

The rice leaf roller is a migratory pest, which occurs 7 to 8 generations a year. Overwintering with larvae or pupa on weeds such as grass, but the wintering insect source is not easy to find. Adults have phototaxis and tend to green, dense and clustered, and eggs are scattered on the leaves. The larvae are divided into five ages, and the food intake is greatly increased after the third age. A larva can damage 5 to 9 leaves in a lifetime. The mature larvae are mostly in the lower part of the rice grove or the leaves are reversed to make sputum. Generally cloudy and rainy, high humidity and too thick green leaves, are conducive to adult eggs and egg hatching and larval damage. The third generation of early rice (from the end of May to the beginning of June) and the sixth generation of late rice (from the end of August to the beginning of September) are the main damages. Early rice is often heavy in late rice.

Rice leaf roller

(3) Main prevention methods

The peak period of egg hatching is suitable for prevention and control. Each acre is sprayed with 60~8o ml spray, 20% anti-sweet WP WP 100~120g with water 45~6o kg spray, and it can also be faster with knockdown speed. For mixed use or rotation.

3. Chilo suppressalis, Sanhua

(a) harmful symptoms

The larvae of the stem borer and the stem borer are mainly harmful to rice. The hatching larvae of the newly hatched larvae cause damage to the ear, and the larvae after the 2nd instar, they will break into the interior of the rice plant to carry out the hazard. The rice tillering stage causes the "dry heart seedling", and the booting stage causes the "dead booting", breaking The heading stage causes "white spikes", which cause insect damage in the mature stage.

(2) Characteristics of occurrence

The larvae overwinter in the rice piles, and the pupa emerges in the spring. The adults have phototaxis. They like to lay eggs on the multi-fertilizer and verdant rice. One egg has dozens to more than 100 eggs. In the tillering stage of rice, from the late booting stage to the heading stage, the ants intrusion rate is high. Mosquitoes hatched by an egg block are invaded by nearby rice plants, causing "bone heart nest" or "white ear group". The winter and spring are dry and warm, which is beneficial to the wintering and phlegm of larvae, which will be heavier in the same year.

The stem borer occurs in China from 1 to 5 generations from north to south. The first and third generations endanger the early and late rice paddy and tillering stages respectively, causing dead seedlings; while the second and fourth generations endanger early and late rice heading stages respectively. , causing white spikes. The stem borer can occur in the distribution area for 2 to 7 generations.

(3) Main prevention methods

(1) Eliminate the source of overwintering insects. After the late rice is harvested, the winter ploughing winter is carried out, and the winter is not left in the plate field. In the spring season, it is generally in the middle of March, and the rice field is properly irrigated before the larvae and cockroaches are immersed.

(2) Chemical control. In the case of a heavier year, it is necessary to recapture the control of the field, including the removal of the egg mass. Pay attention to the prevention of white spikes, and apply them 1 to 2 days before the breakage period or the peak of egg hatching to prevent ants from invading. You can use 20% 螟手手乳油 to spray 60~80ml per acre, spray foot (not less than 45kg per acre).

Rice locust

(a) harmful symptoms

Rice locusts are also known as rice mites and locusts. It mainly harms rice and also harms many grass weeds. The larvae spore the leaves and become scorpion, and they eat away, which causes nicks and eats the leaves. In the case of serious occurrence, the whole field, or even the rice leaves of a paddy field, can be eaten.

Rice aphid

(2) Characteristics of occurrence

There are many varieties of rice borers. In China, the main hazard is the straight-line rice aphids, which occur intermittently in some areas. Southern rice larvae usually overwinter on wind-sheltered fields, gullies, ponds and lake shoals, low-wet grassland and other grass weeds, or winter between late rice cultivars or regenerating rice roots and stalks. . Adults lick out at night, often sucking honey on various flowers during the day, and eggs are scattered on rice leaves. Therefore, it occurs in mountainous rice fields, new rice areas, rice-cotton intercropping areas or lakeside areas, and the damage is heavier. Straight-line rice locusts occur in Guangdong, Hainan, and Guangxi in the first 6 to 8 generations; south of the Yangtze River, north of Nanling, such as Hubei, Jiangxi, Hunan, Sichuan, and Yunnan, 5 to 6 generations; 1 year north of the Yangtze River 4 to 5 generations occur; 3 generations occur in the north of the Yellow River in 1 year; 2 generations occur in Liaoning in 1 year. In the mid-season rice areas of Hunan, Jiangxi, Sichuan, Guizhou, Hubei and other places, the main damage period of rice aphids is from late June to July, especially for mountain rice. Late season rice in the lakeside area is also often exposed to a large area of ​​damage.

(3) Main prevention methods

(1) Artificial killing. In the early stage of larval damage, combs, pats, pinches, etc. can be used to kill insects before removing the mites or rice.

(2) Chemical control. In general, pesticides for controlling aphids and rice leaf roller are also effective against this insect, so they can often be cured. If the amount is large, it needs to be controlled separately. For the 3rd instar larvae, use 18% insecticidal double agent 100~150g spray per acre or 2~2.5kg powder with 2.5% enemy powder; 3rd age After the larvae, you can use 100% to 150g of 9o% trichlorfon, or 100g of 50% eucalyptus emulsifiable concentrate, or 50% phoxim 100g and 50~60 liters of water. It can also be used to prevent and control 50 liters of water sprayed by 200 grams per mu of B. Because rice mites feed or change at night, the application effect is better after 4 pm. After application, it is best to leave a shallow layer of water in the field. Focusing on late rice fields, we will control the age of young larvae and apply them when there are 10-20 heads per 100 bushes of rice. Use 90% crystal trichlorfon 75~100g, or 50% killing pine oil 100~250ml, or Bt emulsion 150~200ml, choose one, water 70~100kg conventional spray, or water 5~7.5 kg low spray.

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