What are the common rice diseases and insect pests and their control measures?

(1) Rice blast. (1) seedling blight. Fusarium wilt of seedlings occurred before the three-leaf stage and was caused by bacteria carried by seeds. The seedling base is gray-black, the upper part is yellow-brown, curly and dead. After the third leaf stage, obvious disease spots are formed on the leaves, which have the same symptoms as leaf blast, and are called seedling leaf blast. The control methods are as follows: a. Seed disinfection. 1% lime water soaking and strong chlorine essence disinfection. B. chemical control. 40% Fuji 1 80g/ mu can be used to control 1 time or 25% KLOC-0/00g can be used to control 60g/ mu. ② Leaf blast. Leaf blast can occur in the whole growth period, and it is more harmful from tillering to jointing stage. The lesion was spindle-shaped, the outermost layer was yellow, the inner ring was brown and the center was gray. There are brown necrosis lines at both ends of the lesion extending outward in a long strip shape, and a gray-green mold layer is produced on the back of the lesion. It occurs after the three-leaf stage to the ear stage. The prevention and control methods are as follows: once the disease center of leaf blast appears, spray 4% kasugamycin 40g/ mu or 40% isoprothiolane 80g/ mu 1 ~ 2 times in time. ③ Ear neck plague. It occurs in the ear and neck, and the affected area is brown or dark green. Ear and neck plague occurs early and often forms "all white ears"; If you are late, you will not have enough food. The diseased ear often falls off from the neck, forming a hanging neck. The control method is: apply 1 time at the ear breaking stage and full heading stage, and use 40g of 75% tricyclazole or 80g of 40% isoprothiolane per mu.

(2) Rice sheath blight. Rice sheath blight, also known as rice moire disease and rice cloud spot disease, is one of the main diseases. Generally, early rice is heavier than late rice, which often leads to insufficient seeds and an increase in empty shell rate, and even leads to lodging and death of plants. The prevention and control methods are as follows: ① Rescuing sclerotia and reducing bacterial source. Sclerotinia sclerotiorum in the field is the main source of infection in the following year. Generally, when the whole field is irrigated, the wave slag floating on the downwind water surface should be removed with a dustpan. ② Taking fertilizer and water management as the center, do a good job in cultivation and disease prevention. Pay attention to the stable application of nitrogen and phosphorus fertilizer, increase the application of potassium and zinc fertilizer, and apply sufficient base fertilizer and ear-protecting fertilizer as the principle. It is not suitable to apply nitrogen fertilizer to raise seedlings in the middle growth stage of rice. Irrigation should implement the principle of "shallow before, dry in the middle and wet after". ③ Prevention is the main way of chemical control. At the initial stage of the disease, spring rain 1 +5% Jinggangmycin aqueous solution150ml or 30% Jiebiao 24g/mu was sprayed. When spraying, it is necessary to ensure the water consumption and spray it to the middle and base of rice plants; At the initial stage of rice sheath blight, 50 ~ 70g of iodophor wettable powder and 60kg of water were evenly sprayed on the base of rice stem per mu. This medicine has a special effect on rice sheath blight.

(3) false smut. The false smut of rice is a fungal disease in the late stage of rice, also known as false smut of rice and bluish pink disease, commonly known as "high-yielding fruit". This disease only occurs in the ear and harms some grains. At the onset, the pathogen infects the rice glume and forms a nearly spherical "rice koji" with a diameter of about 65438±0cm. False smut of rice will also produce toxins, which will directly endanger human health. The control methods are as follows: ① Agricultural control. Choose disease-resistant and early-maturing varieties, strengthen cultivation management, timely apply fertilizer, and avoid partial and late application of nitrogen fertilizer. ② Seed disinfection. Soak seeds with 500 times solution of 50% carbendazim wettable powder 12 hours. ③ Chemical control. When using chemical agents for prevention and control, it is necessary to grasp the prevention and control period and choose pesticides. The suitable period for controlling false smut of rice is about 6 days before stubble breaking in late rice, and the available pesticides are 400 ml of 5% Jinggangmycin or 50% carbendazim wettable powder 100 g and 60 kg of water per mu. 20% Wen Qu Science and Technology 120g is very effective for water spraying. The liquid medicine is mainly sprayed on the upper part of plants. You can also use 30%DT bactericide 100 ~ 150g, and spray 1 time at the late booting stage and the early breaking stage of rice, with good effect.

(4) Rice planthopper. Rice planthoppers, commonly known as tapeworms, are mainly white-backed planthoppers and brown planthoppers. In general, the white-backed planthopper is dominant in the early stage of rice, and the brown planthopper is dominant in the later stage. White-backed planthopper mainly harms tillering stage to jointing stage. Nilaparvata lugens mainly harms booting to maturity. Control methods: ① Breeding and popularizing insect-resistant and high-yield varieties, such as hybrid rice Y Liangyou 302. ② Comprehensive control measures should be taken to control rice planthopper. First of all, it is necessary to strengthen cultivation management, not to apply nitrogen fertilizer unilaterally, to prevent green plants from growing in the later stage, to do a good job in the open field, to reduce the canopy and humidity in the field, and to control the fertility and reproduction speed of rice planthoppers, so as to lay a foundation for improving the control effect in the later stage. (3) Chemical control: 300 ml of 80% dichlorvos is used in paddy fields, mixed with dry and wet fine sand (soil) 15 ~ 20 kg, and sprayed on sunny days12: 00 ~14: 00; From the peak period of nymph hatching to the peak period of 2 ~ 3 instar nymph occurrence, the average population density per cluster reached 10 ~ 15, and 60 grams of 25% buprofezin or thunderbolt 100 ml was sprayed per mu. Pay attention to the use of pesticides. No rain for 4 hours after application can ensure good control effect.

(5) worms. Rice stem borers are mainly Chilo suppressalis and Chilo suppressalis. The control of stem borers should be based on agricultural control, supplemented by chemical control. The prevention and control methods are as follows: ① Scientific fertilizer and water management. Pay attention to the rational application of nitrogen, phosphorus and potassium, increase the application of organic fertilizer, implement shallow water irrigation and timely dry land to ensure the healthy growth of rice. ② Eliminate the source of overwintering insects. Through ploughing or shallow rotary tillage, the residue of rice piles can be reduced, the straws can be cleaned, the water bamboo and weeds on the edge of fields and ditches can be eradicated, the source of insects can be reduced, the overwintering place of stem borers can be destroyed, and the overwintering survival rate of stem borers can be reduced. ③ Drowning kills pupae. Because the newly hatched Chilo suppressalis harms the leaf sheath of rice, if the late-maturing winter fields and grass seeds are left in Taneda and flooded for 3.5 ~ 6.5 cm during pupation, most of the pupae can be drowned. Or drain the field water at the mature stage of the first and second generation larvae, let the larvae drill into the rhizosphere to pupate, and immerse them in deep water for 3 days at the pupation stage, which can drown most of the pupae, and the insecticidal effect can reach more than 90%. ④ Chemical control. It is best to use it in larval stage, and spray it with 200g/mu of 40% dimehypo or 1.8% avermectin150ml/mu of water. You can also use 5% Regent Suspension Concentrate 30 ~ 40ml per mu and spray 40 ~ 50l of water, and the drug effect can last for 20 ~ 30 days.

(6) Rice leaf roller. Rice leaf roller is also called leaf roller. On the basis of agricultural control, chemical control and physical control should be adopted in due course. The control methods are as follows: ① Select insect-resistant varieties. ② Increase the application amount of potassium fertilizer to improve the hardness of rice straw. ③ Physical prevention and control measures. Use insecticidal lamps to trap moths and reduce the number of insect sources. ④ Chemical control. It is best to use it in the larval stage of 1 ~ 2, and spray 3.0% avermectin 100ml/ mu or 40% dimehypo 150g/ mu with water. The application time is better in the evening and morning when the dew is still wet, and the application effect is better in the evening, and it is good in cloudy days and rainy days in Mao Mao.

Systematic spraying of Tongtianbao can induce rice disease resistance, reduce the susceptibility rate of rice blast, sheath blight and false smut, and reduce the harm of rice planthopper, stem borer and rice leaf roller.