During the whole growth period of rice, the common diseases are rice blast, bacterial leaf streak, bacterial leaf blight, sheath blight and false smut. (1) Rice blast can occur from seedling stage to heading stage. According to the symptoms of the disease in different growth stages and different parts, it can be divided into five types: seedling rice blast, leaf rice blast, rescue rice blast, ear rice blast and grain rice blast. A few yellow leaves 1. Yellow leaves with bacterial blight. Spread from bottom to top, the diseased leaves turn yellow to dry white. After injury, dark green spots first appeared at the tip or edge of the leaves, and then turned into yellow strip lesions. The boundary between the diseased part and the healthy part is obvious, just like a ripple. There is micrococcus glue on the leaves in the later stage. Cut off the leaves, clamp them with two pieces of glass, drop water on them, and smoke-like bacteria will spray out. 2. Yellow leaf yellow dwarf disease. It starts from the top leaf and its lower 1 ~ 2 leaves, spreads upward and downward, and then gradually develops into yellow leaves or mottled leaves. Plants have short internodes, drooping leaves, many black roots and few new roots, and often wither and die. 3. Physiological premature aging yellow leaves. Spread from bottom to top, the diseased leaves are mostly orange-yellow, with metallic luster, in pieces or all over the field. There are no spots and pus on the yellow leaves. 4. Chemical fertilizer harms yellow leaves. Improper application of ammonium bicarbonate, ammonia water and pesticides. It can cause poisoning, causing patches of rice leaves to be smoked into bright yellow or golden yellow, and sometimes there are brown spots on the yellow leaves. Second, several leaf spot diseases 1. Rice blast leaf spot At the onset of rice leaves, the lesion was acute, dark brown at first, then oval, with gray-white mildew on the back of leaves, and chronic, the lesion was spindle-shaped, reddish brown on the side, gray-white in the center, and there were 1 brown lines running through the lesion. When wet, gray-green mold can be seen on the back of the lesion. 2. Flax leaf spot disease, which looks like a small spot as big as a needle at first, gradually forms an oval spot and looks like sesame. Rough spots are dark brown and darker than rice blast spots. Look carefully, the color is divided into three layers: yellow halo on the periphery, wide edge layer, dark brown, and mostly grayish yellow in the center. Characteristics: When the dark brown part of the lesion looks at the light, there are often thin wheel lines looming, and there are no necrosis lines at both ends of the lesion. 3. Brown stripe leaf spot. The disease started on the midvein at the base of the leaf, and then extended up and down like a brown stripe. The diseased part falls off and emits milky juice, which seriously damages the diseased plant and leads to the lower part rot. There is a rancid smell. The diseased leaves wither, and the heart leaves die in the kernel and become withered seedlings. Three kinds of bacterial wilt 1. Micrococcus nucleatum Fields often appear in groups, and there are several plants in a hole. The basal tissue of rice plants is soft rot with dark brown spots. The most recognizable feature: the basal leaf sheath and stem are stripped off, and there are many black sclerotia smaller than amaranth seeds. 2. Rotten green orange based on bacteria. Occurred sporadically in the field, 1 ~ 3 strains became ill at 1 point, and the diseased plants were gray rot at the base. Features: Peel off the stem at the base, fill it with smelly water, and there are sterile seeds. 3. Physiological bacterial wilt. The stem of rice plant is shriveled, and the base of rice stem is shriveled by hand, which is easy to lodging, like the sclerotia of brown planthopper. However, there is no diseased spot at the base of the stem, and the sterile nucleus in the leaf sheath and stem mostly occurs near the mature stage of late rice, which is green and withered in pieces. Four, several kinds of give up 1. The moth is dead. Wormholes or dung can be seen at the lower part of the rice plant, which is easy to be pumped up if you give up. Crabs will kill you. There are no wormholes or feces in rice stems. Dead plants are easily pulled up, and the stems and roots are torn apart. 3. Stripe leaf blight. The heart leaves of the diseased plant have yellow stripes, curled into paper twists, and bent and drooped into a "fake dead heart". There is no wormhole in the base, it does not rot, and it is not easy to pull up after giving up. Five, a few white nails 1. White spike of Chilo suppressalis. There are wormholes and dung on the upper part of the rice stem, the white ear is easy to pull up, the ear neck is not damaged, and the white ear group in the field is obvious. 2. Rice ear blast and white ear. There is no wormhole on the rice stem, the white ear is not easy to pull up, and there are dark brown spots on the ear neck, ear axis and branches. Ear neck or branches are easy to break, and there is gray-green velvet mold on the affected part when wet. 3. orange stripe disease with white ears. Dark green spots began to appear on the tip, leaf or ear neck and stem, and then expanded into oval square lesions with brown edges and light brown to grayish white in the middle. The basal tissue is soft and white ears fall to the ground. Prevention and control of several common rice diseases prevention and control of rice planthopper

Rice planthoppers in our city are mainly white-backed planthoppers and brown planthoppers. Their insects originated in southern rice areas and migrated with the southwest and southeast airflow after the middle and late April every year. Rice planthoppers have the characteristics of concealment and outbreak, and most of them live on the leaf sheaths at the lower part of rice clusters to lay eggs. The symptoms of the upper part are not obvious, and it is generally not easy to attract people's attention. After the increase of insect population, the rice leaves in the whole field can be scorched like fire in a short time, and some rotten stems fall off. The masses call it ". The control of rice planthopper is usually carried out from mid-June to early July and from mid-July to early and middle August, when there are 1500-2000 insects per 1000 panicle of rice. Each acre can be sprayed with 50% Bao Dao A 1 bag (which can cure the second-generation borer and sheath blight), 40% Bao Dao B 1 bag (which can cure the second-generation borer V), 50 g of 25% chlorpyrifos wettable powder or 20 g of 10% imidacloprid water. Control of Rice Ear Blight During rice ear breaking and heading, 20% tricyclazole 1 00g or 40% isoprothiolane (Fuji1No.) EC100ml or Kewen powder100ml was sprayed with 50-60kg of water at 4pm.

Prevention and control of rice false smut: The main period of rice false smut is from booting stage to full heading stage. General control measures: ① Select disease-resistant varieties. ② Applying less nitrogen fertilizer and more phosphorus and potassium fertilizer from jointing stage to full heading stage can reduce the incidence of rice diseases. (3) Chemical control mainly applies 1 time from the middle booting stage to the full heading stage, and chemicals such as 25% triphenyltin acetate wettable powder, 5% cuprammonium complexing agent, 77% Hufengan (copper hydroxide) wettable powder and 5% Jinggangmycin wettable powder can be used. Prevention and control of rice blast Prevention and control of rice blast: Rice blast mainly includes seedling blast, leaf blast, node blast, ear neck blast and grain blast. It can happen in the whole growth period and can be hurt in all parts. Control measures: ① Select disease-resistant varieties. (2) Deal with sick grain and straw in time to reduce the source of germs. (3) Apply sufficient base fertilizer, topdressing by stages according to seedling conditions, avoid excessive and late application of nitrogen fertilizer, and appropriately increase the application of phosphorus and potassium fertilizer. Irrigation should master shallow water irrigation, dry, wet and dry. In the late tillering stage, the field should be put aside properly to promote the health of rice plants and enhance the disease resistance. ④ The key to chemical control is to seize the opportunity. In general, the diseases in Liaoning rice-growing areas are serious from mid-July to mid-August, and the rice should be controlled at rice breaking stage, full heading stage and filling stage 1 time. Spraying 40-50kg water per mu with Plague Sweep 100 ~ 120ml, or spraying 40-50g Xianbami15-20kg water, or spraying 60-75kg water with 75% tricyclazole wettable powder 20-30g; 50 ~ 70 ml of 40% Fuji 1 No.,and 50 ~ 60 kg of water is sprayed on the leaves.

Prevention and treatment of bakanae disease: the disease can occur from seedling stage to heading stage, especially at tillering stage. The diseased seedlings are taller and thinner than the healthy seedlings, the leaves and leaf sheaths are narrow and long, yellow-green, the root system is underdeveloped, the root hairs are reduced, and the bacteria die one after another before or after transplanting. After Honda was planted, diseased plants appeared 1 month, and the symptoms were similar to those in seedling stage, with little or no tillering, obvious elongation of internodes, and many adventitious roots were born in internodes, especially in basal internodes. The disease is mainly carried by bacteria, and the field occurrence period at seedling stage is 1 ~ 3 leaf stage; The onset time of Honda is 10 ~ 30 days after transplantation. Control measures: ① Select disease-resistant varieties and disease-free seeds. (2) The sowing and germination time should not be too long; When transplanting seedlings, the root system should be damaged as little as possible, avoiding high temperature and transplanting at noon, and reducing the incidence. (3) eliminate the source of bacteria, remove the diseased plants in time, and focus on incineration. Sick straw should not be piled up in the open air, but should be burned. (4) Chemical control, and chemical treatment of seeds. Newer seed soaking agents include 85% strong chlorine, 2.5% or 65,438+00% propafenone, 25% or 45% Spock, 45% mancozeb and 65,438+00% seed soaking agent.