Rice blast disease, also known as rice fever, is commonly known as "burning" and "hanging". One of the three major diseases of rice can cause a significant reduction in production. When serious, it can reduce production by 40% to 50%, and even the grain can't be harvested. Every rice region in the world occurs evenly. The disease occurs in all parts of the country, of which the occurrence of leaf, nodules occurred, after the occurrence can cause varying degrees of reduced production, especially the ear and neck spasm or thrift occurs early and heavier, can cause white ear and even out of production.
First, symptom recognition
The whole growth period can occur. According to the different parts of the disease, diseases such as seedlings, leafhoppers, knots, panicles and grains can be formed.
1. Seedlings occur mainly on the leaves of the seedling stage, forming brown, fusiform or amorphous lesions, sometimes forming a gray green mold layer on the lesions.
2. Leafhoppers usually occur after the tillering period. Due to different species and meteorological conditions, there are four symptoms of leafhoppers, except for brown spots (resulting in resistant varieties) and white spots (production of susceptible varieties on young leaves). There are common acute and chronic lesions in the field.
1 Acute lesions: When the weather is favorable, the lesions are faded green, nearly round, oval, or irregular, and the lesions are densely covered with grey-green mildew.
2 chronic lesions: when the meteorological conditions change greatly, or by the acute lesions, the lesions are mostly spindle-shaped, spindle-shaped, usually brown, gray in the center, and the outermost layer is yellow or pale yellow halo. Ring, a brown necrotic line at each end of the lesion. In the humid climate, the back of the lesion also produces a gray green mold layer. In later stages, multiple spots can be fused into irregularly shaped large spots, causing the entire leaf to die.
3. Frugality occurs mostly in the first to second sections under the flag leaves, and is initially dark brown dots, gradually expanding. The lesions can surround part or all of the joints, causing the joints to become black, and the diseased sections shrink and shrink. The rice plant is broken off and lodging, affecting the sturdiness, grouting, and the formation of white spikes.
4. Panicle blast occurred in the neck, cob, branch stems, the lesion was a dark brown spot at the beginning of the disease, and then expanded up and down to form a dark brown streaky spot. The light affected the firmness, irrigation paddles, and even increased grain size. The formation of white spikes is not strong.
5. Grain pods occur on husks or cultivars, beginning with brown dots and then expanding into brown irregular lesions, sometimes turning the whole grain brown, dark gray, and becoming husks.
Second, pathogen identification
Rice blast disease is caused by the semi-mycotic subphylum, the caterpillar fungus, Pyricularia oryzae Cav. (Pyrus spp.) caused by fungi. There is a gray green mold layer on the lesion, which is the conidial stem and conidia of the pathogen. The conidiophore stem does not branch, but has a septum, the base is light brown, and the lighter the color is. The conidia are colorless, pear-shaped, mostly 2 septa, apical apex, base blunt, with small projections, size 14-60 microns X 6-13 microns. The bacteria have physiological differentiation. There are 7 groups of 43 races in the country, and 7 groups of 15 races in Heilongjiang Province.
Third, the infection cycle
The bacteria used hyphae to overwinter on diseased straw and diseased seeds. In addition to disease seedlings in the conditions of drought and eel seedlings may occur, the main pathogen is overwintering on diseased straw, the next year, temperature and humidity are suitable, pathogenic bacteria on rice straw can produce conidia, spread by air flow to rice, encountered When the temperature and humidity conditions are suitable, it will germinate quickly, directly penetrate the epidermis and invade the leaves, cause initial infestation, make leaf aphids occur, and then cause reinfestation through airflow propagation, making the aphid aggravate, and producing a large number of conidia, by airflow Spreading, which leads to the occurrence of panicles and necks, knots, and grain pods. After harvesting, the pathogenic bacteria overwintered on diseased rice straw and diseased seeds.
Fourth, the incidence conditions
1. There is a significant difference in resistance among different varieties of resistant varieties. The most resistant varieties used in current production are vertical resistant varieties, and their resistance can only maintain a certain period of resistance due to physiological race composition, once the inferior varieties become dominant In races, some species lose their disease resistance and cause disease.
2. The number of pathogenic bacteria was as large as the number of diseased seeds, and soaking and disinfection was not carried out. In particular, diseased rice straw, diseased pods and valleys were not destroyed or incompletely treated, and there were many pathogenic bacteria in the winter and the incidence was heavy.
3. Meteorological conditions such as rainy days at the tillering stage, rainy days and rainy days, and high humidity, low temperature, and low sunshine (less sunshine hours) environment can reduce the disease resistance of rice, which is beneficial to the occurrence of leafhoppers; In rainy weather, there are more rainfall days and more rainfall, resulting in high humidity, low temperature, and low sunshine conditions, which are unfavorable for dry rice growth. However, it is beneficial to the production of spores and spore germination of pathogens, among which, the spores of high-moisture-prone pathogens germinate and invade; Low-temperature and low-illumination conditions often cause heavy weights in the head and neck, knots and grains.
4. If the management of rice fields is too much and too late with nitrogen fertilizers, frequent cold water irrigation and deep water irrigation will reduce the disease resistance of rice and can aggravate the disease.
In short, the occurrence and epidemic of rice blast are the combined effects of the above four factors.
V. Prevention methods
Take the premise of destroying the overwintering bacteria source, select the disease-resistant and high-yield varieties as the center, based on agricultural cultivation techniques, and use chemical control as an auxiliary comprehensive prevention and control strategy. Rice blast disease is a multi-circle disease mainly based on airflow propagation. Prevention and control should focus on the selection of disease-resistant varieties and chemical control.
1. Choose high-quality, high-yield, disease-resistant or disease-resistant varieties: pay attention to changes in physiological races, to prevent the loss of disease resistance of the varieties, it is best not a single species, you can use 2 to 3 disease-resistant varieties with planting. At present, disease-resistant varieties in Heilongjiang Province include mainly Yukyu 131, Hejiao 16, Hejiao 19, Dongnong 416 and Dongnong 415.
2. Seed processing
1 Seed coating has better control effect on rice blast disease at seedling stage.
2 Seeds soaked with 1% lime water before sowing, early rice soaking at 10-15°C for 6 days, late rice immersed for 1 ～ 2 days at 20-25°C, lime water layer about 15 cm higher than seeds, and standing still After soaking, wash with water 3 to 4 times.
3 Soak 20% formalin for 20-30 minutes and remove the stuffy species with a thin film for 3 hours.
445% carbendazim WP, 700% thiophanate-methyl (also known as thiophanate-methyl) wettable powder, 50% rice bran NET EC, and 40% IGRP. Early rice is soaked with 1 000-fold liquid for 48-72 hours, and late rice is soaked with 500-fold liquid for 24 hours. Early rice was soaked in formalin 300 times for 48-72 hours, late rice was soaked in 200-fold liquid for 24 hours, developed into a wettable mixed powder with Sanhuan and paclobutrazol, and early rice was soaked with 0.3% liquid for 48 hours.
3. Reducing bacterial sources: timely treatment of diseased rice straw can cause diseased straw to be concentrated and burned. It is not possible to use diseased rice straw huts, cover sheds, pad pool stalks, or water inlets. The diseased seeds should be disinfected to reduce the bacteria source.
4. Strengthen field fertilizer and water management and improve disease resistance of rice: Under the premise of cultivating strong and strong broodstock, early tilling and multiple basal fertilization should be done, and early fertilization should be done. Do not apply too much nitrogen fertilizer too late or scientifically apply nitrogen. , phosphorus, potash fertilizer. In the premise of leveling the land, we should implement reasonable shallow irrigation, and carry out drainage and drying of fields at the end of the tillering stage, and superficial irrigation should be done at the booting stage to the heading stage to meet the requirements of paddy rice water requirements. Sun-water pools should be installed in areas with conditions to increase the irrigation temperature. It helps rice growth and disease resistance.
5. Field investigation and chemical control: In order to accurately and promptly use drugs, the disease should first be investigated, usually before the rice tillering period, and after the rainfall, it should be carried out at the high fertilizer fields, water inlets, and manure piles (deeply growing areas) of the susceptible varieties. Investigations were conducted to observe the presence or absence of acute lesions. If there are acute lesions, they should be immediately administered with chemical control. About 10 days after application, the condition is still developing and can be applied once more. Such as leaf lice in the booting period began to occur, the condition is not heavy, combined with the prevention of pancreatic fistula for prevention and treatment. General panicle blast prevention is carried out from the end of the panicle to the beginning of the earing period. No matter whether the occurrence or weight of the pansy occurs, the chemical should be controlled once. In order to control the development of the panicle blast, it is better to conduct another chemical control at the heading stage.
The available agents are:
140% Fuji No. 1 (Potassium) wettable powder, or 30% rice blast spirit, 900 to 1125 grams per hectare, add water spray;
220% tricyclazole wettable powder, 1125-1500 g/ha, or 75% beryllium (tricyclazole) wettable powder, 300-450 g/ha, add water spray:
325% SPK (Cicamba) EC, 1125 to 1500 ml/ha, add water spray;
42% aqueous solution of kasugamycin, 1125 to 1500 ml/ha, add water spray;
50.4% oligo-oligosaccharide water, 3000 ml/ha, add water spray.
In order to ensure efficiency, the following matters should be noted:
1 The amount of water should be enough for even spraying. In particular, aircraft spraying, the amount of water should be increased, the amount of liquid spray per hectare can not be less than 75 liters.
2 Grab (è¶) clear spray, because the northeastern region to control leafhoppers, panicles and necks coincide with the rainy season, rainy days, affect the normal spraying, in order to prevent and control timely, should seize the opportunity to seize the sunny day (4 hours No rain) Spray.
3 According to many years observation of frugal occurrence is also heavier. In the control of leafhoppers and panicle blasts, all nodes of the rice plant should also be sprayed with the drug. Regardless of whether it is leafhopper, panicle-necked or thrifty, it should be done as early as possible and timely, and should be sprayed evenly and thoughtfully before it can play a preventive and curative role.
Electronic Cigarette of Various of products, including Mechanical Mod Kit series and Mechanical Mod Tube series, provide product pictures and basic parameters, we are committed to supply chain management, we are a professional Chinese manufacturer of Mechanical Mods Kit and we are looking forward to your cooperation.
Electronic Cigarettes Vape,Hybrid Original Vape,Box Kit Vape,Good Starter Vape
Dongguan Marvec Electronic Technology Co.,Ltd , http://www.marvec-cn.com