Pictures of common brown rot symptoms of yam and prevention methods
The symptoms of yam brown rot and the prevention and treatment methods, yam brown rot is mainly harmful to root-like tubers, causing tuber rot. The symptoms were not obvious early, and they were found to be ill at harvest. When the tubers are infected, they appear as rot-like irregular brown spots, which are slightly sunken. The diseased blocks are often deformed, slightly rotted, and the diseased part becomes soft. After the incision, the diseased part is discolored, and the affected part is larger and deeper than the external lesion. When the diseased part is completely rotted. (2) Prevention and treatment methods: 1 When the harvest is completely removed, the disease is completely destroyed, and the soil is dried and the film is sealed to carry out high-temperature disinfection of the soil, or rotation is carried out to reduce the occurrence of diseases. 2 Use disease-free planting to make seeds, and if necessary, cut the noodles into dried noodles for 20~25d. 3 chemical control: spraying 70% thiophanate-methyl WP 1000 times solution and 75% chlorothalonil WP 1000 times solution, or 50% thiophanate-sulphur suspension 800 times solution at the beginning of the disease. 10d spray once, continuous prevention 2~3 times. (a) erythema 1. Symptoms Yam erythema is a disease caused by nematodes, which mainly damages the roots of yam. The diseased tubers are small and light. The onset of yam erythema is the formation of reddish brown near-circular to irregularly concave lesions on the tuber. The diameter of a single lesion is 2~4mm. When the disease is heavy, the lesions are densely fused and merged to form a large dark brown plaque. The surface has fine mottled lesions, which are 2~3mm deep and the deepest is more than 1cm. It is brown and dry. 2. Transmission route and disease conditions The yam nematode can survive in the soil for more than 3 years. The stalk disease and diseased soil are the main ways to infect erythema. The life cycle of the yam nematode is extremely irregular. It is only two generations a year, only infecting yam. When new tubers begin to form in June, the nematodes can infect, and then the infection continues to increase until the harvest, and the nematodes grow from the base to the long. It can be infested at 40cm, with more lesions above 20cm. 3. Prevention methods (1) Rotation with crops that are not easily infested, such as wheat, corn, sweet potato, potato, cotton, tobacco, pepper, carrot, watermelon, etc., for more than three years. (2) Using the 0.1%~0.3% TMK dipping disease for 24h, the disease prevention effect is over 95%; in the case of heavy planting, 2kg of TMK granules per 667m2 ditch before sowing, the control effect is more than 75%. (3) Select breeding plants without diseased fields, and cooperate with rotation and application of harmless fertilizers. (2) Anthrax 1. The symptoms are mainly harmful to the leaves, but also to the stems. On the leaf veins of the leaves, the small spots of the primary brown depressions turned black-brown. After the enlargement, the lesions were brown in the center, and the black spots on the spots were scattered (conidial discs). The stem vines are mostly in the vicinity of the ground, and the lesions are dark brown and slightly sag. When the damage is serious, the leaves fall early and the stems die, causing the plants to die. A diseased spot on a leaf or stem that often produces a reddish viscous substance (conidial mass) when the air is wet. 2. Routes of transmission and pathogenesis Anthracnose is a disease caused by the infection of the genus Aspergillus spp. The pathogen mainly overwinters the mycelium in the diseased tissue, and the conidia spreads through the wind and rain, and the disease occurs in the hot and rainy season. 3. Prevention methods (1) Agricultural control: The diseased plots are rotated for more than 2 years; after harvest, the diseased bodies left in the field will be burnt down, and the soil will be deepened to reduce the source of overwintering bacteria; high scaffold management will be used to improve the field microclimate; Management, timely cultivating and weeding, loose soil drainage; reasonable close planting, improving ventilation and light transmission, reducing field humidity; rational fertilization, mainly based on decomposed organic fertilizer, appropriate application of phosphorus and potassium fertilizer, less application of nitrogen fertilizer, cultivation of strong seedlings, enhancement of plants Disease resistance, excessive nitrogen fertilizer will cause the plant to be tender and susceptible to disease. (2) Disinfection of the plant: Before sowing, soak the seeds with 50% carbendazim WP 500-600 times or pick up the lime from the yam plant. (3) Chemical control: After emergence, spray 1:1:50 Bordeaux mixture for prevention, spray 2~3 times every 10d. After the onset, use 58% of the metalaxyl-manganese-zinc wettable agent 500 times solution, 25% of the Rydore WP 800-1000 times solution, 80% of the anthrax esthetic WP 800 times, with 70% Ketobuzu WP 1500 times solution, 50% phlegm 1000~1500 times solution, 77% can kill 500~600 times solution, or use citrus fungicide (with prevention, treatment and eradication effect) 7d once, Even spray 2~3 times, and spray it in time after spraying. (3) Brown spot disease (also known as gray spot disease or brown leaf spot disease) 1. The symptoms are mainly harmful to the leaves. Leaf spots appear on both sides of the leaf, from round to irregular, depending on the host, generally 2~21mm, the center of the leaf spot is grayish white to brown, often 1~2 dark brown thin line rings, some It has a yellow to dark brown water-immersed halo around it. When the temperature is high, there is a gray black mold layer on the lesion. The back of the leaves is light and harmful. 2. Transmission route and disease conditions The pathogen of yam brown spot disease is the fungus of the genus Dioscorea zingiberensis. The mycelium and conidia are overwintered on the diseased body in the mycelium and conidia. In spring, when the temperature and humidity are suitable, the conidia are spread by the airflow for initial infection, and the diseased part produces conidia again. Dyeing and infusing are mainly transmitted by wind and rain. The onset condition is warm and humid, especially during the growth period, frequent storms or yam racks, poor ventilation and light transmission conditions, high air humidity, and easy onset. 3. Prevention and treatment methods (1) Clean the garden in time after the autumn harvest, and concentrate the diseased body deeply or burn it. (2) Spray 75% chlorothalonil WP 600 times solution or 50% carbendazim WP 600 times solution or 50% thiophanate-sulphur suspension 800 times solution when the rainy season arrives. (4) Leaf spot disease 1. There are four kinds of coal leaf spot (red spot disease), brown spot leukoplakia (spot disease), gray brown spot disease and brown round spot disease, among which there are many coal spot diseases. Coal spot disease is a erythema erythema on the leaf surface, which expands into a nearly round or irregular shape with no obvious boundary. It is about 1~2cm in size and sometimes aggregates into large spots. The lesions of brown leukoplakia penetrate the surface of the leaves, the spots are small, round or irregular, the periphery is russet, slightly convex, brown in the middle, and then turned to taupe to grayish white. The lesions of gray brown spot and brown round spot have obvious concentric rings. On the back of the lesions of the above four leaf spot diseases, there are gray-black molds, among which there are many mildews caused by coal leaf spot, and other leaf spot diseases produce less mildew. 2. Transmission route and disease conditions The four leaf spot diseases of yam are caused by fungal infection of the genus Cercospora. The pathogen is overwintered in the field by attaching a mycelial mass (mold layer) to the diseased body of the cowpea plant. In the second year, the spring conditions are suitable to produce conidia, and the initial infection with airflow and rainwater transmission causes disease. In the future, it can be infested many times in the field, causing constant disease. When the temperature is between 25 and 30 ° C and the relative humidity is above 85%, it is easy to cause disease. Poor ventilation, high temperature and high humidity in the protected area, high temperature and rain in summer under open conditions are important conditions for the onset of disease. 3. Prevention methods (1) Agricultural control: rational close planting, appropriate increase of row spacing, improve ventilation and light transmission conditions in the field; cultivation of cultivated land should be carried out by sorghum planting, mulching, timely ventilation and cooling, to prevent excessive humidity in the field; Fertilizer, increase the application of phosphorus and potassium fertilizer, improve the disease resistance of the plant; keep the field clean, remove the diseased leaves in the early stage of the disease, thoroughly remove the diseased body when pulling, concentrate burning, and reduce the pathogen. (2) Chemical control: highlight the word "early". At the beginning of the disease, it can be used 1:1:200 Bordeaux mixture, or 50% carbendazim WP 500 times solution, or 50% methyl thiophanate WP 500. Double solution, or 75% chlorothalonil WP 600 times solution, or 58% of metalaxyl-Jumbo WP 600 times alternately spray, spray once every 5~6d, even spray 3 times. (5) Fusarium wilt (commonly known as Dead Rattan) 1. Symptoms The disease mainly affects the base of the stem and the underground tubers. In the early stage of the disease, there are rib-shaped wet-stained brown lesions at the base of the stems. Afterwards, the lesions continue to expand, causing the entire epidermis of the base to rot. When the surface of the epidermis rots rapidly to the circumference of the stem, it will cause the ground. The leaves of the part gradually yellowed and fell off, and the stems quickly died. If the base of the stem is cut, it can be seen that the susceptible part turns brown. If the tuber is susceptible, rounded to irregular dark brown lesions appear around the lenticels, and the roots and internal tissues become brown and dry rot. The entire tuber is severely susceptible to browning. Wilt disease can continue to expand during storage and cause harm. 2. Transmission route and disease conditions The yam wilt is caused by the fungus Fungus Fusarium oxysporum. The mycelium of the yam wilt and the original stalk spore can survive in the soil for many years. When the conditions are appropriate, the newly germinated sprouts and yam plants can be directly infested. Yam mouth and seed blocks can also continue to infect with bacteria. If the diseased seed or germinating shoots are infected by pathogens, it is difficult to completely control. The suitable temperature for the development of yam wilt pathogen is 13~35 °C, which is most suitable for 29~32 °C. When the humidity is high, it is easy to develop, so it is easy to develop in the high humidity and high temperature season. Continuous cropping, low-lying land, water accumulation in the field, poor drainage and soil viscosity are beneficial to the disease, which is a common disease in the hot season. In addition, excessive application of nitrogen fertilizer, soil acidity is easy to occur, if the disease is found, it should be replaced immediately. 3. Prevention methods (1) Select the disease-free yam plant for seeding: If necessary, soak the yam mouth 10~20mm with 70% mancozeb WP 1000 times before planting. (2) Apply 1:50 lime slurry to prevent rot at the incision of the yam mouth before entering the sputum. (3) Apply compost prepared by enzyme bacteria. (4) Chemical control: In mid-June, the base of the stem was sprayed with 70% senseng zinc WP 600 times or 50% sterilized king water-soluble powder 1000 times, sprayed once every 10 days, a total of 5~6 Times. (6) Rhizome rot 1. Symptoms The beginning of the yam rhizome rot is the formation of brown irregular spots at the base of the vine, and then the spots expand to form a dark brown long-shaped lesion, the central part of the lesion is sunken, and the base of the vine shrinks when severe, causing the stem to die. The surface of the lesion often has an indistinct pale brown filamentous mold. Tuber disease often forms brown irregular shaped lesions near the apical bud. If the root system is ill, it can cause root death. 2. Routes of transmission and pathogenesis The pathogen of yam root rot is the wintering of mycelium or sclerotium in the soil or on the diseased body. It can survive in the soil for 2 to 3 years, through soil, rainwater and application of pathogens. Fertilizer spread. It is easy to develop under high temperature and high humidity conditions, and it is mild when it is dry, and it is seriously affected when it is heavily soiled and accumulated in the field. 3. Prevention methods (1) Completely collect the sickness and burn it early at the time of harvest. (2) Implement rotation and avoid continuous cropping. (3) Chemical control: In the early stage of the disease, 75% chlorothalonil WP 600 times liquid, 53.8% can kill 2000 dry suspension 1000 times liquid or 50% Fumei double powder 500~600 times liquid spray control. Spray once every 7~20d, and continuously control 2~3 times. (7) Brown rot (corruption disease) 1. The symptoms are mainly caused by rooted tubers, causing tuber to rot. The symptoms were not obvious early, and they were found to be ill at harvest. When the tubers are infected, they appear as rot-like irregular brown spots, which are slightly sunken. The diseased blocks are often deformed, slightly rotted, and the diseased part becomes soft. After the incision, the diseased part is discolored, and the affected part is larger and deeper than the external lesion. When the diseased part is completely rotted. 2. Transmission route and disease conditions The yam brown rot is caused by the fungus Fungus Fungus. The bacteria are overwintered on soil, sick bodies and plants by mycelium, chlamydospores or conidia, and can be spread by rain, running water, agricultural tools and field operations. Long-distance transmission is mainly a diseased plant. The pathogen can survive for a long time in the soil and is difficult to eradicate once it is infected. The growth and development temperature of the pathogen is 13~35°C, and the optimum temperature is 29~32°C. High temperature and high humidity are beneficial to the disease. It is conducive to the disease when continuous field, low field, water accumulation in the field, poor drainage and soil viscosity. 3. Prevention methods (1) Thoroughly remove the diseased materials during harvest, concentrate on burning, and deepen the soil and film seal to carry out high-temperature disinfection of the soil, or carry out rotation, which can reduce the occurrence of diseases. (2) Use disease-free planting to make seeds, and if necessary, cut the surface of the plant for 20~25d. (3) Chemical control: spray 70% methyl thiophanate WP 1000 times solution and 75% chlorothalonil WP 1000 times solution at the beginning of the disease, or 50% thiophanate-sulfur suspension 800 times solution Spray once every 10 days, and continuously control 2~3 times. (8) Black spot disease 1. In the early stage of the symptoms, the stems, shoots, roots and underground stems are damaged. In severe cases, the seedlings are broken. In the later stage, it mainly damages tubers, forming irregular dark brown lesions on the tubers, reaching the xylem and reducing the commercial value of the tubers. 2. The route of transmission and the condition of the disease are caused by a nematode infestation. Nematodes overwinter in plants, diseased bodies and soils. Diseased plants and diseased seedlings are the main mediators of transmission. The nematodes invade from the attachment points of the seedlings, and move along the subcutaneous layer and the marrow to parasitize life. Into the tuber formation stage, the nematode enters the top of the tuber from the vine and develops in the depth of the tuber. The nematode invades the parasite from the natural orifice and root of the tuber, and forms dark brown plaque on the tuber. 3. Control methods: disease-resistant varieties and disease-free plants were selected to establish distant disease breeding fields; rotation with grass crops for more than 3 years; timely removal of diseased plants in the field; before planting, the plants were dried in the sun and used 1: 1:150 Bordeaux liquid soaking seeds for 10min disinfection; combined with soil preparation or excavation backfilling, soil disinfection with 50g of 50% phoxim emulsifiable concentrate per 667m2 at 20~30cm from the surface. (9) Spot blight 1. Symptoms The yam spot blight is mainly harmful to the leaves. The lighter leaves the leaves dry, and the severe ones can cause the whole plant to die. The earlier the onset, the heavier the yield. In the early stage of yam spot blight, brown spots appear on the leaf surface, and then the lesions enlarge, showing polygonal or irregular lesions, ranging in size from 6 to 10 mm. The center is brown, the edges are dark brown, and the black dots are on the top. This is the conidia of the bacteria. The condition continues to develop, and in severe cases, the whole leaves are dry, which in turn can kill the whole plant. 2. Transmission route and disease conditions The yam spot blight is caused by the fungus fungus, the genus Dioscorea. The pathogens are overwintered on the diseased leaves by conidia. In the spring of the next year, when the temperature conditions are suitable, the conidia release conidia, and the first infestation and multiple reinfections are carried out by means of wind and rain. The disease can occur at the seedling stage, and the suitable temperature for mycelial growth and conidia formation is about 25 °C. Under suitable temperature and humidity conditions, the pathogen can invade the leaf tissue of the yam within 48 hours. Therefore, warm and humid and cloudy, heavy fog is conducive to the occurrence of spot blotch. However, if the air is dry, it will inhibit mycelial growth and sporulation. Therefore, the incidence of high temperature and dry weather is relatively mild. When the temperature is above 15 °C, the disease is also prone to epidemic when it is rainy, soil is deficient, and plant growth is weak. 3. Prevention and treatment method After the onset, use 58% metalaxyl-manganese-zinc wettable powder 500 times liquid or 25% Rydore WP 800-1000 times liquid for spraying prevention; or use 80% anthrax defame WP 800 times Liquid, 70% thiophanate-methyl WP 1500 times solution, 50% chlorhexidine WP 1000-1500 times solution, 77% can kill micro-particles 500-600 times solution, 7d once, even spray 2~3 Once, after the spray, it will be sprayed in time. (10) Streak disease (column brown spot, chalk disease) 1. The symptoms mainly affect the leaves and stems of the yam, causing the leaves to dry and the stems to die. In the early stage of the onset of the leaf, a yellow or yellowish white edge on the leaf surface is formed, and then gradually enlarged. The enlargement is often restricted by the veins, and it is irregular or polygonal, with a size of 2 to 5 mm, which becomes a brown lesion and has no ring pattern. In the late stage, the edge of the lesion is slightly convex, with a light brown in the middle, and scattered black dots, that is, conidial discs. In severe cases, the lesions are fused, which may lead to perforation or death of the leaves, but generally the leaves die without falling leaves, so chalk and anthrax There are obvious differences in the disease. Stem sensation and the symptoms of the petiole are similar, and there will be oval or irregular brown lesions. In severe cases, the upper and lower lesions will fuse together, causing the stems to die. 2. Transmission route and disease conditions The plaque disease is caused by the fungus of the fungus fungus Dioscorea zingiberensis. The pathogen is overwintered by the conidia disc and mycelium on the diseased residue. When the conditions are appropriate in the second year, the pathogens on the diseased body will form conidia, which will spread with the wind and rain, first in the lower leaves of the plant. Onset, the formation of the first infection. When the pathogen invades the stems and leaves, the hyphae grows between the cells in the stem and leaf tissue, forming conidia discs and conidia under the skin. When the conidia matures, they will break through the epidermis of the stems and leaves when encountering suitable humidity and temperature. After 1~2d of incubation, conidia can germinate again and cause disease to spread. The suitable temperature for the onset of yam plaque is 25~32 °C, so it is easy to develop in the hot and rainy season. It is the most serious from mid-July to mid-August and can be continued until the harvest. The incidence of plaque disease is related to the amount of nitrogen fertilizer applied, and it is easy to develop when there is too much nitrogen fertilizer. 3. Prevention methods (1) Implement rotation and avoid continuous cropping. (2) Remove the diseased body in time after harvest, concentrate it deeply or burn it, and reduce the initial infection. (3) Advocate the application of compost made by enzyme bacteria. (4) Spraying 53.8% from the beginning of June can kill 1000 times of 1000 suspensions, 50% of Fumei double powder 500~600 times, or 1:1:200~300 times of Bordeaux mixture, sprayed every 7~10 days 1 time, continuous prevention 2~3 times. (11) Root knot nematode disease In recent years, with the expansion of yam cultivation area, the occurrence and spread of yam root knot nematode disease has gradually increased, with light yields reduced by 20% to 30%, and severe cases reduced by more than 70%, and the quality of commodities has decreased significantly, seriously restricting the target yam production. Further development. The hazard characteristics and prevention measures are introduced as follows: 1. Symptoms The root-knot nematode disease of yam is mainly harmful to the underground tubers. There are no obvious symptoms in the aboveground part. In severe cases, the upper part shows pale leaves, weak growth and poor plant luxuriance. After the root tuber of the yam is infected with root-knot nematode disease, a similar shape of the head is produced on the epidermis of the tuber. The tumors heal and overlap each other to form a larger tumor (commonly known as big sputum). A small amount of short white roots are produced on the body. The skin color of the affected area is significantly darker than the normal skin color, which is yellowish brown. The color of its internal organization did not change significantly. On the fine roots of the tubers, there are root knots of millet size. The quality of the damaged part is reduced, and the severely damaged part, except the epidermis becomes dark brown, the internal tissue becomes dark brown rot, which resembles dead wood, completely loses the edible value and causes great economic loss. The yam nematodes are mainly distributed in the soil layer of 0~30cm, and the soil layer below 30cm has less incidence. The high dry sand block has a serious incidence, and the incidence of continuous cropping is heavy. 2. Control measures Because of the damage of the yam tuber root-knot nematode, many large and small tumors are produced, so that the surface soil is broken and a large crack is formed, which is similar to the case where the roots of the hawthorn are expanded to break the surface soil. Because the nematode is small, it can only be observed under the microscope. Farmers do not understand or pay attention to it. Therefore, their prevention and control are often ignored. In addition, root-knot nematode is a soil-borne disease, chemical control is difficult, and the investment is large. At present, there is no ideal agent for controlling nematodes, so chemical control can only be used as an auxiliary measure, and comprehensive prevention measures must be taken. (1) Phytosanitary: When transporting yam species, strict quarantine should be carried out. Farmers should pay attention to borrowing or purchasing yam species. They should not be introduced from the ward, and do not need diseased yam species to choose healthy and diseaseless yam. Propagation materials to prevent artificial transmission. (2) Reasonable rotation: water and drought rotation is carried out in places where water is available, and vegetables are planted after 3 to 4 years of rice replanting. Or rotation with corn and cotton can significantly reduce the amount of nematodes in the soil, which is a simple and easy prevention measure. (3) trapping and controlling, reducing the density of insect population: planting some susceptible green-leaved nematodes, such as Chinese cabbage, coriander, lettuce, spinach, etc., can be harvested in about 1 month in the growth period, when the roots are covered with roots. However, it has little effect on production. When harvesting, it is uprooted, the ground is edible, and the roots are taken out of the field for centralized destruction, which can reduce the amount of nematodes in the soil, which is a feasible prevention method. (4) Eliminate the diseased body and increase the application of organic fertilizer: take the diseased plant out of the field, concentrate on drying, burning or deep burying, and remove the weeds such as leeks in the field to reduce the number of mites. Apply fully decomposed organic fertilizer as base fertilizer to ensure good water and fertilizer supply during the growth of yam and make it grow robust. (5) Seed treatment: For the yam plant or yam section used as a seed, the wound (ie, the section) should be immediately stained with lime powder to play the role of disinfection and sterilization. Then, the reserved yam species are dried in the sun, and turned 2 or 3 times a day to promote wound healing, form callus, and enhance the disease resistance and germination potential of the seeds. (6) Chemical control: Before yam is planted, use 3% of Miller's granules for 3~5kg per 667m2, or 10kg of filaria granules for 1.5kg of fine soil and 30kg for spreading into the planting ditch. Hook it, the depth is about 10cm, mix with the soil, and then ditch and plant. (7) Biological control: The use of bio-pesticide Bei Nong Ai Fu Ding emulsifiable concentrate to control root knot nematode disease. Its usage is: before planting, use 1.8% of Beixiang Aifufu emulsifiable concentrate 450~500ml and mix 20~25kg of fine sand for every 667m2, evenly spread the surface, and then plow 10cm, the control can reach more than 90%, and the effective period is about 60d, or Control with Green Heng Awei, recommended reading: yam field cultivation and land preparation and fertilization technology introduction, agricultural technology common sense: how to apply fertilization of yam cultivation, yam planting fertilization method and method of increasing yield This article URL: yam common disease brown rot symptoms picture and prevention measures Sarms Tablets,High Purity Mk--2866,Medical Grade Sarrms Mk 2866,Muscle Bodybuilding Shaanxi Hongbaiyi Biotech Co., Ltd. , https://www.sxhongbaiyi.com