Damage to the tubers of Maling tree, there are nearly round to amorphous cork-like scabby light brown spots or patches on the surface of the tubers, and the texture is rough by hand. It is generally divided into two symptoms: reticular spot and cracked spot (easily mistaken for potato powdery scab). Usually, although the lesion is limited to the cortex, the quality and yield of the damaged potato pieces can still be reduced, which is not resistant to storage, and the appearance of the diseased potato is unsightly, and the commodity grade is greatly reduced, resulting in certain economic losses.
Overview of potato scab: pathogen: an actinomycete microorganism.
Transmission route: the pathogen overwinters in diseased potatoes and soil, and invades from lenticels and wounds of potato blocks.
Susceptible conditions: serious illness in neutral or slightly alkaline sandy loam; It is easy to occur in high temperature and drought areas in summer.
Susceptible symptoms: the disease occurs in tubers, with brown spots or central depression on the surface, which is scabbed-like, seriously affecting the appearance and quality of potato pieces.
Comprehensive prevention and control:
Choose healthy potato seeds. Be sure to adjust the seeds from the disease-free area and pay attention to the disinfection of potatoes.
Implement crop rotation. Rotation with non-solanaceae crops for more than 5 years, try not to plant potatoes in plots prone to scab.
Regulation of water. Dry weather is conducive to actinomycetes infection, and if the drought time is prolonged, the condition will be more serious. Therefore, keeping the soil moist and watering it in time in case of drought can inhibit the occurrence and aggravation of diseases.
Harvest at the right time. If the tuber has been infected at the formation stage, when it is close to maturity, it can be harvested in advance when the potato volume reaches a certain size to avoid further expansion of the disease spot.
Common diseases of potato and their solutions
Characteristics of potato early blight symptoms: it mainly harms leaves and tubers, mostly starting from the lower old leaves.
Leaf damage: at first, there were some scattered brown spots, which later expanded into irregular concentric wheel patterns with narrow fading rings around them; When wet, black mold appears on the surface of the spot; In severe cases, black spots are formed and the leaves are dry and fall off. Damage to tubers: dark brown, nearly round to amorphous, slightly concave spots appear on the surface of tubers with obvious edges, and the potato pulp tissue under the spots turns brown and dry rot.
Prevention and control methods:
① Choose early-maturing and disease-resistant varieties; Rotation with non-solanaceae crops for more than 2 years; Choose a place with high terrain and fertile soil for planting; Increase the application amount of phosphorus and potassium fertilizer to promote plant growth; Reasonable close planting, keep ventilation; Clean up the diseased branches in the field in time to reduce the source of the disease. ② The following agents can be selected for prevention and treatment at the initial stage of the disease: mancozeb, zineb, difenoconazole and trifloxystrobin? Tebuconazole, azoxystrobin or pyraclostrobin.
Harmful symptoms of potato late blight
Dangerous characteristics: mostly from the tip or edge of the lower blade.
Leaf damage: waterlogging, green-brown spots on the tip or edge of leaves, and gray-green halo on the edge; When the humidity is high, white mold appears on the outer edge, which is more obvious on the back of leaves; When dry, the affected part becomes brown and dry, such as tissue paper, which is fragile and easy to crack.
Tuber damage: large dark brown patches appear on the surface, and the subcutaneous potato meat is reddish brown, gradually expanding and rotting. Petiole damage: brown stripes are formed; * * When there is a white mold layer; In severe cases, the leaves droop and curl, and the whole plant is black rot.
Prevention and control methods:
(1) Selecting disease-resistant varieties; Choose a place with high terrain and fertile soil for planting; Increase the application amount of phosphorus and potassium fertilizer to promote plant growth; Reasonable close planting, keep ventilation; Clean up the diseased branches in the field in time; Establish disease-free land or virus-free seed potato to reduce the source of disease. ② At the initial stage of the disease, the following agents can be selected for prevention and treatment: zineb, mancozeb, dimethomorph, cymoxanil, cyazofamid, zolpidem or fluazinam.
Harmful symptoms of potato scab
Hazard characteristics: mainly infects tubers. After the tuber is infected, it first produces light brown small protrusions on the epidermis, which gradually expand, cork and have a rough surface, and later forms a convex or concave scabby lump on the surface of the lesion. The lesion is confined to the epidermis and does not go deep into the potato.
Prevention and control methods:
(1) Selecting disease-resistant varieties; Rotation with non-solanaceae vegetables for more than 5 years; Choose a place with high terrain and fertile soil for planting; Reasonable close planting, keep ventilation; Clean up the diseased branches in the field in time; Apply acid fertilizer to improve soil acidity. (2) Select the disease-free potato blocks to keep the seeds, soak the seeds in 200 times of 40% formalin for 2 hours, and then cut into pieces, otherwise phytotoxicity will easily occur.
③ At the initial stage of the disease, the following drugs can be selected for prevention and treatment: copper chloramphenicol, agricultural streptomycin, shuimycin or copper clothianidin.
Harmful symptoms of potato powdery scab
Cross section of the diseased part of tuber
Hazard characteristics: it mainly harms tubers and roots.
Tuber disease: Small brown spots with translucent halo appear on the epidermis at the initial stage, and then the spots gradually swell and expand, becoming "scar spots" of different sizes. With the development of the disease, the epidermis of "scar spot" is broken and rolled back, and the subcutaneous tissue is orange, releasing a lot of dark brown powder.
Root disease: an isolated or aggregated tumor the size of a bean grows on one side of the root.
Prevention and control methods:
Strict quarantine, strengthen the blockade of epidemic areas and prohibit external transfer; Implement crop rotation; Strengthen field management, cultivate in high border to avoid flooding; Increase the application of base fertilizer and phosphorus and potassium fertilizer, and apply more lime or plant ash; Choose potato without disease, spray seeds with azoxystrobin or metalaxyl seed coating agent if necessary, dry and sow.
Harmful symptoms of potato lobular disease
Hazard characteristics: the compound leaves grown from the heart leaves of plants begin to become smaller, which is obviously different from the lower leaves. The newly grown petiole is erect, the leaflets are often deformed and the leaves are rough. There are three main symptoms.
Mosaic type: in severe cases, the leaves are atrophied, the whole plant is dwarfed, and sometimes the veins are transparent.
Necrotic type: brown necrotic spots can be seen on leaves, veins, petioles, branches and stems, and the diseased spots develop and become necrotic stripes. In severe cases, the whole leaf dies or withers and falls off.
Leaf rolling type: the leaves turn inward along the main vein or from the edge, becoming hard and leathery, and in severe cases, each leaflet is tubular.
Prevention and control methods:
(1) adopt non-toxic seed potato, eliminate diseased potato, and promote virus-free shoot tip tissue; Improve farming measures, implement intensive cultivation, high ridge cultivation, timely soil cultivation, intertillage weeding and flood prevention; Avoid partial application of nitrogen fertilizer and increase the application of phosphorus and potassium fertilizer; Early removal of diseased plants; If aphids are found, prevent them in time. ② At the initial stage of the disease, the following drugs can be used for prevention and treatment: Ningnan; Guanidine? Copper acetate; Trichloroisocyanuric acid; Lentinan or moroxydine hydrochloride.
In the early stage of Fusarium wilt, potatoes withered, hyphae were found in the diseased parts, and the humidity was high.
Hazard characteristics: at the early stage of the disease, the branches wilted, the diseased stems were cut open, and the potato vascular bundles turned brown. When the humidity is high, white to pink hyphae often appear in the affected area.
Control methods: ① implement crop rotation; Establish a disease-free seed field and sow whole potatoes as much as possible; Clean up the sick and disabled people at the scene in time; Strengthen the management of fertilizer and water in the field. ② If necessary, you can choose: 500 times solution of 50% carbendazim wettable powder or 50% trichloroisocyanuric acid tablet 1000 times solution to soak the seed potato. ③ The following drugs can be used for prevention and treatment at the initial stage of the disease: benzoxazole, benzamide, Bijunling, Weixiuling, or acrylic acid? Mildew? Nail cream, or 10% copper chloride aqueous solution is used for root washing.
Potato bacterial wilt: the diseased plant is short and the leaves are light green. The cross section shows that the vascular bundle turns brown.
Hazard characteristics: at the early stage of the disease, the branches wilted, the diseased stems were cut open, and the potato vascular bundles turned brown. When the humidity is high, white to pink hyphae often appear in the affected area.
Control methods: ① implement crop rotation; Establish a disease-free seed field and sow whole potatoes as much as possible; Clean up the sick and disabled people at the scene in time; Strengthen the management of fertilizer and water in the field. ② If necessary, you can choose: 500 times solution of 50% carbendazim wettable powder or 50% trichloroisocyanuric acid tablet 1000 times solution to soak the seed potato. ③ The following drugs can be used for prevention and treatment at the initial stage of the disease: benzoxazole, benzamide, Bijunling, Weixiuling, or acrylic acid? Mildew? Nail cream, or 10% copper chloride aqueous solution is used for root washing.
Harmful symptoms of potato soft rot
Hazard characteristics: it mainly occurs in the late growth period and storage period, which is very harmful to potato pieces.
Stem damage: the epidermis first appeared water spots, and then spread inward, showing watery soft rot and brown rot tissue; When the humidity is high, there are flocculent hyphae on the surface and small black balls in the middle.
Leaf damage: the lower old leaves come on first, with irregular dark brown spots, and rot when the humidity is high. Stem damage: the pith tissue is rotten, the branches and leaves on the upper part of the diseased stem wilt and droop, and the leaves turn yellow.
Prevention and control methods: ① strengthen management during cultivation, keep ventilation and light transmission, and reduce field humidity; Avoid flooding; Pull out the diseased plants in time and disinfect them with lime. (2) stop watering 5-7 days before harvesting; Sterilizing in potato cellar before storage; Selecting mature and harmless potatoes, storing them in the shade for 2-3 days, and preparing for storage; Keep ventilation during storage. ③ At the initial stage of the disease, the following agents can be selected for prevention and treatment: trichloroisocyanuric acid, zhongshengmycin, agricultural streptomycin sulfate or kasugamycin.
Harmful symptoms of potato dry rot and tuber cross section disease
Hazard characteristics: at the early stage of onset, it is only brown and slightly depressed. After swelling, many wrinkles appear in the affected area, showing concentric wheel patterns, and sometimes gray fluffy particles grow on it, that is, the fruiting body of pathogenic bacteria.
In the later stage, the inside of the potato block turns brown, often hollow, and the cavity is covered with hyphae; Finally, the potato meat becomes grayish brown or dark brown, stiff, dry and hard. When the diseased potato is cut open, it can be seen that it is hollow, the cavity is covered with hyphae, and the inside of the potato turns dark brown or grayish brown, which eventually leads to the whole tuber being stiff or dry and rotten and inedible.
Prevention and control methods: remove the diseased plant residues in time; Clean the pit bottom before into the pit, spray fludioxonil and fumigate with sulfur powder; When entering the cellar, take out the diseased, injured and insect-bitten tubers and pile them in a cool and ventilated place for about 3 days, so that the water on the surface of the tubers can be fully evaporated, and then enter the cellar after the wound is healed; Keep the basement ventilated.
Sclerotinia brownii
Hazard characteristics: it mainly harms tubers. White filamentous hyphae densely grow on the potato block, with brown round rape-like sclerotia, and the subcutaneous tissue of the diseased potato is brown after cutting.
Prevention and control methods: ① implement crop rotation in seriously ill areas; Deeply ploughing the soil and transferring the bacteria to the lower soil can reduce the incidence rate; Before sclerotia is formed, the diseased plants are removed and disinfected with lime; The incidence of decomposed organic fertilizer and appropriate topdressing of ammonium sulfate and calcium nitrate is low; Strengthen the management of fertilizer and water in the field. ② At the initial stage of the disease, the following drugs can be used for prevention and treatment: thiophanate methyl; Every 7 ~ 10 days, apply mixed soil such as triadimefon or procymidone to the stem base 1 time. Or methyl-chloropicrin * * or spraying 1 ~ 2 times, every 15 ~ 20 days 1 time.
Potato anthracnose, the initial leaves weakened and the top leaves folded back.
Hazard characteristics: In severe cases, some plants may die and dry up, causing root rot.
Leaf disease: at the beginning of the disease, the leaves turn pale, the top leaves turn back slightly, and then the whole plant wilts, turns brown and dies.
Infection of underground roots: the cortex tissue from the ground to the potato block is rotten and easy to peel off, the lateral roots turn brown locally, and the diseased plants are easy to pull out.
Stem infection: there are many small gray spots and many black granular sclerotia in the cavity at the base of the stem.
Control methods: ① implement crop rotation; Clean up the sick and disabled people at the scene in time; Strengthen the management of fertilizer and water in the field to avoid high temperature and humidity. ② At the initial stage of the disease, the following agents can be used for prevention and treatment: azoxystrobin, difenoconazole or trichloroisocyanuric acid.
Potato virus disease: common mosaic type, yellowing leaf type.
Hazard characteristics: Potato virus disease is one of the most serious diseases in potato production.
Common mosaic type: the leaves are dark green and light yellow mottled along the veins, and the leaves are shrunk to some extent. Some varieties only show light flowers and leaves, some varieties are obviously dwarfed, the whole plant leaves are necrotic, the whole plant dies from top to bottom, the tuber is small, and there are necrotic spots inside.
Yellow leaf type: the leaf edge of the diseased plant is turned upwards, and the leaves are yellow-green. In severe cases, the leaves are rolled into a tube shape, but they do not shrink, and the leaves are thick, brittle and easily broken. The seriously ill plants are short and some die young.
Atrophic mosaic disease type: the symptoms of mosaic disease and common mosaic disease are mosaic disease atrophy, smaller leaves, severe top atrophy, obviously short plants, hydrangea-shaped, non-flowering, early death and extremely small tubers.
Control methods: ① Cultivate and select virus-free healthy potato seeds, and pull out diseased plants in the process of reproduction; Timely prevention and control of aphids, prevention and control of virus transmission. ② Seed potato treatment: Treating seed potatoes at 35℃ for 56 days or at 36℃ for 39 days can remove the virus contained in seed potatoes, and adopting temperature change treatment, especially cutting into pieces, is more effective than whole potatoes. ③ At the initial stage of the disease, the following drugs can be used for prevention and treatment: moroxydine hydrochloride and ningnanmycin; Guanidine? Copper acetate; Trichloroisocyanuric acid; Lentinus edodes polysaccharide aqueous solution or amino oligosaccharide.
Potato black spot: symptoms of stem base injury and tuber injury.
Hazard characteristics: it mainly harms buds, stem bases and tubers.
Bud infection: some rot before digging to form bud rot, resulting in lack of seedlings.
Infection after digging: the leaves at the lower part of the initial plant turn yellow and brown pits are formed at the base of the stem. Lesions or stem bases are often covered with gray hyphae, and sometimes stem bases and tubers produce massive or flaky sclerotia with different sizes and shapes, which are scattered or aggregated.
Mild symptoms are not obvious, and severe ones can form withering or top wilting, or the leaves curl into a boat shape, the internodes of the heart leaves are long, and purple pigments appear; In severe cases, the axillary buds of stem nodes produce purple or green aboveground tubers, or underground stems produce many small potatoes with no economic value, and many black-brown sclerotia are scattered on the surface.
Control methods: ① selecting disease-free potatoes, cultivating disease-free seedlings and establishing disease-free seed fields; In areas with serious illness, especially in high-altitude cold Liangshan areas, special attention should be paid to timely sowing to avoid premature sowing; Once the diseased plants are found in the field, they should be pulled out in time, buried far away from the planting plots and disinfected with lime. (2) Seed potato treatment: 35% thiram wettable powder 1000 times solution 10 minute, or 50% thiram 0.4% solution for 5 minutes. ③ At the initial stage of the disease, the following drugs can be used for prevention and treatment: benzene? Propiconazole; The dosage of hymexazol and tebufenozide per mu is 14 ~ 20ml, and the stems and leaves are sprayed with water for 40 ~ 60l.
Silver rot of potato
Hazard characteristics: it has been infected during the potato growth period, which mainly harms tubers. When harvesting, especially when it is wet, diseased spots will appear on tubers.
The lesions are mainly distributed on the tubers at the base of the stem, with irregular fading spots on the surface, which are light to brown and gradually expand, and in severe cases shrink. The lesion covers most of the surface of tuber, and the tissue below the lesion is healthy, which has a great influence on the appearance of tuber.
Prevention and control methods:
(1) clean the bottom of the pit before the new potato into the pit, and fumigate it with sulfur powder; When entering the cellar, take out the diseased, injured and bitten tubers and pile them in a cool and ventilated place for about 3 days to reduce the humidity of the tubers and reduce the incidence; Keep the basement ventilated. ② Tubers were treated with 45% carbendazim before storage and aerosol during storage.
Potato leaf spot: the harmful symptom of potato cercospora leaf spot
Hazard characteristics: it mainly harms the leaves and stems of the above-ground parts, and the tuber does not get sick. Primary yellow to light brown round lesions, irregular yellow-brown spots after expansion, and some leaf spots are not obvious; * *, a dense gray mold layer appeared on the back of the leaves, that is, conidiophore and conidia of pathogenic bacteria.
Prevention and control methods: ① Deep ploughing after harvest; Implement crop rotation. ② At the initial stage of the disease, choose to spray the following agents: 50% carbendazim+Wanmeiling wettable powder 1000 ~ 1500 times, or 600 times of 75% chlorothalonil wettable powder, or 400 times of 30% basic copper sulfate suspension, every 7 ~ 10 days,/kl.
Harmful symptoms of potato gray mold
Hazard characteristics: Botrytis cinerea is a potato disease, which can infect leaves, stems and sometimes tubers. The diseased potato skin is dry, brown and semi-wet, and a thick gray mold layer grows on the wound.
Prevention and treatment methods: ① Strictly select seed potatoes to minimize trauma; Keep the cellar cold and ventilated. ② At the initial stage of the disease, the following drugs can be selected for prevention and treatment: 40% pyrimethanil suspension 600- 1000 times, 50% ethephon dimethachlon wettable powder 1000 times, or 80% procymidone wettable powder 1000-2000 times.
Potato root rot nematode disease: there are small dark brown spots in the early stage, and the spread of the disease spots causes rot.
Hazard characteristics: it mainly harms the roots, dwarfs the plants seriously, turns the aboveground parts yellow, and produces dark brown spots or brown ulcer spots on the surface of potato pieces, which will cause rot after the disease spots expand during storage.
The wounds caused by nematodes provide conditions for bacterial infection, so the plots with heavy nematodes will aggravate the occurrence and spread of soil-borne diseases such as Fusarium wilt and Verticillium wilt.
Control methods: ① implement crop rotation; YEATION seeds, planting wireless insect seed potatoes; Immediately after harvesting, remove the sick and disabled, and concentrate on deep burial or incineration; Before planting, dry chicken manure 150 ~ 500 kg was applied per mu, and the control effect was high. ② Before planting, use 5% thiamethoxam granules, or 0.5% avermectin 10-20 times solution, or 10.5% avermectin. The ditch spacing and ditch depth are 60 cm and 65,438 0.5 cm, respectively. After spraying the medicine evenly, cover the soil.