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Methods and Technical Key Points for Controlling Rice Pests and Diseases in the Mid-to-Late Stage
This year's rice insect pests are mainly migratory and boring pests, with an estimated affected area of 730 million mu-times. With multiple pests and diseases jointly affecting mid-to-late stage rice, experts recommend using a combination of agroecological control techniques and chemical control measures.
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Rice "Three Controls" Fertilization: Frequently Asked Questions
The rice "Three Controls" fertilization technology targets prominent problems in current rice production such as excessive application of chemical fertilizers and pesticides, low and unstable yields, low fertilizer use efficiency, and serious environmental pollution. It is a high-efficiency, safe fertilization and supporting
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What are the multiple control methods for sweet potato black spot disease
Sweet potato black spot disease, also known as sweet potato black scar disease, has become one of the most widespread and serious diseases in sweet potato producing areas of China. According to statistics, the annual yield loss caused by this disease in China is 5%-10%, and livestock eating diseased tubers can also cause poisoning, with severe cases leading to death. I. Symptoms
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What are the control methods for sweet potato soft rot?
1. Harvest at the right time and avoid mechanical injury. Summer sweet potatoes should be harvested completely around the time of Frost's Descent, and autumn sweet potatoes should be harvested completely before the Start of Winter. Choose a sunny day for harvesting, and when digging the potatoes, minimize or avoid causing wounds. 2. Select healthy potatoes carefully to ensure safe storage in the cellar. Before the sweet potatoes are put into the cellar, they must be carefully selected,
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What are the control methods for sweet potato weevil
The sweet potato weevil is also called the sweet potato ant-weevil; in Guangdong it is called shazi bug or shala bug, and it is one of the main pests harming sweet potatoes. In autumn sweet potatoes cultivated on dry sloping land, it occurs rather severely in the middle and late stages, with a general damage rate of 10%-15%, and in severely affected plots up to 40%-50%. Control methods
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Methods for controlling freeze injury in sweet potato cultivation
Sweet potato freeze injury, also called hard-heart sweet potato. [Disease diagnosis] When storage roots are frozen, at first the skin color shows no obvious difference from healthy roots, only slightly losing its luster. Later, the skin can be seen to take on a slightly dark, lusterless appearance; pressing the frozen part lightly with a finger gives a springy feeling; cutting open a frozen sweet potato shows that the flesh near the skin rapidly turns brown, does not exude white milky sap, and squeezing it by hand releases clear water. Generally, based on the speed at which the flesh turns brown, the degree of freezing can be estimated; the faster the browning, the more severe the freezing. Frostbitten storage roots often form a hard heart, taste bitter, and will not cook soft. After storage roots are frozen, they are easily attacked by weakly parasitic fungi, causing rot. ⟦4 <p>Sweet potato freeze injury, also called hard-heart sweet potato. </p><p></p><p>[Disease diagnosis] When storage roots are frozen, at first the skin color shows no obvious difference from healthy roots, only slightly losing luster. Later, the skin can be seen to take on a slightly dark, lusterless appearance; pressing the frozen part lightly with a finger gives a springy feeling; cutting open a frozen sweet potato shows that the flesh near the skin rapidly turns brown, does not exude white milky sap, and squeezing it by hand releases clear water. Generally, based on the speed at which the flesh turns brown, the degree of freezing can be estimated; the faster the browning, the more severe the freezing. Frostbitten storage roots often form a hard heart, taste bitter, and will not cook soft. After storage roots are frozen, they are easily attacked by weakly parasitic fungi, causing rot. </p><p>[Cause] When storage roots are exposed to a low-temperature environment below 9°C for a relatively long time, their physiological functions are disrupted, the flesh tissue is frostbitten, a hard core forms, and the skin and tissue become necrotic. However, after freezing, a period of time must pass before rotting begins. The lower the temperature, the more severe the freeze injury. The longer the low temperature lasts, the more severe the freeze injury. When storage roots suffer freeze injury, rotting generally has two peaks: one is when harvesting is too late in production and the roots freeze in the field, called freeze injury outside the storage pit, and rotting begins about 15 days after being put into the pit; the other is during the middle and late stages of pit storage, when freezing occurs because the pit is shallow or cold protection and insulation are poor and the pit temperature is low, followed by rotting. Generally, at 4-5°C, rotting begins after lasting half a month, and at 6-7°C, rotting occurs only after 1 month. </p><p>[Control measures] (1) Harvest and put into the pit at the proper time to prevent storage roots from freezing. The suitable harvest time for sweet potato should be when the local average temperature of the ten-day period drops to about 14-15°C. Harvest promptly on a sunny day, and the storage roots should be put into the pit on the day of harvest. (2) Disinfect the storage pit. Before the storage roots are put into the pit, a layer of soil should be scraped from the walls of an old pit, and then chemicals should be used for disinfection: fumigate with 30-40 milliliters of 402 water-based fungicide per cubic meter of space, or spray the walls around the pit with a 50-fold formalin solution; in either case, it must be sealed for two days, then opened for ventilation, and used after another two days. (3) Carefully select storage roots. Any storage roots that are diseased, insect-bitten, or frostbitten by frost should be removed and must not be put into the pit. (4) During harvesting, transport, and pit storage, handle them carefully, lifting and setting them down gently, and prevent wounds as much as possible. (5) Manage the temperature and humidity of the storage pit well. To prevent storage roots from freezing and ensure safe storage, the pit temperature should be kept at 11-13°C and the relative humidity at 75%-80%.</p>
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What are the control methods for sweet potato stem nematode disease?
Sweet potato stem nematode disease, commonly known as "chaff heart disease." [Pathogen nematode scientific name] Ditylenchus destrutor Thorne. [Host crops] Sweet potato, potato, lily, ginseng, mint, Angelica sinensis, etc. [Disease diagnosis] It mainly damages the tuberous roots, followed by the stems and vines. Tuberous roots affected
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Control Methods for Sweet Potato Wrinkle Mosaic Disease
Sweet potato wrinkle mosaic disease, also known as sweet potato latent virus disease. [Virus English name] Sweet potato latent virus, abbreviated SPLV. [Host crops] Sweet potato, Convolvulaceae, Chenopodiaceae, and some Solanaceae crops. [Disease diagnosis] During the seedling-raising period, diseased seed potatoes sprout in greater numbers than healthy potatoes
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What are the control methods for sweet potato violet root rot?
Sweet potato violet root rot, commonly known as "red vein net," "retained skin," etc. [Pathogen scientific name] Helicobasidium mompa Tanaka [Host crops] Sweet potato, potato, soybean, peanut, cotton, mulberry, tea, fruit trees, forest trees, etc. [Disease diagnosis] It damages the tubers and underground stems
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Control Methods for Stem Rot in Sweet Potato Cultivation
Sweet potato stem rot, also known as sweet potato wilt, fusarium wilt, stem blight, etc. [Pathogen scientific name] Fusarium bulbigenum Cke. et Mass. Var. botatas Wollenw. [Host crops] Sweet potato and other Convolvulaceae plants. [Disease diagnosis] Diseased seedlings show swollen, bluish roots, with the vascular bundles turning brown and the upper parts turning yellow and thin. When mature plants are affected, the diseased plants are stunted, with swelling at the stem base and a bluish halo on the surface. When the diseased part is cut open, the vascular bundles can be seen to have turned brown after infection, extending upward from the stem base for 20 to 30 cm. Apart from a few green leaves at the top, all other leaves of the diseased plant turn yellow, and the lower old leaves successively wither and drop off. In the later stage, the cortex of the diseased part cracks, appearing fibrous, and pink mold-like growth appears on the surface. When storage roots are affected, the root end becomes rotten, and a cross-section of the discolored vascular bundle area in the upper part of the diseased root shows dark brown ring-shaped spots. The pathogenic fungus is Fusarium oxysporum f. sp. batatas. Macroconidia are sickle-shaped, with slightly pointed apical cells and slightly curved tips on the end cells, having 3 to 5 septa. Microconidia are single-celled, oval to elliptical. Chlamydospores are brown and spherical.</p><p>[Disease occurrence pattern] The pathogen overwinters as mycelium and chlamydospores in diseased storage roots or attached to diseased residues in the soil. The pathogen can also survive in the soil in a saprophytic state. The pathogen mostly invades through wounds and spreads along the vascular bundles. The cut end of transplanted seedlings is the most important invasion site, and wounds on roots and leaf scars can also allow invasion. The pathogen can also invade poorly growing seedlings. The disease can spread over long distances through diseased storage roots and diseased seedlings, and over short distances mainly through soil, flowing water, and farm tools. A soil temperature of 27 to 30°C and high soil moisture favor disease development. Frequent rainfall and large amounts of rain often cause severe outbreaks of the disease.</p><p>[Control measures] (1) Select disease-resistant varieties, such as Chaoshanbai, Nanjing 92, Jinshan 247, Taichengshu, Nanruishao, Jinqing No. 9, Xuzhou 18, etc. (2) Select disease-free seed storage roots and raise seedlings in disease-free soil. (3) Before planting, soak the sweet potato seedlings in 0.2% "401" antimicrobial agent for 10 minutes for disinfection. (4) Apply fully decomposed manure. Irrigate appropriately and drain field water promptly after rain. (5) In heavily infested plots, carry out crop rotation with grain crops for more than 3 years; rotation with rice for 1 year can already be effective. (6) Remove diseased plants promptly when found and burn them in a centralized manner or bury them deeply. (7) In the early stage of disease, spray promptly with 30% Luyedan wettable powder at 800 times dilution, or 50% benomyl wettable powder at 1500 times dilution, or 40% Shuangxiaoling aqueous solution at 800 times dilution, or 50% thiophanate-methyl wettable powder at 500 times dilution. </p>
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