The prevention and control of sweet potato diseases and insect pests should be implemented: "prevention first, prevention and control at the same time", early, small treatment, cure", the use of highly toxic, high residue pesticides should be strictly prohibited, only low toxicity, low residue pesticides should be used, and the use of biochemical pesticides that are non-toxic to people and animals and have no pollution to the environment should be advocated.
The main diseases of sweet potatoes are: black spot disease, potato plague, soft rot, cranberry disease, root rot, virus disease and so on.
<h1 class= "pgc-h-arrow-right" >1</h1>
Black spot disease, also known as black scar disease and plaster disease, is a quarantine disease in sweet potato production, widely distributed, and has occurred in all potato producing areas in China. The pathogen spreads through the soil, potato cellars, seed potatoes, and potato seedlings, invading the wounds of sweet potatoes. The seedling stage, growth stage and storage period can be affected by pathogens, mainly harming the root and the base of the seedling stem, and not infecting the aboveground part. At the seedling stage, the stem base grows spindle-shaped brown spots, which gradually develop into oval black spots, slightly concave, and in severe cases, the seedlings die in the shape of black feet, or rot in the soil before they are unearthed, and the seed potatoes become black and rotten, resulting in rotten beds. The disease of potato blocks, mainly showing round depressions and black spots, gradually expands to the depths of potato blocks, and the sick potatoes become bitter and inedible.
Prevention and control methods:
(1) Strict quarantine, do not transfer seed potatoes and potato seedlings from the diseased area.
(2) Implement crop rotation stubble, and the rotation period should be more than 5 years.
(3) Select disease-resistant varieties and establish disease-free planting fields.
(4) Seed potato treatment, one is that the seed potato is treated with high temperature (35 °C ~ 38 °C) for 3 days and nights before entering the cellar, which promotes wound healing, and produces sweet potato acetone to inhibit the germination of black spot spores. Then quickly cool down to 10 °C ~ 14 °C and then put into the cellar storage. The second is the treatment of the agent, with 50% carbendazim wettable powder 500 times liquid soaked in seed potatoes for 3 to 5 minutes and then dried into the cellar.
(5) Agent soaking seedling disinfection, with 50% methyl tolbuzin wettable powder 500 ~ 700 times liquid or 50% carbendazim 2500 ~ 3000 times liquid, soaking the base of the seedling 6 ~ 10 cm deep, time 2 ~ 3 minutes.
<h1 class= "pgc-h-arrow-right" >2</h1>
Farmers in the potato area also call it a sweet potato disaster, which is a quarantine disease. By the bacteria from the root tip or plant wound invasion, the seedling disease at the base of 1 to 3 leaves wilt, the stem base becomes yellow-brown, the upper leaves gradually wither, the early disease does not produce potatoes, the middle disease of potatoes less, potato skin has yellow-brown spots, easy peeling, potato blocks are not cooked.
(1) Strict quarantine, blockade and restriction of epidemic areas.
(2) Rotate with rice, and the pathogen is destroyed after more than half a year of flooding.
(3) Select disease-resistant varieties and cultivate disease-free seedlings.
<h1 class="pgc-h-arrow-right" >3</h1>
Soft rot, also known as soft rot and water rot, is one of the main diseases in the storage period of sweet potatoes. It is widely distributed and occurs in all potato-producing areas of the country. The disease infects potato pieces and first occurs at the wound. There is no obvious change in the potato meat tissue at the beginning of the disease, and then it becomes water-stained, the potato pieces become soft, gradually decayed, and have a wine flavor, and the potato meat becomes yellowish brown or light brown. The skin is off-white.
(1) Harvest at the right time, try to bring potatoes into the cellar as much as possible, and avoid frost damage and mechanical damage.
(2) Clean the potato cellar, disinfect and sterilize. The old cellar should be cleaned, or the cellar wall should be shaved with a layer of soil, and then fumigated with sulfur (15 grams of sulfur per cubic meter).
(3) Use 50% methyl tolbucin wettable powder 500 to 700 times liquid before entering the cellar with potato blocks, or 500 times liquid with 50% carbendazim wettable powder, dip the potato blocks, dry them and enter the cellar.
<h1 class= "pgc-h-arrow-right" > 4</h1>
The disease is also called vine blight, stem rot, and blight. In addition to harming sweet potatoes, it also harms crops such as tobacco, cotton, corn, and soybeans. Infects stems and potato blocks. The disease develops upward from the base of the main stem, the leaves of the diseased plant are yellowed and shed from bottom to top, and finally the whole vine dies, the stem is damaged, the stem base is expanded, the longitudinal rupture is exposed, the marrow is exposed, the vascular bundle is black-brown by dissection, and the vascular bundle of the transversely cut potato is brown spots.
(1) Selection of disease-resistant varieties, it is forbidden to transfer potato seeds and potato seedlings from the diseased area.
(2) Soak the seeds in warm water, soak the seeds with 51 °C ~ 54 °C warm water for 10 minutes, and cultivate disease-free seedlings.
(3) Soak and spray plants with 50% methyl tolbuzin 500 times liquid.
<h1 class= "pgc-h-arrow-right" >5</h1>
The disease, also known as rotten root disease, is a more serious disease in sweet potato production. In addition to harming sweet potatoes, it is also harmful to spiral flowers such as morning glory. Harmful seedlings, starting from the tip or middle of the whisker root, local blackening and necrosis, and then expanding to the whole root become black and rotten, and spread to the underground stem, forming brown concave longitudinal crack spots, loose subcutaneous tissue. The aboveground vines are internodal shortened and dwarfed, and the leaves are yellow. In the case of severe disease, all the underground rhizomes turn black and rot, and the main stem withers from bottom to top, so that the whole plant dies. The surface of the diseased potato block is rough, covered with black-brown spots of different sizes, cracked in the middle and late stages, and the subcutaneous tissue becomes black. Root rot is caused by fungal infections, which are mainly transmitted by soil.
(1) Select disease-resistant seeds.
(2) Seriously ill fields are rotated for more than 3 years.
(3) Deep ploughing and turning the soil, increasing the application of organic fertilizer, no application of bacterial fertilizer. Strengthen cultivation management, spring potatoes are planted appropriately early to improve disease resistance.
<h1 class= "pgc-h-arrow-right" >6. Sweet potato virus disease</h1>
The disease is also called mosaic disease, leaf shrinking disease. It has two types of presentation: one is mosaic virus disease, the leaf veins are reticulated, the leaf flesh is transparent, and later yellow-green spots appear ( there are green spots in the middle ) . The second is the wrinkle leaf virus disease, the leaves are small and slender at the beginning of the disease, the edges are not neat, the leaves are uneven in the late growth period, the leaf margins are rewinded, the contraction is twisted, and the growth is slow. The disease is mainly transmitted by pests such as aphids and other sucking mouthparts, and the infection is fast. After the sweet potato is infected with the disease, the species degenerates, the yield is low, and the quality is poor.
(1) Adopt tissue culture detoxification technology to cultivate detoxified seedlings and seed potatoes, and promote detoxification cultivation.
(2) Whether it is seedlings or fields, the diseased plants should be uprooted in time and isolated and destroyed.
(3) Timely control of planthoppers and aphids, and eliminate the media.
(4) At the beginning of the disease, spray potassium permanganate 1000 times liquid or virulence 1000 times liquid in time, once every 5 days, and spray 2 to 3 times.