Occurrence and Prevention Technology of Main Diseases of Sesame

Sesame is an important oil crop and export commodity, and it is also a major economic crop. With the continuous improvement of economic value, the country's planting area continues to expand. The growth period of sesame is only a short period of 85 days, but the whole growth period is in the hot and rainy season, and suffers many kinds of diseases. Such as sesame wilt disease, sesame stem blight, etc., is the main reason for the long-term low and unstable sesame yield. In order to increase production and increase income for farmers, we have studied the occurrence and prevention techniques of sesame disease after several years of hard work. We will now summarize it for reference.

First, the main diseases of sesame

1. Sesame stem blight sesame stem blight commonly known as "black root disease", "black stalk disease", is the most important disease in sesame production, the general incidence of 10% -15%, severe 60% -80%, mainly Occurs in the period of flowering and podging of sesame. It starts from the root or stem and develops to the upper part of the stem. When the roots become susceptible, they turn brown; after the stems become sick, they quickly develop melasma around the stems. There is no clear boundary at the edge, and the gray surface of the middle is shiny. There are many black granules on it. When the disease is severe, the leaves of the plant curl up and wilting from the bottom up, the tip of the plant is bent downward, the leaves and pods turn dark brown, and the plant shape is short. The cortex and phloem of the victim's rhizome are corroded, leaving only the fibers. The stems are hollow and easily broken. The pathogen of sesame stem blight is mainly transmitted through the wintering of sclerotia on the seeds and soil in the diseased body. High temperatures and rain, low-lying terrain, and long-term soil moisture are the prevailing environmental conditions.

2. Sesquito bacterial wilt The sesame wilt disease has occurred in every sesame producing area in the country. In the early stage of disease, green lesions appeared on the stem and became black strip lesions. The leaves suddenly wilted from top to bottom and the old leaves hang down. The early evening can still return to normal. The whole plant is blue and dies after 3-5 days. The damaged plants are shorter than the healthy plants, the vascular bundles of the roots and stems turn brown, and finally spread to The pith, resulting in empty pods, bacteria spilled inside and outside the stem, and gradually turned into dark and shiny particles. After the leaves have become infected, the veins of the leaves are dark green, sometimes criss-crossing into a mesh, with a light-filled perspective. The center of the veins is yellow, and the back veins are yellow and wavy. The more the leaf edges are curled, the more the edges are curled. . The pods were immersed in water after the illness, and they gradually changed to dark brown stripes with uneven thickness. The diseased pods shrank and the affected seeds turned red-brown. The sesame wilt is mainly caused by wintering and spreading of diseased seeds and diseased bodies. In general, after a heavy rain storm, the disease will be outbreaks.

3. Sesame wilt disease sesame wilt disease commonly known as "half yellow", the general incidence of 5% -10%, more than 30% in severe cases, is also the main disease in sesame production, seedling stage disease, the whole plant trip; late onset, leaves Blight gradually wither from the bottom up; the roots of susceptible plants often turn brown in their roots and extend upward along the stems, turning the corresponding stems into reddish-brown, blotchy spots, giving rise to a pink layer on the lesions when wet. Powder, brown or brown tube of diseased stem. The lower leaves of the diseased plants drooped first and then gradually developed toward the upper leaves. The leaves of the affected half were half yellow and gradually withered and fell off. The fungus of sesame Fusarium overwintered with the seeds and the diseased bodies.

4. The symptoms of sesame epidemic sesame epidemic mainly manifest in the stem base. After the damage, the plant formed a round of plume on the base of the stem, which was initially dark green with a watery immersion, gradually turned reddish-brown, slightly sunken, and grew like a sickly filament in the wet condition. The damage on the upper part of the stem can cause the victim to die. After the leaves have become infected, they can form large yellowish-brown lesions with a slight rim. The pathogenic bacteria of sesame epidemic become the primary infestation source by wintering in the soil with hyphae or oospores.

Second, the comprehensive prevention and treatment of sesame disease

Due to the wide variety of sesame diseases and the wide range of sources of the disease, the occurrence of diseases is often closely related to external environmental conditions (such as temperature, humidity, etc.) and their cultivation and management (such as density, fertilization, etc.). Therefore, in the prevention and control of sesame disease, we advocate The comprehensive prevention and control measures are mainly based on agricultural control and supplemented by chemical control. In terms of comprehensive prevention and control, the first selection of disease-resistant varieties, the implementation of rotating crops, according to local conditions, the use of ditch small education cultivation, supplemented by the four aspects of the prevention and control of drugs.

1. Selection of disease-resistant varieties: Through tests, although there is no high-resistance variety for sesame disease, there is a significant difference in disease resistance among varieties. To spread new varieties of high-yield and disease-resistant varieties according to local conditions is an economic and effective measure to prevent and control sesame disease. Such as Yuzhi No. 4, Yuzhi No. 10, Yuzhi No. 11 and so on.

2. Implementing crop rotation: Carrying out crop rotation is an important measure to prevent diseases and increase production. To promote the rotation system for 4-5 years, it can reduce or avoid the occurrence of diseases. Most of the diseases of sesame are caused by the residue of bacteria in the soil and survive in the winter. The sclerotia of sesame stem blight can survive for up to two years in the soil. Therefore, avoiding continuous cropping and implementing many years of crop rotation have a great effect on reducing disease. According to our test, the longer the period of rotation is, the lighter the incidence is. The incidence of five years of one crop is 8.3%, the incidence of one crop of three years is 14.7%, and the incidence of continuous cropping is 38.4%. The effect of rotation crop production is obvious. We are in Zhengyang, Henan Province. The county's South Point test has an annual incidence rate of 81.3% for stem blight, 12.25kg per mu, 2.5% for no weight, 59kg per mu, 72.9% for heavy cuts, 58.9% for one year, and 32.5% per mu. The control rate for the kilograms was not 10.8%, the yield per mu was 62.5 kg, and the weight reduction was 48%.

3. Adoption of small culture in the ditch cultivation: Sesame is a kind of intolerant crop, especially after the flowering period, the stain resistance is worse, the field water accumulation hinders the normal breathing of the plant, the plant growth is weak, and it is vulnerable to death caused by bacteria. July-August is the period of precipitation, which is also a critical period for the growth of sesame. It is an important period for sesame flowering, scab, and grain formation. The conditions of high temperature and high humidity are favorable for the occurrence and spread of sesame disease. Shortening the time of field water accumulation is the main measure to reduce the disease. In 2003, we promoted the cultivation of small educated ditch in small areas of Shangcai County and Funan County in Henan Province. We received good results when the rainfall exceeded twice the normal number. The incidence of flat planting in Donghong Town, Shangcai County was 85.8. %, 9.3 kg per mu, gully incidence 8.7%, 30.4 kg per mu, trough the yield increased by 69.4% compared to the flat plant; Funan County Sanlidian township planting rate of 87.8%, 8.5 kg per mu, ditch incidence 17.5%, 36.8 kilograms per mu, ditch than flat production increased 76.9%.

4. Chemical control (1) Seed treatment: Most of the sesame diseases are seed-borne bacteria. Seed treatment can effectively kill germs on the seed surface. It has obvious effect on prevention and treatment of sesame diseases, especially seedling stage diseases. 40% more bacteria can be used for seed dressing. Ling seed amount 0.3%, 70% thiophanate-methyl seed content 0.1%, the test proved that the use of 12.5% ​​Teprazole, 2.5% Si Le Shi, 2.5% Puli Meng seed dressing disease prevention effect is more obvious. (2) Control of growth period Pharmacy: The outbreak and epidemics of sesame disease are fast. Therefore, the prevention and control of pesticides must be carried out before the occurrence of the disease or at the early stage of the disease. Sesquito bacterial wilt, sesame wilt, and sesame stem blight can use 90% of schizophrenia 50-100 grams per mu watered 30 kg, or 25% metalaxyl 50 g per mu watered 30 kg, or 10 % Polaroid 1500 times spray.

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