Occurrence and Control Techniques of Ramie Wilt Disease


Ramie is an important oil crop, especially when the current energy shortage is becoming a global problem. Its comprehensive development and utilization value is even more important. The development field involves energy, environmental protection, pharmaceutical chemicals and high-tech fields. Not only the castor bean has high development and utilization value, but also its by-products are of considerable value. The rods can be used for papermaking and leaves can be fed with ramie silkworms, and the castor bean cakes can also be comprehensively utilized. The detoxification treatment is a high-quality livestock and poultry feed; For the cultivation of edible mushrooms, mushroom waste is a good fertilizer. At present, a large area of ​​ramie planting is being prepared. One of the problems to be solved is the prevention and control of diseases and insect pests, of which wilting disease (also known as blight) is one of the major diseases.

First, the symptoms of castor wilt

Ramie wilt disease mainly occurs between April and May. Based on the period of emergence, it can be divided into two types: young shoot rot and seedling tumbling. Shoot rot mainly occurs in seedlings that have not yet been excavated after germination. The young shoots or seeds just broke and even if the seeds did not germinate, they could become infected and rot in the soil. There were also young shoots that had not yet been excavated, and the young white shoots were infected and rotted together. The seedling stage tripping occurred after the emergence of the seedlings to 5-6 true leaf stages, with more cotyledons. At the time of onset, the base of the young stem near the soil surface was reddish-brown or black-brown. The diseased spot turned around the stem, and the diseased part was curled up and rotted. It fell to death on rainy days. When it was fine, the young stems were fine and silky and stood upright. wilt. When the seedlings have several true leaves, the lesions on the stem base become brown, rot or flaking, and the leaves are blue and dry, and rot sometimes occurs on one side of the stem. After nineteen true leaves, the disease no longer occurs.

Second, pathogens and epidemic conditions

1, pathogens. There are two pathogens of Castor wilt: First, non-invasive pathogens, mainly due to low-lying land, water in the soil or the lack of oxygen in the roots of seedlings due to continuous cloudy rain and suffocation, wilting of the aboveground; the second is the invasion of pathogens. Dyeing, this is the main reason. There are three types of fungi that cause fusarium wilt: Pythium aphanoidea and several Fusarium species in the phytophthora layer. These three types of fungi are soil habitual bacteria that can survive long-term in the soil.

2. The epidemic conditions of Ramie wilt disease. The sclerotia formed by the above three types of fungi and the latent organisms latent in the diseased tissue are the main sources of the incidence of seedlings. These germs can invade a wide variety of plants; cucumbers, peppers, beans, and many herbaceous flowers and many forest seedlings. The germs need high humidity during reproduction and infestation of plants, and have a wide range of adaptation to humidity. For example, the growth temperature range of Pythium and Rhizoctonia is 4-28°C; Pythium is at a soil temperature of 12-23°C. The most serious harm. Fusarium is a serious hazard at soil temperatures of 20-30°C. Diseases are severe under the following conditions: continuous cropping of susceptible crops, accumulation of pathogens in the soil, continuous low temperature and raining after sowing, slow emergence of seedlings, lack of light, thin and weak plants, resistance to disease, mechanical damage or immature seeds After sowing, there are many opportunities for unearthed and poorly developed infections; planting areas are low-lying, watery, sticky, and extensively managed. Because ramie is a crop that is hi light, drought-resistant, and untainted.

Third, prevention and control technology

Timely sowing and cultivating strong seedlings are one of the important measures to achieve high yields. To effectively control Ramie wilt disease, comprehensive control measures must be taken before sowing.

1. Nutrient seedlings: After the nutrient soil has been prepared, mix 50% carbendazim WP with 0.5% of the soil weight and then soak the seeds. Each seedling has three seeds, one for one hole during planting, and the rest is used for supplementing seedlings.

2, medicine soil cover species: to soil weight of 0.5-0.8%, 75% of the enemy of dexamethasone WP and soil mix cover species.

3, strengthen the management of the cultivation of strong seedlings: seedling period timely cultivating fertilization, in particular, should pay attention to the exclusion of field water, prompt seedlings robust growth, increase resistance to disease.

4, chemical control: After the onset of seedlings, it should be immediately prevented. The commonly used good finisher is: 50% carbendazim WP is watered 800-1000 times (or 60% anti-mildew Pod - carbendazim hydrochloride); 60% anti-virus WP can water 500 Times; 5% procymidone wettable powder 800 times; 1:1:100 Bordeaux mixture, etc. You can also use 15% lime water drenching roots.

5. Discard the dead seedlings in time, and use the quicklime to disinfect the diseased points and remove the seedlings in time.


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