Rice false smut pollution affects rice yield How to control rice false smut

Rice false smut is one of the main rice diseases in eastern Hebei. The disease not only directly affects the yield of rice, but also seriously pollutes rice and affects the health of people and animals after eating.

Rice false smut

(1) symptom identification

Rice false smut is a fungal disease caused by Sclerotinia oryzae, which causes large black grains and is easy to identify.

(2) occurrence regularity

The pathogen overwintered mainly as sclerotia in the paddy field, and some diseased grains were mixed in the seeds or the diseased spores were attached to the seeds. When the conditions are suitable in the next year, the sclerotia germinates and the diseased spores spread by airflow, infecting the flowering organ and young glume of rice, which is called flowering infection. After rice flowering and closing glume, the pathogen can no longer invade, and the disease begins to appear at flowering and filling stage of rice. The occurrence is more serious in the general corners of the field, partial application of nitrogen fertilizer, the development of rice is green and luxuriant in the later stage, and the disease is more serious in the period of rainfall and high temperature during flowering. The optimum temperature for the development of the pathogen was 26-28 ℃.

For the rice planting susceptible varieties, the application of panicle fertilizer is too late or the amount of fertilizer is too large, which makes the rice grow too luxuriant and green after heading, and the high wet weather of continuous rain during flowering is easy to cause a large area of disease. The false smut of rice was very serious in the 1980s, and it was very light in 1990-1993, so it was very difficult to do the experiment. However, after the variety Jijing 14 was replaced in 1994, the disease became popular again that year, so it had a great relationship with the varieties.

(3) Prevention and control measures

The prevention and control of rice false smut focuses on prevention, one is reasonable fertilization to ensure the healthy growth of rice plants, and the other is early chemical protection on the premise of rice break, which is the key.

The pesticides for the control of rice false smut can be divided into copper preparations, organic fungicides and biological fungicides. The use of organotin preparations has been banned in our country and is no longer introduced.

The main results are as follows: (1) Copper preparation: 30%DT (100g / mu), 14% copper chelate suspension (350,400 ml/ mu), 23% copper chelate (125mu), 27.12% copper noble (basic copper sulfate 30-50ml / mu).

It is required to apply pesticide 3-10 days before the break of rice (from the time when the sword leaf is just exposed to the full growth of the flag leaf, which should be controlled at the same time as the sword leaf pillow and the inverted second leaf pillow). During this period, the earlier the better. DT, ammonia copper can not be applied after the break of rice, nor can it be mixed with other agents, otherwise it will produce crucial points, but copper can be mixed with nobility.

(2) Organic fungicides: 10% Yang (hexazolol) 40g/ mu, 12.5% Wo Guoli (diniconazole) 20g/ mu, spraying 3-5 days before rice break.

(3) Biological fungicides (antibiotics): 5% Jinggangmycin water agent 150,200 ml/ mu, also for the treatment of rice false smut and sheath blight. It takes more than 2 times to use the medicine. The rice sword leaf is sprayed once when the tip is just exposed, and again in a few days.