Recently, many farmers and friends have reacted that the leaf sheath of rice has become black, and the rice grain has also become brown or black grain, and I don't know what the reason is. It is understood that rice sheath rot is heavier than last year, especially the storm is more, the leaves are easily injured, infected with germs, prone to all kinds of diseases, the following look at a picture sent by a farmer friend, what is the disease?
From this picture, plants with more brown grains in the shell, such as leaf sheath rot disease, sword leaf sheath damage, young spikes when the ear is drawn by the shell by the disease bacteria also became diseased. If there are more plants in the field, considering that there have been multiple local rainy processes recently, it is necessary to pay attention to the combination of drugs for the prevention and control of rice blast to prevent the aggravation of the disease. Applicable drugs include pyrazole ether ester (coo), fluorocyclic azoxystrobin, benzopyroxystrobin and so on. When it is not too heavy, a mixture of carbendazim and imidamine can also be used.
Rice leaf sheath rot disease, also known as sheath rot disease, is a fungal disease, with Fusarium graminearum accounting for the absolute majority, followed by Fusarium beads and crospora, and the severely damaged rice ears appear brown. After the occurrence of the disease, there are many brown grains, high black rice rate, increased grain grain rate, decreased 1,000 grain weight, poor rice quality, yield loss of 10%-20%, and heavy ones reached more than 30%.
First, leaf sheath rot disease mainly manifests pathologies: irregular spots from brown to dark brown on the leaf sheath of the sword leaf, light in the middle, black and brown on the edges, and severe tabby striated spots, expanding to the entire leaf sheath, causing the leaf sheath and young ears to rot. The growth of the affected rice was hindered, which seriously affected the yield of rice.
Second, the main causes of the disease:
1. Number of fungal sources. There are many remnants of sick straw placed in piles, many diseases, and serious diseases.
2. Water and fertilizer management. Too much or too little nitrogen fertilizer can aggravate the disease, and the combination of nitrogen, phosphorus and potassium is mild.
3. Climatic conditions. Temperature and humidity are the main causes of disease occurrence. The temperature is 20-25 °C, relative humidity of more than 90% as appropriate, therefore, the temperature from the gestational stage to the panicle stage can basically be met, and the climatic conditions that affect the humidity are rainfall, so that the rainfall is large, the rain is more, the incidence is heavy, and vice versa, the onset is light.
III. Prevention and Control Measures:
1. Select disease-resistant varieties, deal with diseased straw in time, and eradicate weeds on the edge of the field and ditch. In combination with other rice diseases, seed disinfection is carried out to reduce the source of bacteria. Rational use of fertilizer water, the use of formula fertilization technology, to avoid partial application, more nitrogen fertilizer, so that the fertilizer is applied in stages, to prevent the late defertilization of premature aging, sandy soil should be appropriately increased potassium fertilizer. In addition, it is necessary to do shallow water irrigation, roast the field in a timely manner, and strengthen fitness cultivation to improve the disease resistance of rice plants. The wide and narrow row method is adopted when planting seedlings, which is conducive to field ventilation and light transmission, and reduces the degree of field closure, thereby reducing field humidity and reducing the chance of pathogen infection.
2. When rice has been pumped, spraying pyrazole ether esters, azoxystrobin, benzopyrosyl esters is an applicable drug for the prevention and treatment of sheath rot, and the addition of pentazool and carbendazim will be more stable.
Compiled by "Yun Zhongdi", for reference only, please indicate the source of the reprint!