Banana yellow leaf disease is a devastating disease caused by Fusarium anatipestifers that infects bananas in Fusarium oxysporum. It occurred in large areas in Panama at the beginning of this century, resulting in the loss of large banana gardens. Destroyed, and thus commonly known as "Panama disease." The cause of the disease is believed to be due to lack of elements such as zinc and magnesium. The disease occurs more severely in acid soils or in continuously planted banana groves. The rapid growth period of bananas (May to June) coincides with the rainy season and the rise of groundwater level is the onset of the disease. Banana yellow leaf disease has already invaded all kinds of bananas in more than 1,100 kinds of banana germplasm resources in the world. It is highly valued by banana growing regions in the world. At present, our province mainly adopts methods such as chemical prevention, antibacterial soil, paddy-upland rotation, leisure rotation, selection of disease-resistant and disease-resistant varieties, and other methods for prevention. However, there is currently no cure for yellow leaf disease.
Yellow leaf disease in banana disease occurs in more than 50 countries around the world. Because of its rapid spread, it is difficult to eradicate. Once it occurs, the plants yellow and die and cause the destruction of the plantation, which is classified as dangerous by most countries in the world. Plant quarantine disease. The disease is a disease of Wiesen. Its long-distance transmission routes are mainly planting diseased propagules and flowing water on the soil surface. The primary infestation source for soil transmission is residual diseased tissue and chlamydospores of pathogenic bacteria in the soil. Pathogens can survive in the soil for a long period of time at least 3 years after the parasitic and saprophytic alternations. When the conditions are suitable, the bacteria invade the wounded lateral roots and sense the wounded rhizomes; afterwards, the extended contaminating ducts expand the catheter, blocking the ducts, turning brown, and impeding the transport of water. , And the leaves are wilting, causing the death of the plant. Therefore, if the disease does not change after the occurrence of the disease, continue to grow bananas, and even a strong young plant will soon die. Yellow leaf disease mainly depends on water, soil, and other substances as media, and long-distance transmission is the most direct way, seedlings.
The old leaf margin of the diseased banana plant is yellowed firstly, gradually expanding to the middle rib, the petioles softening and sagging, finally withered, and the young leaves are gradually yellowing. Finally, the entire banana plant withered and died, and sometimes the diseased plant's pseudo-stem periphery Leaf sheaths occur longitudinally from the base. The pseudo-stem or tuber of the diseased plant can be found to have browning phenomenon. In the later stage of disease, the tan-colored vascular tissue runs up and down through a long strip. Sometimes germs invade and suck buds from the stem of the mother plant through the site of attachment to the sucker.
Incidence pattern: yellow leaf disease is a fungal disease. The pathogen is Fusarium oxysporum and its variants. The pathogenic bacteria can produce small conidial spores and thick-film spores in the diseased tissue, but mainly in the soil with thick-film spores. Surviving, its survival can be as long as several years. In general, acidic sands are prone to occur, and poor drainage and rooting can promote the disease. There are four physiological races of this pathogen, which caused the yellow race of plantain (Borrocarpus, Cinnamon) to be the fourth race race, which caused L. guineensis (plantain) yellow leaf disease to be the first physiological race. Pathogens from the infection to the appearance of external signs, incubation period can be as long as 5 to 6 months, the province's southern banana planting period in the 3 to 5 months, it is generally only after October each year began to appear external symptoms. The disease is a sexually transmitted disease in the soil. The pathogenic bacteria can be spread by diseased soil and flowing water. Sometimes the pathogens invade and suck buds from the tuber of the mother plant through the connected parts of sucking buds. Pathogens live in the soil with thick-film spores for many years, and they can also survive in the weeds of sedges, cycads, and other days.
At present, there are three major problems in the prevention and control of yellow leaf disease in Guangdong: First, insufficient funds; Second, weak awareness of farmers; Third, local governments do not pay enough attention. Most banana production areas are seriously underfunded. Some local governments did not include the banana yellow leaf disease prevention and control project in their budget, did not establish a compensation mechanism for epidemics, and did not designate disease-affected areas, buffer zones, and protected areas.
Banana is a pillar industry of Zhongshan fruit industry. Zhongshan City has done a lot of experimental work in the prevention of banana yellow leaf disease. After several years of comprehensive prevention experiments, a set of effective measures for prevention and control was concluded. The main contents are:
1. Change 100-110 strains of mu plants to 120-140 strains and maintain more than 100 effective plants per acre to ensure relatively stable yield benefits;
2. Change free irrigation to low pressure micro sprinkler;
3, to change the water deep ditch sorghum to water deep ditch sorghum, rake loose soil and more water for the loosing water, to avoid damage to the roots and reduce the occurrence and spread of disease;
4. The planting of spring planting is planted throughout the year. The proportion of spring planting plants in the city is reduced from 90% to 60%, and the proportion of planting plants in summer and autumn is increased from 10% to 40%.
5, change over-application of chemical nitrogen fertilizers, hormones, for the application of organic fertilizers and the rational use of hormones;
6. To promote soil chemical prevention and the addition of trace elements, the comparative test of the banana tree treated with Tianan can reduce the incidence of 7%, and the banana trees treated with calcium silicate can reduce the incidence of 14%.
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