Emile Frison, president of the International Plantain Improvement Network (INIBAP), warned in the New Scientist magazine in January 2003 that blight will extinguish bananas within ten years! Although this statement has a sensational taste, it is not unreasonable to see from the development trend of the disease.
Fusarium wilt of banana Fusarium is also called yellow leaf disease and Panama disease. At present, banana wilt disease has spread and spread in China's Guangdong, Hainan, Guangxi, and other places, which has caused destruction of bananas in the Pearl River Delta.
symptom
Fusarium wilt is a vascular disease with obvious internal lesions. In the early stage of the disease, the cross section of the lower rhizome of the plant shows yellow or red-brown spots between the middle pith and cortical parenchyma. Large seedling stage and adult stage diseased plants first yellowed from the leaf margin to the midrib in the lower leaves, and this condition was sometimes significantly deficient in potassium, especially in dry and cold seasons.
1. Sweet banana
The rapid development of banana yellow leaves from the lower part to the upper part of the banana leaves, and the development of the edges of the leaves and cracks. This is an important feature that distinguishes other yellowing physiological diseases.
2. Pink banana and dragon teeth
The pink and yellow teeth were evenly yellowed, and the green and yellow leaves were clearly differentiated. After leaf yellowing, the base of the petiole was withered and wilted, and then the other leaves drooped one after another. The color changed from bright yellow to dark yellow, and finally dried and sloppy. The leaves of the diseased plants were also all uniformly yellowed around one week and then dried. The diseased leaf sheaths of the dragon teeth in Zhongshan showed a loose-leafed appearance, with the base of the pseudo-stem cracking, extending inward to the heart and leaves. Pink bananas often have this symptom, but not many bananas.
Newly occurring leaves gradually become smaller and deformed, and bananas sometimes have dead leaves. Although late-sensible plants were able to bud, but the growth was stagnant and the leaves soon withered, the fruits did not develop normally and the pseudo-stems also died. Dead bulbs can still attract new suckers, but the vast majority are sick, and a few can grow and grow normally. They rarely harvest buds.
pathogen
The pathogen is Fusarium oxysporum of the semi-known phylum Subgenus. It has been found that there are 4 physiological races, the first race is harmful to D. grandis, R. edulis, and pink banana; the second race is responsible for the damage of plantains. 3rd race is affected by the genus Heliconia of the family Hennaaceae; the 4th race is responsible for more than 500 kinds of bananas, including bananas, but most of the fruit fingers have banana cultivars with water chestnuts on the 4th. Resistant.
The new classification method is to use the vegetative growth compatibility group to divide the Cuban transformants of Fusarium oxysporum infected with bananas into 35 races, in which the tropical race No. 4 capable of infecting the banana fruit contains 66 races in which the vegetative growth is compatible. The minor races of the group 01213 and 01216 have the highest invasiveness.
Occurrence
1. Infection process
The Fusarium oxysporum f. sp. tritici is mainly propagated from the rhizomes of the yam banana tree through the suction tube to the buds used for propagation. When the diseased buds are used for breeding, the disease will spread. The soil around the root of the diseased banana is also a place where the germs remain.
When the environmental conditions are appropriate, conidia can be produced in the diseased part of the infected host. If banana plants are grown on diseased soil, pathogens can invade from the roots and develop through the host vascular bundles to the stems. The way the bacteria invade the host in the soil is generally through injured or uninjured young roots, or injured rhizomes, and then spread to the pseudostem and leaves. Germs that invade the stem base can enter the sucker along the catheter system. When the mother plant has withered, the sucker can continue to grow for a period of time. After the whole plant has died, pathogenic bacteria can live in the soil. The mycelium and size conidia of the disease can be killed by some fungicides. However, the chlamydospore can survive for a long time under harsh conditions and germinate and multiply once conditions are suitable.
From the seedling stage to the late fruit-bearing period, all the plants were susceptible to disease. The new roots of the plants at the budding stage were less, the resistance was weakened, and the susceptibility was more. The roots of disease-resistant and disease-resistant varieties are resistant to pathogenic mycelium and are not easily infested. And if you use disinfectants or auxiliary agents can increase resistance.
2. Transmission route
The disease can be spread by seedlings, running water, soil, agricultural implements, and agricultural operations. It has a clear epidemic center. The staff in the garden will walk and the shoes will carry germs. Pathogens usually infect during the rainy season (May-June), peaking from October to November. Roots of tissue culture seedlings were treated with gonococcus, and the incubation period could be shortened to 15 days to show symptoms. The disease spreads faster in sandy loam than in brick red soil. Once the sandy loamy banana plantation occurs, it can generally not be planted within two years, while red loam soil can endure for three to four years.
Resistant (resistant) banana varieties
Ordinary determination of tropical race 4 is based on whether it can infect bananas. According to the author's preliminary identification of the disease resistance of banana varieties in severely afflicted areas (more than 50% of the land mass of newly planted Brazilian bananas), the resistant (resistant) varieties (strains) of bananas are as follows.
Xinbeijiao (Baojiao GCTCV218) harvest rate of 65% to 90%, GCTCV219 harvest rate of more than 90%, GCTCV215 harvest rate of 85%, Nongke No. 1 harvest rate of 65% to 85%, Yueyou Kang No. 1 harvest rate of 85% Above, anti-blow No. 1 harvest rate of 65% to 85%, anti-blossom No. 5 harvest rate of more than 85%, Nantian disease-resistant banana (yellow, cyan, red) series of strains harvest rate of 85% to 97%, etc.; The harvest rate of the Haigon bananas was more than 95%, the rose banana harvest rate was over 95%; the harvest rate of the black bananas and bananas of the dragon tooth bananas was more than 80%, the harvest ratio of the powder crabs 1 was more than 90%, and powder Plantains, such as native pink plantains and Bengal bananas, most plantains with water chestnuts have certain resistance to the fuzz races No. 1 and No. 4. Ordinary pink banana varieties (including red pink bananas) exhibited high-level fusarium wilt disease 1 in the field and resistance to wilt disease on the 4th.
Control methods
1. Introduction requires strict quarantine
When importing banana varieties from abroad, strict quarantine measures must be implemented to isolate and observe them for two years. If no pests and diseases occur, the planting should be promoted. The introduction of the test tube seedlings prevents the introduction of new diseases. The introduction of soil-carrying banana seedlings from the ward is forbidden.
2. Breeding resistant varieties
Strengthen the breeding work against the disease-hearing banana varieties, and continuously improve the economic and biological characteristics of the disease-resistant sweet banana, so as to meet the market requirements. Plant disease-resistant varieties, medium-resistance varieties (strains): Baodao Hejiao, No. 1 Agricultural Science, Nantianqing, Nantianhong, Fencha No. 1 and Jiali. High-resistance strains: Nantian yellow and Haigou banana. According to the circumstances of the land before the decision to plant varieties. Severe disease, planting high-resistance varieties with short intervals, and planting high-resistance varieties with soil acidity.
3. Ensure that the provenance is not sterilized
The planting seedlings without pathogens were selected as planting materials to prevent the introduction of pathogens; the planting of bananas in the new district should introduce uninitiated test tube seedlings to cultivate large seedlings themselves, and it is not recommended to buy seedlings in the field; the new planting areas in the wards should be selected from black sugarcane, leeks, and corn. Rice, sugar cane, papaya and other crops have been used for 3 years.
4. Kill diseased plants in time
The diseased plants were found to be immediately killed with herbicides, burned in place, and soil sterilized. The planting point is covered with Plastic Film after being disinfected with 600 grams of lime nitrogen. It can also be diluted with formalin from 20 to 50 times and applied to the soil. Lime and soil disinfectants can also be used for disinfection at the planting points. Insulate around the diseased plants and try not to enter the isolation area.
5. Reasonable selection
The pink plantain should choose the uncultivated plantain or banana plantation. The upstream of the irrigation water has not been planted with pink plantains, over-mountain aromas, loose soil and well-drained sandy loam to clay loam soil. It is not appropriate to choose Taisha sandy soil. In the mountainous area, there should be no mango (acidic). Paddy fields must be planted in sorghum and deep trenches. It is best not to plant Brazilian bananas in large areas where the surrounding environment is severely affected.
The diseased spot can be changed into plantain, Haigung banana (anti-disease emperor banana), disease-resistant powder hybrid No. 1 and so on. Fusarium prefers weakly acidic soils, improves soil physical and chemical conditions, increases soil amendments, alkaline organic fertilizers, regulates soil pH to 7.0, causes an unfavorable environment for the propagation of pathogens, controls root nematodes, and reduces the possibility of invading bacteria. Applying more bio-fertilizers and organic fertilizers increases the ability of the plants to resist pathogenic bacteria, so that the plants can be harvested early and harvested early.
6. High-incidence areas should be replanted
The incidence rate is higher than 20%. When more than one point occurs, rice, lotus root, corn, leeks or varieties that are resistant to disease should be replanted, but soil disinfection should be performed before planting. Soil fumigation and disinfection before the new planting of the ward, with calcium cyanamide 60 kg / acre, leaching and immersed in plastic film covered 15 days after the colonization.
7. Strengthen field management
Field management, grass, fertilization, stakes, irrigation, root damage, root cutting, injury to bulbs, reduce the chance of infection. In the early days of the garden, there are more grasses, chemical weeding or grass-straw suppression, reducing grass and banana composting, reducing pests, and reducing manual removal of roots. After planting, especially after drawing buds, the wind should be staked, or the belts should be connected with each other, and the wind should be connected in series; irrigation and trenching should be conducted. The requirements of the pink banana are very sensitive to the water. The groundwater level must be less than 60 cm. Otherwise, the plants will grow poorly and they will easily induce bad head disease.
8. Prevention and treatment of resistant varieties
The middle leaves of the resistant varieties or high-resistance plants yellowed the edges of the leaves, yellowed at the cracks, or had new leaves missing and yellowing as symptoms of initial onset. It is necessary to adjust the pH of the soil to 5.0 or more, increase the organic fertilizer bio-fertilizer, and spray hymexazol and chitosan to alleviate the symptoms. Restore growth.
Single Tunnel Greenhouse,Invernadero Greenhouse,Vegetables Fruit Greenhouse,Garden Film Greenhouse
Qingzhou JuLong Agriculture Equipment Co.,Ltd , https://www.julonggrowtech.com