Symptoms, Prevention and Control Methods and Cultivation Techniques of Banana Fusarium Wilt
Although nutritious, soft and glutinous bananas can be bought everywhere around the world, this is thanks to its large annual output and convenient transportation. Because bananas are actually only produced in tropical and subtropical regions. And sometimes, because some diseases are prone to occur during the cultivation of bananas, the yield of bananas is significantly reduced.
Symptoms and Prevention and Control Methods of Banana Fusarium Wilt
1. Symptoms
External symptoms: In the adult plant stage, the diseased plant first shows a distinctive yellow color on the lower leaves and the outer leaf sheaths. It initially occurs at the leaf margins, then gradually expands toward the midrib, contrasting markedly with the dark green parts of the leaf.
Internal symptoms: In and around the pith of the central column, there are yellow-red diseased vascular bundles, appearing as spots or lines. The closer to the stem base, the darker the color of the diseased area. The woody vessels of the roots turn reddish-brown and gradually become dark brown and dry up. The corm turns dark brown and gradually rots, with a peculiar odor.
2. Prevention and Control Methods
1. Strictly implement the quarantine system. Strictly restrict the introduction of banana seedlings and Manila hemp seedlings and the soil attached to them from diseased areas.
2. Select and plant disease-free seedlings and disease-resistant varieties. To ensure that the banana plantation is free of fusarium wilt, disease-free banana seedlings should be selected and planted. The basic method is to introduce seedlings from areas without banana fusarium wilt. In addition, disease-resistant varieties should be selected as much as possible.
3. Block off diseased areas to prevent the spread of the disease. If scattered diseased plants are found in the banana plantation, they must be immediately pulled up by the roots, chopped up, put into plastic bags, lime added, the bag openings sealed, and moved out and away from the banana plantation to let them rot.
4. Treatment of diseased soil. In order to eliminate the source of infection and cut off opportunities for transmission, treatment of diseased soil is a very important measure.
5. Strengthen cultivation management, apply more fertilizer, dig ditches for drainage, and enhance plant disease resistance. In severely affected banana plantations on flat land, where conditions permit, flooding and fallowing for half a year or rotation with rice can be carried out.
6. Use agents such as carbendazim, hymexazol, and metalaxyl-hymexazol to disinfect the soil of affected fields 2-3 times to reduce the number of pathogenic bacteria in the soil.
Main Causes of Banana Fusarium Wilt
The pathogen belongs to the Deuteromycotina, Hyphomycetes, Fusarium genus in fungi and is a soil-inhabiting fungus. The most suitable pH value for the pathogen's hyphae is 5.0-6.0, and it grows at a temperature of 26-30 degrees. The disease is severe under conditions of many years of continuous cropping, poor soil drainage, poor air permeability, acidic soil, relatively high soil temperature, and poor soil fertility.
Cultivation Techniques for Bananas
1. Planting and intertillage
The best time for field planting is spring planting. Combined with the soil conditions of the banana base in Gengma County, the planting methods use trench planting and pit-pond planting. Paddy fields use trench planting, requiring deep plowing of the soil followed by making beds, one bed with two rows, with a ditch between each bed 0.5 m deep and 0.3 m wide, and a bed length of 100 m, with secondary drainage ditches set up to facilitate irrigation in the dry season and drainage in the rainy season. The planting spacing is 1.7×2.2 m in wide and narrow rows, planting 176 plants per mu; dry land uses the pit-pond planting method, with a planting spacing of 1.7×2.6 m in wide and narrow rows, planting 150 plants per mu.
2. Fertilizer and water management
After planting, fertilization must adhere to "frequent application, light application, and key application." 2-3 weeks after planting, use dilute manure water or a small amount of quick-acting chemical fertilizer mixed with 5 kg of water, applying once every 7-10 days (carried out on sunny days, poured 10-15 cm away from the banana head), until bud emergence, and as the plant grows, gradually expand the fertilization range along the canopy cover. In addition to daily topdressing, it is also necessary to combine intertillage and earthing up with two heavy fertilizations. The first is the stalk-changing fertilizer, carried out from late April to early May, applying 0.3 kg each of phosphate fertilizer and potassium fertilizer per plant, and 3 kg of ash manure; the second is the fruit-changing fertilizer, carried out at the beginning of autumn or from late June to early July, applying 5 kg of ash manure and 0.5 kg of compound fertilizer per plant.
Prevention and Control of Banana Pests and Diseases
1. Black spot disease
Symptoms: In the early stage, many small black spots are produced on the leaf veins or around them and gather together (the conidia of the pathogen). In the middle stage, the gathered small spots (conidia) turn brown, and the leaf veins and surrounding areas turn yellow. In severe cases, the entire banana leaf dries up.
Prevention and control methods: The main strategy for the prevention and control of black spot disease is "early prevention, comprehensive measures, and mainly protective agents."
1. Adjust planting density and enhance the ventilation and light transmission of the banana plantation.
2. One month after banana transplanting and before and after budding, use 24% Kairun at 1500 times dilution for foliar spraying 3 times.
3. In the early stage of the disease, use Roushuitong at 3000 times dilution + 70% Namixxin at 700 times dilution + 80% Dacheng at 500 times dilution and continuously spray 2-3 times (can also control leaf spot disease).
4. In the middle stage of the disease, use 12% myclobutanil at 800 times dilution + 24% Yingde at 1000 times dilution + 50% thiophanate-methyl (aqueous agent) at 600 times dilution and spray 2-3 times, once every 7 days.
2. Root-knot nematode
Disease symptoms: After being damaged, the aboveground parts of the crop grow slowly, the leaves turn yellow and lose luster, and the internodes shorten as if there were a lack of fertilizer and water; the underground root system grows many milky-white root galls, which later turn yellow-brown to dark brown. In severe cases, the roots rot and the entire crop dies.
Prevention and control methods:
1. Improve the soil and apply more organic fertilizer (such as decomposed human and livestock manure, humic acid, and amino acids).
2. Frequently turn the soil and expose the ground to the sun, destroying underground insect eggs through farming operations and direct sunlight.
3. Chemical control: In the early stage of the disease or in March and April and October and November each year, use 1.8% abamectin at 3000 times dilution + 40% phoxim at 600 times dilution for root irrigation, or broadcast 3% Dichongsaxing (4 kg per mu).
The symptoms of banana fusarium wilt are still relatively obvious. Everyone still needs to observe carefully during the planting process. This pathogen is also called the AIDS of bananas, and its impact on bananas is very great. Growers must not ignore it.