The Main Diseases and Insect Pests of Banana and Control Techniques

Abstract: Doing a good job in the prevention and control of banana diseases and insect pests is the premise of improving banana yield and quality. By using ecological means and pollution-free control technology for banana planting, water and fertilizer and soil management are carried out in accordance with the principles of prevention first and comprehensive control to ensure the healthy growth of pollution-free banana trees. This paper introduces the occurrence symptoms and control measures of the main diseases and insect pests of bananas, and provides a reference for the majority of farmers to plant pollution-free bananas and improve the economic benefits of pollution-free bananas.

1. The main diseases of banana and control measures

1.1 Fusarium wilt

1.1.1 Symptoms

Banana fusarium wilt is a common disease in banana growth. It mainly occurs in the middle and late stages of banana budding. After the plant is mature, the lower leaves of the banana and the outer sheath of the pseudostem will gradually turn yellow, and the base of the petiole will become softened. The yellowed leaves gradually wither, until all the leaves of the diseased plant wither, and the fruit is small, few or deformed.

1.1.2 Control technology

1) Agricultural control

Rotational planting is to plant rice, sugarcane or some aquatic plants on the plots where bananas are grown. The rotation crops can secrete substances that inhibit pathogens to achieve the purpose of inhibiting pathogens. Under normal circumstances, the crop rotation time should be more than 5 years. However, it should be noted that the crop rotation must adopt the cultivation method of high-row cultivation, which can effectively avoid the impact of stagnant water on crops, and can also effectively isolate pathogenic bacteria to prevent them from spreading through rainwater and causing other crops to suffer. Rotational fertilization is mainly based on the application of organic fertilizer or lime nitrogen fertilizer, such as nitrogen fertilizer, phosphate fertilizer, potassium fertilizer, calcium fertilizer and magnesium fertilizer, which can not only optimize and improve the soil environment of crops, but also effectively inhibit the growth environment of pathogens and promote rapid growth of crops. In addition, when selecting seedlings, be sure to choose varieties with strong disease resistance and disease resistance. If diseased plants are found, glyphosate and carbendazim can be used to inject the diseased plants in proportion. The yellow leaves and diseased branches must be cut off in time, and sprayed with lime water to prevent the spread of bacteria. 

2) Chemical control

Sprinkle 5% abamectin granules on the planting area to control the damage of underground pests and root-knot nematodes to banana roots. The dosage of 1.5% abamectin granules was 52.5 kg/ha.

3) Biological control

The use of antagonistic Pseudomonas fluorescens, Streptomyces, and Pseudomonas aeruginosa in banana planting plots can effectively prevent and control Fusarium Wilt. Choosing banana varieties with strong disease resistance can reduce the chance of disease and insect pests.

1.2 Leaf spot disease

1.2.1 Symptoms

Spots appear when banana leaves are infected by the fungus, and the old leaves of the banana tree first develop the disease until it spreads to the entire leaves, affecting the photosynthesis of the banana tree.

1.2.2 Control technology

1) Eliminate the source of bacteria

Choosing banana varieties with strong disease resistance and disease-free banana seedlings can improve the disease resistance and growth rate of banana trees. During the growth period of bananas, the diseased leaves and branches on the banana trees should be cut off in time, and the burning and disinfection should be carried out in a centralized manner to effectively inhibit the spread of bacteria sources, reduce humidity and reduce the breeding of bacteria.

2) Strengthen fertilizer and water management

In the rainy season, the accumulated rainwater should be cleaned up in time to prevent bacteria from contaminating the water source. In the dry season, it is necessary to do a good job of replenishing water to ensure the water needed for the growth and development of bananas. In addition, it is necessary to increase the application of decomposed organic fertilizers to reduce the incidence of banana plants. The ratio of nitrogen, phosphorus and potassium of organic fertilizer should be controlled in the range of 1:0.5:3, and trace elements such as calcium and magnesium should be added to improve the disease resistance of banana plants.

3) Chemical control

Before the budding of banana trees, alternately spray 80.0% thiophanate-methyl 750 times, 12.5% epoxiconazole 750 times or 30% difenoconazole-propiconazole 750 times, spray three times continuously, Spray once every 25 days.

2. The main pests of bananas and control measures

2.1 Stephanitis typica

2.1.1 Symptoms 

When the temperature reaches 28 degrees, the reproductive cycle of the stephanitis typica is 34.5 days. At this time, the larvae and adults of the stephanitis typica will attach to the back of the banana leaf and gnaw, causing the banana leaf to gradually become yellow-white mottled, and the back of the leaves will also show dense brown spots, causing the leaves to appear yellow, wither and other symptoms. The stephanitis typica mainly occurs in a relatively dry environment in summer, and it is very harmful to bananas.

2.1.2 Control technology

1) Eliminate insect sources in time

Cut off the banana leaves attached with the larvae and adults of the stephanitis typica to prevent other leaves from being infested. The cut leaves must be destroyed in a centralized manner, or the leaves are buried deep, so as to control the problem of secondary transmission from the source.

2) Chemical control

When preventing and controlling the harm of young larvae, 750 times of high chloride and emamectin with a concentration of 5.5% or 750 times of 4.5% high-efficiency cyfluthrin can be used, and the banana leaves can be sprayed according to the rotation method, so as to completely kill the stephanitis typica larvae.

2.2 Cotton leaf worm

2.2.1 Symptoms

At the larval stage, cotton leaf worm mainly uses soil crevices or the back of leaves as habitats. It hatches in the morning and is active during the day, with a habit of foraging in groups. After 2 years of age, it will gradually disperse and forage at night, and its activity is highest at midnight. After cotton leaf worm is transformed from larvae to adult, it will stick to the back of banana leaves during the day, and become active at night, prefer light and lay eggs on banana leaves. Its habit of lurking during the day and active at night is very harmful to the growth of bananas.

2.2.2 Control technology

In addition to competing with banana trees for nutrients, the weeds in the growth process of banana trees are also a hiding place for some pests. These weeds should be eradicated and burned in time. Then, spray 2.5% methylamino abamectin benzoate EC 1500 times liquid or 1.8% abamectin EC 1500 times liquid on the front and back of banana tree leaves alternately.

3. Conclusion

In summary, the above measures provide a reference for farmers to prevent and manage diseases and insect pests in the process of banana cultivation. By taking the above scientific and effective measures to prevent and control diseases and insect pests, the quality and yield of bananas can be better guaranteed.