Pest and Disease control (Bananas)

1. anana Bacterial Wilt (BXW)  

1. BXW Symptoms :
   • This disease is also known as Banana Xanthomonas wilt or BXW and it is native in Ethiopia and outside Ethiopia reported in 2001 ( Rwanda, Kenya, DRC, Uganda and Tanzania)
   • BXW infects all parts of the plant. 
   • a progressive yellowing and wilting of leaves
   • With fruits ripening prematurely and unevenly with internal brown discoloration.
   • When stems are cut, a pocket of pale yellow bacterial ooze appears within 5-15 min
   • Yellow or brown streaks occur in vascular tissues of the infected plan
   • Gradual wilting and plus wilting of the bracts and shriveling of the male buds.
   • flower stalks turning yellow-brown
   • Plant death commonly results from the infection.
2. Management of the Banana Xanthomonas Wilt

Example of some control measure are as follow:

• Use of clean planting materials,
•  Clean tools which are sterilized in fire or diluted sodium hypochloride, de-budding by breaking the male buds with a forked stick,
• Cutting and burying of the diseased plants,
• Crop rotation.

Fusarium wilt (Banana panama disease)

• Panama disease is caused by the fungus Fusarium (the full name is Fusarium oxysporum f. sp. cubense). It is a soil pathogen which infects the root system and goes on to colonise the plant through the vascular system – hyphae of the fungus can even reach the leaves. The disease cannot be controlled or cured other than by soil treatments, which unfortunately have such a detrimental effect on the environment that they are prohibited almost everywhere. Biological methods under development are showing great potential, however. One of the worst effects of Panama disease is the production of so-called chlamydospores , or resting spores, which survive in the soil for decades. As soon as a susceptible banana plant is grown nearby, these spores germinate, infect the plant, and kill it.
• This is a soil – borne fungal disease and gets entry in the plant body through the roots.
• It is most serious in poorly drained soil.

1. Symptoms :

The first internal symptoms develop in feeder roots, the initial sites of infection (1,11). They progress to the rhizome and are most prominent where the stele joins the cortex. As the pseudostem is colonized, faint brown streaks or flecks become evident on and within older leaf sheaths. Eventually, large portions of the xylem turn a brick red to brown color.

The first external symptoms of Panama disease are a yellowing of the oldest leaves  or a longitudinal splitting of the lower portion of the outer leaf sheaths on the pseudostem. This is followed by a wilt and buckling of leaves at the petiole base. In some cases, these leaves remain green. As the disease progresses, younger and younger leaves collapse until the entire canopy consists of dead or dying leaves.

1. Disease Control :

Prevention is the most effective disease control measure. To help prevent Panama disease tropical race 4 from infecting your property, implement on-farm biosecurity practices such as wash-down and decontamination procedures and always use clean, disease free planting material such as tissue culture plants or plants from a proven disease free source.

Managing access to properties and training staff in hygiene management and early disease detection is vital to ensuring early identification and preventing disease introduction. 

SIGATOKA BANANA DISEASE ( Black and Yellow banana Sigatoka)

• Sigatoka is one of the serious diseases affecting banana crop.

Symptoms :

The first symptoms of black Sigatoka disease are tiny, chlorotic spots that appear on the bottom (abaxial) surface of the 3rd or 4th open leaf. The spots grow into thin brown streaks that are limited by leaf veins (Figure 1). The color of the streaks becomes darker, sometimes with a purple tinge, and visible on the top (adaxial) surface. The lesions then enlarge, becoming fusiform or elliptical, and darken to give the characteristic black streaking of the leaves (Figure 2). Adjacent tissue often has a water-soaked appearance, especially under conditions of high humidity.

Control and Management :
 

 Fungicide is frequently applied in areas that have succumbed to the disease, marking no-tolerance zones in areas where there used to be some fungal activity.

Affected leaves are carefully removed without contact with the rest of the plants in the hectare, to isolate the disease to a single region of a plant.
As a precaution, herbs are planted with adequate spacing in between "individuals" (although most bananas in a plantation are of one genotype).

Pools of water where spores could rest during their journey of infection are minimized by building drains that sufficiently collect and channel water to a region far from the banana plantation.

Banana Weevil (Cosmopolites sordidus )

Symptoms

The infestation by C. sordidus begins at the base of the dying outermost leaf-sheath and in injured tissues at the lower part of the pseudostem. Initially the young larvae make several longitudinal tunnels in the surface tissue until they are able to penetrate to adjacent inner leaf-sheaths; the larvae then bore into the pseudostem base and rhizome (in bananas, also into the base of suckers and into roots). Larval tunnels may run for the entire length of fallen pseudostems.

Infested plants have dull yellow green and floppy foliage. Young infested suckers often wither and fail to develop. In a high wind more than average numbers of plants blow down, at times with severe losses.

The young suckers attacked by the borers wither and die very quickly because of larval feeding and tunneling between the lateral roots and the corm. An indication that a young plant is infested is the withering and drying of the curled roll of unopened leaves or growing part of the plant.

 

Control measures

 

• Pest traping Surround the banana plant with Banana pars in a distance of 20 centimeters from banana tree because its eggs or pest can go for hiding under them. The fourth day, collect the pests and kill them or burn them
• Plant stems or mats should be cleaned of plant debris.
• Use of resistant varieties such as Kayinja, FHIA 17and FHIA 25,
• Clean planting material before planting using a hot water treatment: immerse clean trimmed suckers in a
• bath with hot water at 52 to 55°C for 15 to 27 minutes before planting (place a candle  in the hot water –
• when it melts the temperature will be at about this level);
• Good agricultural practices: remove old leaves, rhizome, keep mulch away from the tree (60 cm),
• weeding, application of fertilizers where required
• Pare suckers to remove weevil larvae and eggs as well as nematodes;
• Replace infested plantation with different crops (among food crops)
• and replant banana after 3-4 years.

Picture showing banana weevil collection 

An infected banana plant and bunch

Banana bunchy top disease affects the banana fruit and foliage, and is caused by a single-strand DNA virus, the banana bunchy top virus. BBTV can infect species of the Musaceae family, which includes bananas, plantains, abaca, and more. It is best to establish a banana production area where these alternate hosts are not present. Any age plants can be infected by this virus, but some varieties of banana, including the Cavendish, are more susceptible to the virus. In areas where the virus is less common, the disease is usually spread by planting diseased suckers at the beginning of the season, which means the season is started with a diseased crop.

Control measures

• There are no resistant varieties of banana against BBTV, so the most common method of control is chemical control of the aphid vectors.
• Another way to help control the virus is to remove and destroy any infected plants before the virus can spread.
• Quarantines are also implemented to prevent the import of any potentially infected plant materials, Fruit is not often produced on infected plants, but if it is, the fruit will be deformed, which easily identifies if there is any virus present in the fruits to comply with quarantine regulations;
• Since bananas are not the only host, the alternate hosts for both the virus and the aphid must also be monitored for disease, and sprayed with pesticides to control the aphids more.

Banana Streak virus

Banana streak virus (BSV) is a plant pathogenic virus of the family Caulimoviridae. The primary symptoms of disease are chlorotic streaks on leaves and splitting of the pseudostem. In later stages of the disease, these streaks may become necrotic, and the heart of the pseudostem may rot, ultimately leading to death of the plant.

Control measures

• Infected plants should be destroyed and replaced with virus free plants.
• Only tissue cultures derived from meristems from virus-tested plants should move internationally and be mass multiplied. Even then, care must be taken because of the possible de novo synthesis of the virus in tissue culture.