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Symptomatology

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Fusarium wilt symptoms



External symptoms


Affected plants wilt rapidly, older and then younger leaves become yellow and brown, and plants eventually die. Yellowing of the leaves may differ in symptomology between banana varieties and Foc races involved. In some cases, the base of pseudostems split.

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FABI split pseudostam2.BMP
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Internal symptoms

Very typical in rhizome and pseudostem. Internally, a deep golden discolouration of the inner rhizome develops, while the vascular bundles in the pseudostem will turn yellow to reddish-brown.

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Other banana wilt diseases

Bacterial diseases: External symptoms of Moko disease, blood disease and Xanthomonas wilt are often similar to that of Panama disease. However, leaf yellowing in these diseases often start with the youngest to the older leaves, which is different to the progression of plants affected by Foc. Also, a yellow ooze is exuded in plant tissue affected by bacteria.

Pythium root rot and Armillaria rot can also display symptoms similar to Fusarium wilt. Pythium root rot is uncommon and limited to young plants in wet environments, whereas Armillaria root rot is often localised to a few plants, and shows white fungal tissue in affected plant material.

     Blood disease

Bacteria oozing out of the flesh of the fruit
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Younger leaves are more severely affected
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Abiotic stresses

Water-logging, drought and lightning can all cause leaf yellowing that could be wrongly identified as Fusarium wilt symptoms. None of these abiotic stresses will show any internal symptomology similar to Panama disease, and the fungus cannot be isolated from the rhizomes and pseudostems.

      Cold damage

Cold damage-old leaf2.jpgBananas affected by cold winter temperatures
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        Lightning

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