Plants turn yellow and die

Bacterial corm rot

Cause: The bacteria Pectobacterium spp. (formerly known as Erwinia spp.) that are common soil inhabitants. Plants that are stressed during the dry season can succumb to invasion during the wet season. 

Solution: No chemical treatments are available. Ensure adequate moisture levels are maintained during the dry season and provide good drainage during prolonged wet seasons. 
Water-logging after planting can also cause small and stunted plants.

Water-logging

Cause: Not enough oxygen for the roots caused by too much water in the soil from rainfall or irrigation. 

Solution: Avoid planting in areas that are often water-logged and in heavy soils. Install and maintain the drainage system for your plantation. 
Left: early stage showing the yellowing of leaves. Right: late stage after the leaves have dropped.

Panama disease (Fusarium wilt)

Biosecurity Alert

Cause: The fungus Fusarium oxysporum f. sp. cubense which is a soil—borne organism. It is spread in water, soil and planting material. The fungus enters the plant through the roots and blocks the conducting tissue within the plant, resulting in wilting, yellowing of leaves, splitting of pseudostem and death of the plant. There are several “races” of the disease which affect different varieties.

Solution: There is no cure for affected plants. Use only approved planting material and do not plant in previously infested areas.

Biosecurity obligation: Panama is a notifiable disease and you must report any suspicious plants. If you suspect Panama disease you must notify Biosecurity Queensland immediately (13 25 23). 
More info:
 

Herbicide damage (glyphosate)

Cause: Glyphosate spray drift onto green parts of the plant. The first symptom is yellowing of leaves.

Solution: No cure for damaged plants. Be extremely careful when using glyphosate.