Corm smelly, rotting or discoloured

Corm smelly, rotting or discoloured

Panama disease (Fusarium wilt) (discoloured)

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. It 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.
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:
The rotting corm has a strong odour.

Bacterial corm rot (smelly, rotting, discoloured)

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.

Moko disease (discoloured)

Biosecurity Alert

Cause: The bacteria Ralstonia solancearum race 2. Moko is a soil-borne disease and is spread with soil, in water, on implements, in planting material and by insects from flower to flower. The infection enters the plant through the roots and spreads through the host, blocking conducting tissue and resulting in plant yellowing, wilting and death.

Solution: There is no chemical control for Moko. All plants plus an adequate buffer zone around the diseased plants must be destroyed. The area must be quarantined and only non-host plants grown.  
Biosecurity obligation: If you suspect Moko disease you must notify Biosecurity Queensland immediately (13 25 23). 
More info:
Note discoloured edge of corm.

Burrowing nematode (discoloured)

Cause: Burrowing nematode feeding in the banana corm. Planting nematode-infected corm pieces is the most common method of spread to new areas.
Solution: Do not use banana corms with visible signs of nematode damage as planting material.  

Tunnelling in corm

Tunnnelling in corm

Severe infestation reduces plant vigour and the tunnelling allows the entry of rot organisms, which result in faster corm breakdown.

Banana weevil borer

Cause: Tunnelling by larvae of Cosmopolites sordidus.
Solution: Use stem baits to establish the severity of the infestation. If necessary treat with an appropriate chemical. Follow label directions regarding application method and timing to maximise the effectiveness of the treatment. 

Damaged roots or no root hairs

Damaged roots or no root hairs

Note burnt root tips.

Fertiliser burn, drought or water-logging, poor drainage, air burn, soil compaction.

Cause: There are several causes of root tip burn. They include fertiliser burn from too much fertiliser or poor placement; aluminium or manganese toxicity caused by low soil pH; and soil drying out or staying too wet for too long. As well as these causes, air burn or soil compaction can cause root hairs to be lost. 

Solution: Determine the cause with soil and tissue analyses. Broadcast fertiliser evenly and at recommended rates. Watering heavily to leach salts out of the root zone can alleviate problems of excess fertiliser. Maintain soil pH between 5 and 6 and avoid planting in areas with poorly drained soils. 
Note chewed roots.

Greyback cane beetle

Cause: Chewing by larvae (cane grubs) of Dermolepida albohirtum

Solution: Correct timing of insecticide application is crucial. The chemical must be applied when larvae are close to the surface between November and January. 
Note lumps (galls) within roots and missing root hairs.

Root-knot nematode

Cause: Meloidogyne spp. Root-knot nematode invades the root when young. When mature the females form special feeding cells that appear as galls within the roots. 

Solution: Root-knot nematode is not usually an economic problem to banana production in the tropics. Most mature banana plants with adequate irrigation and fertilising can compensate for any damage. Root-knot nematode may become a problem in very young plants, or on very sandy soils.