Better Bananas

Damaged roots or no root hairs

Posted on 2018-02-20 by Better Bananas

Damaged roots or no root hairs

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.

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.

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.

Leaves bunching at top of plant

Posted on 2018-02-20 by Better Bananas

Leaves bunching at top of plant

Choking of leaves

Cause: Choking can be due to a genetic abnormality related to a particular variety or off-type, or from stresses (water-logging, cold, water or nutrient shortage, 2,4-D, banana streak virus and bunchy top). These causes limit the normal elongation of the true stem so that the leaves appear ‘bunched up’.

Solution: Choose varieties less prone to choking and cull tissue-cultured off-types showing these symptoms. Check for diagnostic virus indicators. Improve management to limit stresses on plant.

Green leaves dropping

Posted on 2018-02-20 by Better Bananas

Green leaves dropping

Bacterial corm rot

Cause: The bacteria Pectobacterium spp (formerly known as Erwinia spp.) are widespread in most soils. Plants that are stressed from heat or lack of water during the dry season can succumb to bacterial invasion during the early part of 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.

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. 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:

Queensland Department of Primary Industries

ABGC Grower Support Biosecurity (Grower kit)

Plant Health Australia

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Water stress

Cause: Mild water stress during periods of high evaporation.

Solution: Apply more water during periods of high demand.

Internal stem discolouration

Posted on 2018-02-20 by Better Bananas

Internal stem discolouration

Moko disease

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:

Plant Health Australia

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. It enters the plant through the roots, and blocks the conducting tissue within the plant resulting in wilting, yellowing of leaves, splitting of the 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:

Queensland Department of Primary Industries

ABGC Grower Support Biosecurity (Grower kit)

Plant Health Australia

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Stem shatters

Posted on 2018-02-20 by Better Bananas

Stem shatters

2,4-D damage

Cause: Injection of 2,4-D will kill the plant. Overspray or drift from herbicide application may cause lesser symptoms.

Solution: Be extremely careful with chemical applications.

Banana streak virus

Cause: The banana streak virus (BSV). Symptom expression is sporadic. Symptoms of cucumber mosaic are similar.

Solution: Do not take planting material from infected plants. Eradicate infected plants where symptoms are observed. Confirm diagnosis by looking for yellow black streaks or flashes on leaves or by laboratory tests.

Frost

Cause: Frost during the growing season.

Solution: No cure for damaged plants. Slightly damaged plants may grow out of it.

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. It enters the plant through the roots, and blocks the conducting tissue within the plant resulting in wilting, yellowing of leaves 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:

Queensland Department of Primary Industries

ABGC Grower Support Biosecurity (Grower kit)

Plant Health Australia

More images

Tissue-cultured off-type

Cause: A genetic abnormality that occurs in tissue-cultured plants.

Solution: Remove affected plants and set additional following suckers on nearby plants.

Small and stunted plants

Posted on 2018-02-19 by Better Bananas

Small and stunted plants

Banana bunchy top

Biosecurity Alert

Cause: The banana bunchy top virus (BBTV) which is spread on infected planting material and by the banana aphid, Pentalonia nigronervosa. BBTV is not present in tropical Australia, and movement of planting material is controlled by legislation.

Solution: There is no cure for this disease and all infected plants must be eradicated.

Biosecurity: Under state legislation, banana bunchy top disease must be reported. If you have seen plants with banana bunchy top symptoms within the Southern Queensland banana biosecurity zone, or the NSW Banana Bunchy Top Virus Control Zone contact the Banana Bunchy Top Hotline on 1800 068 371.

If you have seen banana bunchy top outside of these areas, you must report it within 24 hours to the Biosecurity authority in your state (Biosecurity Queensland on 13 25 23, or NSW DPI Biosecurity Hotline 1800 680 244) or the Exotic Plant Pest Hotline on 1800 084 881.

More Info:

Australian Banana Growers Council

Department of Primary Industries

NSW Department of Primary Industries and Regional Development

Plant Health Australia

Banana weevil borer

Cause: Tunnelling by larvae of Cosmopolites sordidus in the corm. Sever infestation reduces plant vigour.

Solution: Use stem baits (traps) to establish the severity of the infestation. If numbers exceed an average of 4 weevils per trap, treat with appropriate insecticide. Pheromone traps are also available.

Burrowing nematode

Cause: Severe root damage caused by burrowing nematode affects the plant’s ability to take up water and nutrients from the soil.

Solution: Check a random sample of roots from the whole field to determine if nematodes are the problem and if a nematicide treatment is necessary.

Not enough water/dry conditions

Cause: Insufficient water for plant growth.

Solution: Use water scheduling techniques to supply sufficient water to meet the plant’s requirements.

Tissue-cultured off-type

Cause: A genetic abnormality occurring in tissue-cultured plants.

Solution: Remove affected plants and set additional following suckers on nearby plants.

Plants turn yellow and die

Posted on 2018-02-19 by Better Bananas

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.

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.

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:

Queensland Department of Primary Industries

ABGC Grower Support Biosecurity (Grower kit)

Plant Health Australia

More images

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.

Plants kink, bend or fall over

Posted on 2018-02-15 by Better Bananas

Plants kink, bend or fall over

Banana weevil borer (plants fall over)

Cause: Tunnelling by larvae of Cosmopolites sordidus in the corm. Sever infestation reduces plant vigour.

Solution: Use stem baits (traps) to establish the severity of the infestation. If numbers exceed an average of four weevils per trap, treat with appropriate insecticide. Pheromone traps are also available.

More info:

Banana weevil borer – general information

Borrowing nematode (plants fall over)

Cause: Burrowing nematode feeding on roots weakens the plant’s root system.

Solution: Check roots over the whole field to determine if nematodes are the problem and if a nematicide treatment is necessary. Propping or tying string between plants may prevent some losses.

Heat stress/lack of water (plants bend or kink)

Cause: Extreme heat and or dry conditions.

Solution: Use water scheduling techniques to supply sufficient water to meet the plants’ requirements.

Poor tying (plants bend or kink)

Cause: Incorrect bunch and tree support.

Solution: Ensure tying or propping is done correctly.

Fruit rotting after harvest

Posted on 2018-02-15 by Better Bananas

Fruit rotting after harvest

Anthracnose

Cause: The fungus Colletotrichum musae. Spores are produced on dead banana material and are spread to young fruit in water droplets. The fungus remains dormant in the tissue until the onset of ripening.

Solution: Handle harvested banana fruit with care to avoid damage. Apply appropriate post-harvest fungicide treatment.

Crown rot

Cause: Several organisms can be responsible for causing crown rot symptoms. These include Musicillium theobromae, Fusarium equiseti-incarnatum (species complex), Colletotrichum musae and Thielaviopsis musarum. Symptoms can vary from fungal growth ‘fluff’ present on the cut crown surface through to complete breakdown of fruit.

Solution: Application of appropriate post-harvest fungicides will assist in minimising symptoms in the supply chain.

More info:

Crown end rot research

Fruit rotting in field

Posted on 2018-02-15 by Better Bananas

Fruit rotting in field

Cigar end

Cause: The fungus Musicillium theobromae (formerly known as Verticillium theobromae). It enters the fruit from the dead floral parts and extends 10 to 20 mm into the fruit.

Solution: Cigar end is a minor disease and specific control measures are not warranted.

Mixed ripe

Cause: Various stresses (severe leaf spot, pest damage, water and nutrition) reduce the rate of fruit filling.

Solution: Improve crop management to limit stresses on the plant.

Sunburn

Cause: Insufficient bunch shading during prolonged high temperatures.

Solution: There is no cure for affected fruit. Maintain good canopy cover and ensure bunch covers are applied properly. It may be necessary to pull a leaf down over the bunch for protection.