Black Sigatoka Disease in Jamaica

Black Sigatoka (Mycosphaerella fijiensis) is the most damaging and costly disease affecting banana in Jamaica. The use of natural products and effective fungicides in the control strategy complements other good agronomic and cultural practices and is critical to reducing the high cost of Sigatoka control.

Technical services by the Banana Board to minimize and control the disease on the susceptible varieties include:

1. Monitoring the susceptible crops for resistance of the disease to the fungicides that are necessary to control the disease

2. Assessing the levels of commercial control being achieved by the farmers own control efforts and contracted services at implementing the recommended disease management strategies

3. Technology transfer for greater efficiencies to control the disease with novel and natural products.

 

 

Fungicide Sensitivity Monitoring (FSM) is the process of screening for fungicide resistance in black Sigatoka disease. This ensures that farmers are not using fungicides that are not potent. Monitoring is important for early detection of fungicide resistance and to prevent and or delay the development of resistant strains of the disease from becoming established. Fungicide resistance or sensitivity management is vital to maintaining the usefulness of fungicide products. Monitoring is one of the major activities of the Pathology Unit. Results of the tests are specific to a particular farm or group of farms in the same area and provide the ability to detect early changes in fungal sensitivity over a period of time. It is critical that fungicides used in the control of Black Sigatoka remain extremely effective. Loss of effectiveness leads more frequent spraying with other non-systemic less potent fungicides with shorter activity periods.

In Jamaica, FSM and strategies used to counteract early onset resistance is very successful in that all fungicides remain active and cost of control remain at 5-18% of total production cost compared to well in excess of 30% in counties such as Costa Rica. The number of applications remains between 18-22 compared to up to 52 in Costa Rica.  All fungicide groups with various modes of action remained effective in Jamaica.

Monitoring levels of commercial black Sigatoka disease control is done on 20 reference farms in different geographical and micro-climatic locations. The aim of black Sigatoka disease monitoring is to maintain (ideally) 10 functional young leaves on unflowered plants with 8 being the critical threshold. In order to monitor the level of leaf spot disease in any given area, a method of measuring the severity at any given time is needed. Two methods which are used in Jamaica are the Youngest Leaf Streaked and the Cronshaw method.

Cronshaw (1982) method provides information on the occurrence of early Sigatoka stages on the youngest leaves. It also gives indication of the rate of disease development. The Cronshaw method has the advantage of showing quick response to fungicides application, can be carried out on the small followers (suckers) in a production field and importantly can predict outbreaks of disease.

The Youngest Leaf Streaked method is quick, simple, practical and it gives a good idea of the disease intensity at any time but it assesses infectious stages of the disease and therefore it is not predictive.

Transfer of Technology to control Sigatoka Disease with Novel Product

The use of natural products and effective fungicides in the control strategy, complemented with the application of good agronomic and cultural methods, is important in reducing the high cost of Sigatoka control. A commercial trial was established to determine the efficacy of Lixiviate (banana and plantain stalk leachate) and Bellis (pyraclostrobin and boscalid) under the conditions of heavy disease pressure in Bog Walk, St. Catherine. This was done by comparing their effect on black Sigatoka to that of the fungicides presently used for disease control in Jamaica. The experiment was designed in randomized complete blocks with three replicates. All products were applied according to a pre-determined management strategy, which consisted of alternation of the benzimidazoles, fenprophimorph, dithiocarbamate; an application of propiconazole at the beginning of the trial and also at the beginning and end of the rainy season.

The strategy with Bellis performed at the level of the standard commercial treatment in controlling the infectious stages of the disease with significant distinction in increasing the number of functional leaves on the banana plants. The standard treatment, Bellis and all three dilutions of Lixiviate were curative and able to bring the severely infected black Sigatoka diseased plots to commercial control standards by the end of the six month period. Bellis  and the 50% lixiviate dilution performed significantly in reducing the disease to non-infectious levels over time and with proper management is recommended for further validation and development into  commercial control treatments on farms in the banana zones.

 

 

More information on Black Sigatoka here

More information on Lixiviate here

 

 

 

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Banana Board
10 South Ave
Kingston Gardens
Kingston 4, Jamaica
Tel: (876) 922-5490
(876) 922-4327
Email: bananaboard@cwjamaica.com

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