“BBS CONTROL👌“

Control of Bacterial Black Spot (BBS) on Mango orchards

Oct. 29-Nov. 1, 2019 ADRA GHANA

Causal Organism

The bacterium that causes BBS is called Xanthomonas campestris pv. mangiferaeindicae.

• Is a motile, monoflagellated, rod-shaped bacterium, • It is a wound pathogen

• Mango BBS affects all aerial parts of the mango plant. Mango leaves, stem and fruit are susceptible to infection

• The bacterial pathogen can infect through wounds and natural openings

• Disease severity depends on favourable climatic conditions.

• Yieldlossmayexceed80%underfavourableclimaticconditions

Fruit symptoms

• Fruit lesions are the most important economically.

• Fruit lesions develop as water-soaked around

lenticels or wounds.

• Lesions soon become raised and then blacken and crack open.

• Fruitlesionsproduceagummyinfectiousexudate

• Fruit drop occurs, especially when infection starts on

young fruits or when fruit stalk become infected.

• Black scabby spots are formed on fruit, often with star shaped cracks within them. The spots have water- soaked margins.

Leaf symptoms

• Lesionsonleavesstartsasangular,water-soaked spots, leaf spots are black and raised

• Twigandstemlesionsareblackandcrackedand can be an important means of survival for the black spot bacterium.

Wound-associated twig canker.

Symptoms and effects of BBS

Epidemiology and spread

• Young trees are more susceptible than older trees

• Young leaves are resistant to infection, but infections can

occur through stoma

• The susceptibility of fruits increases with age

• And lenticels and wounds are efficient entry points

• Rain is essential for the redistribution of inoculum

• Winds enhance disease development by causing micro-wounds

• Long-distance spread of the pathogen occurs via diseased propagation materials

Mode of Spread

• The disease can spread from tree to tree in the field by wind-driven rain.

• Implements used for pruning.

• Infection is favoured by warm humid conditions with intermittent rain.

• Through natural openings in leaves, fruit and stems.

• The reason is that wind damage, such as abrasions, provides additional entry points for infection.

• Protectionofmangotreesbywindbreaksreducestheincidenceand severity of BBS.

• It is assumed windbreaks reduce wind velocity at tree height and thereby reduce the dispersal of the bacteria by wind.

Survival of the bacteria over seasons

• The bacteria live all year round as an epiphyte on mango

• High concentrations of inoculum are harboured in leaves and stem lesions

(cankers)

• On seedlings and on bud wood which act as reservoirs from which the disease can spread to leaves and fruit.

• The bacteria may be present without visible symptoms and may not be detected until the mango plant has grown.

• It is in this form that the bacterium is most likely to be introduced into new areas.

Control

• Spray of copper compounds during rainy weather also combat the disease.

• Number of spray required will vary according to environmental conditions, cultivar susceptibility and when the cultivar bears fruit.

• Early-maturing resistant cultivars may require only two or three sprays during the season.

• Late-bearing susceptible cultivars in a high rainfall area will require sprays every 2 weeks during the season.

• Additional sprays during the off-seasons will enhance control

Control continues

• Several copper spray formulations are registered in the country and recommended

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• •

For example, a 500 g/kg formulation of copper oxychloride is applied at the rate of 30 g/12 L (or 4 kg/ha) or a 400 g/L

Formulation of copper oxide is applied at the rate of 40-50 mL/12 L. Either formulation is applied every four weeks from flowering to fruit-set.

Both have a withholding period of one day.

Other copper formulations may be suitable and can be used if they are registered. Refer to the label.

• Champion 80 WP at 100g/15 L of water

• Funguran at the same rate. Start spraying from flowering to fruit set

Cultural practices/sanitation

• Chemical control should be used in conjunction with the following management practices which will help to keep the pathogen away, prevent its dispersal or minimise the initiation of infection:

• Use disease-free planting stock.

• Prune to remove infected branches (sources of inoculum) and to improve aeration within the tree.

• Practice hygiene such as sterilisation of pruning and harvesting implements.

• Provide windbreaks to minimise wind damage (creation of infection sites) and the spread of the bacterium by wind.

TIPS to Better Control

▪ Copper sprays are protectant fungicides and need to be applied prior to disease infection

▪ Apply a good even coverage of copper to plant and fruit surfaces. ▪ The protective layer of copper diminishes over time

and only offers short-term protection under certain conditions

(ie in wet or humid climates)

▪ If infection is likely over longer periods then re-application

may be necessary

▪ Smaller particle size results in better rainflashes

and retention of the copper product

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TIPS to Better Control cont’d

Always apply copper sprays on their own

he pH of the water used to apply copper should be >6.0.

Choose a product and rate that minimises the amount of copper More frequent applications using lower rates of copper are just as effective and cause less

phytotoxicity than applying high rates in fewer applications

Don’t over-apply copper

Don’t apply copper when fruit or leaf temperatures are high, humidity

is low or the

BION for the Control of BBS

A water dispersible granular agricultural remedy which stimulates the natural defense mechanisms of various plants into providing protection against damage caused by unde- sired microbes as indicated.

Allow 21 days between last applica- tion and harvest of crops :

PRODUCT PROPERTIES

▪BION is a plant activator which induces the plant’s own resis tance against bacteria and fungi.

▪Due to its particular mode of action, BION has to be applied before infection takes place as the plant needs time for its natural defense mechanisms to be acti vated.

▪BION is taken up rapidly and effectively through the plant stems and leaves and is translocated acropetally and basipetally within the plant tissue.

▪BION stimulates plants to become more resistant against: bacterial black spot (Xanthomonas campestris pv. mangife raeindicae) in mango’s

Application rates

❑ BION should form part of the disease management programme.

❑ For protection against bacterial black spot of mangoes apply BION in combination with suitable copper* compounds. BION will stimulate the plants natural defense mechanisms and the copper will reduce the inoculum levels by its direct action against the pathogens.

❑ Always ensure complete coverage of the leaves and fruit with the spray mixture. On bearing trees apply the first application at bud break (candle flame stage) and the second application at fruit set and thereafter at a maximum of 28 day intervals throughout the

season. Six applications per season are recommended.

❑LOW - MEDIUM COVER SPRAY 12,5 g /100 l water PLUS copper*

COMPATIBILITY AND MIXING AND SPRAYING INSTRUCTIONS

Compatibility of BION with other products may be influenced by the formulation of the products involved as well as the quality of the dilution water. Since the formulation of other products may change, without the knowledge of the manufacture (Syngenta) and the quality of water may vary from farm to farm, a physical compatibility test should always be carried out prior to application.

Make sure application equipment is clean and not contaminated. Flush the sprayer with clean water after application or at the end of the day by spraying the rinsate at a dilution rate of at least 1:10 (spray mixture; water) on the crop.

If BION is tank mixed with other products, add the products to the water in the spray tank in the following order: First BION, second, mixing partners. If mixing partners are packed in water soluble bags, first add the water soluble bags and then BION.

❑ Fill the spray tank 1/3 with water.

❑ Continuously agitate.

❑ Remove the filter on the top of the tank. Pour the requiredquantity of product

directly into the tank and continue to agitate the mixture.

❑ Continue agitating and fill the tank with water.

Important

Do not first prepare BION as slurry in a bucket.

When filling the spray tank the filling hose should always be above water level

in order to prevent the solution being sucked back.

Ensure thorough agitation of the mixture in the tank during mixing and spraying. Replace cover after mixing.

❑ ❑

▪

COMMENTS

• Copper must be used at the registered dosage rate.

• Follow the recommendations on the particular copper labels. Not for use on the mango cultivar Hayden.

KNOW THE APPLICATION LABELS

Eg 12.5g/100l water ?

30 g/12 L (or 4 kg/ha) or a 400 g/L

PRECAUTIONS

❑ Do not inhale product dust or spray mist.

❑ Avoid contact with skin, eyes and clothing with granules or spray mist.

❑ Wear rubber gloves and face shield when handling granules.

❑ Wash hands and entire body with soap and water after use.

❑ Wash contaminated clothing after use.

❑ Do not eat, drink or smoke while mixing or applying the pro duct, wash

hands and face before doing so.

❑ If any indisposition occurs, stop work, follow first aid measures and call

a physician.

❑ Avoid drift of spray mist onto other crops, pastures, rivers, dams,

boreholes and areas not under treatment.

• Dust may irritate skin and eyes.

• Harmful if swallowed, inhaled or absorbed through the

skin.

• Toxic to fish and other aquatic organisms.

• Store in original tightly closed containers away from

sun and damp in a well ventilated area. Avoid

temperatures below 10°C and above 35 °C.

• Store away from food and feed.

• Keep out of reach of children, uninformed persons and

ani mals.

• Re-entry: Do not enter treated area until spray deposit

has dried unless wearing protective clothing.

THE CHALLENGE ON OUR HANDS

▪ The disease still prevail in many parts of the Country despite farmers attempt to control.

▪ Inefficient spraying???

THANK YOU