South African Mango Growers Association - MANGO MONTHLY ORCHARD MANAGEMENT

MANGO MONTHLY ORCHARD MANAGEMENT - November & December

By Theo Bekker

Tags: mango , Orchard Management
Others articles in: Orchard Management

MANGO MONTHLY ORCHARD MANAGEMENT - November & December

Tshifhiwa Radzilani

The main focus at this stage (fruit development stage) will be to continue maintaining the mango fruit with a characteristic acceptable to the market. To achieve this, a suitable spray programme for the control of mango fruit diseases should be considered. Times for treatment are according to the development stage of fruit. A few management practices should be considered for the success.

Fruit Development

Sufficient water needs to be supplied at all critical stages of fruit development. Water stress during the fruit development stage may result in fruit with poor size and taste. Therefore, it is essential to ensure that sufficient water is applied during all stages of fruit development. The size of the fruit that a tree can bear is primarily determined by the nutrient reserves (tree reserve level). Fruit drop on the other hand is governed physiologically by the size of nutrient reserves in the tree and also by climatic conditions prevailing during this period. Even if trees have enough reserves, soil moisture deficit during the fruit development phase or pest and disease attacks on developing fruits may act as limiting factors to the size of the final crop. Therefore, at this stage trees have to be managed very well by providing all necessary inputs correctly. This includes taking leaf and soil samples for fertilizer applications. Note that, leaf and soil samples should be taken as from October to November. Leaf samples should be collected annually, while soil samples every second year for fertilization purposes. Contact your technical advisor in your area for assistance.

Fruit protection program

Different production regions have different climatic conditions, which are either favourable for certain cultivars but create problems for others. The development stage of each fruit crop comes with its own problems. The main focus at this stage is to protect fruit from various diseases such as anthracnose, bacterial black spot and soft brown rot, the reason being to sustain the final size and quality of mango fruit. The crutial thing here is to deal with the fungal disease caused by rainfall. Let’s have a look at the fruit protective spray program!

Anthracnose symptoms, appears as “tear stains” leading to cracked spots on the skin of ripe mango fruit while, Bacterial black spot symptoms are small, black spots, which expand.

Protective spray program with CuOx (250g/100l) fungicides for the local best bacterial, while Benomyl (25g/100l) + Mancozeb (200g/100l) are allowed as from week 46 until two-weeks before harvest for the local market. All these fungicides should be applied as a full cover spray. This program should be applied at two to three week’s interval, or as a mixture depending on disease pressure and weather condition. Take a special note on the MRL’s for European market while Mancozeb is prohibited to other markets.

Bacterial black spot! Apply Copper Oxychloride (250g/100l) every 14 to 28 days depending on weather condition. During October/November one should also go through the fields and remove malformed blossoms. ‘Ortiva’ may also be applied for the control of anthracnose and soft brown rot. When using this chemical, take special note of the pre-harvest interval of 21 days. Each grower has his own preferences on the fungicides to be sprayed to control the above-mentioned diseases.

Insect management

Continue to monitor for fruit fly population. Orchard sanitation may also be helpful to bring the population down. Remove all fruits on ground & spray registered chemical in combination with fruit fly bait.

Sanitation

Fruits dropped on the ground triggered prematurely by internal physiological disorders or insect damage should be collected and buried in the ground as they might serve as the breeding ground for certain pests favouring the development of other diseases. Sanitation may also help to prepare the orchard for harvesting, when the fruit reaches the desired stage of maturity level, which will allow pickers easy access to the trees.

Harvesting

Achar! The fruit is harvested while still relatively small. The seed should not be allowed to harden because this causes rejection by the factories.

Export and local market! If the fruit is to be marketed locally it can be allowed to mature on trees and this will result on better fruit with good colour and shape. The mango fruit is regarded as being mature when it reaches desirable stage of physiological maturity. SAMGA have the internal maturity chart, which is useful in determine when to start picking. Note that chemical changes during ripening process usually involve the conversion of starch to sucrose and reducing sugars. The extent of this conversion affects the sweetness of ripe and mature mango fruits as well as their retention on the tree.

Conclusion

Poor initial management planning, uneven flowering, fruit set and growth, post harvest losses and finally unfavourable climatic condition affect the economic production of mango crop. In order to avoid loss, it will be necessary to take steps from the initial stage so that the orchard is maintained by performing a proper management operation. It will also be helpful if farmers can use the mango management calendar as it guides growers on what they should be aware of during each specific stage of the crop. Therefore, to seek advice from a competent technical advisor in your area will be important in this regard.

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