Strategies For Managing Mango Flowers To Boost Yields

Mango (Mangifera indica) is one of the most important tropical fruits in India. India is the largest producer of mangoes in the world, accounting for about 21 million metric tons in the year 2022. Mango flowering is a critical stage as it directly affects the yield of the fruit. Flowering in mango is highly dependent on the variety and environmental conditions. Thus, proper management strategies taken during the mango flowering stage can improve the potential number of fruit production.  

Mango Flower initiation:  

Mango trees typically begin to flower after 5–8 years of growth when they reach maturity. Mango flowering season generally starts from December to February. However, depending on the time of flower initiation, fruit development starts from January to May. Cooler temperatures (15-20°C during daytime and 10-15°C during night hours) with bright sunshine are an important requirement for the mango flower initiation. High humidity, frost or rain during the flowering period affects the flower formation. Cloudy weather during flowering favours the spread of mango hoppers and diseases, hampering mango growth and flowering.  

How does flowering affect fruit production in mango? 

Mango flowers are small, yellowish or pinkish-red coloured, clustered together in panicles, which hang down from the branches. They are hermaphrodite flowers but cross-pollination by pollinators contributes to maximum fruit set. Common pollinators include bees, wasps, moths, butterflies, flies, beetles and ants.  

The number of flowers produced, and the duration of the flowering stage can directly affect the yield of fruits. However, flowering is influenced by several factors such as temperature, humidity, sunlight, pest and disease incidence and availability of water and nutrients. These factors affect the timing and intensity of the flowering. If the above factors are not optimal during the flowering stage, it will result in fewer or smaller fruits. Not all flowers produced will set fruit. Proper pollination is essential for the fruit to set and develop fully. Even after adequate pollination, only a few proportions of flowers set fruits because of a massive drop of flowers and fruits due to several factors such as weather conditions and pest infestations. This ultimately affects the yield and quality of fruits. The timing, duration, and intensity of flowering can significantly affect fruit production in mango trees. 

Know how effective management of flowering can increase yield in mango: 

1. Intercultural operation:

Pruning mango trees can induce flowering. Lack of pruning leads to the dense growth of the mango canopy, preventing light from penetrating the interior portions of the tree and thus reducing the flowering and yield. Pruning the tips of shoots may initiate flowers. The best time to prune is after harvest, usually during October to December. Tip pruning which is done 10 cm above the last internode may improve flowering. Girdling is a method used for inducing fruit bud formation in mango. It involves the removal of a strip of bark from the trunk of the mango tree. This enhances flowering, fruit set and fruit size by increasing foliar carbohydrates and plant hormones in the above parts of the girdle by blocking the downward translocation of metabolites through the phloem. The fruit set is increased when girdling is done at the time of inflorescence emergence. Care should be taken regarding the depth of the girdling. Excessive girdling depth could harm the tree.  

2. Plant Growth Regulators (PGRs):

PGRs can be used to control flowering and increase yields by influencing the physiological processes that regulate plant growth and development. Paclobutrazol is a common plant growth regulator used in mango trees which helps in reducing vegetative growth and promotes flowering. Ethephon and NAA also help in inducing flowering, preventing shedding of flower buds and fruit ripening. They help in enlarging fruit size and increasing and improving the quality and yield of fruits.

Product name	Technical content	Dosage	Application time
For trees < 10 years of age: 8 ml per tree dissolved in water For trees > 10 years age: 16 ml per tree dissolved in water (Apply to the root zone in both cases)	Paclobutrazol 23% SC	Three months before flowering and after applying two irrigations may be required.	For trees < 10 years of age: 8 ml per tree dissolved in water For trees > 10 years of age: 16 ml per tree dissolved in water (Apply to the root zone in both cases)
Taboli  Plant growth regulator	Paclobutrazol 40%, Paclobutrazol (PBZ)
Ethrel Growth Regulator	Ethephon 39% SL	Foliar: 1 – 2.5 ml/lit water	The first spray in mid-October or early November totals 5spraysy at fortnightly intervals (For breaking alternate bearings) Commencing from early November total 5 sprays at weekly intervals (Induce flowering)
Katyayani NAA	Alpha Naphthyl Acetic Acid 4.5% SL	Foliar: 0.2 – 0.3 ml/lit water	Spray when tender fruits are of pea size

(NOTE: PGRs must be carefully managed to avoid negative effects on plant growth and development, such as excessive branching, reduced fruit size, or delayed flowering. Check the dosage and time of application before use)

3. Nutrient Management:

Nutrient management plays a crucial role in inducing flowering in mango trees. Nitrogen is essential for the growth and development of plants. However, excessive nitrogen can delay mango flowering by promoting vegetative growth instead of flowering initiation. This can also cause an imbalance in other nutrients like P and K which are important for flowering. Over-use of nitrogen increases susceptibility to pest infestation due to an increase in vegetative growth. The optimum amount of N should be used to manage flowering. Phosphorus is essential for flower initiation and fruit set in mango trees. Apply phosphorus fertilizer during the pre-flowering stage to promote flower initiation. Adequate potassium levels can enhance flowering in mango trees and increase the number of flowers and fruit. Potassium helps in the transport of nutrients and water to the fruit, which is essential for its growth and size. It also helps in increasing resistance in plants against moisture stress, heat, frost and disease. 

Application of micro-nutrients gives better results by improving flowering, and quality of fruits and controls the dropping of fruits. 

Time of application: 2 – 3 sprays at an interval of 25–30 days between the sprays starting from flower initiation  

Product name	Nutrient	Dosage	Features
Shamrock Overseas Limited NPK 13:00:45	Potassium Nitrate – KNO3	Foliar: 5gm/lit water	Helps in pollination,and improves flower & fruit setting, resulting in quality produce and higher yield
Multiplex Multimax	Mix of Zn, Mn, Fe, Cu, B, Mo	Foliar: 3 gm/lit water Fertigation: 10 – 15 gm/lit water	Helps in fruit setting and increases yield
Multiplex Chamak (or)	Ca & B	Foliar: 3 g/lit water	Green CalBo Micronutrient
Reduces flower and fruit drop, increases fruit setting Helps against climatic fluctuations and reduces flower or fruit droppings.		Foliar: 2 ml/lit water	Enhances flower & fruit setting & checks fruit dropping
Multiplex Multi Mag	Mg	Foliar: 3 – 4 g/lit water	Helps in more synthesis of chlorophyll which in turn increases the yield
Anshul Maxbor (or)	B	Foliar: 1 gm/lit water	Helps to control flower shedding
Allbor-Boron 20%
Anshul Phalmax	Bio-organics and traces of micronutrients	Foliar: 2 ml/lit water	Induces more flowering and helps in fruit setting
Bioprime Prime Verdant	Botanical Extracts-12% & Aqueous Base-88%	Spray/Drenching: 5 – 8 ml/lit water	Reduces flower and fruit drop, increases fruit set Helps against climatic fluctuations and reduces flower or fruit droppings.

4. Pest and Disease Management:

During flower and fruit formation, there is a high chance of pest and disease infestation leading to a risk of losing flowers and premature fruits. Mango hoppers, flower gall midge, mealy bugs and leaf webber are the major pests attacking the mango flowers. Mango Powdery mildew, mango malformation and anthracnose are the diseases affecting mango flowers leading to reduced fruit development.

5. Pollination: The mango

The mango flower has both male and female reproductive parts in the same flower. However, mango flowers are relatively small and do not produce a large amount of nectar or pollen. Therefore, they are heavily dependent on pollinators such as flies, wasps and other insects, to transfer pollen between flowers. Without pollination, mango flowers may not produce fruit, or the fruit may be small or misshapen. Cross-pollination increases the yield of mango. It is important to note that pesticides and fungicides should not be sprayed during the Full Bloom stage since pollination by insects will get affected at this time leading to reduced yield.

6. Weather conditions:

Optimal weather conditions during flowering can lead to a higher rate of successful fruit sets and increased yields. For example, Excessive wind speed causes mass destruction of flowers and fruits. Thus, it is essential to provide wind protection to mango orchards by planting windbreaks/shelterbelts.

7. Water Management:

A sufficient amount of water is required for mango trees, especially during the growing season. Inadequate or excessive watering can lead to reduced yield and quality of fruit. Proper water management can also help to prevent disease and pests, which thrive in moist environments.  In hot and dry climates, irrigation can help to increase humidity levels and reduce temperature fluctuations, providing a more favourable environment for mango growth. Excessive irrigation may reduce soil temperature, which in turn leads to reduced plant growth and development. On the other hand, inadequate watering can lead to a rise in soil temperatures, damaging the plant roots and leading to reduced yields. Thus, effective water management is essential to ensure healthy plant growth and fruit production.

Conclusion: 

Managing mango flowers for higher yields involves a combination of strategies aimed at optimizing plant growth, managing pests and diseases, and ensuring optimal environmental conditions for flower development and pollination. Following these management practices can increase flower and fruit production, leading to higher yields and improved fruit quality.