Jan. 23, 2020
Blooming and PollinationMango trees less than 10 years old may flower and fruit regularly every year. Thereafter, most mangos tend toward alternate, or biennial, bearing. A great deal of research has been done on this problem which may involve the entire tree or only a portion of the branches. Branches that fruit one year may rest the next, while branches on the other side of the tree will bear.
Blooming is strongly affected by weather, dryness stimulating flowering and rainy weather discouraging it. In most of India, flowering occurs in December and January; in northern India, in January and February or as late as March. There are some varieties called "Baramasi" that flower and fruit irregularly throughout the year. The cultivar 'Sam Ru Du' of Thailand bears 3 crops a year-in January, June and October. In the drier islands of the Lesser Antilles, there are mango trees that flower and fruit more or less continuously all year around but never heavily at any time. Some of these are cultivars introduced from Florida where they flower and fruit only once a year. In southern Florida, mango trees begin to bloom in late November and continue until February or March, inasmuch as there are early, medium, and late varieties. During exceptionally warm winters, mango trees have been known to bloom 3 times in succession, each time setting and maturing fruit.
Mango flowers are visited by fruit bats, flies, wasps, wild bees, butterflies, moths, beetles, ants and various bugs seeking the nectar and some transfer the pollen but a certain amount of self-pollination also occurs. Honeybees do not especially favor mango flowers and it has been found that effective pollination by honeybees would require 3 to 6 colonies per acre (6-12 per ha). Many of the unpollinated flowers are shed or fail to set fruit, or the fruit is set but is shed when very young. Heavy rains wash off pollen and thus prevent fruit setting. Some cultivars tend to produce a high percentage of small fruits without a fully developed seed because of unfavorable weather during the fruit-setting period.
ClimateThe mango is naturally adapted to tropical lowlands between 25°N and 25°S of the Equator and up to elevations of 3,000 ft (915 m). It is grown as a dooryard tree at slightly cooler altitudes but is apt to suffer cold damage. The amount of rainfall is not as critical as when it occurs. The best climate for mango has rainfall of 30 to 100 in (75-250 cm) in the four summer months (June to September) followed by 8 months of dry season. This crop is well suited to irrigated regions bordering the desert frontier in Egypt. Nevertheless, the tree flourishes in southern Florida's approximately 5 months of intermittent, scattered rains (October to February), 3 months of drought (usually March to May) and 4 months of frequently heavy rains (June to September).
Rain, heavy dews or fog during the blooming season (November to March in Florida) are deleterious, stimulating tree growth but interfering with flower production and encouraging fungus diseases of the inflorescence and fruit. In Queensland, dry areas with rainfall of 40 in (100 cm), 75% of which occurs from January to March, are favored for mango growing because vegetative growth is inhibited and the fruits are well exposed to the sun from August to December, become well colored, and are relatively free of disease. Strong winds during the fruiting season cause many fruits to fall prematurely.