MANGO
Black tip
- Coal fumes of brick kilns containing sulfur dioxide, ethylene, and carbon monoxide are observed to be responsible for black tip.
- The damage has been noticed in the mango orchards located up to 200 meters of distance from brick kiln. It is characterized by depressed spots of yellowing tissues at the distal end of the fruit, which gradually increase in size, become brown and finally black.
- The necrotic area is always restricted to the tip of the fruit.
- The growth of the fruit is almost at stand still and the fruit becomes soft after premature ripening.
control measure:
- Spraying of 2% sodium carbonate or 0.6% borax is recommended as a control measure.
Spongy tissue in fruit:
- A non edible sour patch developed in the mesocarp of mango fruit is broadly termed spongy tissue.
- The malady has been reported only in Alphonso.
- The peculiarity of this malady is that external symptoms of the fruit affected by spongy tissue are not apparent at the time of picking or at the ripe stage.
- These can be detected only on cutting the ripe fruit.
Malformation
- The problem is not serious in the grown-up trees. The affected new shoots on the old trees, however, become thick, stunted, and develop a whorl of small leaves.
- Floral malformation, in contrast, is very virulent and can cause the loss of the entire crop.
- In severe form, the affected panicle, appears like a compact mass, being more green and sturdy. It bends down due to its own weight. It is found that the application of 200ppm NAA during the first week of October as spray resulted in considerable reduction of floral malformation.
Fruit drop:
- The maximum drop of fruits in ‘Langra’ and ‘Dashehari’ takes place in the first three weeks of April and differs significantly from the drops in the following weeks.
- Fruit drop is to some extent associated with the variety, as the variety ‘Langra’ is more prone to fruit drop than ‘Dashehari’.
- Deficient nutrition of many developing embryos may be the most important internal factor leading to post-fertilization drop in mango.
- 2,4-D produced better results at concentrations below 20ppm, because at higher concentrations fruit and seed development is retarded.
- Single spray of NAA or 2,4-D each at 20ppm or Alar 100ppm at pea stage of fruit gives promising results.
Zinc deficiency
- The major nutritional disorder in mango is little leaf caused by the deficiency of zinc.This leads to stunted growth of roots, shoots and leaves.
- The lamina of leaves turn pale yellow while midrib remain green.
- Leaves become very small, little with interveinal chlorosis.
- Yellowing, necrotic patches develop on old leaves with drying of leaves.
- Two sprays of 1-2% Zinc sulphate, one at the time of flowering and the other at one month after the first spray correct the disorder.
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