Black rot of pineapple, is a post-harvest disease. It is also known as water blister, soft rot or water rot. Penetration of a fungus inside cells occurs through wounds and stem cutting, causing infection.

Fruit may be bruised or wounded during picking, packing, storage and transportation. The wounds pave the way for fungal infection. Conditions of high humidity tend to encourage development of black rot.

Early stages

At the early stage of infection, the fruit exhibits a juicy and water soaked appearance. At advanced stage, it is covered with blacks spores and the flesh becomes totally black. As the decay intensifies, the affected area emits a bad odour. The rot eventually destroys the entire fruit. Infestation starts at the stalk-end of the fruit, resulting in small, circular, water-soaked spots that are very soft.

Management tips

Care should be exercised during harvesting and packing so that the fruit is subjected to minimal injuries. Fruit may also be dipped in a fungicide after harvesting, to give protection against infections. Avoid contaminating the central base of the plant with disease-infected soil especially during the hilling-up operation. If polyethylene mulch is more practical and economical, use it on raised beds.

Good soil drainage is a necessary. Where rainfall is heavy or soils are not well drained, soil management techniques such as ridging must be used to improve drainage.

Planting material

Planting material that is cured before planting has less rot problems. Crowns and slips can be exposed to the sun for several days before planting.

Maintaining weed-free areas around fields reduces inoculums and therefore disease problems.

Field plantings of pineapple are usually in double-row beds. Plantings of small fresh fruit are advisable.

(Utpal Dey, PhD scholar, Department of Plant Pathology, Marathwada Krishi Vidyapeeth, Parbhani, Maharashtra and Dr. D. N. Dhutraj is Associate Dean and Principal, College of Agriculture, Osmanabad, Maharashtra, email: utpaldey86@gmail.com, mobile: 08275824103)

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