The fruits crack when the sun comes out after a downpour during the wet season. It is acknowledged that this is due to high internal pressure caused by the fruit or trees' inability to transpire during the humid days. Pressure builds up and as a result, the fruits crack. Some think that gibberellic acid can somehow be used to manage fruit cracking, but we actually have no definite management strategy for it. Some growers found that by harvesting the mangoes at 90 DAFI (Days after flower Induction) for the green market, they were able to avoid losses due to fruit cracking.
Boron deficiency occurs especially in high temperature, high rainfall and soil having high acidity that also causes cracking in mangoes from the centre of the fruit. Apply borax @5kg/hac or 0.25% borax at 10days interval.
Cracking could be due to water deficits, or deficiencies of calcium or boron. Extremes of temperature, humidity and rainfall could also contribute to the problem. Certain mango varieties, for example , the mango cultivar "Dashehari", are more sensitive to cracking.
Was there a sudden change in your weather recently? For example a sudden increase in temperature or rainfall?