A publication from the Department of Primary Industries and Regional Development states that splitting in citrus fruits is likely as a result of the fruits accumulating water and plant sugars far too quickly than their rinds can expand and cope with, thus the cause for a burst, which usually occurs at the weakest point on the rind called the navel. And this quick accumulation can be caused by a combination of several factors which include temperature, relative humidity, wind, soil-moisture, rainfall, and fertilizer application.
For example, a hot, dry wind can cause trees to desiccate and loose moisture which dries them out, and then with the application of water or the onset of rainfall, the plant absorbs too much moisture which is translated into the fruits, and thus, they burst open due to excessive pressure.
Or, say, too much fertilizer application which causes excessive nutrients to be absorbed into the fruits and thereby causing them to burst open.
What trees are more susceptible to fruit splitting?
Younger trees are more susceptible to fruit splitting than older trees because they have a much narrower root area which isn’t sufficient to gather moisture, thus, sending them into other areas including the fruits.
Trees with greatest crop load are also speculated to be more susceptible to fruit splitting that other trees, just as different varieties are too.
When does fruit splitting occurs the most?
It is believed that citrus splitting is more prominent at the end of the season, although it can begin as early as mid-summer.
How can you prevent fruits from splitting on the trees?
There isn’t an exact solution to prevent fruits, especially those of navel oranges, tangelos, mandarins and some other varieties of oranges from splitting, but there are things that can be done to minimize such effect, according to the publication.
First is to make sure trees have access to water and nutrient in a sufficient manner. This will ensure that the tree isn’t getting too dried or too wet and malnourished or overfed.
For the adequate water requirement of your tree, consult the seed manual.
Secondly, use mulch to retain soil moisture,