Was thinking that this year I was finally going to get a decent amount of fruit from my sweetheart.
While in the yard yesterday I noticed that some of the fruits were starting to show color.
Started looking and discovered that a lot of them have some splitting going on.
Not from over watering, because we have been pretty dry and I don't go out of my way to water.
Would under watering cause fruit splitting, the trees are not showing any signs of stress.
googled & may 1986 answer is::: From South Africa via Australia :::
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FRUIT CRACK IN LITCHIS
SCIENTIFIC NAME: Litchi chinensis
FAMILY: Sapindaceae
One of the most common problems in litchi production is the large percentage of fruit that crack during the ripening process. The causes of fruit crack cannot be attributed to a single factor, and the phenomenon can differ from orchard to orchard or from one region to the next. Fruit crack occurs during the third stage of fruit development. This is after cell division has ceased in the pericarp (skin) and cell stretching takes place.
It has been established that cell division in the skin ceases about 70 days after fertilisation. From this stage until the end of the fruit growth period, i. e. after another 35 days (Stage III), cell stretching takes place in the skin. During this period, the edible portion (aril) that grows between the seed and the skin, enlarges very rapidly, causing tremendous inner tension against the skin which then has to stretch very quickly.
Skin strength, i. e. resistance to cracking, is determined by the number of cells formed during the first 10 weeks of fruit development. Since the litchi skin has this weak characteristic, it is essential that optimum conditions for cell division be created during fruit growth Stages I and II. Any lack, for example, of water or nutrients at this stage, will hamper cell division and too few cells will be formed. The tension in the cells during Stage III will then be very high, resulting in skin crack. It is notable that the skin cracks after long, wet spells when much water is taken up. The skin cracks according to an easily identifiable pattern across the length (tip) of the fruit.
A second cause of fruit crack is skin damage during Stage III when only cell stretch takes place. Damaged cells cannot recover during this period and since the cells are dead at that time, they will also not be able to stretch and the skin will tear as the tension (pressure) of the enlarging aril increases inside the skin. This tension causes the skin to crack at damaged or weak spots. The most common factors that play a role in this regard are insect, hail and sunburn damage when relative humidity is low.
Browning is a symptom of cell necrosis which starts in the internal cell layers (mesocarp) of the skin once cell division has stopped and the cell begin to stretch. In an advanced stage, the browned cells die and dry out. It has been established that browning is not caused by insect damage or fungal diseases. However, as yet, the primary cause of browning has not been established, but the following factors could be directly involved:
Early ageing and dying of the cells due to an imbalance in nutrients.
The tremendous cell tension in the pericarp that could cause cell damage.
High temperatures together with low humidity during the fruit growth period.
Secretion of volatile, harmful substances by the actively-developing aril that could adversely affect the ageing pericarp cells.
To summarise, browning is a condition of early cell deterioration and necrosis. To prevent fruit crack, it is recommended that litchis be grown in such a way that all the deleterious factors can be restricted or eliminated.
(Reprinted from Farming in South Africa 1983). Extract from Sunshine Coast Sub Tropical Fruits Association Newsletter May, 1986.
A. J. Joubert,
Citrus and Subtropical Fruit Research Institute,
Nelspruit, South Africa
DATE: May 1986
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Home » Acta Horticulturae » Acta Horticulturae 1211
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Cracking of lychee fruits: responsible factors and control
Authors
D. Mandal, S. Mitra
Abstract
Lychee, a juicy, attractive and excellent fruit of Sapindaceae family, is preferred by consumers for its extraordinary taste and aroma. India, the second largest producer of the crop, has got an important position in the export of lychee as it possesses attractive colour, good size and excellent taste. However, fruit cracking is the most serious problem of quality lychee production in major lychee growing belts of India, viz. Bihar, West Bengal, Jharkhand, Assam, Tripura, etc. During seven years (2007-2013), systematic research on lychee fruit cracking at the Horticulture Research Station, BCKV, West Bengal, revealed that occurrence and extent of fruit cracking differed among the lychee cultivars and it was found that relatively early cultivars with more tubercle density and thin pericarp were more prone to cracking than late cultivars or with less tubercle density. High temperature during rapid growth period coupled with low relative humidity was the potential reason behind this disorder. It was observed that internal pressure of developing fruits had positive correlation with cracking whereas aril or peel calcium had no coinciding relationship with it. Fruits located at west and north side or at inner canopy had minimal cracking problem. Application of irrigation at 40% pan coefficient through sprinkler irrigation had significant effect to overcome the cracking problem of fruit. Drip irrigation and mulching with fallen lychee leaves was also found effective to tackle the disorder. Use of agro-shade net (50% light transmission) and foliar application of Boron at 0.5% had potential influence to control this disorder. Besides, delayed harvesting by the application of gibberellic acid (50 mg L-1) at 21 days after fruit set also reduced the problem.
Citation
Mandal, D. and Mitra, S. (2018). Cracking of lychee fruits: responsible factors and control. Acta Hortic. 1211, 35-44
DOI: 10.17660/ActaHortic.2018.1211.6
https://doi.org/10.17660/ActaHortic.2018.1211.6Keywords
lychee, fruit cracking, agro-shade net, irrigation, canopy
Language
English
Full text
https://doi.org/10.17660/ActaHortic.2018.1211.6Acta Horticulturae 1211
V International Symposium on Lychee, Longan and Other Sapindaceae Fruits
Article number
1211_6
Pages
35-44
Groups
Division Tropical and Subtropical Fruit and Nuts
Workgroup Lychee, Longan and other Sapindaceae Fruits
Audio is low and my ears don't pick it all up But The Transcript is Great:::
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How to fruit cracking in litchi and remedy?
Litchi cracking is a common problem. It can be caused by weather, hormones, affected by insects, etc.
So we are going to look at the problems first.
• After a period of long draught there can be litchi cracking. Irregular or sudden irrigation or sudden too much rainfall after hot weather also are the reasons to have a crack in litchis.
• It has been found that litchis which are cracked than those which are normal or good, have more hormones in peels, shells, and in seeds. Gibberellin, Sito Kainin, and a basis acid have been found in litchis which are cracked.
• Lack of Nutrition such as lack of Potassium, Calcium, Zinc, Boron, Copper, Molybdenum, Manganese will increase the chance of having a crack in litchis.
• Because of defective irrigation management litchi cracking may increase. Lack of humidity of the soil and not proper irrigation are also the reason for Litchi cracking.
Symptoms:
• For many days of drought or heat of the sun, peels of the litchis will get strong
• Sudden rainfall or sudden irrigation will make the litchis large inside the peels
• But outside the peels cannot be large enough and it remains strong
• So litchis crack by this.
Now we will see how to save litchis from cracking and what are the remedies to the problem
• We need to put organic and chemical fertilizer in the proper portion in 3 terms i.e. before and after the rainy season and finally after there is litchi flower.
• In the summer season when it is time of drought, we need to do irrigation 10-15 days intervals
• When it is the time of growing litchis we need to give a lot of water in proper portion
• During the time of growing litchis we also need to spray Jink Sulfate ( 5 gram in a per litter) and Borik Acid ( 5 gram per litter)
• Litchi cracking will be also decreased by applying the hormonal spray. Naphthalin Acetic Acid by 25% ppm and gibberellic acid by 50% ppm in 10 days interval we need to spray.
