Sapota flower drop and fruit drop causes, control methods
Sapota commonly known as Chiku is mainly cultivated in India for its fruit value. Planting can be done in any season. Grafts are generally planted at the beginning of the rainy season. In areas having heavy rainfall, the crop can be planted as late as September. Inadequate irrigations result in the Sapota flower drop.
Different varieties of Sapota
There are many species of Sapodilla found around the world, among them only a few are commercially grown. Some common varieties of Sapota cultivated in India are;
- Cultivated in Gujarat, Maharashtra and North Karnataka.
- Broad, thick leaves and oblong fruits.
- 350 to 400 fruits per tree.
- Grown in the states of Karnataka, Tamil Nadu, West Bengal, Maharashtra and Andhra Pradesh.
- The fruit is large in size, round and sweet with granular pulp.
- Grown in Tamil Nadu.
- It is a hybrid variety grown out of a cricket ball and oval.
- Starts bearing in four years.
- Fruits are oblong, large, sweet and fleshy.
- The weight of the fruit is around 125 g and TSS is 18%.
Grown in Tamil Nadu and this is a medium-sized tree with oblong fruits. The average weight of the fruits is around 125-150 g and TSS is 23%.
- Famous fruit in Tamil Nadu.
- Fruits used for table purpose and trees bear profusely.
- Fruits are medium-sized and rich in sugars.
- Average weight is around 80 g and TSS is 23%.
- Grown in Gujarat and Maharashtra.
- The weight of the fruit is 400 to 500 g.
- Found in Tamil Nadu and Andhra Pradesh.
- It is a high yielding variety.
- Fruits are egg or oval shape with thin skin and rich flavour.
- Variety from Tamil Nadu.
- A crossbreed of Vavivalasa and cricket ball.
- Bears fruits from 4th year onwards.
- The fruits are light brown, sweet to taste and oblong.
- The average yield of fruits per tree is around 157 kg annually.
And, the other varieties of Sapota found in India are Guthi, Kirtibarathi, Bangalore and PKM (2, 3, 4 and 5) oval, Dhola Diwani, Chhatri and Dwarpudi.
A guide to Sapota flower drop causes, fruit drop causes
Conditions required for Sapota cultivation
- Sapota fruit requires good nutrition and responds well to fertilization. Among major nutrients, the most important element is nitrogen, which influences the productivity and growth of Sapota.
- Sapota is grown in a variety of soil but deep alluvial, black soil and sandy loam soil having good drainage are ideal for doing Sapota farming. The pH having 6.0 to 8.0 is optimum for Sapota farming. Avoid cultivation in shallow clayey soil and high calcium content.
- Planting can be done in any season by provided irrigation facilities. Grafts are generally planted at the starting of the rainy season. In areas having heavy rainfall, the crop can be planted as late as September.
- In summers irrigation is given at the interval of 12 days and in winters irrigation is done at an interval of 30 days. Drip irrigation is done as it will decrease up to 40% water. In the initial stage i.e. during the first 2 years, two drippers are laid at the spacing of 50cm from the tree, and then till 5 years, 4 drippers are laid at the spacing of 1m from the tree.
- On average, 130 plants are planted at a spacing around 8.5m. High-density planting with a spacing of 5×5 m. up to the age of 13 years has been adopted successfully.
- In light soils, pits of 60x60x60 cm. size, and heavy, gravely soils pits of 1x1x1 m. size is made in April-May and exposed to the sun for 15 days. The pits are later on filled with farmyard manure or well-rotten compost, 3 kg superphosphate, and 1.5 kg muriate of potash and these pits are then left to monsoon rains for settling and planting is done at the appropriate time.
- Grafts, budded plants, or layers are planted one in each pit and care is taken so that the graft or bud joint is as a minimum 15 cm. above the ground level. After planting, stakes are arranged to protect from wind damage. Young plants are protected from the sun by arranging dry grass thatch on top and 3 sides excepting the south-east for sunlight.
Nutrients required for Sapota cultivation
About 50 kg of farmyard manure, 1 kg. N, 0.5 kg. P2O5 and 0.5 kg. K2O per tree per year is applied and the dose is regulated based on the age of the tree and status of nutrients in soil particularly of K and P. In rainfed conditions, fertilizers are applied before the onset of monsoon. In irrigated conditions, it should be applied in 2 splits, one half at the starting of monsoon and the remaining half in the after-monsoon period (September to October).
To grow a sapodilla tree, propagation is done by seed, which will be viable for years although some commercial growers use grafting and other practices. Once germinated, use some patience as it takes 5 to 8 years to grow a sapodilla tree of bearing age. As mentioned, the fruit tree is tolerant of most conditions but prefers a warm, sunny, and frost-free location in most any type of soil having good drainage capabilities. Additional care for sapodilla trees advises fertilizing the young trees with 8% nitrogen, 2 to 4% phosphoric acid, and 6 to 8% potash every 2 or 3 months with ¼ pound (113 g.) and increasing gradually to 1 pound (453 g.). Not only are sapodilla trees tolerant of drought conditions, but they can take soil salinity, requires very little pruning, and are mainly pest resistant.
Flowering and fruiting stage of Sapota tree
Under tropical climate Sapota flowers throughout the year, with two main seasons i.e. July to November and February to March. In sub-tropical conditions, it also flowers twice in October to November and April to May. The flowers are protogynous i.e., the stigma of the ovary becomes receptive earlier than the stamens produce pollen.
Hence, Sapota is a cross-pollinated crop. There is sufficient fruit set but retention is low. This may be due to several reasons; mainly low auxin level in ovary just after fruits set or due to sudden change in temperatures in December and in May to June. The fruit retention can be increased by spraying GA2 (gibberellic acid) by l00ppm at full- bloom and fruit set. Or NAA (Naphthaleneacetic acid) by 300ppm twice. It takes around 10 months for the full maturity of the fruit. Sapota is a climacteric fruit and fruits can be harvested when fruits are still hard.
The tree flowers continuously in several flushes at short intervals in the entire year. But there are two seasons when flowers will be produced profusely i.e., February to March and October to November. Grafted Sapota begins to bear in the 3rd year after planting. Sapota fruit production increases up to 30 years followed by a decline. Fruits mature about 4 months after flowering.
The Sapota fruit and flower drop causes and control
If you are growing Sapota on a commercial scale, you must be aware of Sapota flower drop causes. Sapodilla is an upright, slow-growing, long-living evergreen tree. Tropical specimens can grow to 100 feet, but grafted cultivars are much smaller at 30 to 50 feet in height. Its foliage is medium green, glossy and alternate, and makes a lovely ornamental addition to the landscape, not to mention its delicious fruit.
The Sapota tree blooms with small, bell-shaped flowers many times per year, although it will only yield fruit two times in a year. A milky latex, known as chicle, exudes from the trunk and branches. This latex sap is used in chewing gum. The fruit, actually a large ellipsoid berry, is round to oval and about 2 to 4 inches across with brown, grainy skin. The flesh is yellow to reddish-brown or brown with a sweet, malty flavour and often containing anywhere from three to 12 black, flattened seeds. Sapodilla fruit drop is not a common problem with the trees if the trees are healthy. Sapodilla problems are minimal provided the tree is in a warm location, although sapodillas are not strictly tropical. Young trees are less established and will be killed or damaged. So, a sudden cold snap might be one reason for fruit dropping from a sapodilla plant.
Another major problem regarding the Sapota crop is heavy flower and fruit drop. Sapota produces a large number of flowers thrice in a year with different flushes. But fruits and flowers tend to drop down at different stages of development right from its setting to maturity. Though, fruit drop at later stages of development drastically decreases the yield causes the losses to farmers. In recent years considerable attention has been given to improve fruit set and to check fruit drop of several fruit crops with the help of plant growth regulators. A different group of plant growth regulators like gibberellins, auxins, and growth retardants at various concentrations have been reported to influence flowering, retention, fruit set, development, and quality characters of several fruit crops. Hence, the objective was to study the effect of growth regulators on fruiting, flowering, and quality of Sapota.
Fruit drop is a major problem in Sapota. Spraying with GA3 by 50-100 ppm at the time of flowering is quite effective for getting an improved fruit set and also preventing Sapota fruit drop. Sapota is less prone to damage by different pathogens as compared to other fruit crops. Though, in recent past years incidence of fruit drop disease caused by Phytophthora palmivora has increased which limits the successful production, storage of fruits, and marketing. Fruits, those develop in rainy season express symptoms at any stage. In general, fruits of 40 days old or more are more affected by a fungal infection. The chemical pesticides are causing serious problems and more alarming amongst them are pollution of water, air and soil, residual toxicity and development of resistance in the pathogen against chemicals, their escalating prices, and harmful effects on non-target organisms. Thus, an integrated approach for the management of Phytophthora palmivora fruit drop in Sapota seems to be imperative, under agro-climatic Conditions.
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Sapodilla tree care
Sapota is a tropical fruit and needs a warm, humid climate for growth and development. The Sapota trees grow well up to an altitude of 1000 m. The coastal climate is considered much suitable for Sapota cultivation. The minimum average temperature required is about 10 to 38°C and the annual rainfall should range in between 1250 to 2500 mm higher temperatures lead to flower drop. The minimum humidity of the area should be more than 70%.
Proper care of a sapodilla tree will ensure a nice long life of bearing fruit. Keep in mind that sapodilla will take anywhere from 5 to 8 years to bear fruit. Young trees mayflower, but not set fruit. Sapodillas are remarkably tolerant trees. Ideally, they prefer a sunny, warm, frost-free location. They do well in both humid and arid environments, although consistent irrigation will help the tree to flower and fruit. This specimen also does well as a container plant. Sapodillas are wind tolerant, adapted to many types of soil, are drought resistant, and soil salinity tolerant. Young trees should be fed in the first year every two to three months with ¼ pound of fertilizer, increasing gradually to a full pound. Fertilizers should contain 6 to 8% nitrogen, 2 to 4% phosphoric acid, and 6 to 8% potash. After the first year, apply fertilizer two to three times per year. Sapodilla problems are generally few. All in all, this is an easy tree to care for. Cold stress or “wet feet” can adversely affect the sapodilla, potentially resulting in not only sapodilla fruit drop but also the death of the tree. Also, although the tree likes sun, especially immature trees, get sunburned so it might be necessary to move it under cover or provide a shade cloth.
Harvesting and handling of Sapota fruit
Sapota is a climacteric fruit hence, must be harvested at full maturity. It is a little difficult to judge proper fruit maturity due to the overlapping of fruiting and flowering. If unnatural fruit is harvested, these take more time to ripen and quality is always poor. It takes around 10 months to mature Sapota fruit.
The mature fruits shed off the brown color scaly scurf from the skin. Mature fruits do not show green tissue underneath the brown skin of the epicarp. A full-grown tree can yield over one quintal of fruit up to 25 to 30 years of age of the tree.
The harvested Sapota fruit is graded into large. Medium and small sizes. The fruits are packed in wooden carts which are padded with paper cuttings, banana, or straw leaves. After ripping Sapota fruits become very soft and can but are kept for long.
That’s all folks about Sapota flower drop and fruit drop. In case if you are interested in this: Profit in Dry Fruit Business in India.