SCI-TECH & AGRI

Custard apple — promising crop for tropics

By Our Agriculture Correspondent

Custard apple is a commercial fruit in the arid regions. (Inset) Oil extracted from the seeds is used as an eco-friendly insecticide.

Custard apple is a commercial fruit in the arid regions. (Inset) Oil extracted from the seeds is used as an eco-friendly insecticide.  

CUSTARD APPLE (Annona squamosa -Sitapazham in Tamil and Sitaphal in Hindi), the woody, semi-deciduous tree, which grows unattended in several southern Indian States, is a promising tree of commercial importance. Several exclusive orchards with high yielding and choice varieties selected from Balanagar near Hyderabad have sprung up in Andhra Pradesh and Maharashtra in recent times.

The hardy fruit tree thrives naturally in rocky terrain with shallow, gravelly, well-drained soils. However, they do extremely well in arable, red, sandy shallow soils slightly acidic in nature. Heavy soils and waterlogged fields are not suitable for its cultivation. It does well in calcareous soils with as high as 50 per cent lime content.

Being a cross-pollinated crop, custard apple has wide variations in forms and sizes of fruit as well as colour of the pulp.

Depending on the external fruit colour, it is distinguished into green, red and yellow. But green ones are the most common and popular varieties that head to the market. The popular varieties of green custard apple are Balanagar, Barbados seedling, British Guinea, Kakarlapahad, Local Sitaphal, Mahaboobnagar, Saharanpur Local and Washington.

Traditionally propagated by seeds, this fruit tree can be multiplied vegetatively by grafting.

Well-conditioned plants of about 30 cm height can be used for planting in the main fields. Pits of 60 cm by 60 cm by 60 cm are ideal for planting the young seedlings or grafts.

A spacing of about 5 m by 5 m is ideal for commercial orchards. About 400 plants can be accommodated in a hectare. The pits are filled with ripe organic manure, vermicompost, powdered rock phosphate, powdered neem cake and a host of beneficial microbial bio-fertilizers to get the best establishment, growth and yield from the plants.

Watering is done in the initial phase of establishment, and being a drought-tolerant crop, it can remain green and healthy even during protracted dry spells.

The crop is free of most pests and diseases. The only pest that attacks this crop is mealy bug, and it can be controlled by the inundative release of natural enemies or by spraying with suitable botanical insecticides.

Custard apple starts bearing fruits from the fourth year of planting, and yield declines gradually after the fifteenth year.

It yields fruits during August to October season in south India and during September to November in the northern parts of the country.

On maturity, the fruits turn light green in colour. The inter-areolar space widens, and the fruits turn creamy white.

The fruits are harvested manually when they are fully mature and still firm. About 5 to 6 pickings will be needed to harvest all fruits during a season. On an average, a well nurtured, seven-year-old tree will produce about 100 to 150 fruits, and a total yield of about 7 tonnes can be harvested from a hectare.

The fruits ripen in about three days after plucking. The medium sized fruits of 250 g to 300 g with sweet pulp and peasant aroma will have about 60 to 80 seeds each. The seeds are of insecticidal value.

The oil extracted from the custard apple seeds are used as potent insecticide along with neem formulations. The immature custard apple fruits are used as fish baits by the local people in Karnataka and in tribal regions.

The leaf extract is used to repel honeybees by the tribals while extracting honey from the beehives.