It is the most tropical of all the Annonaceae, the custard apple Family. Below a mean minimum temperature of 15-25°C trees produce almost no fruit. They also will under-perform if temperature and humidity is outside that preferred i.e. >30°C and less than 30% respectively. Young trees are killed by only a light frost and larger trees may defoliate.
It prefers deep, rich, well-drained semi-dry soil, but can cope with a wide range of soil types, including acid and sandy soil and limestone. Optimum pH is 5-6.5. Water logging is not tolerated. The custard apple does best in low-lying, deep, rich soil with ample moisture and good drainage. It runs wild in light sand and various other types of soil in the New and Old World tropics but is doubtless less productive in the less desirable sites.
Seed is the usual means of propagation. Nevertheless, the tree can be multiplied by inarching, or by budding or grafting onto its own seedlings or onto soursop, sugar apple or pond apple rootstocks. In experiments, utilizing, soursop, custard apple, Annona sp. as rootstocks showed best results when custard apple scions were side-grafted onto self-rootstock, soursop, or A. sp. Af. lutescens. Custard apple seedlings are frequently used as rootstocks for the soursop, and sugar apple.
Custard apple trees should be planted in full sun and at least 15 to 20 ft (4.6-6.1 m) from adjacent trees and structures and power lines. Trees planted too close to other trees or structures may not grow normally or produce much fruit due to shading.
The tree is fast-growing and responds well to mulching, organic fertilizers and to frequent irrigation if there is dry weather during the growing period. The form of the tree may be improved by judicious pruning.
Dry periods during flowering, fruit set and maturation should be addressed with irrigation. NPK, given as two applications per year, should increase with tree size and production. Zinc deficiency is common and may be corrected with a zinc sulphate spray. Mulching is helpful
Dry Fruit Rot. Dry fruit rot or mummification of the fruit is caused by several fungi. Fruit appear purplish-black to black and may remain on the tree for some time. Usually fruit are colonized by these fungi after emergence of the adult annona seed borer from the fruit. Please contact your local County Agricultural Cooperative Extension Agent for control information.
Fruit Rot. Fruit may be attacked by fungi which cause the fruit to rot before or after harvest. Fruit symptoms are very similar to dry fruit rot. Please contact your local County Agricultural Cooperative Extension Agent for control information.
Harvesting and Yield
The custard apple is picked when it has lost all green color and ripens without splitting so that it is readily sold in local markets. If picked green, it will not color well and will be of inferior quality. The tree is naturally a fairly heavy bearer.
With adequate care, a mature tree will produce 75 to 100 lbs (34-45 kg) of fruits per year. The short twigs are shed after they have borne flowers and fruits.