Custard Apple Diseases and Pest Management: A Research-Based Guide

Research published by ICAR-NRC for Arid Horticulture and Anand Agricultural University identifies mealy bug, fruit borer, and leaf spot disease as the three most economically damaging threats to custard apple orchards across India. Survey data from Maharashtra and Andhra Pradesh orchards documents yield losses of 30 to 40 percent in seasons where mealy bug infestations go unmanaged and fruit borer damage is left untreated. Unlike many horticultural crops, custard apple has very few registered chemical pesticides approved for use, making integrated pest management combining cultural, biological, and targeted chemical controls the only reliable and safe strategy for protecting orchard productivity.

Mealy Bug: The Most Destructive Custard Apple Pest

Research from the University of Agricultural Sciences Dharwad confirms that mealy bug, particularly Ferrisia virgata and Planococcus citri species, is the most widespread and economically damaging pest of custard apple in India. Mealy bugs colonize young shoots, flower buds, and developing fruits, sucking sap and secreting honeydew that promotes black sooty mould growth, reducing photosynthesis and making fruits unmarketable. Studies document that mealy bug populations peak between October and January coinciding with the main fruiting season. Effective control begins with cultural practices: banding tree trunks with 25 cm wide alkathene sheets coated with grease prevents wingless crawlers from climbing from soil to canopy. Biological control using Cryptolaemus montrouzieri beetles released at 10 beetles per tree at first infestation sign has shown 60 to 70 percent reduction in mealy bug population in ICAR trials. When chemical intervention is needed, imidacloprid 0.5 ml per litre or dimethoate 2 ml per litre spray at 15 day intervals gives effective control.

Fruit Borer: Silent Destroyer of Custard Apple Yield

Annona fruit borer, Cerconota anonella, is documented by ICAR as one of the most damaging insects specific to custard apple and other Annona species in India. The female moth lays eggs on developing fruits between the carpel segments. Hatching larvae bore into the fruit, feeding on pulp and seeds, causing the fruit to turn black and drop prematurely. Research from Andhra Pradesh Agricultural University found fruit borer damage ranging from 15 to 35 percent of total fruit set in unprotected orchards during peak infestation periods from August to November. Bagging individual fruits using white paper bags or muslin cloth bags after fruit set to marble size is the most effective physical control method documented in research, reducing infestation to near zero in bagged fruits. Spraying carbaryl 2 grams per litre or quinalphos 2 ml per litre at 15 day intervals starting from fruit set stage provides chemical control when bagging is not practical at scale.

Leaf Spot and Dieback: Fungal Diseases to Watch

Colletotrichum gloeosporioides causing anthracnose and Phytophthora causing root and collar rot are the two most important fungal diseases of custard apple documented in research from IIHR Bangalore and Maharashtra agricultural universities. Anthracnose produces dark brown to black spots on leaves, twigs, and fruits during humid conditions, with severe defoliation reducing next season's flowering capacity. Phytophthora root rot causes sudden wilting and death of entire branches or whole trees, particularly in poorly drained soils. Research recommends preventive copper oxychloride sprays at 3 grams per litre at monthly intervals during monsoon season for anthracnose control. For Phytophthora, soil drenching with metalaxyl-mancozeb 2.5 grams per litre around the root zone twice yearly in June and October has shown significant reduction in disease incidence in orchard trials.

Stem Borer Management

Stem borers of the Batocera and Plocaederus species attack custard apple trunks and main branches, particularly in older orchards above 8 years of age. Research from Tamil Nadu Agricultural University documents that stem borers weaken structural integrity of main branches, causing sudden limb breakage during fruit load, and can kill entire trees over 2 to 3 seasons if entry holes are not detected and treated early. Regular inspection of trunks from October to February is recommended. Fresh sawdust frass outside entry holes indicates active infestation. Injecting petrol or chlorpyrifos solution diluted 1 ml in 5 ml of water into borer holes using a syringe and sealing the hole with moist clay immediately after treatment is the most effective field management method documented in state agricultural university research.

Integrated Pest Management Calendar

Research from ICAR recommends a season-wise IPM calendar for custard apple orchards. During May and June before monsoon onset, remove and burn all dead wood and apply fresh whitewash of lime plus copper sulphate mixture to trunks to prevent fungal and borer entry. In July and August at flowering stage, apply copper oxychloride spray for fungal protection and install alkathene banding for mealy bug prevention. From September to November at fruit development stage, begin fruit bagging for borer control and release Cryptolaemus beetles if mealy bug is observed. In December and January at harvest time, inspect all fruits before harvest and remove any borer-damaged or mealy bug affected fruits from the orchard immediately to prevent carry-over pest populations to next season.