IPM Stratergies for Custard Apple

154 ratings Custard Apple Diseases Anthracnose Leaf spot Diplodia rot Black canker Spiral nematode and Stunt nematode IPM ...

154 ratings

Custard Apple Diseases

1. Anthracnose
2. Leaf spot
3. Diplodia rot
4. Black canker
5. Spiral nematode and Stunt nematode
6. IPM for Custard Apple

Anthracnose

Disease symptoms

• Infection begins at blossom-end of the fruit and later spreads on entire fruit surface, affected fruits shrivel and they may cling to the tree or fall down.
• Necrotic spots of 2-10 mm in diameter appear on unripe fruits which turn into dark brown to black spots. These spots coalesce later and cover entire fruit.

Favourable condition

• Wet and windy conditions favour the disease

Survival and spread

• Older fruits left on the trees provide inoculum for disease spread.

Leaf spot

Disease symptoms

• Alternaria leaf spot: Small yellowish spots first appear along the leaf margins, which gradually enlarge and turn into brownish patches with concentric rings. Severe infection leads to drying and defoliation. Dark brown-purplish patches appear on the infected fruits andrachis just below its attachment with the shoots.
• Cylindrocladium leaf spot: Upper: dark purple spots about 1 to 2 mm in diameter develop first on the shoulders of the fruit and then spread down the sides. Spots enlarge and then later dry out and crack. Similar in appearance to spotting bug damage, but spots are irregular in shape whereas spotting bug lesions are round, and damage does not extend very far into the fruit.

Survival and spread

• The pathogen survives through spores (conidia) or mycelium in diseased plant debris or other hosts.

Favourable conditions

• Relative humidity above 70% coupled with warm weather (12-25 ºC temp.) and intermittent rains favours disease.

Diplodia rot

Disease symptoms

• Diseased fruits show symptoms of purplish to black spots or blotches confined to the surface of the fruit and eventually covered with white mycelia and black pycnidia.
• Diplodia rot is distinguished by its dark internal discolouration and the extensive corky rotting produces.
• The penetrated flesh eventually softens or hardens and cracks, depending on the presence of secondary microbes.

Favourable condition

• Optimum temperature is 25.9°C to 31.5°C and relative humidity is 80%

Survival and spread

• The pathogen persists in infected plant parts which serve as source of inoculums.

Black canker

Disease symptoms

• Irregularly shaped spots ranging from small specks to large blotches.
• Spots have an indistinct ‘feathered’ edge.
• Tissue damage under the spots is no more than 10 mm deep.

Favourable conditions

• The disease is favored by extremely wet weather and cool-to-moderate temperatures (15ºC to 20ºC). When prolonged rainy periods exist in the spring and provide at least six hours of continuous wetness

Survival and spread

• The pathogen persists in infected plant parts which serve as source of inoculums.

Spiral nematode and Stunt nematode

Life cycle

• Nematodes molt four times during each life cycle with a molt occurring at the end of each larval stage.
• Therefore, molts separate the first and second larval stages, the second and third larval stages, the third and fourth larval stages, and also the fourth larval stages and immature adults.
• The 5th stage larva grows to the limit of its new cuticle, at the same time developing into a sexually mature adult male or female.

IPM for Custard Apple

To know the IPM practices for Custard Apple, click here.

Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage

 

3.01   

 

118 ratings and

Custard Apple Insect management

1. Mealy bug
2. Fruit borer/ Fruit boring caterpillar
3. Fruit fly
4. Scales
5. IPM for Custard Apple

Mealy bug

Biology

• Egg: The egg period is 28-32 days. Female and male adults live for 23 to 28 days, respectively. Pre-oviposition, oviposition and post-oviposition periods is 6-7, 8.-9 and 1-2 days, respectively. The total life span of female and male is 46 -49 and 23 -29 days. The reproduction took place both sexually as well as parthenogenetically and female laid an average of 155 eggs during its life period.
• Nymph: Yellow to pale white in colour. It has three to four nymphal instars and the total nymphal period is 21 to 29 days.
• Adult: Females apterous, long, slender covered with white waxy secretions. The life-span of the adult female is 12-31days.

Symptoms of Damage

• The tiny small bugs usually suck sap from twigs, leaves and flowers. Infested fruits will have uneven shapes, poor quality, and are susceptible to secondary infections by pathogens.

Natural enemies of mealybug

• Predators: Ladybird beetle namely Menochilus sexmaculatus, Rodolia fumida, Cryptolaemus montrouzieri

Fruit borer/ Fruit boring caterpillar

Biology

• Eggs: Eggs are laid singly on immature fruit. Upon hatching, the caterpillar bore into the fruits where they pupate.
• Larva: Fully developed gray to black coloured caterpillars are about 20 mm long.
• Adult: Light brown with transparent wing.

Damage symptoms

• Caterpillar makes irregular tunnels and damages the mesocarp by feeding the internal content of the fruits.
• The presence of excreta of the caterpillars near the entry holes on the affected fruits
• The growth of affected fruits is arrested and later fall down.

Natural enemies of fruit boring caterpillar

• Predators: Chrysoperla zastrowii Sellimi, coccinellids, king crow, common mynah, wasp, dragonfly, spider, robber fly, reduviid bug, preying mantid, fire ants, big eyed bugs (Geocoris sp), pentatomid bug (Eocanthecona furcellata), earwigs, ground beetles, rove beetles etc.

Fruit fly

Biology

• Egg: Under optimum conditions, a female can lay more than 3,000 eggs during its lifetime, but under field conditions from 1,200 to 1,500 eggs per female is considered to be the usual production. Development from egg to adult under summer conditions requires about 16 days.
• Larva: The mature larva emerges from the fruit, drops to the ground, and forms a tan to dark brown puparium.
• Pupa: Pupation occurs in the soil. About nine days are required for attainment of sexual maturity after the adult fly emerges.
• Adult: Brown or dark brown with hyaline wings and yellow legs.

Damage symptoms

• Maggots bore into the semi ripened fruits and feed on the pulp.
• Affected fruits become shrivelled, deformed, rot and drop.

Natural enemies of fruit flies

• Parasitoids: Diachasmimorpha longicaudata, D. tryon, D. kraussi, Fopius arisanus.

Scales

Biology

• Egg: The eggs are pink to dark red and are laid under the scale’s wax covering of adult females. Females lay about 2000 eggs.
• Nymph: First stage (instar) nymphs, called crawlers hatch from eggs over a period of 2 to 3 weeks. Immediately after hatching the first instar crawlers come out which are pink in colour. They disperse on the leaves and twigs and find a suitable feeding place to settle. The crawlers undergo three moults and develop into adults. The wax-covering secreted around their body gives them a star-like appearance. Soft scales have 3 or 4 instars in the female and 5 in the male
• Adult: The adults are elliptical, reddish brown with short anal process. The adult female is reddish which is coated with a thick layer of pinkish-white wax. Adults are mostly found on twigs and branches. The size of the female is about 2 to 4 mm in length and 1 to 3.5 mm in width. Males are not known in this species. Females have 2 to 3 immature stages without any pupa-like instars while males have 4 immature stages with the two pupa-like instars.

Damage symptoms

• The direct damage is caused by insertion of stylets during feeding by the nymphs, which causes premature leaf drop and drying of twigs.
• Sooty mould develops on honeydew excreted by these scale insects and incase of severe infestations shoots or branches die and host’s death may also occur.

Natural enemies

• Parasitoids: Coccophagus lycimnia, Metaphycus eruptor and Scutellista cynea

IPM for Custard Apple

To know the IPM practices for Custard Apple, click here.

Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage

 

3.03   

 

139 ratings

Custard Apple Pests

1. Pests of national significance
1. Insect and mite pests
2. Diseases
3. Nematodes
4. Weeds
1. Grasses
2. Broadleaf
3. Sedges
5. Rodents
2. IPM for Custard Apple

Pests of national significance

Insect and mite pests

• Mealy bug: Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae)
• Fruit fly: Bactrocera spp, B. zonata Saunders (Diptera: Tephritidae)
• Scales: Ceroplastes floridensis Comstock (Hemiptera: Coccidae)
• Fruit boring caterpillar: Heterographis bengalella Ragonot (Syn: Anonaepestis bengalella) (Lepidoptera: Pyralidae)

Diseases

• Fruit rot & Anthracnose: Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. (Perfect stage Glomerella cingulata (Stoneman) Spauld. & H. Schrenk
• Alternaria leaf spot: Alternaria spp.
• Cylindrocladium leaf spot: Cylindrocladium colhounii and Cylindrocladium scoparium
• Diplodia rot: Botryodiplodia theobromae Patouillard
• Black canker: Phomopsis annonacearum (Bond) Mont.

Nematodes

• Spiral nematode: Helicotylenchus spp.
• Stint nematode: Tylenchorhynchus spp.

Weeds

Grasses

• Bermuda grass: Cynodon dactylon (L.) Pers. Poaceae
• Annual brachiaria: Brachiaria deflexa (Schumach.) Robyns Poaceae
• Viper grass: Dinebra retroflexa (Vahl.) Panzer. Poaceae
• Dropseed: Sporobolus diandrus (Retz.) P. Beauv., Poaceae

Broadleaf

• Horse purslane: Trianthema portulacastrum L. Aizoaceae
• Black nightshade: Solanum nigrum L. Solanaceae
• False amaranth: Digera arvensis Forssk. Amaranthaceae
• Puncture vine: Tribulus terrestris L. Zygophyllaceae
• Common cocklebur: Xanthium strumarium L. Asteraceae
• Asthma herb/Spurge: Euphorbia hirta/geniculate L. Euphorbiaceae
• Carrot grass: Parthenium hysterophorus L. Asteraceae
• Stone breaker: Phyllanthus niruri L. Euphorbiaceae
• Sensitive plant: Mimosa pudica L. Fabaceae
• Broadleaf woodsorrel: Oxalis latifolia Kunth Oxalidaceae
• Common Purslane: Portulaca oleracea Portulacaceae

Sedges

• Purple nut sedge: Cyperus rotundus L. Cypraceae

Rodents

• Soft furred field rat: Millardia meltada Gray
• Indian mole rats/Smaller: Bandicoota bengalensis Gray
• Common house rat: Rattus rattus Linn
• Bats

IPM for Custard Apple

To know the IPM practices for Custard Apple, click here.

Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage

 

2.99   

 

141 ratings

Custard Apple: Crop stage-wise IPM

1. Pre planting*
2. Planting*
3. Vegetative stages (1-5 years)
4. Flowering and fruiting

Management	Activity
Pre planting*
	Common cultural practices: • Timely sowing should be done. • Field sanitation, rogueing • Destroy the alternate host plants • Apply manures and fertilizers as per soil test recommendations
Nutrients	• Pits (50 x 50 x 50cm) are to be dug during summer season and kept open for controlling soil borne pests. • Pits should be filled with a mixture of top soil and farmyard manure in 1:1 ratio a fortnight before planting.
Weeds	• Cultivate the field before planting to destroy existing weeds in the field. • Summer ploughing is helpful in destroying weeds seeds and rhizomes in the soil. • Adopt stale seed bed technique
Resting stages of diseases &pests and nematodes	Cultural control: • Dig the planting pit during summer season and keep it open for at least one month. • Soil solarization: Cover the pits with polythene sheet of 45 gauge (0.45 mm) thickness for three weeks before sowing for soil solarization which will help in reducing the soil borne pests. • Apply neem cake @ 2 kg/pit.
Planting*
	Common cultural practices: • Use healthy, certified and weed free seeds.
Nutrient	• Planting is done in rainy season at a distance of 4m x 4m. • Add Trichoderma and Mycorrhiza mixture @ 50 g per pit at the time of planting. • Apply 300 g of fertilizers mixture of Urea, Single super phosphate and muriate of potash in equal proportion are added in each pit.
Weed	• Remove existing weeds in and around the pits at the time of planting. • Mulching with organic or biodegradable material.
Soil borne diseases and nematodes	Cultural control: • Make a trench keeping the distance from the main stem as per the plant canopy width and apply neem cake @ 2 kg/ plant/pit.
Vegetative stages (1-5 years)
	Common cultural practices: • Destroy crop debris • Avoid water logging • Avoid water stress • Enhance parasitic activity by avoiding chemical spray, when 1-2 larval parasitoids are observed • Custard apple bears flowers on current season growth and very rarely on older branches. The early completion of season is essential for the initiation of new growth. Therefore manual defoliation during the mid-summer is recommended. Common mechanical practices: • Use light trap @ 1/acre and operate between 6 pm and 10 pm • Install pheromone traps @ 4-5/acre for monitoring adult moths activity (replace the lures with fresh lures after every 2-3 weeks) • Erecting of bird perches @ 20/acre for encouraging predatory birds such as King crow, common mynah etc. Common biological practices: • Conserve natural enemies through ecological engineering • Augmentative release of natural enemies
Nutrient	Application of manures & fertilizers: (per plant) The bearing trees of Custard apple should be fertilized as follows 2nd to 5th year FYM 30 kg N 400 g P 250 g K 800 g • Nitrogen should be applied in the form of FYM and oil cakes each at 25% and the remaining 50% with chemical fertilizers. While P2O5 in the form of super phosphate and K2O in the form of sulphate of potash. • Manures are applied in 2 to 3 equal doses i.e. first dose in December-January, 2nd done in June-July, 3rd dose in September, Potash application can be reduced if the soil is rich in this nutrient. • Nitrogen containing fertilizers should be applied in three equal splits in January, July and November months; phosphorus containing fertilizers in two splits in January and July months and Potassium containing fertilizers may be applied as singly dose in January. • Adopt ring method of fertilizer application. • A mixture of zinc sulphate 0.5%, manganese sulphate 0.2%, boric acid 0.1%, urea 1% and lime 0.4% has to be sprayed two or three times in a year to control chlorosis in leaves. • Intercrops: During pre bearing period short growing crops like groundnut, ragi, bajra wheat, pulses and vegetables (except solanaceous crops) can be profitably grown in the inter spaces. • In the bearing orchards green manure crops like sunhemp, green gram, cowpea etc., are raised and incorporated into the soil during the monsoon period.
Weeds	• Timely Interculture and hand weeding should be done with hand tools for initial 5 years. • Mulching: After weeding and manuring, application of dry-leaf mulch or paddy husk to a thickness of 8 cm in the basin keeps down the weed growth and decreases the number of irrigations, and improves the fruit quality. • In the initial years of planting, intercrops like groundnut, minor millets, linseed and gram should be grown.
Mealy bug	Cultural control: • Collect and destroy the mealy bug infested leaves, twigs and fruits. • Flooding of orchard with water in the month of October kill the eggs. • Ploughing of orchard in November. • Avoid plant stresses - healthy plants are much less susceptible to attack Biological control: • Release Cryptolaemous montrouzieri beetles @ 10/tree or @ 30 larvae/plant twice at 15 days interval. • The Coccinellid Menochilus (Chilomenes) sex maculatus (F) is a predator of the nymphs and adults, and the Hymenopterous parasite Anaysis alcocki (Ashm.) Anagyrus dactylopii and Aenasius advena are three parasitoids on mealy bugs. • Release of coccinellid Scymnus coccivora @ 10 beetles /tree or @ 30 larvae/plant is a good predator of both nymphs and adults.
Scale insect	Cultural control: • Collect and destroy damaged leaves • Apply well rotten sheep manure @ 4 t/ acre in two splits or poultry manure in 2 splits • Control ants and dust which can give the scale a competitive advantage. Biological control: • Field release of ladybird beetle. • Spray dormant oil in late winter before spring. • Spray horticultural oil, if needed, year round.
Anthracnose	Cultural Control: • Prune dead twigs before flowering, and remove infected fruit and dead leaves regularly. • Leaf and soil analysis should be done to maintain adequate nutrient concentration in plants particularly calcium and nitrogen • Avoid planting susceptible varieties.
Leaf spot(S)	Cultural control: • Collect and burn the infected plant parts to minimize the spread of the disease. • Increase air circulation by proper training and pruning.
Flowering and fruiting
Nutrient	• The bearing trees of Custard apple should be given 250 g N, 125 g P2O5, and 125 g K2O per plant before the commencement of rainy season. 6th year onwards (per plant) FYM 30 kg N 600 g P 500 g K 1200 g
Weeds	• Remove weeds from basins around the trees by hand weeding followed by mulching with organic materials. • Control weeds between rows by shallow cultivation and grow the cover crops as mentioned in vegetative stage.
Mealy bug	Cultural control: • Collect and destroy the mealy bug infested leaves, twigs and fruits. • Flooding of orchard with water in the month of October kill the eggs. • Ploughing of orchard in November. • Avoid plant stresses - healthy plants are much less susceptible to attack Biological control: • Release Cryptolaemous montrouzieri beetles @ 10/tree or @ 30 larvae/plant twice at 15 days interval. • The Coccinellid Menochilus (Chilomenes) sex maculatus (F) is a predator of the nymphs and adults, and the Hymenopterous parasite Anaysis alcocki (Ashm.) Anagyrus dactylopii and Aenasius advena are three parasitoids on mealy bugs. • Release of coccinellid Scymnus coccivora @ 10 beetles /tree or @ 30 larvae/plant is a good predator of both nymphs and adults.
Fruit borer/ Fruit boring caterpillar	Cultural control: • Collect and destroy affected fruits. Physical Control: • Adopt bagging of fruits. Biological control: • Use of braconid parasitoids (Apanteles spp.) to parasitize larvae;
Fruit fly	Cultural Control: • Collect fallen infested fruits and destroy them. • Provide summer ploughing to expose the pupae. Physical control: • Immersion of fruits in hot water (45 to 47°C) for 60 minutes to kill eggs and maggots • Use 10 traps per acre of methyl eugenol. Biological control: • Field release of natural enemies Opius compensates and Spalangia philippines.
Scale insect	Cultural control: • Collect infeseted plant parts and destroy them. • Apply well rotten sheep manure @ 10 t/ ha in two splits or poultry manure in 2 splits • Control ants and dust which can give the scale a competitive advantage. Biological control: • Field release of Vadalia and Australian ladybugs. • Spray dormant oil in late winter before spring.
Anthracnose	Cultural Control: • Prune dead twigs before flowering, and regularly remove infected fruit and dead leaves. • Leaf and soil analysis should be done to maintain adequate nutrient concentration in plants particularly calcium and nitrogen • Avoid planting susceptible varieties.
Leaf spot (s)	Cultural control: • Collect and burn the infected plant parts to minimize the spread of the disease. • Increase air circulation by proper training and pruning.
	Cultural control: • Mulch under trees to reduce soil splash. • Remove dead twigs and mummified fruit each season. • Prune tree skirts to 50 cm above the ground. • Regularly monitor fruit for infection during the season so that spraying can start before fruit diseases get too severe.
Diplodia rot	Cultural control: • Use mulching under trees to reduce soil splash. • Remove dead twigs and mummified fruits. • Maintain proper plant canopy to reduce the high humidity by appropriate pruting and training. Pruin trees 50 cm above the ground.
Black canker	Cultural control: • Use mulching under trees to reduce soil splash. • Regularly monitor the diseases and remove dead twigs and mummified fruits. • Follow proper plant canopy by appropriate prunning and training. • Prune trees 50 cm above the ground.
Spiral nematode (Helicotylenchus sp.) Stunt nematode (Tylenchorhynchus sp.)	Cultural control: • Fallow, flooding and deep summer ploughing, • Timely planting, manuring and irrigation, • Use cover crops, antagonistic crops, trap crops, • Follow crop rotation • Grow resistant/tolerant varieties Physical control: • Practice soil solarization • Phytosanitary measures: Follow International/ Domestic regulatory measures.
Note: The pesticide dosages and spray fluid volumes are based on high volume sprayer. * Apply Trichoderma viride/harzianum and Pseudomonas fluorescens as seed/seedling/planting material, nursery treatment and soil application (if commercial products are used, check for label claim. However, biopesticides produced by farmers for own consumption in their fields, registration is not required).

Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage

 

Nutritional deficiencies of Custard Apple

1. Iron
2. Sulphur
3. Manganese
4. Magnesium
5. Nitrogen
6. Boron
7. Potassium
8. Boron toxicity
9. Manganese toxicity
10. Zinc toxicity
11. Disorders
12. IPM for Custard Apple

Iron

• Cause: Insufficient iron available to the tree. Generally caused by poor root health or over-liming.
• Identification notes: Causes an overall yellowing or whitening of leaves with the veins remaining green.
• Treatment: Apply a foliar spray of iron chelate or soluble ferrous sulphate.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. To avoid over-liming, calculate lime or dolomite rates carefully in accordance with soil analysis results. Mulch trees to improve root health.

Sulphur

• Cause: Insufficient sulphur available to the tree.
• Identification notes: Healthy leaf (bottom) for comparison. Causes a uniform yellowing of the leaves but the veins do not remain green. Rarely seen in well-managed orchards.
• Treatment: Not serious enough to warrant treatment.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. Where deficient, use fertilisers with higher sulphur content.

Manganese

• Cause: Insufficient manganese available to the tree. Generally caused by high soil pH or high levels of soil phosphorus or zinc.
• Identification notes: Affected leaves are a mottled pale-green, with green veins. Yellowing is more pronounced towards the leaf tips. Rarely seen in well-managed orchards.
• Treatment: Apply foliar spray of manganese sulphate and urea.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. Apply manganese to the soil when indicated by leaf and soil analysis results.

Magnesium

• Cause: Insufficient magnesium available to the tree. Generally results from excessive use of potassium.
• Identification notes: Yellowing occurs in bands on either side of the midrib while the margin of the leaf remains green. A reddish-brown discolouration sometimes develops in the yellow areas. Most common in acid sandy soils.
• Treatment: Do leaf and soil analyses to check soil pH and magnesium levels. Apply dolomite or magnesium oxide (choice depends on pH level). A short-term response can be achieved with a foliar spray of Epsom salts and urea.
• Prevention: Do annual leaf and soil analyses to monitor soil pH and nutrient levels. Apply magnesium to the ground under the trees according to leaf and soil analysis results. Do not apply excessive amounts of potassium fertiliser.

Nitrogen

• Cause: Insufficient nitrogen available to the tree.
• Identification notes: Left: mild symptom showing the pale green leaves. Right: severe symptom where the oldest leaves turn bright yellow and fall prematurely.
• Treatment: Do a leaf analysis to confirm the diagnosis. Adjust the fertiliser program according to the leaf analysis results.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. Apply appropriate amounts of nitrogen fertiliser throughout the growing season.

Boron

• Cause: High uptake of boron from the soil. Generally caused by applying boron unevenly or at high rates.
• Identification notes: Leaves near growing point yellowed, growth bud appear white or brownish dead tissue.
• Treatment: Apply boron at 2.0 g/m2 and broadcast over the ground area under the canopy. Boron and calcium sprays during flowering and early fruit set are beneficial in reducing internal fruit browning.
• Prevention: Do annual leaf and soil analyses to monitor boron levels. Take particular care to apply boron at the correct rates.

Potassium

• Cause: Insufficient potassium available to the tree. Generally caused by an imbalance of potassium, calcium and magnesium in the soil. More common in light soils where heavy leaching occurs and in trees with heavy crop loads.
• Identification notes: Yellowing begins at the margin of the leaf and spreads towards the veins. Small black spots develop within affected areas.
• Treatment: Do a leaf analysis to confirm the diagnosis. Adjust the fertiliser program according to the results.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. Apply appropriate amounts of potassium fertilizer throughout the growing season.

Boron toxicity

• Cause: High uptake of boron from the soil. Generally caused by applying boron unevenly or at high rates.
• Identification notes: Note the small brown spots developing inside the burnt margin.
• Treatment: No applicable
• Prevention: Do annual leaf and soil analyses to monitor boron levels. Take particular care to apply boron at the correct rates. Apply boron evenly when spraying it on the ground or applying it by fertigation.

Manganese toxicity

• Cause: High uptake of manganese from the soil. Occurs in soils with high manganese levels when pH falls below 5.5 (1:5 water test).
• Identification notes: Affected leaves have an irregular yellow or whitish margin.
• Treatment: Do a leaf analysis to confirm the diagnosis. Apply lime or dolomite to raise soil pH to 6.5 (1:5 water test).
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. In high manganese soils, maintain soil pH at 6.5 or above (1:5 water test).

Zinc toxicity

• Cause: Insufficient zinc available to the tree. Generally caused by high soil pH or high levels of soil phosphorus.
• Identification notes: Affected leaves are yellow-green with green veins, smaller than usual, narrow and slightly distorted.
• Treatment: Apply zinc to the ground under the tree. In severe cases, also spray chelated zinc onto the spring flush.
• Prevention: Do annual leaf and soil analyses to monitor nutrient levels. Apply zinc to the ground under the trees annually according to leaf and soil analysis results.

Disorders

1. 
2. Stone Fruits: Some fruits instead of attaining full size remain very small and become brown and dry up. These are known as stone fruits which are retained on tree for a long period. Competition among the developing fruits and high temperature are supposed to cause stone fruit formation.
3. Fruit Cracking: This usually happens from a heavy rainfall or irrigation after a prolonged dry spell. Evenly distributed irrigation schedule and constant and uniform moisture level in the soil will reduce this Problem.

IPM for Custard Apple

To know the IPM practices for Custard Apple, click here.

Source: NIPHM, Directorate of Plant Protection, Quarantine & Storage