Sapota Pests, Diseases (Chiku/Sapodilla), Control Methods

Introduction to sapota pests and diseases

Sapota (Achras zapota) is mainly cultivated in India for its fruit value. Sapota is also called as Chiku, spelled zapote, a plant of the sapodilla family (Sapotaceae) and its edible fruit. Sapota is grown in a variety of soil but deep alluvial, sandy loam soil and black soil having good drainage are ideal for doing Sapota farming. pH value 6.0-8.0 is optimum for Sapota farming and avoid cultivation in shallow clayey soil and high calcium content.

A step by step guide to Sapota pests and diseases with their control measures

The common pests found on Sapota trees are leaf Webber, hairy caterpillars, budworm, stem borer, scale insects, mealybug, lead minor, and fruit borer, etc. The diseases that infect the Sapota plants are sooty mold, leaf spot, anthracnose, base rot, and flattened branches, etc. Maintaining proper sanitation in the farm area is the first important step for preventing the occurrence of disease and pests in Sapota.

Conditions for Sapota cultivation

The Sapota tree is a hardy perennial and evergreen tree and grown on a wide range of soils. Drainage is most important and there should not be a hardpan in the sub-soil. Deep and porous soils make good plant growth. The Sapota can tolerate the presence of salts in the soil or irrigation to some extent. The important and widely adopted Sapota varieties are Kali Patli and Cricket Ball. The other varieties are pili patti, Bangalore, Baramati, Dwarapudi, etc.

For Sapota farming, well-prepared land is required, and to bring the soil to a fine tilth, plowing is done 2-3 times followed by leveling. It can be propagated through grafting and air layering. The air layering method is done during monsoons (July-August). Then, the percentage of success in air layers can be improved by applying 100 to 200ppm of Indole butyric acid solution on the ringed bark before wrapping with moss grass and plastic sheet. On average, 130 plants are planted at a spacing of 8.5 meters. High-density planting with a spacing of 5×5 meters up to the age of 13 years has been adopted successfully.

In light soils, pits of about 60x60x60 cm. size, whereas in heavy and gravely soils pits of 1x1x1 m. size is made in April-May and exposed to the sun for 15 days. Then, the pits are later on filled with well-rotten compost or farmyard manure, 3 kg. superphosphate and 1.5 kg. muriate of potash. The pits are then left to monsoon rains for settling and planting is done at a suitable time.

Grafts, budded plants, or layers are planted one in each pit, and also care is taken so that the bud joint or graft is at least 15 cm above the ground level. After planting, stakes are provided to avoid wind damage and young plants are protected from the sun by making dry grass thatch on top and three sides excepting the south-east for sunlight.

The Sapota is a tropical fruit crop and can be grown from Sea level up to 1200 meters height. It prefers warm and humid weather and grows in dry and humid areas. Areas with an annual rainfall of 125 to 250 cm are highly suitable. The optimum temperatures range from 12 to 36°C. It is a hardy plant and can tolerate scarcity of soil moisture fairly well. For good growth and high yield, plants can be irrigated at an interval of 7-10 days in summer and 20-25 days in winters.

It is a climacteric fruit and it improves in quality after harvesting but immature fruits should never be harvested. A well-grown Sapota tree yields 2500 to 3000 fruits weighing about 150 kg every year, for 50 to 60 years during its productive age.

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Sapota pests and their management

The Sapota crop is affected by insect pests. The important Sapota insect pests are;

Fruit fly

Symptoms of damage

It is a polyphagous pest and Sapota is one of its preferred hosts. Then, the attack is more in the mixed orchard of mango and Sapota. The adults are yellowish golden while maggots are pale white. The affected fruit deteriorates completely and unfit for human consumption. Moreover, its infestation results in an onetime loss for buying but for the producer it imposes a recurring loss i.e., a loss of goodwill.

Treatment – A regular installation of the methyl eugenol trap in Sapota orchard can efficiently reduce the population.

Hairy caterpillar

Symptoms – They destroy the Sapota plant by feeding themselves on new shoots and twigs.

Treatment – Spraying of quinalphos by 300ml in 150 liters of water per acre is done.

Stem borer

Symptoms of damage

• Presence of small holes at the collar region and extrusion of frass through the boreholes at the collar region
• Yellowing and shedding of leaves
• Drying up of twigs and gradual death of the tree.

Identification of pest

Adult – medium-sized reddish-brown beetle.

Head and thorax – dark brown or almost black.

Management

• Collect and destroy the damaged plants
• Field sanitation
• Swab Coal tar and Kerosene by 1:2 or Carbaryl 50 WP 20 g / l on the basal portion of the trunk ( 3 feet height)
• The padding with monocrotophos 36 WSC 10 ml in 2.5 cm /tree soaked in absorbent cotton.
• If infestations are severe then apply the copper oxychloride paste on the trunk of the Sapota tree.
• Apply carbofuran 3G 5 g per hole and then plug with mud.

Chiku moth

Larvae feed on leaves, buds, flowers, and sometimes even on tender fruits and the web together leaves with silken threads to feed on green tissue from within hiding between the plant leaves or within the loose tunnel made up of excreta.

Management – Remove and destroy all the infected clumps and spray with neem seed kernel extract (4%) or Chlorpyrifos 20EC (2ml/L).

Budworm

The Bud worms are moth caterpillars that destroy the vegetative buds by feeding themselves on it.

Symptoms of damage

• Webbed flowers and buds
• Shedding of buds and flowers.
• Boreholes and excreta seen on attacked Sapota flowers.

Treatment

• Spraying of quinalphos by 300ml or fame 20ml in 150 liters of water per acre is done.
• Spray phosalone 35 EC 2 ml/lit or phosphamidon 40 SL 2 ml/liter.
• Application of neem oil about 2% of neem seed kernel extract 5 %.

Green Scale

Symptoms of damage

• Nymphs and adults suck the sap from plant leaves
• Yellowing of leaves

Identification of pest

Nymph: Pale lemon yellow

Adult: green, flat oval soft scale

Management

• Prune and destroy the infested shoots at the initial stage of infestation.
• Spray monocrotophos 1ml/lit or phenthoate 1ml/lit
• After two weeks release 20 predator beetles, that is, C. montrouzieri beetle per tree.
• Encourage parasitoids, that is, Aneristis sp Coccophgagus cowperi, C. bogoriensis

Bud Borer

Symptoms – The caterpillars feed on the contents inside flowers and also flower buds by boring into the tender tissues at the base. Sometimes, the affected flower buds are webbed together and such flowers and also flower buds dry up and drop in considerable numbers.

Management – Then, spraying Bt (1ml/L) at fortnightly intervals brings down the bud borer infestation. In case of severe infestation, spray dichlorvos 76EC (2 ml/L).

Seed Borer

Symptoms – Tiny exit holes after the emergence of larvae from fruits are the indication of infestation and such fruits when cut open have damaged seeds.

Management – First spray when the fruits are of a small lime size and then repeat at fortnightly intervals during main fruiting season, alternating with deltamethrin 2.8EC (1 ml/L) and Bt (1 ml/L).

Fruit mite

Symptoms –The fruit mite is red which damages the marble-size fruits. Then, it scrapes the fruit and sucks the cell sap due to which an outer surface becomes rough and black. Thus the quality of fruit deteriorates and the market price will be reduced.

Management – Two sprays at 15 days interval either of monocrotophos 0.05% or ethion 0.05% or dichlorvos 0.03% at marble-size fruit can effectively control the fruit mite pest.

Leaf miner

Symptoms –It is a minor pest and the tiny larvae mine young and tender leaves feed within and the affected leaf show glistering galleries get distorted dry and ultimately fall. Up to 15 to 18 percent damage is recorded from June to September

Management – Variety PKM-1 is reported to be tolerant against the attack of leaf miner pest. In case of severe infestation spray lambda-cyhalothrin 5EC (0.5 ml/L) or quinolphos 25EC (2ml/L).

Sapota diseases symptoms and their management

The main diseases in the Sapota tree reported are leaf spot, base rot, heart rot, and anthracnose. Application of Dithane M-45, copper oxychloride (3 g./l.), etc are effective.

Leaf spot

Deep purplish-brown color spots that are white from the center and round in shape are seen. Long spots are seen on the stem of Sapota fruits and petals.

Treatment – Spraying of copper oxychloride by 400gm per acre is done.

Heart rot

It is a fungal disease that causes the decay of wood at the center of the trunk and branches.

Treatment – Spraying of Carbendazim by 400gm or Z-78 by 400gm in 150 liters of water per acre is done.

Anthracnose

On stem and branches, deep sunken wounds of canker are seen and on plant leaves, brown color stains are seen.

Treatment – Spraying of copper oxychloride or M-45 by 400gm per 150ltr water is done to get rid of anthracnose.

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Mechanical practices of pests in Sapota tree

• Neem cake must be incorporated by 40 Kg/acre, to protect from pest attack.
• Growing of forage crops as a mixed crop helps in “maintaining ecological balance”.
• Timely planting must be done.
• Plant material for laying quality fruit orchard must be obtained from the registered nursery.
• Avoid planting of saplings infested with scales, borers, and diseases.
• Don’t grow plants in the nursery at the same site every year.
• Use of disease-resistant rootstock and also scion for managing the collar rot.
• For the rising of nurseries, the soil selection is made which is free from pest infestation.
• Then, delay planting until the soil is reasonably dry and plant before the buds begin to burst.
• Growing flowering plants particularly marigold and maize on the peripheries will help in the conservation of both predators and parasites. In rich soils, the fertilizer doses can be half or applied based on the leaf analysis report.
• Make use of neem cakes as raising plant nurseries to ward off any soil pests.

Integrated pest management strategies of various pests of Sapota

The following good agricultural practices must be adopted for the management of various pests of Sapota;

• Collect and destroy the mealybug infested plant leaves, twigs, and fruits.
• Flooding of the orchard with water in October kills the eggs and plowing of an orchard in November.
• Avoid plant stresses and healthy plants are much less susceptible to attack
• Release Cryptolaemous montrouzieri beetles by 10/tree or 30 larvae/plant twice at 15 days interval.
• Release of coccinellid Scymnus coccivora by 10 beetles/tree or 30 larvae/plant is a good predator of both nymphs and adults.
• Collect fallen infested Sapota fruits and destroy them.
• Provide summer plowing to expose the pupae and immersion of fruits in hot water (45 to 47°C) for 60 minutes to kill eggs and maggots.
• Control ants and dust this can give the scale a competitive advantage.
• Field release of ladybird beetle and spray dormant oil in late winter before spring.
• Spray horticultural oil, if needed, year-round and adopt bagging of fruits.
• Use of braconid parasitoids to parasitize larvae.

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