Fruit Borer in Pomegranate: Symptoms, Causes, Control, and Treatment

The Pomegranate is a fruit with a sweet, tart flavor and thick, red skin. The fruit’s skin is not edible, but hundreds of sweet seeds can be eaten plain or sprinkled on salads, oatmeal, hummus, and other dishes to enhance the dish’s flavor. Various studies have shown that pomegranates do well in semiarid conditions, and they can be grown as high as 500 meters above the mean sea level if grown in certain conditions.

Fruit Borer in Pomegranate
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When irrigation facilities are available, it can thrive under hot, dry summers and cold winters if irrigation facilities are available. However, the tree needs a hot, dry climate during fruit development and ripening to grow properly. Pomegranate is cultivated in Maharashtra, Gujarat, Madhya Pradesh, Rajasthan, Chhattisgarh, Himachal Pradesh, Odisha, Andhra Pradesh, and Karnataka.

Among these states, Maharashtra is one of the leading producers of Pomegranate. This crop is grown on an average of 109.2 thousand hectares in India. In fruit crops, most insect pests that cause damage are fruit borers, bark-eating caterpillars, fruit-sucking moths, mealy bugs, and thrips.

Fruit borer in Pomegranate

Fruit borer

The Pomegranate fruit borer, or Pomegranate butterfly, is one of the most destructive, widespread, polyphagous, and widespread pests found in India and all over Asia. In addition to being known as Pomegranate Fruit Borer, Anar Butterfly is another name for this insect. It is common for butterflies to lay their eggs on the calyx of fruits, buds, or small fruits. Upon emerging from the fruit, larvae make a hole in the flesh and crawl inside to feed on the emerging arils. 

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Fruit Borer in Pomegranate2
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The larva creates a hole in the fruit through which fungi and bacteria can enter and cause the fruit to rot. Infested fruits emit an unpleasant odor that is difficult to ignore. The drop in fruit and decline in the fruit quality can seriously impact production, especially during August during the monsoon season and during November/December during the winter harvest season. As a result of an infestation from flowering to the button stage, up to 50 percent of the fruit will be lost   

Pomegranate fruit borer biology

  • The larva hatches and bores into the fruit, with the larval period lasting for 18-47 days. Pupation lasts for 7-34 days.
  • Full-grown larvae are dark brownish with short hairy and white patches all over the body surface and measure about 16 to 20mm long.
  • Pupation occurs either inside fruits or on the stalk holding them. Pupal period 7-34 days.
  • Adults lay eggs on the stalks or flower buds with an incubation period lasting 7-10 days. 
  • Adults are glossy bluish in the case of males and brownish violet color in the case of a female, with a conspicuous orange patch on the forewings, and the life cycle is completed in 1-2 months.
  • A Female lays an average of 13.29 eggs, and the incubation period is 4-5 days. 
  • Four generations were completed in a year.

Damage symptoms

  • The pest causes up to 70% yield loss under severe infestation. The moths lay eggs on fruits at the pea stage, and upon hatching, the newly emerged caterpillars bore into fruits, feed on the pulp near the seed, and accumulate fecally.
  • The first and second instar larvae feed on the fruit superficially, but the third to fifth instar larvae feed internally and damage the pulp around the seed. The full-grown larvae were found to feed on the soft immature seed at the initial stages of fruit development.
  • It is important to note that damage can occur from the flowering stage to the button stage of the period. As the fruit is covered with leathery skin or rind, it is mainly yellow, mostly with a light or dark pink or dark red overlaid on top of it.
  • This tropical fruit has an interior shell composed of a membranous membrane and a white spongy tissue, which divides it into a compartment filled with transparent sacs filled with a tart, fleshy-juicy pulp in a red, pink, or whitish color. One or more seeds in each sac may be white, red, angular, soft, or hard. Approximately 52% of the weight of the whole fruit is made up of seeds.
  • As a result, this is one of the major problems with offensive odors and the excreta of caterpillars that come out of the entry holes and that adhere to the entrance holes. In addition, unattended fruits are more likely to rot and fall off on their own if they’re left for too long.
  • In turn, this eventually leads to the rest of the fruit being exposed to disease, and it is usually rotting off the tree because of the holes that have been made in it.
  • The female butterfly lays eggs on flowers, buds, and the calyx of developed fruits. A caterpillar hatches inside a fruit, enter it and feeds on the arils and the inner parts of the fruit after hatching.
  • The symptoms are the odious smell that emanates from the entry holes and the excreta of caterpillars that eventually result in the rot of the fruits and the damage to fully mature fruit.
  • Fruit rotting and dropping may occur.

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Pomegranate Disease
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Pest monitoring 

  • Start monitoring after the tree has started flowering use a light trap for monitoring. Look at the top of the fruit for the presence of the insect and its eggs. The eggs are grouped. They are small and white.
  • Look for the larva and the pupa under the soil around the tree. They are both pink Starts controlling the problem when you see at least five larvae on ten trees in the orchard.
  • Application of physical barriers such as covering the 30 to 50 days old fruits with bags of butter paper in isolated and small scale.
  • Removal and destruction of all the damaged fruits showing exit holes.
  • Clipping off the calyx cup of flowers immediately after pollination will help to reduce the egg load on the fruits and damage level.
  • Clipping off the calyx cup immediately after pollination and two rounds of spraying with neem oil at 3 percent also controlled pest infestation effectively.

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Dry Pomegranate
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Biological control

  • The parasitoid Trichogramma species is effective in controlling the pest. Release them at 1.0 lakh/acre four times at ten days intervals. They can be placed in the middle and on the edges of the field. 
  • It is possible to avoid infestation by covering the fruits with polythene or paper bags. It is, therefore, important to always consider an integrated approach, including preventive measures and biological treatments.
  • Predators of D. Isocrates are lacewing, ladybird beetle, spider, red ant, dragonfly, robber fly, reduviid bug, and praying mantis. 
  • Furthermore, species of wasps, big-eyed bugs (Geocoris sp), earwig, ground beetle, and pentatomid bug are reportedly effective against the fruit borer. Bird species will also feed on the caterpillar. The calyx cup should be clipped off immediately after pollination as fruit borers lay eggs on the calyx cup, and this should be followed by applications of neem oil (3%) during the flowering stage. Set clean mud (heated by the sun) around the base of the fruit to protect it from the insect.

Chemical control management

There is a way to reduce the infestation by removing all the affected fruits and destroying them. The following chemicals can be sprayed on the surface:

  • As soon as the flowering begins, spray Azadirachtin 1500ppm at 3.0ml/lit of water at 15 days intervals starting from the initiation of flowering up to the harvesting, depending on the presence of the fruit borer.
  • Dimethoate (2 ml/lit), indoxacarb (1 g/lit), cypermethrin (1.5 ml/lit), and profenophos (2 ml/lit) should be applied at a fortnightly interval from flowering to fruit development.
  • Pomegranate fruit borer control can also be achieved by applying lambda-cyhalothrin, a chemical pesticide.
  • On initiation, spray need-based neem seed kernel powder at 500 g (5%) per acre or ready-to-use neem-based pesticides at 10 ml (1% EC) to 40 ml (0.15% EC) per 10 lit of water.
  • Spray with Bacillus thuringiensis, a bacterial-based powder, at 15 g per 10 lit of water.
  • Two sprays of emamectin benzoate 5 SG at a rate of 0.25 g/liter of water or spinosad 45 SC at a rate of 0.20 ml/liter of water resulted in the greatest reduction in fruit damage.
  • Spray applications of fenvalerate 0.005%, carbaryl 0.2 %, quinalphos 0.06%, or decamethrin 0.0028% effectively control the pest.
  • Spray with decametric at 0.0028% when more than 50% of fruits were set. Repeat after two weeks with carbaryl at 0.2% or fenvalerate at 0.005%. In nonrainy season quinalphos at 0.06% was effective.
  • Spray with malathion 50 EC at 2 ml per L or carbaryl 50WP at 4 g per L or monocrotophos 36 SL at 1 ml per L of water starting from flowering to harvesting stage at an interval of 21 days for effective management of the pest.
  • Spraying with methyl parathion 50 EC at 1 ml per L or carbaryl 50 WP 0.2% can also control this pest.
  • Among the new group of insecticides, spinosad and emamectin benzoate were found effective in checking the pomegranate borer, D.epijarbas infestation. The pyrethroids, namely cypermethrin, and deltamethrin were equally productive. 
  • In the earlier stage, biopesticides were found effective, as the infestation, even in control, was less. Overall the biopesticides did not prove much effective.
  • From an economic point of view, Rynaxypyr, the most effective insecticide in managing the pest, was not much remunerative due to its high cost.
  • Spinosad was better on the economic front, also. Cypermethrin was the best option as for as the economics of the treatments is concerned, followed by deltamethrin due to the high benefit-cost ratio, mainly due to less cost of these pesticides
  • Covering the entire orchard with a nylon net followed by spraying with contact insecticide has been recommended.
  • The use of light traps at 1/ha can be used to monitor the activity of adults in the area
  • Applying malathion 50 EC 0.1% or dimethoate 30 EC 0.06% is recommended during two rounds, the first at flower formation and the second at fruit set.
  • Remove the remaining fruit from the trees or fallen that have been attacked after harvest between seasons. Plow the soil around the tree to remove the insect young that live and sleep in the soil. Remove flowering weeds of the same families.

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Pomegranate Fruit Disease
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Preventive measures

  • Keep an eye on your field regularly to see if any branches are dry.
  • A light trap should be set up at 1/acre to monitor adult butterflies.
  • As soon as the damaged fruits are collected, they should be destroyed as far away from the field as possible.
  • It is recommended to clip off the calyx cup of flowers immediately after pollination to reduce the egg load on the fruit and ensure a lower level of damage to the fruits,
  • It is necessary to remove all weeds as well as plants that act as alternative hosts.
  • The fruits should be bagged as soon as possible (usually when they reach the size of five cm) with butter paper, rough cloth, or muslin cloth, which has a thickness of 300 gauge, to create a barrier against borer attack.
  • In the immediate after-harvest, the pupae of the pomegranate tree should be exposed to predatory birds, other natural enemies, and the sun to survive.

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Pomegranate Fruit Pest
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Conclusion

Fruitborers can be controlled most effectively by being defensive against them. A healthy, vigorous plant is less likely to be infected than a weak, underpotted, or stressed plant. In addition, healthy plants are less likely to attract these pests in the first place, so make sure your plants are healthy.

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