MANAGEMENT OF CITRUS PEST AN GLOBAL ISSUE ARTICLE ID. : 10 Misal M. R, Kendre A. H and Khaire P. B

1Assistant Professor, Department of Agriculture Entomology, SSJPs, COA, Khandala, Vaijapur, (M.S.) 2Scholar, Department of Plant Pathology, VNMKV, Parbhani (M.H) 3PhD Scholar, Department of Plant Pathology, PGI, MPKV, Rahuri (M.H)

Abstract

Citrus is amongst the most significant fruit and one of the largest global fruit markets, produced in far more over 52 countries around the world. In India, 250 insect species and mites were recorded to infest various citrus species. Major pests of khasi mandarin oranges in the NEH region of India have been reported i. e. Trunk borer, Leaf miner, citrus psylla, red scale, mealy bugs and aphids. Such pests make a significant contribution to the declines of citrus in the area. The rejuvenation plan can be designed with a multi-disciplinary approach to the management of such pests. Better study is needed on some of the main elements necessary for eco sustainable protection Bio- monitoring through the increase and conservation of parasitoids combined with other non- pesticide approaches needs to be evaluated with a holistic citrus strategy. Further emphasis should be placed to the awareness of the biology and ecology of parasitoid organisms. Bio- pesticides, like botanicals, can provide a safe and efficient alternative to traditional pest management pesticides and herbicides under an integrated pest management plan.

Key words: Citrus, insect-pest, management

Introduction Among the most valuable fruit which is one of the biggest fruit industries in the world is citrus, cultivated in more than 52 countries worldwide. Mahmood et al., 2014 recorded that Brazil and China have become the leading citrus exporter in the world, generating about 45 million tonnes (MT) of citrus fruit collectively, preceded by the USA, India, Mexico and Spain, generating 10.7, 8.6, 7.2 and 5.5 MT each. India is 4th largest producer of citrus fruit in 1 | Page VOLUME 01 ISSUE 02: FEBRUARY 2021

the globe. Citrus fruit emerged in the tropics and subtropics of South East Asia, especially China and India. Throughout India, citrus is grown commercially in approximately 10.42 lakh ha with a yearly output of 100.90 lakh tonnes and a productivity of 9.7 t/ha (NHB, 2013) and is began the great in Maharashtra, Andhra Pradesh, Punjab, Karnataka, Uttaranchal, Bihar, Orissa, Assam and Gujarat. It is of specific importance due to its high concentration of vitamin C and soothing juices. Including its different forms of citrus fruit cultivation in India, orange (mandarin or santra), sweet orange (mosambi) and lime/lemon have been of commercial significance. The (NEA) North Eastern Area is among the wealthiest repositories of genetic variation of Citrus as the main and secondary centre of origin of a large number of citrus species and has been identified as among the key centres of diversity for citrus across both cultivated and wild types (Singh et al., 2006). NEA Comprehensive explorative study of mandarin orange revealed that Citrus indica is among the most basic citrus species available in the country. iSome successful indigenous thus far established as commercialised are cytron (C. medica), sweet lime (C. lamittoides), sour orange (C. aurantium), sweet pumalo (C. grandis), sour pumelo (C. megaloxycarpa), khasi pdaa (C. latipes), roughlemon (C. jambhiri), and so on. Heavy rain falls, big enough to hold humidity with suitable ambient temperature and planting and/or incidence of a number of wild and growing species of citrus harbour with the greatest amount of insects and pathogens of citrus throughout this area. The Total 250 insect species and mites were recorded to infest diverse citrus species (Wadhi and Batra, 1964) in india. The trunk borer, Anoplophora versteegi, Citrus psylla, Diaphorina citri and black aphids (Toxoptera aurantii and T. citricidus) are significant citrus threats. Throughout NEA, Leaf Miner, Phyllocnistis citrella is incredibly important and harm to nurseries and crops throughout each newly flush. Many insects of great economic importance contain lemon butterfly, leaf mining beetles, tobacco caterpillars, leaf folder, looper, mealy bugs, scales, orange bugs, bark eating caterpillars, fruit sucking moths and fruit flies, etc (Azad Thakur et al.,2012).

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CITRUS BUTTERFLY Economic Importance : These are most destructive pests of citrus seedlings in nurseries stage. This pest is widely distributed in Burma, Bangladesh, Sri Lanka, India and Pakistan. It infests almost allcitrus varieties though Malta (Citrus sinensis) is its preferred host. It can feed and breed on all varieties of cultivated or wild citrus and various other species of family Rutaceae. Besides citrus, it also attacks ber, wood apple, curry leaf.

Marks of Identification : P. demoleus is a big beautiful butterfly with yellow and black markings on all the four wings, having wing expanse of about 50-60 mm. Its hind wings have a brick red oval patch near the anal margin and there is no tail like extension behind though common in Papilionidae. P. polytesmales are black and females vary in form. P. helenushas black wings with three white distal spots. The pest of citrus where the early instars (I & II) larva resembles bird droppings is citrus butterfly.

Life History : Female 70-180 Yellowish white, round, smooth eggs are laid singly on tender leaves and shoots by P. demoleus. Egg hatches in about 3 – 8 days. Freshly hatched caterpillars are dark brown and soon develop irregular white markings on their body resembling bird’s drop. The full grown caterpillar is deep green and cylindrical in form and measures about 40-50 mm in length with a hump in front and has a horn like structure on the dorsal side of the last body segment. When the caterpillar is disturbed, it pushes out from the top of its prothorax a bifid, purple structure called osmeterium which emits a distinct smell. The larval duration varies between 11- 40 days. Pupation takes place on plant parts. Pupa which is a chrysalis is seen girdled by a fine silken thread on a twig of the plant. Adult emerges in a week in summer and in 12 –20 weeks in winter. Hibernation is in pupal stage and there are 2-4 overlapping generations per year. All citrus species and other plants like 3 | Page VOLUME 01 ISSUE 02: FEBRUARY 2021

bael, ber, curry leaves, bawachi are Host plant. Pest is active in monsoon season. Damaging stage is caterpillar.

Nature of Damage : The caterpillars feed voraciously on tender leaves right up to the midribs and defoliate the entire seedlings or the tree leaving behind the only midribs. Thus the symptom of damage is leaves fed up to midribs and defoliation in citrus by caterpillar.

MANAGEMENT : In small orchards and nurseries with mild infestation, hand picking and destruction of various stages of the pest. Natural enemies enumerated below suppress the pest population, Egg parasitoids: Trichogramma evanescens; Telenomus sp., Larval parasitoid: Distatrixpapilionis; Brachymeria sp., Pupal parasitoid: Pterolus sp., Spraying of Bacillus thuringiensis formulation (HALT) is found to be effective against early larval instars of citrus butterfly. , Spraying of monocrotophos 1.6 ml/l or dichlorvos 1 m/l or methyl parathion 2 ml/l when the caterpillars are small.

CITRUS FRUIT SUCKING MOTHS Economic Importance : Moths puncture the fruits and causes fruit rot. This pest is distributed in Australia, China, Japan, Korea, Philippines, Hawai, Thailand etc. Besides citrus, it also attacks grapes, apple, castor, ber, pomegranate, guava etc.

Marks of Identification : E. materna: The moth has brownish black forewings with a white stripe and yellowish hind wings with a circular black spot in the middle , E. fullonica: The moth has brownish forewings and yellowish black hind wings with a half moon or kidney shaped black spot and E. ancilla: The forewings of this moth are dark brown with a green band in the middle; hind wings are yellowish with a kidney shaped black spot.

Life History : Eggs are lay singly on tender parts of wild foliage or leaves of weeds. Egg period is about 3-4 days. Caterpillar is a semilooper. Larvae of Eudacima sp feed on foliage of other weed hosts of the family Menispermaceae. Larval period is 13-17 days. Pupation is inside the leaf fold or soil and pupal period is 12-18 days. Pest is active in kharif season. Host plant of Larva is feeds on leaves of gulvel and vasanvel and moth feeds on fruit of citrus, mango, pomegranate, grape, cashewnut etc. Damaging stage of fruit sucking moth is only adults.

Nature of damage : Moth are nocturnal and seen flying in orchards after dusk. The adult moths are harmful and damage the citrus fruits. Moth pierces the ripe fruit with its strong proboscis and sucks the sweet juice. The feeding injury opens way for invasion of bacteria, which makes the fruit rot around the punctures and drop prematurely. Achaea janata moth 4 | Page VOLUME 01 ISSUE 02: FEBRUARY 2021

also sucks the juice from the unripe fruits. The damage results in premature dropping of fruits. Rotting at the site of feeding injury.

MANAGEMENT : Destruction of weed hosts around orchards is recommended to manage fruit sucking moth, Eradication of host plants viz. gulvel and vasanvel, Collection and destruction of rotten and dropped fruits, Smoke generation during late evening hours repels adults of fruit sucking moths from damage (Reason- Smoking of the orchards masks the odour of mature and ripening fruit that attracts the moth, Adults are highly phototropic. One fluorescent light/ha (light trap) one month before fruit maturation between 7.00 PM to 6.00 AM below which poison baits with sugar solution1% + fruit pulp + Malathion1 ml should be placed, Bagging of fruits with polythene or paper covers to avoid damage by adults of fruit sucking moth, Creating smokes in the orchards after sunset to keep the pest away which is also rather laborious, Arranging poison baits during Sep – Nov and Mar – May at fruiting under lights with a solution of malathion 1ml + fruit juice with 1% sugar to attract and kill adult moths.

CITRUS LEAF MINER Economic Importance : Most destructive pest, infestation noticed in seedling stage. The pest is susceptible to be responsible for the spread of bacterial infection causing ‘citrus canker’. It is widely distributed from Australia to Africa. It attacks all species of citrus but prefers sweet oranges. It also infests Ponagamia, jasmine etc. The pest is active all-round the year, except during severe winter (December –February). Maximum damage is caused during May-June and also during August- October, if the temperature is high enough.

Marks of Identification : Adult is a silvery white small moth with brown striped forewings having a prominent black spot near the tip and white hind wings. Both pairs of wings are fringed with hairs. The adult moth measures 6 mm in wing span.

Life History : Minute, flat and greenish yellow eggs are laid singly on midrib tender leaves and young shoots. Egg period is 2-10 days. The full grown caterpillar is slender, yellowish green with brownish mandibles. It is found inside the gallery formed in leaf tissue. Larval period is 15-30 days. Pupation takes place inside the leaf mine or midrib of tender leaves. Pupal period is 5-25 days. Total life cycle takes on an average 20-60 days depending on the climate. There are 9-13 overlapping generations in a year. Host plant of leaf miner is all citrus species. Pest is active in monsoon season and decreases the population during hot summer month.

Nature of Damage : On hatching larva mines in between the epidermal layers of the leaf in a zigzag manner and feeds on chlorophyll which results in distortion of the leaf lamina. The tunnel appears silvery white. New and tender leaves are preferred. Sometimes, the larva 5 | Page VOLUME 01 ISSUE 02: FEBRUARY 2021

mines the outer layer of young green twigs. Serious infestation causes retardation in growth. The infestation predisposes the leaves to canker growth. Symptom of damage is - Characteristic silvery white zigzag galleries below the epidermis of tender leaves.

MANAGEMENT : Pruning of affected plant parts during winter and burning, Spraying of Neem cake solution 5% or Neem oil 5% or dimethoate 2 ml/l or imidachloprid 0.5 ml/l twice at 10 days interval at every new flush time i.e. during June – July, Sep – Oct, Dec – Jan.

CITRUS PSYLLA Economic Importance : Most destructive pests of citrus, also transmit “Greening disease” a mycoplasma disease in citrus. This is widely distributed in India and is considered as a major pest in Punjab.

Marks of Identification : In these regions the pest is active from February to November. Adults are reddish with jumping legs.

Life History : Eggs are laid in tender shoots or clusters in the folds of half opened leaves and the egg period is 8-35 days depending on the season. A single female lays 180 to 860 eggs. There are five nymphal instars and the nymphal period is 9-38 days. Adult life span is 135 days for males and 145 days for females. Host plants is citrus and other plants belonging to Rutaceae. The pest has 16 generations per year.

Nature of Damage : The damage is caused by the nymphs and adult which crowd on the terminal shoots and buds and suck up the juice which results in Curling and cupping of leaves. Defoliation and death of young shoot in severe infestation and the fruits turning undersized and juice content reduced.

MANAGEMENT : Removal of alternate host curry leaf plant, Destruction of infested branches, Use of predators such as Coccinella septempuctata, Spraying of NSKE 5% or Neem oil 5% and Spraying of dimethoate 2 ml/l or imidacloprid 0.5 ml/l at seedling stage on fresh foliage twice at 10 days interval.

CITRUS RUST MITE Economic Importance : Citrus rust mite damage epidermal cells of plant leaves, fruit, and green twigs of all citrus varieties and can be found any time during the year with peak populations usually occurring during June and July in south India.

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Nature of Damage : Minute worm like mites are found on the under surface of leaves and fruits. The nymphs and adult infestation may cause, Browning of leaves, Pale brown and sickly fruits. The affected fruit becomes pinkish, brown red and brittle and is locally called as “mangu” disease. Rust mite is known to avoid most sun exposed portion of the fruit.

MANAGEMENT : Foliar sprays with wettable sulphur 3g/l or dicofol 2.7ml/l or propargite 1ml/l once in a month in Sep, Oct and Nov.

BARK EATING CATERPILLARS Economic Importanse : Occasionally these pests in large numbers cause severe damage especially to old trees.

Nature of Damage : The freshly hatched larva feed on the surface of tree trunks. When strong enough, they bore inside the trunks and move about inside the concealed silken gallery and feed on the bark by scraping which interrupts the translocation of cell sap adversely affecting growth and fruit setting capacity of the tree. Ribbon like or pipe like webbings on the stem near forks or angles of branches and the tree trunk is the clear indication of its damage. Only one caterpillar is seen in a gallery. Bark caterpillar remain hidden in the tunnel during day time and come out at night feed on the bark.

Management : A. Cultural control - Keep orchards clean and avoid overcrowding of trees. B. Mechanical control - Inserting an iron spike or thrusting of flexible wire in the active holes and plugging with mud to kill the larva is found quite effective. C. Chemical control - Cleaning the tree trunks by removing all the webs and placing cotton wool soaked in chloroform, kerosene, petrol and, carbon disulphide and sealing the same with mud or Plugging of bore hole with cotton swabs soaked in 10ml dichlorvos/petrol is also effective.

CITRUS BLACKFLY AND WHITE FLY Economic Importance : It is found mainly in North India. It infests during post rainy season and disappears in summer. It also infests coffee.

Marks of Identification : Adults are tiny, moth like slaty black with white markings at the edge of wings. Eggs led on underside of leaves.

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Nature of Damage : Both the nymphs and adults suck sap resulting in loss of plant vigour and formation of black sooty mould due to excretion of honey dew. The blackish coating commonly called “Kolshi” diseases.

Management : - Avoid closer planting and water logging to avoid attack of whitefly and blackfly, Predators like Brumus sp., Scymnus sp. and Chrysoperla sp suppress the pest population and Spraying profenophos 2.0 ml /l or chlorpyriphos 20EC @2 ml/l or imidacloprid 0.5 ml/l. SCALE INSECTS Economic Importance : Scales are unusual insects, appearing to lack legs and eyes. Eleven species have been found on citrus in Western Australia.

Life History : Adult stages • Female scales do not need to mate in order to lay eggs. Some species of scale lay eggs, others give birth to live young. Eggs or crawlers are laid into the body cavity or into the waxy cover. The female dies after laying eggs and eggs and crawlers may remain under her body for a few days. To check if eggs or crawlers are present, lift up the scale cover. If you find ‘powder’ under the scale, these are likely to be eggs. Males are insect-like with legs and wings and are highly mobile. They are short lived (1 day or less) and do not feed. Males are rare in many scale species. Immature stages • Crawlers are minute: usually less than 1 mm in size. They can be dispersed by wind, pickers and by birds. After a few hours or days, crawlers settle in small depressions on twigs, fruits, or leaves. Once they have found a suitable feeding site, the crawler inserts its piercing mouthparts into the plant and begins to produce a waxy covering. The crawler moults (sheds its skin) to become a first instar. Depending on the species, there can be up to three moults or instars between the crawler and adult stage.

Nature of Damage : Large number of scales sucks sap from undersurface of leaflets which turn yellowish, finally wither and dry up, thus reducing vitality of plant. Scale produces honeydew (a sugary substance) as they feed. Sooty mould (a fungus) grows on top of the honeydew, coating leaves, twigs and fruit in a black powder. Sooty mould can delay colour break and interfere with photosynthesis. At high populations, scales can defoliate trees and kill twigs, but this type of damage is rare.

Management :

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Scale are not normally a serious problem in citrus, unless the predator and parasite complex (beneficials) has been destroyed. Scales are best controlled when crawlers and newly settled young scales are present. 1. Biological control – Parasite - The only commercially available parasites are for control of red scale. These are Aphytis lignanensis, which is suited to tropical conditions, and Aphytis melinus, which is more suited to temperate conditions. For A. lignanensis, releases are recommended from March-April. For A. melinus, release from November-March. Aphytis are supplied as adults. More than one release may be required. 2. Predators - Mealybug ladybird (Cryptolaemus montrouzieri) Target: cottony cushion scale, soft brown scale, black scale, citricola scale, citrus mealybug Cryptolaemus are sold as adults, but may also occur naturally in the orchard. 3. Green lacewing (Mallada signata) Target: Soft scales, aphids, white flies. Lacewings are supplied as eggs; the larvae hatch shortly after their arrival. 4. Chemical control Soil applied insecticides such as Confidor are effective at reducing scale populations on young trees that are not fruit bearing. However, they do disrupt IPM programs since all prey on the trees are killed.

Table 1. List of citrus pest

Orde Insect pest Scientific name Family r Citrus fruit sucking Eudocima fullonica (C.) E.materna (L.) Lepidopte Noctuidae moth Achoea janata ra Papilionida Lepidopte Lemon/citrus Butterfly Papilio demoleus (Linn) e ra Gracillariid Lepidopte Citrus leaf miner Phyllocnistis citrella (S.) ae ra Hemipter Citrus psylla Diaphorina citri (K.) Psyllidae a Homopter Citrus aphid Toxoptera citricidi Aphididae a

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Cerambyci Coleopter Citrus stem borer Chelidonium cinctum dae a Citrus shoot and bark Metarbelida Lepidopte Indarbela tetraonis (M.) caterpillar e ra Thysanop Citrus thrips Scirtothrips citri (A.) Thripidae tera Aleyrodida Hemipter Citrus whitefly Dialeurodes citri (A.) e a Aleyrodida Hemipter Citrus black fly Aleuorcanthus woghlumi e a Pseudococc Hemipter Citrus mealybug Planococcus citri idae a Eriophyida Citrus Rust mite Phyllocoptruta oleivora Acarina e

Hemipter Scale insects Ceroplastes sinensis Coccidea a

Conclusion: Citrus insect pests have rich natural foe groups and are largely below natural control. Any of the pests, including such waxy bug Drosicha stebbinji, fruit flies Bactrocera spp., butterfly, leaf miner, Aoinidiella spp. And citrus psylla ought to be prioritised. These pests also have natural predators groups, but some of farming techniques have an effect on natural enemy which need to be established. Strategies that promote natural management ought to be created.

References: 1. Atwal, A.S. (1976). Agricultural Pests of India and South East Asia. Kalyani Publishers, Ludhiana. 2. S. Reddy (2018). Applied entomology. 3. Smith., G.A. Beattie & R.H Broadley (1997). Citrus pests and their natural enemies, integrated pest management in Australia. Queensland Department of Primary Industries.

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4. Dennis S Hill (1987). Agricultural Insect Pests of tropics and their control, Cambridge Universtiy Press, New York. 5. Raghavaiah G., Dayakar G., Deva Prasad V., Hari Prasad N., Loka Reddy K., Madhumathi t., Seetrharamu P. and Sreedevi T. (2011-12). Study material Pests of crops and their management. Acharya N G Ranga Agricultural University

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