IPM Stratergies for Citrus

Citrus Pests Pests of National Significance Insect pests Diseases Nematodes Weeds Pests of Regional Significance ...

Citrus Pests

1. Pests of National Significance
1. Insect pests
2. Diseases
3. Nematodes
4. Weeds
2. Pests of Regional Significance
1. Insect and mite pests
2. Diseases
3. IPM for Citrus

Pests of National Significance

Insect pests

• Aphid: Toxoptera aurantii (Boyer de Fonscolombe) (Homoptera: Aphididae)
• Citrus psylla: Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae)
• Citrus leaf miner: Phyllocnistis citrella (Stainton) (Lepidoptera: Gracillariidae)
• Mealybug : Planococcus citri (Risso) (Hemiptera: Pseudococcidae)
• Fruit sucking moth: Eudocima fullonica, E. materna (Clerck) (Lepidoptera: Noctuidae)
• Citrus/Lemon butterfly: Papilio demoleus, P. polytes (Linnaeus) (Lepidoptera: Papilionidae)

Diseases

• Gummosis: Phytophthora spp.
• Fruit rot: Phytophthora palmivora (Butler)
• Anthracnose: Colletotrichum gloeosporioides
• Scab: Elsinoe fawcettii (Bitanc & Jenkins)
• Sooty mould: Capnodium citri (Berk and Desm), Meliola butleri (Briosi and Pass)
• Citrus canker: Xanthomonas axonopodis pv. citri (Hasse)
• Tristeza: Citrus Tristeza Virus
• Greening: Candidatus liberibacter (Jagoueix)

Nematodes

• Citrus nematode: Tylenchulus semipenetrans (Cobb) (Tylenchida: Tylenchulidae)
• Lance nematode: Hoplolaimus indicus (Sher) (Tylenchida: Haplolaimidae)
• Lesion nematode: Pratylenchus coff ee (Goodey) (Tylenchida: Pratyleanchidae)

Weeds

Broad leaf weeds

• Tropical spiderwort: Commelina benghalensis L. (Commelinaceae)
• Swine cress: Coronopus didymus (L.) Sm. (Brassicaceae)
• Horse purslane: Trianthema portulacastrum L. (Aizoaceae)
• Black nightshade: Solanum nigrum L. (Solanaceae)
• False amaranth: Digera arvensis Forssk. (Amaranthaceae)
• Puncture vine: Tribulus terrestris L. (Zygophyllaceae)
• Field bindweed: Convolvulus arvensis L. (Convolvulaceae)
• Common cocklebur: Xanthium strumarium L. (Asteraceae)
• Spurge: Euphorbia hirta L. (Euphorbiaceae)
• Carrot grass: Parthenium hysterophorus L. (Asteraceae)

Grassy weeds

• Bermuda grass: Cynodon dactylon (L.) Pers., (Poaceae)
• Annual brachiaria: Brachiaria defl exa (Schumach.) Robyns (Poaceae)
• Viper grass: Dinebra retrofl exa (Vahl.) Panzer. (Poaceae)

Sedges

• Purple nut sedge: Cyperus rotundus L., (Cyperaceae)
• Flat sedge: Cyperus iria L. (Cyperaceae)

Pests of Regional Significance

Insect and mite pests

• Citrus blackfly : Aleurocanthus woglumi (Ashby) (Hemiptera: Aleurocanthus) (Punjab, Maharashtra, Karnataka, West Bengal and Madhya Pradesh)
• Root grub: Holotrichia spp. (Coleoptera: Scarabaeidae)
• Soft scale: Coccus hesperidium (Handlirsch) (Hemiptera: Coccoidea) (South India).
• Armoured scale: Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) (Meghalaya, Punjab, Uttar Pradesh, Maharashtra,West Bengal and Karnataka)
• Stem borer: Chloridolum alcmene (Guenee) (Lepidoptera: Noctuidae) (Tamil Nadu)
• Mites: Eutetranychus orientalis (Klein) (Prostigmata: Tetranychidae) (Meghalaya, Punjab, Madhya Pradesh, Rajasthan, Haryana, Karnataka, Delhi, Jammu & Kashmir)
• Thrips: Scirtothrips citri (Shull) (Thysanoptera: Thripidae) (Jammu & Kashmir)

Diseases

• Powdery mildew: Oidium citri (Link) (Uttar Pradesh)
• Sapling wilt: Fusarium solani (W.C. Snyder & H. N. Hansen)
• Blue mould rot: Penicillium italicum (Wehmer)(Tamil Nadu, Haryana, Maharashtra and Uttar Pradesh)
• Green mould rot: Penicillium digitatum (Pers & Sacc) (Maharashtra, Tamil Nadu and Uttar Pradesh)
• Sour rot: Geotrichium candidum (Link) (Maharashtra, Himachal Pradesh and Madhya Pradesh)

IPM for Citrus

To know the IPM practices for Citrus, click here.

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

 

3.06   

 

139 ratings

Citrus: Crop stage-wise IPM

1. Pre planting*
2. Planting *
3. Vegetative growth stage * (1-5 years)
4. Vegetative growth stage (1-5 years)
5. Fruiting stage (5-20 years)

Management	Activity
Pre planting*
Nutrients	• Pits of 1 metre cube are dug in square system during summer season and kept open for controlling soil borne pests.
Weeds	• Deep ploughing before establishment of orchards • Remove the weeds mechanically.
Pests, nematode and soil borne pathogens	• Deep summer ploughing of fields to control nematodes and soil borne diseases • Use of resistant / tolerant varieties
Planting *
Nutrients	• Pits should be filled with a mixture of pond silt, red soil and FYM. • Two- three Kg of bone meal or single super phosphate per pit should be applied.
Weeds	• Inter-cropping • Inter culture operation and hand weeding • Where mechanical removal is not possible apply 2,4-D Sodium salt Technical (having 2,4-D acid 80 % w/w) (Earlier Registered as 80% WP) 0.5-1.28 Kg in 240 l of water/acre or apply Diuron 80% WP @ 1-2 Kg in 240 l of the water/acre (only for sweet orange) for control of weeds such as Cyperus iria, Tribulus terrestris, Digera arvensis, Commelinanudiflora.
Vegetative growth stage * (1-5 years)
Nutrients	• Nitrogen is 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 muriate of potash. • Manures are applied in 2 to 3 equal doses ie. first dose in December-January, 2nd dose 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; phosphorus containing fertilizers in two splits in January and July and potassium containing fertilizers may be applied as single 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 and vegetables (except solanaceous crops) can be profitably grown in the inter spaces. • In the bearing orchards, raise green manure crops like sunhemp, green gram, cowpea etc and incorporate into the soil during the monsoon period.
Vegetative growth stage (1-5 years)
Weeds	• Timely interculturing and hand weeding should be done. • Mulching - After weeding and manuring, apply dry-leaf mulch or paddy husk to a thickness of 8 cm in the basin. • Inter-cultivation - Shallow ploughing or light hand digging should be done during monsoon season. The soil in the basin is likely to become hard under continuous irrigation and therefore it should be given a light hand-digging with spade after every three irrigations so as to maintain porosity and tilth. Under no circumstances should weeds be allowed to grow rampant in the orchard.
Fruiting stage (5-20 years)
Weeds	• Cultural operations same as in vegetative stage.
Citrus blackfly**	Mechanical control: • Collect and destroy the damaged plant parts along with nymphs, pupa and adults. • Use light trap (wavelength of 550 nm) • Yellow sticky traps or cards reduce the density of black flies Biological control: • Pupal parasitoids: Encarsia formosa, Eretmocerus spp • Predators: Chrysoperla zastrowi sillemi, Coccinellids, Spiders.
Citrus aphid	Mechanical control: • Use yellow sticky trap Biological control: • Conserve and enhance population of Predators: like Lacewings birds, earwigs, some ground beetles and rove beetles, spiders. Chemical control: • Foliar spray with dimethoate each at 30% EC @ 594-792ml in 600-800 l of water/ acre. • Foliar spray with chlorpyrifos 20% EC @ 600-800ml in 600-800 l of water/acre • Foliar spray with monocrotophos 36% SL @ 600-800ml in 200-800 l of water/acre • Foliar spray with oxydemeton-methyl 25% EC @ 480-640ml in 600-800 l of water/ acre
Citrus psylla	Mechanical control: • Collect and destroy the infested plant parts Biological control: • Conserve parasitoids such as Tamarixia radiata, Diaphorencyrtus aligarhensis • Conserve predators such as Chrysoperla zastrowi sillemi, coccinellids, syrphids. Chemical control: • Systemic insecticides like imidacloprid 17.8% SL @ 50 ml depending on size of tree & Protection equipment used are very effective at controlling both the nymphs and the adults. • Foliar spray thiamethoxam 25% WG @ 40 g in 400 l of water/acre. • Foliar spray with oxydemeton-methyl 25% EC @ 600-800 ml in 600-800 l of water/ acre
Fruit sucking moth	Mechanical control: • Destruction of larval hosts (alternate host) around orchards. • Collection and destruction of rotten and dropped fruits. • Collection and destruction of moths during night time using battery or flame torch in addition to installation of one fluorescent light trap/acre before one month of fruit maturation between 7.00 PM and 11.00 PM.
Mealybug	Cultural control: • Prune affected shoots during winter. • Destroy ant colonies. • Grow attractant plants to attract the defenders • Bachelor’s Buttons or cornflower (Centaure acyanus), coriander attract wasps. Mechanical control: • Collect and destroy the damaged leaves, twigs and stems • Use sticky barrier (5cm length) on trunk Biological control: • Field release of Australian ladybird beetle (Cryptolaemus montrouzieri) @10 beetles per tree. Chemical control: • Use fish oil rosin soap 25 g/lit • Spray with methyl demeton or dimethoate 2 ml /l or confi dor 200 SL @ 4 ml/acre
Citrus leaf miner	Mechanical control: • Use pheromone trap @ 5/acre. • Pruning of affected parts during winter and burning Chemical control: • Carbofuran 3% CG @ 20000 g/acre • Foliar spray with imidacloprid 17.8% SL @ 50 ml and use spray volume depending on size of tree & protection equipment used • Foliar spray permethrin 25% EC @160-240 ml in 400 l of water/acre • Foliar spray with phorate 10% CG @ 6000 g/acre
Citrus/Lemon Butterfl y	Cultural control: Grow attractant plants: Carrot family, sunflower family, buckwheat, alfalfa, corn, shrubs (lacewing) • Nectar rich plants with small flowers i.e. anise, caraway, parsley, mustard, sun flower, buckwheat and cowpea (Braconid wasp) Mechanical control: • Hand pick the larvae and destroy. Biological control: • Conserve the parasitoids such as Trichogramma evanescens. • Telenomus spp on eggs Brachymeria spp, Cotesia on larvae and Pterolus sp. On pupae. Chemical control: • Spray Malathion @ 1 ml/ lit. • Foliar spray with quinalphos 25% EC @ 600-800 ml in 200-400 l of water/acre
Mite**	Cultural control: • Water stress often aggravates mite problem. Make sure that trees are well irrigated, particularly during the stress in late summer. Biological control: • The most important natural enemies of citrus mite are a predacious mite Euseius hibisci and the predators Agistemus sp. and Amblylseisus hibisci. Chemical control: • Foliar spray with monocrotophos 36% SL @ 374.8-500 ml in 200-800 l of water/acre
Scale**	Cultural control: • Pruning of the scale infested twigs. • Natural predators usually keep this insect in check. • Control ants and dust which can give the scale a competitive advantage. • Field release of Vadalia and Australian ladybugs. Biological control: • Spray dormant oil in late winter before spring. • Spray horticultural oil, if needed, year round. • Apply mixture of manure compost tea, molasses and citrus oil. • Garlic-pepper tea also helps. Chemical control: • Foliar spray with quinalphos 25% EC @1680-2240 ml in 200-400 l of water/acre.
Citrus scab	Cultural control • Collect and destroy the infested leaves, twigs and fruits. Chemical Control • Spray with 0.3 % COC or 1.0% Bordeaux mixture or 0.2% chlorothalonil at 15 day interval
Citrus canker	Mechanical control: • Select seedlings free from canker for planting in main field • Prune out and burn all canker infected twigs before monsoon. • Maintain proper aeration by training and pruning for reducing the leaf wetness period. Chemical control: • Captan 75% WP @ 666.8 g in 6-8 l of water/acre • Streptomycin Sulphate 9% + Tetracycline Hydrocloride 1%) SP Spray Streptocycline 50 to 100 ppm solution repeatedly at an interval of 15 to 20 days after the appearance of new growth. • Cover the foliage and young fruits fully.
Citrus tristeza disease	Cultural control: • Use certified budwood free of CTV • Remove all diseased trees as and when the disease is noticed. Fresh plantings to be taken with virus free materials on tolerant rootstocks. For sweet orange and mandarin avoid susceptible rootstocks. Chemical control: • For acid lime, use seedling immunised with mild strain of Citrus Tristeza Virus (Cross protection). • Periodic sprays of insecticides like Monochrotophos 0.05 % controls the population of citrus aphids that reduces secondary spread of the disease in the orchard. • Copper oxy chloride 50% WP @ 1 Kg in 300-400 l of water/acre
Gummosis	Cultural control: • Disease spread can be controlled by removing diseased bark and a buffer strip of healthy, light brown to greenish bark around the margins of the infection. • Preventive measures like selection of proper site with adequate drainage. • Use of resistant rootstocks and avoiding contact of water with the tree trunk by adopting ring method of irrigation are effective. Chemical control: • Aureofungin 46.15% w/v. SP @ 300 (1%) gm /ml/acre.
Powdery mildew**	Cultural control: • Nitrogen fertilizers encourage dense leafy growth, nitrogen should be applied at precise rates, less than 0.03175 metric per acre, to decrease severity. Chemical control: • Sulphur 80% WP @ 1252 g in 300-400 l of water/acre
Greasy spot	Chemical control: • Zineb 75% WP @ 600-800 g in 300-400 l of water/acre
Brown rot	Chemical control: • Captan 75% WP @ 500 g in 6-8 l of water/acre
Greening	Cultural control: • Selection of proper site with adequate drainage and high budding (30 to 46 cm or above). • Provision of an inner ring about 45 cm around the tree trunk to prevent moist soil. (Double ring method of irrigation) • Avoid irrigation water from coming in direct contact with the tree trunk. • Avoid injuries to crown roots or base of stem during cultural operations. • Use resistant sour orange rootstocks for propagating economic varieties • Use certified pathogen free bud wood for propagation. Chemical control: • Control psyllids with insecticides like dimethoate or imidacloprid • Applying Bordeaux paste or ZnSO4, CuSO4, lime (5:1:4) to a height of about 60 cm above the ground level at least once a year.

Note: The pesticide dosages and spray fluid volumes are based on high volume spray.

* Apply Trichoderma spp. 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).

** Pests of regional significance

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

 

3.05   

 

133 ratings and

Citrus: Diseases and Symptoms

1. Citrus scab
2. Citrus canker
3. Citrus tristeza disease
4. Gummosis
5. Greening or Huanglongbing
6. Anthracnose
7. Sooty mould
8. Powdery mildew
9. IPM for Citrus

Citrus scab

Disease symptoms:

• Initially small, semi-translucent dots like lesion develops on leaves which become sharply defined pustular elevations. The opposite surface corresponding to the warty growth shows a circular depression with a pink to red centre.
• On the fruit, lesions consist of corky projections which often break into scab affecting larger areas on the fruits

Survival and spread:

• Fungal survive in the infected leaves through overwintering lesions on the fruit or leaves and/or from any scab infections that have developed on the new spring flush.

Favourable conditions:

• Scab can be particularly severe on summer growth flushes. Summer wet periods associated with rain showers and dew is highly conducive for spore germination and infection.

Citrus canker

Disease symptoms:

• Initially, disease appears as minute water soaked round, yellow spots which enlarge slightly and turn brown, eruptive and corky.
• These pustules are surrounded by a characteristic yellow halo.
• Canker lesions on the fruit do not possess the yellow halo as on leaves. Several lesions on fruit may coalesce to form larger canker.
• Due to severe infections the there may be defoliation, and twig and stem may show die-back symptoms.

Survival and spread:

• In lesions on Citrus, and can also survive for long periods in diseased plant tissues
• Citrus leaf miners (Phyllocnistis citrella) help in the dissemination of the pathogen.

Favourable conditions:

• Spring seasion is favourable for the development of disease

Citrus tristeza disease

Disease symptoms:

• Disease affected tree leaves becomes chlorotic in the early stages. Gradually the leaves drop and the defoliated twigs show die-back.
• Diseased trees usually blossom heavily.
• Under the tree bark stem pitting can be observed.
• Trees with stem pitting are stunted and set less fruits.
• The fruits are of smaller size and of poor quality (insipid fruits).

Transmission and favourable conditions:

• The disease is transmitted in semi persistent manner by aphid Aphis gossypii.
• Aphids are more active in warm summer conditions and increase their population as well as spread of the disease.

Gummosis

Disease symptoms:

• Disease starts as water soaked large patches on the basal portions of the stem near the ground level.
• Bark in such parts dries, shrinks and cracks and shreds in lengthwise vertical strips.
• Later profuse exudation of gum from the bark of the trunk occurs.
• Considerable amount of gum formation in sweet oranges may be observed, but relatively little in grapefruit.

Survival and spread:

• The fungus survives in the form of dormant mycelium and under moist conditions. The fungi produces large numbers of motile zoospores, which are splashed onto the tree trunks.
• Secondary infections often occur through lesions created by Phytophthora

Favourable conditions:

• The Phytophthora species causing gummosis develop rapidly under moist and cool conditions.

Greening or Huanglongbing

Disease symptoms:

• Affected leaves show small circular green islands within the chlorotic areas.
• Heavy leaf fall occurs with the onset of summer.
• Twig die-back may also occurs.
• Affected areas of the fruits remain green and gives bitter taste
• Affected fruits show reduction in size, loopsided growth and oblique columella.
• Seeds are poorly developed, dark coloured and aborted.

Transmission and favourable conditions:

• The bacterium is transmitted by the psyllids Triozaerytreae Del Guercio. The bacteria can be acquired by the insects in the nymphal stages and the bacteria may be transmitted throughout the life span of the psyllid.

Anthracnose

Disease symptoms:

• Leaf - common symptoms are a more or less circular, flat area, light tan in color with a prominent purple margin that at a later phase of infection will show the fruiting bodies of the fungus (tiny dispersed black flecks).
• Tissues injured by various environmental factors (such as mesophyll collapse or heavy infestations of spider mites) are more susceptible to anthracnose colonization.
• Fruit - anthracnose usually only occurs on fruit that have been injured by other agents, such as sunburn, chemical burn, pest damage, bruising, or extended storage periods. The lesions are brown to black spots of 1.5 mm or greater diameter. The decay is usually firm and dry but if deep enough can soften the fruit. If kept under humid conditions, the spore masses are pink to salmon, but if kept dry, the spores appear brown to black. On ethylene degreened fruit, lesions are flat and silver in color with a leathery texture. On degreened fruit, much of the rind is affected. The lesions will eventually become brown to grey black leading to soft rot.

Survival and spread

• Once the spores germinate, they form a resting structure that allows them to remain dormant until an injury occurs

Favourable conditions:

• Cool weather (temp 20°C) responsible for development of disease in plants
• Long period of high relative humidity >80% with mists

Sooty mould

Disease symptoms:

• The dark, felty growth from sooty mold can be scraped off of plant surfaces, unlike fruit rots that extend into the rind and flesh.
• Where sooty mold occurs, look for aphids, citricola scale, cottony cushion scale, mealy bugs, whiteflies, and other phloem-sucking insects that excrete honeydew on which sooty mold fungi grow.

Powdery mildew

Disease symptoms: Leaf

• White ‘powdery’ spores develop mostly on the upper leaf surface.
• Young leaves turn a pale whitish-grey-green.
• The ends of mildewed leaves can twist and curl upward.
• Young shoots can whither and die back.
• Severe infections cause defoliation.

Fruit

• White ‘powdery’ spores develop on the young fruits.
• Infected fruit fall prematurely.

Survival and spread:

The fungi produce tiny, powdery spores that can survive on fallen leaves. It can be transported long distances by wind, on people (clothing, hands), equipment (e.g. pruning tools, mechanical harvesters or hedgers) or vehicles.

Favourable conditions:

• Cool and damp weather (temp 20°C) responsible for development of disease in plants
• Long period of high relative humidity >80% with mists and fog are especially conducive for the development of disease.

IPM for Citrus

To know the IPM practices for Citrus, click here.

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

 

3.08   

 

147 ratings

Citrus: Insect and Nematode Pests Management

1. Citrus aphid
2. Citrus/Lemon-butterfly
3. Citrus psylla
4. Citrus leaf miner
5. Mealy bug
6. Fruit sucking moth
7. Citrus blackfly
8. Nematode
9. IPM for Citrus

Citrus aphid

Biology

Egg: Eggs are not produced by this species. Females give birth to living young.
Nymph: There are four nymphal stages of this aphid. The first stage is approximately 1/36 inch in length and the last about 1/17 inch. They are without wings and brownish in color. Newly born nymphs are found grouped together since mothers do not move about while birthing.
Adult: Only females are found. They are oval, shiny black, brownish-black or reddish brown in color, either with or without wings, measuring 1/25 to 1/12 inch in body length and having short black-and-white banded antennae. Winged individuals tend to have darker abdomens and be slightly thinner. The incidence of winged individuals is dependent on the population density and leaf age. This is the only aphid with an audible stridulation or high piercing sound caused by the aphid rubbing two parts of it body together much like crickets. Large colonies will produce this scrapping sound when they are disturbed. About thirty generations succeed each other and overlap throughout the year.

Favourable conditions:

• The development of this aphid is temperature dependent. The optimum temperature for this aphid is 20 to 25°C.
• Lower winter temperatures and particularly summer heat (above 30°C) slow down development.

Damage symptoms:

• It feeds on tender foliage and flowers.
• It transmits Citrus Tristeza Virus disease.
• Nymphs and adults suck the sap of leaves which leads to wilting and flower dropping.
• Infested leaves become cup shaped and crinkled.
• Growth of the plants is hindered.

Citrus/Lemon-butterfly

Biology

Egg: Yellowish white, round, smooth eggs are laid singly on tender leaves and shoots by P. demoleus. Egg hatches in about 3 – 8 days.
Larva: Freshly hatched caterpillars are dark brown and soon develop irregular white markings on their body resembling bird’s drop. The caterpillars feed voraciously on tender leaves right up to the mid ribs and defoliate the entire seedlings or the tree leaving behind only the midribs.
Pupa: The caterpillars attach themselves to branches with silk, transforming into pupae. They remain in the pupal form for 2–3 weeks before emerging as adults.
Adult: 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.
Favourable conditions:

• The larval population density will be high during October to December months and July to December is the most favourable period of its activity in general.
• Citrus butterfly was able to survive during the winter even though temperatures dropped below 0°C.

Damage symptoms:

• Caterpillars prefers on light green tender leaves
• Feeding voraciously and leaving only the mid-ribs
• Severe infestation the entire tree gets defoliated.

Citrus psylla

Biology

Egg: Eggs are 0.2-0.3 mm pear shaped organe to yellow initially turn darker as they are ready to hatch.
Nymph: Its nymphs are yellow, orange or brown with flattened bodies. They are hard to see, since they’re only 1/100 to 1/14 inch long. The nymphs also secrete a sticky substance called honeydew that attracts sooty mold.
Adult: The Asian citrus psylla is a tiny, mottled-brown, winged insect that damages curry leaf plants when it sucks sap out of young leaves. This psyllid grows to be between 1/16 and 1/8 inch long with red eyes and short antennae.
Favourable conditions:

• Summer and rainy seasons.

Damage symptoms:

• Asian citrus psyllids are mottled brown insects that feed directly on the leaf of the curry tree.
• This causes damage to the leaves and stems, and can also introduce bacteria to the tree.
• Psyllids, like other Homoptera, have piercing sucking mouthparts used for feeding on plants.
• Feeding by psyllid adults and nymphs causes newly forming leaves to twist and curl similar to feeding damage from the green aphid.
• Psyllid feeding also results in reduction of shoot length giving a witches’ broom effect
• If heavy feeding occurs early on the developing flush, the new flush will fail to develop or abort.
• In addition to direct feeding damage, honeydew inside the white waxy secretions produced by the nymphs promotes the growth of sooty mold which can reduce effective leaf area for photosynthesis

Citrus leaf miner

Biology

Egg: Eggs are very tiny (about 1.0 mm long and 0.2 mm wide), greyish or yellowish white and slightly translucent. They are laid inside the leaf tissue, just below the leaf surface. In some instances eggs are laid below the epidermis of fruits/pods (e.g. peas). Eggs hatch in about 3 days.
Larva: They are small yellow maggots (about 2 to 3 mm long when fully-grown). They are found feeding inside the leaf tissue, leaving long, slender, winding, white tunnels (mines) through the leaf. They pass through 3 larval stages. After 5 to 7 days the maggots leave the mines and pupate either on the leaf surface or - more commonly - in the soil. In some cases, maggots pupate within the mines.
Pupa: Pupae are very small, about 2 mm long and 0.5 mm wide) oval, slightly flattened ventrally with variable colour varying from pale yellow-orange to golden-brown. They have a pair of cone-like appendages at the posterior end of the body. Adults emerge 4 to 5 days after pupation.
Adult: Adult flies are small, about 2 mm long. They are greyish to black with yellow markings. Female flies are slightly larger than males. The life cycle varies with host and temperature. The average life cycle is approximately 21 days in warm conditions, but can be as short as 15 days. Thus, populations can increase rapidly.
Favourable conditions:

• Citrus leaf miner develops best at temperatures between 70º to 85ºF and greater than 60% relative humidity, but will readily adapt to most California conditions.

Damage symptoms:

• Citrus leaf miner larvae feed by creating shallow tunnels, referred to as mines, in young leaves.
• It is most commonly found on citrus (oranges, mandarins, lemons, limes, grapefruit and other varieties) and closely related plants (kumquat and calamondin).
• The larvae mine the lower or upper surface of the leaves causing them to curl and look distorted.
• Mature citrus trees (more than 4 years old) generally tolerate leaf damage without any effect on tree growth or fruit yield.
• Citrus leaf miner is likely to cause damage in nurseries and new plantings because the growth of young trees is retarded by leaf miner infestations.

However, even when infestations of citrus leaf miner are heavy on young trees, trees are unlikely to die.

Mealy bug

Biology

Egg: Eggs are deposited as white cottony masses called ovisacs on trunk and stems of citrus plants, giving the appearance of cotton spread on plants. The glossy, light yellow eggs are oval and approximately 0.3 mm long. A female can lay from 300 to 600 eggs in her life period, which are deposited in groups of 5 to 20. Depending on the season, egg hatch may occur after 6 - 10 days or several weeks. An average of 29 eggs per day is laid by females.
Nymphs: Nymphs emerge from the ovisacs and typically settle along midribs and veins on the underside of leaves, young twigs, and fruit buttons. Wax and honeydew secreted by crawlers are visible indicators of infestations. First instar female and male nymphs are called crawlers. The nymphs take 6 to 10 weeks to reach maturity. The nymphs are yellow, oval-shaped with red eyes, and covered with white waxy particles The female nymphs resemble the adult female in appearance, while male nymphs are more elongated. Female nymphs have four instars. Males differ greatly; they have three instars and a pre-pupal stage.
Adult: Adult size ranges in length from 3 mm (females) to 4.5 mm (males). The females are wingless, white to light brown in color, with brown legs and antennae. The body of adult females is coated with white wax and bears a characteristic faint gray stripe along their dorsal side. Short waxy fi laments can be seen around the margins of their oval body with a slightly longer pair of fi laments present at the rear end of their body. Female mealy bugs are wingless and, therefore, must be transported to subsequent host plants, although they are able to crawl for short distances. The immature can be blown by wind. Females can live for up to 29 days depending on the host plant. Males are similar in color to females and have two long backward-projecting white wax threads.
Damage symptoms:

• Citrus mealy bug is a sporadic pest of citrus, occurring primarily in older, well-shaded groves planted on heavy soils.
• They will feed on the roots, bark, foliage, and fruit. The citrus mealy bug injects toxic saliva while extracting plant sap resulting in defoliation, fruit discoloration, fruit splitting, and fruit drop.
• Mealy bugs usually gather in large numbers, causing premature leaf drop and twig dieback when they feed. Like psyllids, they secrete honeydew, which attracts black sooty mold.

Fruit sucking moth

Biology

Egg: Eggs may be laid singly, or in egg masses containing 50-750 eggs. Placement may be on the underside of young leaves, or on any part of the host. Sometimes eggs may be placed on unsuitable hosts, particularly when the population density is high.
Larva: There are four molts and five instars. Total development time for larvae is about 21 days. Larvae can be found feeding anytime on the underside or edges of leaves, but typically feed between 5 PM and 10 AM. When in danger, young larvae tend to respond by dropping to the ground, while older larvae may exhibit a characteristic aggressive posture and swaying motion.
Pupa: Pupation occurs in an average of 12.5-17.8 days within a pupal cocoon that may remain in the tree or drop to the ground after drying.
Adult: The adult moth is large and robust. The eyes are large. The area behind the head of the moth, the thorax, is pale to purple-brown and the abdomen is pale brown at the base brightening to yellow-orange at the tip. The forewings resemble a leaf by being olive to purple-brown and may have white and green colored flecks (the colored flecks are more common on females). This leaf-like appearance of the forewings makes this moth difficult to see when it is at rest, especially, because the bright hind wings are not visible. The outer edges of the female’s forewings are scalloped or toothed where those of the male’s are evenly curved. The hind wings are bright orange, have a black comma-shaped mark and are fringed by a black border with white dots.
Damage symptoms:

• It is a serious pest of maturing mandarin fruits.
• The adults puncture the ripening fruits.
• Such fruits drop prematurely as a result of rotting due to fungal and bacterial infections introduced through punctures causing considerable fruit loss.

Citrus blackfly

Biology

Egg: Eggs are laid in a spiral pattern on the underside of the leaf. Each female lays two to three egg-spirals during her 10 to 14 day life span. Eggs hatch within seven to 10 days.
Nymph: The first instar is elongate-oval, averaging 0.30 mm long x 0.15 mm wide and is brown in colour, with two glassy fi laments curving over the body. The first instar lasts seven to 16 days. The second instar is more ovate and convex than the first instar, averaging 0.40 mm long x 0.20 mm wide, and is dark brown in colour with numerous spines covering the body. The second instar lasts seven to 30 days. The third instar is more convex and much longer than the second, averaging 0.87 mm long x 0.74 mm wide. The body is shiny black with spines stouter and more numerous than those in the second instar. The third instar lasts six to 20 days.
Pupa: The fourth instar, or so-called pupa case, is ovate and shiny black with a marginal fringe of white wax. The sex is readily distinguishable. Females average 1.24 mm long x 0.71 mm wide; males are 0.99 mm long x 0.61 mm wide. The pupal stage lasts 16 to 50 days.
Adult: The adult emerges from a T-shaped split appearing in the anterior end of the pupal case. At emergence, the head is pale yellow, legs are whitish, and eyes are reddish-brown. Within 24 hours after emergence, the insect is covered with a fi ne wax powder which gives it a slate blue appearance.
Favourable conditions:

• The development with high density citrus blackfly populations, especially during cool temperature and high humidity seasons.

Damage symptoms:

• Citrus black fly is an endemic pest. The pest attack the crop during all the three flushing periods viz., Ambia (Jan.-Feb.), Mrig (Jun.- July) and Hasta (Oct.- Nov.) bahar and completes three generations in a year.
• Both nymphs and adults suck cell sap and secrete voluminous honeydew on which sooty mould grows wildly that leads to fungal manifestation (Capnodium sp.) locally called as ‘Kolshi’, covering entire plant due to which photosynthesis is affected.
• Plants are devitalized due to excessive desapping and in severe cases fruit bearing capacity of the tree is also affected. Fruits are rendered insipid in
• taste and blackened due to black sooty mould. Such fruits fetch low price in the market.

Nematode

Damage symptoms Symptoms are more prominent in established orchards as trees are stressed, either by suboptimal growing conditions, drought, or root stunting and decay induced by T. semipenetrans infection. Typically, reduced leaf and fruit size, canopy thinning, and exposure of bare crown limbs are the most conspicuous symptoms of slow decline and result in yield suppression

• Slow-decline, die-back, rootlets shortened, soil adhere to gelatinous matrix of egg mass
• Galls on roots, reduction in yield
• Heavily infested roots are darker in colour with branched rootlets
• Swollen and irregular in appearance than in normal ones

IPM for Citrus

To know the IPM practices for Citrus, click here.

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

 

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125 ratings

Citrus: Natural Enemies

1. Natural Enemies of Citrus Insect Pests
1. Parasitoids
2. Predators
2. Flowering plants that attract natural enemies/repel pests
3. IPM for Citrus

Natural Enemies of Citrus Insect Pests

Parasitoids

Predators

Flowering plants that attract natural enemies/repel pests

Natural enemies	Attractant / Repellent / Trap Plants
Citrus aphid
Predators: Lacewings, hover flies, coccinellids, birds, earwigs, some ground beetles and rove beetles, and spiders	• Attractant plant: Carrot family, sunflower family, marigold, buckwheat, (syrphid, predatory mite, lacewing, minute pirate bug, samsel bug and ladybird beetle) • Nectar rich plants with small flowers i.e. dill and mustard (Aphid parasite and Braconid wasp) • Sunflower, buckwheat and cowpea (Braconid wasp)
Citrus black fly
• Parasitoids: Encarsia formosa, Eretmocerus spp. (Pupal) • Predators: Chrysoperla zastrowi sillemi, coccinellids, spiders	• Attractant plant: French bean (Predatory thrips)
Citrus psylla
• Parasitoids: Tamarixia radiata, Diaphorencyrtus aligarhensis (nymphal and adult) • Predators: Chrysoperla zastrowi sillemi, coccinellids, syrphids	• Attractant plants: Carrot family, sunflower family, buckwheat, alfalfa, (minute pirate bug, lacewing, syrphids)
Mealy bug
• Predators: Parasitic wasps, hover flies, ladybugs or mealy bug destroyers (Cryptolaemus montrouzieri)	• Attractant plants: Coriander attracts wasps.
Citrus butterfly
• Parasitoids:Trichogramma evanescens, Telenomus spp., (egg), Brachymeria sp (larval), Pterolus sp. (pupal)	• Attractant plants: Carrot family, sunflower family, buckwheat, alfalfa, shrubs (Lace wing) • Nectar rich plants with small flowers i.e. dill, mustard, sunflower, buckwheat and cowpea (Braconid wasp)

IPM for Citrus

To know the IPM practices for Citrus, click here.

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

 

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149 ratings

Insect Pest of Citrus in Hot Arid Region

1. Citrus leaf miner (Phyllocristis citrella)
2. IPM for Citrus

Citrus leaf miner (Phyllocristis citrella)

• It is widely distributed from Australia to Africa. It is found in all the states where Citrus spp. is grown.

Host Range

• It attacks all species of citrus but prefers sweet oranges. It also infests Pongamia, jasmine etc. The pest is active all-round the year, except during severe winter (December — February).

Nature of damage

• The minute caterpillars mine into the leaf tissues of tender leaves and feed on them leaving the outer tissue intact.
• Making silvery appearance presence on the lower surface of leaves

• Leaves become crinkled with whitish lines.
• Incase of severe infestation leaves turn pale, curl badly and dry off.

Description

• Adult is a silvery white small moth with brown striped forewings having a prominent black spot near the tip and white hindwings.
• Both pairs of wings are fringed with hairs.

• The adult moth measures 6 mm in wing span.
• On hatching, the caterpillar enters tissue and starts mining between the two Layers it is thin and yellowish green in colour.
• This results in V shape curling and cupping of leaves.
• Defoliation and death of young shoot in severe infestation and the fruits turning undersized and juice content reduced.

Description

• Adults are reddish with jumping legs.
• Nymphs are flattish, oval in shape and light orange colour.

• Adult is small, brown in colour and brown colour band present on the half of fore wing
• Eggs are laid in tender shoots and anchored in the tissues by means of short stalks.
• 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 and has 16 generations per year.

Source: Insect Pest of Arid Fruit Crops

IPM for Citrus

To know the IPM practices for Citrus, click here.

 

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17 ratings and

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Nutritional Deficiencies/Disorders of Citrus

1. Nitrogen
2. Potassium
3. Boron
4. Copper
5. Iron
6. Manganese
7. Zinc
8. IPM for Citrus

Nitrogen

Dull green, yellowish, smaller leaves, die back of twigs, thin and bushy appearance of tops with sparse bloom are some of the symptoms of nitrogen deficiency. Deficiency is expressed by light green to yellow foliage over the entire tree. With mild deficiency, foliage will be light green progressing to yellow as conditions intensify. New growth usually emerges pale green in colour, but darkens as foliage expands and hardens. With yellow vein chlorosis, the midribs and lateral veins turn yellow while the rest of the leaf remains a normal green colour.

Correction measure: Foliar sprays urea @ 2% at 15 days interval.

Potassium

The deficiency symptoms of Potassium are

• Slower growth, shedding of leaves at blossom tine, new shoots poorly attached to twig.
• Smaller leaves, twigs die peak, scorching of leaf tips, small brown resinous spots on leaf.
• Small wrinkled spotted leaves.

• Small fruits, thin peel.
• In mandarin – yellowing and bronzing of leaves become twisted, wrinkled and spindy twigs.

Correction measure: Foliar spray of KNO₃ 2% at fortnightly interval. Application of 200g N, 100g P₂O₅ and 200g K₂O / tree/year.

Boron

Deficiency symptoms include

• Premature wilting, water soaked spots on leaves.

• Premature shedding of leaves, bushing appearance curling of leaves, splitting and curling of veins.
• Fruits with gum spots and lumpings, hand abnormal shape and small

Correction measure: Foliar spray of borax @ 0.5%

Copper

Deficiency symptoms include reduced growth and dark green colour of leaves, twin led malformed leaves, new leaves shrivelled and bushy growth

Correction measure: Foliar spray of CuSO₄ each 0.5% at fortnightly interval.

Iron

Thin leaves with interregnal choruses in young leaves. Green tinge at the base of mid rib. Leaf size reduced. Later the leaves become pale or whitish and shed. Die back symptom older leaves remain green, fruits hand, coarse light coloured.

Correction measure: Foliar spray of FeSO₄ @ 0.5% twice at fortnight interval.

Manganese

Fine network of green veins as a light green background on young leaves. Leaf remains fairly green. Dark green irregular bands on mature leaves along the midrib. White spots develop in interregnal area with die back symptom.

Correction measure: Foliar spray of 0.5% MnSO₄ at fortnightly interval.

Zinc

Symptoms include - Irregular and chlorite leaf spots, mottled leaf, small leaves and severe dieback of twigs. The area near midrib and lateral veins remain green. Terminal twigs have narrow small erect leaves. Small, thin skinned fruits.

Correction measure: Foliar spray 2% ZnSO₄ with 1% lime at fortnightly interval.

IPM for Citrus

To know the IPM practices for Citrus, click here.

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

 

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