IPM Stratergies for Cucurbitaceous Vegetable Diseases

Cucurbitaceous Vegetable Diseases Downy mildew Powdery mildew Cucumber mosaic Cercospora leaf spot Fusarium wilt Diseases cy...

Cucurbitaceous Vegetable Diseases

1. Downy mildew
2. Powdery mildew
3. Cucumber mosaic
4. Cercospora leaf spot
5. Fusarium wilt
6. Diseases cycles
7. IPM for Cucurbitaceous Vegetable

Downy mildew

Host range

• Musk melon, Sponge gourd and Bitter gourd etc.

Symptoms:

• Yellow, angular spots restricted by veins resembling mosaic mottling appear on upper surface of leaves
• The corresponding lower surface of these spots shows a purplish downy growth in moist weather
• The spots turn necrotic with age
• The diseased leaves become yellow and fall down
• Diseased plants get stunted and die
• Fruits produced may not mature and have a poor taste

Survival and spread:

• Primary: Oospores in soil and sporangia from perennial collateral weed hosts in the vicinity
• Secondary: Wind borne and rain splashed conidia (sporangia) or autonomous zoospores

Favourable conditions:

• Relative humidity > 90%
• High soil moisture
• Frequent rains

Powdery mildew

Host range:

• Pumpkins, bottle gourd, coccinia, cucumber, ridge gourd, Bitter gourd is less affected.

Symptoms:

• Whitish or dirty grey, powdery growth on foliage, stems and young growing parts
• The superficial growth ultimately covers the entire leaf area
• The diseased areas turn brown and dry leading to premature defoliation and death
• Fruits remain underdeveloped and are deformed

Survival and spread:

• Primary: Dormant mycelium or cleistothecia in infected plant debris or conidia from collateral hosts
• Secondary: Wind borne conidia

Favourable conditions:

• Morning relative humidity > 90%
• Cool and dry weather

Cucumber mosaic

Wide host range:

• Cucumber, Pumpkin, gourds, Cowpea, tomato, chilli, etc. Cucumovirus with spherical particles having ssRNA

Symptoms:

• Symptoms appear on the youngest and still expanding leaves when infection occurs at 6 – 8 leaves stage
• Typical mosaic pattern develops on young leaves
• Leaves curl downwards and become mottled, distorted, wrinkled and reduced in size
• Veins appear bunchy because of shortening of internodes
• When infection occurs at midseason previous growth remains normal and produces normal fruit
• Fruit set is very less if infection occurs early in crop growth
• Fruits are often misshapen, mottled, warty and reduced in size

Survival and spread:

• Primary: Virus particles on collateral and other weeds, ornamentals or crops Hosts: Banana, clover, corn, passion fruit, safflower, spinach, sugarbeet, wild cucumber, Commelina communis, C. diffusa, C. nudiflora, Solanum elaegnifolium, Phytolacca sp., periwinkle, Gladiolus sp., Impatiens sp. and Phlox
• Secondary: Virus particles transmitted by aphids (Aphis craccivora, Myzus persicae) and spotted and striped cucumber beetles

Cercospora leaf spot

Host range:

• Common on watermelon, muskmelon and cucumber

Symptoms:

• Minute water soaked spots or yellow specks develop initially on leaves
• Spots enlarge rapidly and becomes circular to irregular with pale brown, tan or white centers and purple to almost black margins
• Spots coalesce to form large blotches
• The leaf may dry and die presenting the leaf a scorched appearance
• Fruits are also occasionally attacked

Survival and spread:

• Primary: Dormant mycelium or conidia on infected plant debris or collateral hosts
• Secondary: Wind borne conidia

Fusarium wilt

Damage symptoms:

• The first symptom of the disease is clearing of the veinlets and chlorosis of the leaves.
• The younger leaves may die in succession and the entire may wilt and die in a course of few days.
• Soon the petiole and the leaves droop and wilt.
• In young trailing plant, symptom consists of clearing of veinlet and dropping of petioles. In field, yellowing of the lower leaves first and affected leaflets wilt and die.
• The symptoms continue in subsequent leaves. At later stage, browning of vascular system occurs. Plants become stunted and die.

Survival and spread:

• Soil and implements

Favourable conditions:

• Relatively high soil moisture and soil temperature

Diseases cycles

Downy mildew: Pseudoperonospora cubensis

Powdery mildew: Erysiphe cichoracearum DC, Sphaerotheca fuligena (Schltdl.) Pollacci

Cercospora leaf spot: Cercospora leaf spot C. citrullina, C. melonis, C. lagenarium

Fusarium wilt: Fusarium oxysporum Schlecht

IPM for Cucurbitaceous Vegetable

 

 

To know the IPM practices for Cucurbitaceous Vegetable, click here

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

 

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30 ratings

Cucurbitaceous Vegetable Insect Pests

1. Cucurbit fruit fly
2. Red pumpkin beetles
3. Epilachna beetle/Hadda beetle
4. Serpentine leaf miner
5. Pumpkin leaf caterpillar
6. Aphids
7. IPM for Cucurbitaceous Vegetable

Cucurbit fruit fly

It is one of the important pests on gourds like bittergourd, snakegourd, melons, coccinia etc., throughout the country

Biology:

• Egg: The female fly oviposits on soft fruits. Cavity is made by sharp ovipositor and 12 cylindrical eggs are laid in the evening time and exuding gummy substance covers, cements and makes it water proof. Female lays 58-95 eggs in 14-54 days. Egg period is 1-9 days.
• Maggot: The maggots are apodus, acephalous, dirty white, wriggling creatures, thicker at posterior end and tapering at the other to a point. Larval period is 13 days in summer and about three weeks in winter. Mature maggots come out and jump to ground and select suitable place, enter soil and pupate.
• Pupa: Pupa is barrel shaped. Pupal period is 69 days
• Adult: Adult flies emerge from pupa during morning hours and mate at dusk. Adults are reddish brown with lemon yellow markings on thorax with spotted wings. It is active throughout the year. Adults hibernate during winter and they become active in hot weather. Longevity is 14 days.

Life cycle:

Symptoms of damage:

• Only maggots cause damage by feeding near ripe fruits, riddling them and polluting pulp.
• Maggots bore into the fruit and feed on pulp forming lesions.
• Fruits decay due to secondary bacterial infection.
• Damage is more serious in melons. Fruits at early stage also are attacked. Such fruits do not develop. Infestation results in premature drop of fruits.
• Decay of fruits due to secondary bacterial infection
• The damage is more in monsoon season.

Parasitoids:

Opius fletcheri

Predators:

Ants:

Red pumpkin beetles

These insects infest bittergourd, snakegourd, melons, pumpkin, coccinia etc.

Biology:

• Egg: Brownish elongate eggs are laid in the soil and each female may lay about 150 to 300 eggs singly or in groups of 8-9 near the base of plants. Egg period is 5-8 days.
• Grub: Grubs are creamy white with darker oval shield at back. Grub period is 13-25 days.
• Pupa: Pupation takes place in an earthen cocoon. Pupal period is 7-17 days.
• Adult: Raphidopalpa foveicollis has reddish brown elytra; A. intermedia has blue black elytra; and A. cincta has grey elytra with black border.
• Total life cycle takes 26-27 days. There are 5 to 8 generations/year.

Life cycle:

Nature and symptoms of damage:

• Beetles are more destructive.
• They bite holes on leaves and also feed on flowers.
• Beetles injure the foliage, flowers and cotyledons by biting holes into them.
• Early sown cucurbits are severely damaged necessitating resowing.
• Beetle damage results in
• Numrous of holes on leaves.
• Grubs after hatching, feed on roots of plants below soil surface.
• Grubs bore into vines, feed on fruits that come in contact with the soil.

Predators:

Parasitoids:

Epilachna beetle/Hadda beetle

Spotted beetles are distributed from East Asia to South Asia and Australia. They are polyphagous and feed predominantly on cucurbits, cucurbits, potato, and kidney beans as well as eggplant. These beetles are considered to be one of the most serious groups of pests damaging eggplant. In addition, they also feed on other Solanaceous plants such as S.nigrum, S.xanthocarpum, S.torvum, Datura sp, Physalis sp and Withania somnifera.

Biology:

• Egg: The females lay eggs mostly on the lower leaf surfaces. Each female lays about 100-400 eggs. The egg is spindle-shaped and yellowish in color. Eggs are laid in clusters of 10-40. The egg period varies from two to five days
• Grub: The grub is creamy white or yellowish in color with black spiny hairs on the body. The grub period is two to five weeks depending on the temperature. Grubs pupate on the leaves and stem.
• Pupa: The pupa resembles the grub but is mostly darker in color, although it sometimes is yellowish in color. The pupa bears spiny hairs on the posterior, but not the anterior, part of the body. The pupal period is one to two weeks.
• Adult: The subfamily Epilachninae contains plant-feeding ladybird beetles because most other ladybird beetles are predators, not plant pests. These brownish or orange- colored, hemispherical beetles are larger than other ladybird species. E. vigintioctopunctata (in Latin, viginti means 20 and octo means 8) has 28 black spots on the forewing (elytra). E. dodecastigma (dodecam means 12 in Greek) has 12 black spots on the elytra. However, beetles with 14, 16, 18, 20, 22, 24 or 26 spots have been observed under field conditions, due to mating between females of E. dodecastigma and males of E. vigintioctopunctata.

Life Cycle:

Damage symptoms:

The grub and adult have chewing mouthparts. Hence, they scrape the chlorophyll from the epidermal layers of the leaves. The feeding results in a typical ladder-like window. The windows will dry and drop off, leaving holes in the leaves. In severe infestations, several windows coalesce together and lead to skeletonization i.e. the formation of a papery structure on the leaf.

Parasitoids:

Nematodes:

Serpentine leaf miner

Biology:

• Egg: Eggs are minute in size and orange yellow in colour. The egg hatches in 4 days.
• Larva: Apodous maggot feeds on chlorophyll mining in between epidermal layers. Full grown maggot measures 3 mm. Larval duration is about 7 days.
• Pupa: Pupation is in soil. Some pupae are found in leaves. Pupation takes place inside a thin loose mesh of silken cocoon. Pupal period is about 7 days.
• Adult: It is a pale yellowish fly, measuring 1.5 mm in length. The female fly punctures upper surface of leaf to lay eggs singly . Total life cycle takes 3 weeks.

Life cycle:

Damage symptoms:

• Leaves with serpentine mines
• Drying dropping of leaves in severe cases

Favourable conditions:

Warm weather conditions are favourable for multiplication.

Mining on leaves

Parasitoids:

Predators:

Pumpkin leaf caterpillar

Biology:

• Adult: Moth is medium with whitish wings, transparent with brown marginal patches.
• Larva: Elongate bright green caterpillar is seen with two narrow longitudinal white stripes dorsally.

Life cycle:

Symptoms of damage:

It folds the leaves and scrapes the green matter. As a result the leaves get dried up. It can also feed on ovaries of flower, sometimes bore into young developing fruits.

Aphids

This is a cosmopolitan pest and highly polyphagous. It prefers to feed on cotton, cucurbits, eggplant, and okra. Aphids occur during the cool dry season.

Biology:

• Adult: Unlike many insects, most aphids do not lay eggs. They usually reproduce through parthenogenesis (development of embryo without mating with males) and are viviparous (give birth to nymphs directly rather than eggs). The adult color is highly variable and it varies from light green to greenish brown. Both wingless and winged forms occur. Winged forms are produced predominantly under high population density conditions, inferior host plant quality, etc. The wingless forms are more common. They possess a pair of black-colored cornicles on the dorsal side of the abdomen. Aphids mostly are found in groups. Each female produces about 20 nymphs a day, which become adults in a week.

Life cycle:

Parasitoids:

Predators:

IPM for Cucurbitaceous Vegetable

 

 

To know the IPM practices for Cucurbitaceous Vegetable, click here

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

 

2.94   

 

33 ratings

Cucurbitaceous Vegetable Pests

1. Pests of National Significance
1. Insect and mite pests
2. Diseases
2. Weeds
3. IPM for Cucurbitaceous Vegetable

Pests of National Significance

Insect and mite pests

• Cucurbit fruit fly: Bactrocera cucurbitae (big size), B. tau, B. dorsalis (medium size) (Coquillett) (Tephritidae: Diptera) (Assam, Andaman and Nicobar, Delhi, Kerala, Maharashtra, Rajasthan, Tamil Nadu)
• Pumpkin beetles: Raphidopalpa foveicollis, Aulacophora intermedia, A. cincta (Lucas) (Chrysomelidae: Coleoptera) (Assam, Madhya Pradesh, Uttar Pradesh)
• Epilachna beetles: Epilachna vigintioctopunctata, E. dodecastigma (Fabricius) (Epilachninae: Coccinellida: Coleoptera)
• Serpentine leaf miner: Liriomyza trifolii (Burgess) (Agromyzidae: Diptera) (Andhra Pradesh, Gujarat, Karnataka, Maharashtra, Madhya Pradesh, Tamil Nadu, Uttar Pradesh)
• Aphids: Aphis gossypii (Glover) (Aphididae: Hemiptera) (Himachal Pradesh, Kerala, Manipur, Tamil Nadu, Uttar Pradesh)
• Pumpkin leaf caterpillar: Diaphania indica (Saunders) (Pyralidae: Lepidoptera) (Gujarat, Karnataka, Punjab, Tamil Nadu)

Diseases

• Downy mildew: Pseudoperonospora cubensis (Berkeley & M. A. Curtis) Rostovzev (Karnataka, Maharashtra, Punjab)
• Powdery mildew: Erysiphe cichoracearum DC, Sphaerotheca fuligenia (Schltdl.) Pollacci (Haryana, Karnataka, Tamil Nadu, Uttar Pradesh)
• Cucumber mosaic: Cucumber Mosaic Virus (Delhi, Haryana, Kerala, Punjab, Uttar Pradesh)
• Fusarium wilt: Fusarium oxysporum Schlecht (Delhi, Karnataka, Maharashtra, Orissa, Punjab, Rajasthan, Uttar Pradesh)

Weeds

Broadleaf weeds

• Pigweed: Amaranthus viridis Hook. F.
• Swine cress: Coronopus didymus (L.) Sm.
• Black nightshade: Solanum nigrum L.
• Common purselane: Portulaca oleracea L.
• False amaranth: Digera arvensis Forssk.
• Congress weed: Parthenium histerophorous
• Witch weed: Striga sp

Grassy weeds

• Rabbit/Crow foot grass: Dactyloctenium aegyptium (L.) Beauv.
• Crabgrass: Digiteria sanguinalis (L.) Willd.
• Barnyard grass: Echinochloa crusgalli (L.) Scop. Sedges
• Purple nutsedge: Cyperus rotundus L.
• Flat sedge: Cyperus iria L.

Broadleaf weeds

• Lamb’s quarter: Chenopodium album L.
• Scarlet Pimpernel: Anagallis arvensis L.
• Sweet clover: Melilotus indica (L.) All.
• Fine leaf fumitory: Fumaria parviflora Lam.
• Corn spurry: Spergula arvensis L.

Grassy weeds

• Blue grass: Poa annua L.
• Canary grass: Phalaris minor Retz.

IPM for Cucurbitaceous Vegetable

To know the IPM practices for Cucurbitaceous Vegetable, click here.

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

 

2.8   

 

27 ratings

Cucurbitaceous Vegetable Crop stage-wise IPM

1. Pre-sowing
2. Seedling stage
3. Vegetative stage
4. Reproductive stage

Management	Activity
Pre-sowing
Nutrients	Apply farm yard manure (FYM) @ 8-10 t/acre and incorporate in the soil 2 to 3 weeks before sowing.
Weeds	Field is kept weed free before sowing by ploughing.
Soil borne fungus, nematodes, resting stages of insects and weeds	Cultural control: Deep ploughing of fields during summer. Soil solarization: Cover the beds 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. Biological control: Apply neem cake/pongamia cake @ 100 kg/acre in soil at the time of last plouging or reducing nematodes, and soil dwelling pests. Apply Trichoderma spp. @ 2.5 kg/acre along with FYM
Seedling stage
Red pumpkin beetle	Cultural control: Deep summer ploughing exposes the grubs and pupae. Biological control: Conserve predators such as Pennsylvania leather wing beetle (Chauliognathus pensylvanicus); larvae of which feed on pumpkin beetle larva. Conserve parasitoids such as Celatoria setosa (grub) Spray NSKE 5% Chemical control: Apply trichlorfon 5% GR @ 200 g/acre or trichlorfon 5% DUST @ 200 g/acre
Applying Trichoderma as seed and nursery treatment and Pseudomonas fluorescens as seed, 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).
Vegetative stage
Nutrients	Generally cucurbit crops require 40: 32: 24 kg N: P: K/acre Apply N in two splits first one (50%) at 25 days after sowing. Apply entire P and K at the time of sowing. Micro nutrient deficiency should be corrected by foliar spray of particular nutrient. To maintain the sex ratio (more number of female flowers), spray borax @ 1 g/l at 2-4 leaf stage
Weed management	Regular hoeing and weeding should be done to keep the field weed free up to 30 days crop stage.
Fusarium wilt	Cultural control: Use pathogen free seeds Remove and destroy the infected plants and plant debris Adopt crop rotation Avoid water stagnation and maintain proper drainage Use resistant varieties
Serpentine leaf miner	Cultural control: Change in dates of sowing Growing castor, tomato or marigold as a trap crop. Biological control: Cultural and mechanical control: Use yellow sticky traps or cards @ 10/acre Biological control: Conserve parasitoids such as Tetrastichus ovularum (egg), Gronotoma micromorpha (larval and pupal), Diglyphus sp (larval), Opius phaseoli (pupal), Chrysocharis sp, Neochrysocharis formosa (larval) etc. Conserve predators such as lacewings, lady beetles, spiders, fire ants etc. Foliar spray with NSKE 5%
Aphids	Cultural control: Lablab and seed mixture including self-sowing annual and perennial herbaceous flower species are viable options to grow within cucurbits or as field boundary crops to attract and increase beneficial insects and spiders for the control of sap-sucking insect pests. Biological control: Conserve parasitoids such as Aphidius colemani, Diaeretiella spp., Aphelinus spp. Release 1st instar larvae of green lacewing bug (Chrysoperla carnea) @ 10,000/acre Conserve predators such as anthocorid bugs/pirate bugs (Orius spp.), mirid bugs, syrphid/hover flies, green lacewings (Mallada basalis and Chrysoperla carnea), predatory coccinellids (Stethorus punctillum, Coccinella septumpunctata and Menochilus sexmaculata, Hippodamia convergens), staphylinid beetle (Oligota spp.), predatory cecidomyiid fly (Aphidoletis aphidimyza) and predatory gall midge, (Feltiella minuta), earwigs, ground beetles, rove beetles, spiders, wasps etc. Chemical control: Spray imidacloprid 70% WG @ 14 g in 200 l of water/acre
Cercospora leaf spot	Cultural Control: Field sanitation Maintain good soil drainage and good aeration between vines. Chemical control: Spray zineb 75% WP @ 600-800 g in 300-400 l of water/acre
Cucumber mosaic virus	Cultural control: Raise 4 rows of barrier crops such as main or sorghum Avoid planting tomatoes next to cucurbits, spinach, or other vegetables and flowers susceptible to these diseases. Control of aphids (A. gossypii) will help reduce the likelihood of cucumber mosaic. Chemical control: Vector control by spraying imidacloprid 70% WG @ 14 g in 200 l of water/acre
Powdery mildew	Cultural control: Plant resistant varieties Increasing air movement inside the canopy Chemical control: Spray carbendazim 50% WP @ 120 g in 240 l of water or benomyl 50% WP @ 80 g in 200 l of water/acre or thiophanate methyl 70% WP @ 572 g in 00-400 l of water/acre
Downy mildew	Cultural control: Trellising cucumbers Avoiding overhead irrigation or irrigating only in the late morning hours will limit the amount of time that leaves are wet. Control alternate weed hosts (wild cucumber, golden creeper and volunteer cucumbers) in neighbouring fence rows and field edges Chemical control: Spray zineb 75% WP @ 600-800 g in 300-400 l of water/acre or cymoxanil 8% + mancozeb 64% WP @ 600 g in 200-240 l of water/acre
Reproductive stage
Nutrients	Apply the second dose (50%) at 45 days after sowing Micronutrient deficiency should be corrected by foliar spray of particular micronutrient.
Weeds	Left over weeds should be removed from the field to avoid further spread of weed seeds.
Fruit fly	Cultural control: Early maturing varieties are less affected than later ones. Changing of sowing dates. Collection and destruction of infested fruits Slight raking of soil during fruiting time and after the harvest to expose pupae from the soil. Use methyl eugenol (0.1%) based trap Biological control: Conserve parasitoids such as Opius fletcheri (pupal) Spray NSKE 5%

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

 

3.26   

 

35 ratings

Cucurbitaceous Vegetable Nutritional deficiencies

1. Nitrogen
2. Potassium
3. Calcium
4. Magnesium
5. Boron
6. Iron
7. Manganese
8. IPM for Cucurbitaceous Vegetable

Nitrogen

Deficiency symptoms: Both vegetative growth and fruit production are severely restricted plants appear pale and spindly. New leaves are small but remain green, whereas the oldest leaves turn yellow and die. The yellowing spreads up the shoot to younger leaves. Yield is reduced and fruit are pale, short and thick.

Correction measure: Side-dress deficient in-ground crops with 20-50 kg N/ac, or apply fortnightly foliar sprays of 2% urea at high volume.

Potassium

Deficiency symptoms: Potassium deficiency causes yellowing and scorching or older leaves. These symptoms begin at the margins of the leaf and spread between the veins towards its centre. Large areas of tissue around the major veins remain green until the disorder is well advanced. A brown scorch develops in the yellow areas and spreads until the leaf is dry and papery. Potassium from a fertilizer side-dressing will move from the soil surface to the roots only if the soil is very sandy. Potassium fertilizers are therefore best incorporated in the soil before planting. Fertigation or drip feeding can also be used to treat a deficient crop.

Correction measure: Foliar spray of KCl 1% at weekly interval.

Calcium

Deficiency symptoms: Emerging leaves appear scorched and distorted and may cup downwards because the leaf margins have failed to expand fully. Mature and older leaves are generally unaffected. With a severe deficiency, flowers can abort, and the growing point may die. Fruits from calcium-deficient plants are smaller and tasteless, and may fail to develop normally at the blossom end.

Correction measure: Soil application of gypsum as per gypsum requirement based on soil test report or by foliar spray of CaSO4@ 2% solution in water.

Magnesium

Deficiency symptoms: Magnesium deficiency causes yellowing of older leaves. The symptom begins between the major veins, which retain a narrow green border. A light tan burn will develop in the yellow regions if the deficiency is severe. Fruit yields are reduced.

Correction measure: Incorporate magnetite (300 kg/ac) or dolomite (800 kg/ac) into deficient soils before planting. Fortnightly foliar sprays of MgSO4 (2 kg/100 L) at high volume (500-1000 L/ac).

Boron

Deficiency symptoms: Distortion of newer leaves (in severe cases the growing point dies) and the appearance of a broad yellow border at the margins of the oldest leaves. Young fruit can die or abort; abortion rates are high. Stunted development and mottled yellow longitudinal streaks, which develop into corky marking (scurfing) along the skin.

Correction measure: Foliar spray of 0.2% Borax at forthrightly interval. Application of 10 kg borax per hectare to deficient soil before will prevent boron deficiency.

Iron

Deficiency symptoms: Iron deficiency causes a uniform pale green chlorosis of the newest leaves; all other leaves remain dark green. Initially, the veins remain green, which gives a net-like pattern. If the deficiency is severe, the minor veins also fade, and the leaves may eventually burn, especially if exposed to strong sunlight. Good drainage and soil aeration favour iron availability. Foliar sprays of iron sulphate (150 g/100 L) can be used to treat symptoms

Correction measure: Foliar spray of 0.5% FeSO4.

Manganese

Deficiency symptoms: The veins of middle to upper leaves of manganese-deficient plants appear green against the mottled pale green to yellow of the blade.

Correction measure: Spray the foliage with MnSO4 @ 0.1% (100 g/100 L water).

 

IPM for Cucurbitaceous Vegetable

To know the IPM practices for Cucurbitaceous Vegetable, click here

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

 

3   

 

32 ratings