Clove Diseases,Symptoms and Pest Management

  Clove Diseases Seedling wilt Leaf rot: IPM for Clove Seedling wilt Disease symptom: Seedling wilt is...

 

Clove Diseases

1. Seedling wilt
2. Leaf rot:
3. IPM for Clove

Seedling wilt

Disease symptom:

• Seedling wilt is observed mainly in nurseries and causes 5 to 40% death of seedlings.
• Leaves of affected seedlings loose natural luster, tend to droop and ultimately die.
• The root system and collar region of the seedling show varying degrees of discolouration and decay.

Survival and spread:

• The fungus is soil-borne and remains in the soil as saprophyte for 2-3 years.
• The secondary spread is aided by wind, rain and irrigation water.

Favourable conditions:

• High day temperature (30-35˚C).
• Low humidity (50-60%).
• Low soil moisture and alkaline soils

Leaf rot:

Disease symptom:

• It is noticed in the nurseries as well as in the main field both at young and mature stages.
• Infection starts as dark spots at the leaf margin and spreads sometimes with no definite pattern.
• Rotting may be in the whole leaf or at the tip resulting in defoliation.

Favourable conditions:

• The fungus survives on diseased twigs and mummified fruits, either on the tree or on the ground.
• The fungul spores are air-borne and are also spread by rain splash and insects. Moderate temperatures and moist weather during bloom favour the disease

Disease symptom:

• Necrotic spots of variable size and shapes are noticed on the leaves.
• Severely affected leaves wither, droop and dry up.
• Twigs are infected as the symptoms extend from the leaves through petioles.
• The affected branches stand without leaves or only with young leaves at tips.
• Flower buds are attacked by spreading infection from the twigs.
• Shedding of flower buds occurs during periods of heavy and continuous rainfall.

Favourable conditions:

• The fungus survives on diseased twigs and mummified fruits, either on the tree or on the ground.
• The fungus spores are air-borne and also spread by rain splash.
• Moderate temperatures and moist weather during bloom favour twig blight.

IPM for Clove

To know the IPM practices for Clove, click here.

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

 

3   

 

22 ratings

Clove Insect pests

1. Stem borer
2. Scale insects
3. Mealy bug
4. IPM for Clove

Stem borer

Biology:

• Egg: The eggs are laid on the weeds around the basins of clove trees.
• Larva: Early instar larvae feed on the weed plants and the later instars migrate to the clove trees and bore into the stem. The larvae are creamy white with a black head and fully grown larvae measure about 90 mm in length. The dorsal sclerites of the thoracic and abdominal segments are brown.
• Pupa: Pupation occurs within the larval tunnel.
• Adult: The adult is a large sized moth with a wing span of about 110 mm with greyish brown mottled forewings.

Damage symptoms:

• The larva of the stem borer girdles the stem of young clove trees at the basal region and bores downward into the root zone.
• The girdled region and the bore-hole are covered with frass consisting of coarse wood particles that are formed as a mat-like structure.
• The infested trees wilt and defoliate and succumb to the pest attack subsequently.

Natural enemies of Stem borer: Predators: Bird: Wood-pecker

Scale insects

Many species of scale insects infest clove seedlings in the nursery and sometimes young plants in the field.

Black Scale: Paraaissetia nigra

Identification of pest: Female adults are elliptical, flattened and shiny black.

Damage symptoms

• It infests tender leaves, shoots and twigs.
• Sooty mould fungus is observed on leaves due to honey dew secretion.

Masked scale: Mycetaspis personata

Identification of pest: Female adults are elliptical, flattened and black in colour.

• Egg: Eggs are laid under or stay within the female body then hatch to produce nymphs or crawlers. Some species give birth to live young.
• Nymph: First instar nymph is highly mobile. Later instars less so.
• Adult: The mature female is sedentary, headless, legless and wingless and attaches herself to the plant by her mouthparts (stylet) and forms a waxy, leathery or cottony covering over her soft body. They can produce more than 150 eggs then die.

In some species fertilisation is not required and males have not been found. The males of other species live under their protective covering until mature then emerged as winged adults. They tend to live in colonies. They may be tended by ants who feed on the honey dew and protect them from predation.

Damage symptoms

• Dome shaped and greyish brown scale will be seen on the under surface of leaves especially of young clove plants.
• The infested leaves become discoloured and completely yellowish and finally may fall down. Green scale

Green scale

• Egg: Vary in size and color but are generally oval in shape.
• Nymph: Nymphs are yellow "crawlers" migrate to the leaves and settle on the undersides along the midrib and veins.
• Adult: Females vary in size and colour but are generally oval in shape

Damage symptoms:

• Flat and green coloured soft scales are found feeding on leaves and tender shoots.
• Infestation of scales is on leaves and tender shoots, and is serious in the nursery. Young seedlings if attacked are killed soon.

Natural enemies of scale insect:

• Parasitoids: Encarsia sp, Aphytis sp and Comperiella sp
• Predators: Coccinellid and Pharoscymnus flexibilis

Mealy bug

Biology:

• Eggs: Eggs are deposited as white cottony masses called ovisacs on trunk and stems of 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 while males have three instars.
• 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 filaments can be seen around the margins of their oval body with a slightly longer pair of filaments present at the rear end of their body. Female mealybugs are wingless and, therefore, must be transported to subsequent host plants, although they are able to crawl for short distances. 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.

Life cycle

Damage symptoms:

• Damages due to mealy bugs occur by sucking the sap from tender shoots. Affected portions dry up gradually.
• Soft green mealy bug with a white mealy ovisac is seen on the undersurface of tender leaves.
• The feeding causes yellowing and withering of leaves.
• Sooty mold develops on the honey dew secreted by the bug.

Natural enemies of mealy bug:

• Parasitoids: Parasitic wasps,Leptomastix dactylopii
• Predators: Hover flies, Chrysoperla, ladybugs or mealy bug destroyers (Cryptolaemus montrouzieri)

IPM for Clove

To know the IPM practices for Clove, click here.

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

 

2.93   

 

29 ratings

Clove Pests

1. Pests of National Significance in Clove
1. Insect Pests
2. Diseases
2. Weeds
1. Broad leaf weeds
2. Grassy weeds
3. Sedges
3. Nematodes
4. IPM for Clove

Pests of National Significance in Clove

Insect Pests

• Stem borer: Sahyadrassus malabaricus Moore (Lepidoptera, Hepialidae)
• Scale insects: Parasaissetia nigra Nietner, Green scale: Lecanium psidii Green, Wax scale: Ceroplastes floridensis Comstock, Pulvinaria psidii (Maskell),Masked scale: Mycetaspis personata Comstock, Soft scale: Kilifia accuminata Signoret (Hemiptera:Coccidae)
• Mealy bugs: Planococcus sp. and Psuedococus sp.(Hemiptera: Pseudococcidae)

Diseases

• Seedling Wilt: Cylindrocladium sp., Fusarium sp., Rhizoctonia sp.
• Leaf rot: Cylindrocladium quinquiseptatum Boedijin and Reitsma
• Leaf spot and bud shedding: Colletotrichum gloeosporioides(Penz.) Penz. &. Sacc

Weeds

Broad leaf weeds

• Pigweed: Amaranthus viridis Hook. F. Amaranthaceae
• Common purselane: Portulaca oleracea L. Portualacaceae
• False amaranth: Digeria arvensis Forssk. Amaranthaceae
• Carrot grass: Parthenium hysterophorusL. Asteraceae
• Goat weed: Ageratum conyzoidesL. Asteraceae
• Little mallow (cheese weed): Malva parviflora F. Malvaceae

Grassy weeds

• Barnyard grass: Echinochloacrusgalli(L.) Beauv. Poaceae
• Bermuda grass: Cynodondactylon (L.) Pers. Poaceae

Sedges

• Nutsedge: Cyperus rotundus/Cyperus iria/Cyperus difformisL. Cyperaceae

Nematodes

• Ring nematode: Criconemoidesspp.(Tylenchida: Criconematidae)
• Reniform nematode: RotylenchulusreniformisLinford and Oliveira (Tylenchida: Hoplolaimidae)
• Common spiral nematode: Helicotylenchusdihystera(Cobb) Sher(Tylenchida: Hoplolaimidae)

IPM for Clove

To know the IPM practices for Clove, click here.

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

 

3   

 

28 ratings

Beneficial insects of Clove

1. Parasitoids
2. Predators
3. IPM for Clove

Parasitoids

Egg parasitoids

1. Trichogramma                               2. Tetrastichus spp.                       3. Telenomus spp

Predators

1. Lacewing                                        2. Ladybird beetle                      3. Reduviid bug                            4. Spider

5. Robber fly                                        6. Fire ant                                7. Black drongo             8. Common mynah

9. Preying mantid                                         10. Hover fly                 11. Mirid bug                         12. Woodpecker

IPM for Clove

To know the IPM practices for Clove, click here.

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

 

3.01   

 

50 ratings

Clove Crop Stage-Wise IPM

1. Nursery
2. Planting
3. Vegetative stage
4. Maturity/ Fruiting stage

Management	Activity
Nursery
	Common cultural practices: Timely sowing should be done. Field sanitation, rogueing. Destroy collateral host Plants (if any)
Nutrients	Clove requires deep loam soils with high humus content and black loams of semi-forest regions with good drainage. Select partially shaded sites having adequate protection from high winds. Prepare raised nursery beds with fertile soil rich in humus. Sow the seeds at a depth of about 2 cm and a spacing of 2-3 cm. Water the beds regularly. The germinated seedlings are transplanted in polythene bags (25 cm x 15 cm dimension) containing a mixture of soil, sand and well decomposed cow dung in 3:3:1 ratio. The seedlings may again transplanted after 1 year of growth to large polythene bags. The seedlings are ready for transplanting in the field when they are 18 – 24 months old.
Weeds	Destroy all the weeds from planting area by ploughing during summer (before preparing the nursery beds). Remove all the perennial weeds and their rhizomes/suckers before onset of monsoon.
Planting
	Common cultural practices: Use healthy seedlings Do not delay irrigation until the crop exhibits moisture stress symptoms.
Preparation of pits and planting	Select 18 – 24 months old seedlings for planting. Prepare pits of size 75x 75x 75 cm at a spacing of 6 -7 m about a month in advance of planting. Fill the pits partially with compost, green leaf or well decomposed cattle manure and mixed with top soil. Plant the seedlings during the rainy season, upto September.
Weeds	Use weed free planting material.
Nematodes	Biological control: Application of neem cake @ 80 Kg/acre for nematode control.
Scale insects	Cultural control: Removal of affected leaves and branches will prevent the spread. Grow attractant plants for natural enemies viz., sunflower family, carrot family plants, buckwheat. Mechanical control: See the common mechanical control Biological control: Apply mixture of manure compost tea, molasses and citrus oil. Parasitoids such as Encarsia sp.and Aphytis sp. cause effective parasitization. Coccinellids such as Chilocorus sp., Pharoscymnus sp may act as predators
Seedling wilt	Cultural control: Avoid damp and low lying areas. Mechanical control: Refer the common mechanical control
Vegetative stage
	Common cultural practices: Inter-cultural operations and hand weeding. Avoid growing in low-lying areas and water stagnation. Timely irrigation and irrigation should be done by ring method to reduce possibility of wilt. Avoid water stress . Enhance parasitic activity by avoiding chemical spray, when 1-2 larval parasitoids are observed. Common mechanical practices: Remove and destroy collateral wild hosts and weeds Use of pheromone traps @ 4-5/acre. Installation of light trap @ 1/ acre. Collect and destroy the damaged twigs Common biological practices: Conserve natural enemies through ecological engineering. Augmentative release of biocontrol agents
	Fertilizers should be applied on the basis of soil test report and recommendation for the particular area. In general, fertilizers may be applied as mentioned in Table 1. Apply organic manures in May-June with the commencement of south-west monsoon. Apply fertilizers in two equal split doses in May-June along with the organic manures and in September-October in shallow trenches dug around the plant about 1 to 1.5 m away from the base. If soil is highly acidic 500g lime per plant should be applied in alternate years. Apply cattle manure or compost at the rate of 50 kg / tree/year Nutrient management Table 1. Fertilizer requirement of clove. Age of plants N (g/plant/year) P2O5 (g/plant/year) K2O (g/plant/year) 1 st year 20 18 50 2 nd year 40 36 100 Gradually increase the dose 15 years and above 300 250 750
Weeds	Remove weeds before flowering by 2-3 rounds of hand weeding. Slash weeding is a cost-effective method and to keep a cover always over the soil. Mulching with dry leaves or organic matter should be practiced to control weed growth.
Stem borer	Cultural control: Keep field clean. Clean hole and insert cotton wool soaked in emulsion of kerosene or petrol in each hole and plug them with mud. Keep the basins free of weeds. Mechanical control: Refer the common mechanical practices
Scale insects	Same as mentioned in the above planting
Mealy bug	Cultural control: Prune affected shoots during winter. Destroy ant colonies. Grow attractant plants to attract the defenders. Mechanical control: Use sticky barrier on trunk. Biological control: Release parasitoids such as parasitic wasps, Release predators such as Cryptolaemus montrouzieri@10 beetles per tree.
Leaf rot	Cultural control: Refer the common cultural practices. Mechanical control: Remove the rotten portions from the spear and the two adjacent leaves.
Leaf spot	Cultural control: Refer the common cultural practices Mechanical control: Pruning should be done during dry weather.
Maturity/ Fruiting stage
Nutrients	Apply deficient micronutrient if any.
Weeds	Keep the field weed free.
Stem borer	Same as mentioned in the above Vegetative stage
Scale insects	Same as mentioned in the above secondary nursery stage.
Mealy bug	Same as mentioned in the above Vegetative stage.
Seedling wilt	Same as mentioned in the above secondary nursery stage.
Leaf rot	Same as mentioned in the above Vegetative stage.
Leaf spot and bud shedding	Same as mentioned in the above Vegetative stage.

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

 

3