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Central Silk Board, Minisitry of Textiles, Government of India, Bangalore
North Tripura, Tripura

Diseases & Pests of Mulberry Food Plants

FOLIAR DISEASES
1. Leaf Spot

Pathogen : Cercospora moricola

Occurrence : It is more prevalent during rainy season followed by winter. The disease starts progressing 35-40 days after pruning (DAP)/leaf harvesting and becomes severe on the 70th DAP.

Crop loss : 10-12 %

Symptoms : Brownish necrotic, irregular spots appear on the leaf surface. Spots enlarge, extend and join together leaving characteristic ‘shot hole’. Leaves become yellow and wither off as disease becomes severe.

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Leaf spot

Factors responsible for spreading of the disease:

  • The disease is air borne spreading by conidia primarily through rain droplets.
  • Temperature of 24-26 ºC and 70-80 % relative humidity are most congenial for the disease development.
Control measures to be adopted:
  • Spraying of 0.2 % Bavistin (Carbendazim 50% WP) solution on the leaves.
  • Safe Period: 5 days.

2 Powdery Mildew

Pathogen : Phyllactinia corylea

Occurrence : Disease is prevalent during winter and rainy seasons and progresses 40th DAP/leaf harvest becoming severe on 70th DAP.

Crop loss : 5-10%

Symptoms : White powdery patches appear on the lower surface of the leaves. The corresponding portions on the upper surface develop chlorotic lesions. When severe, the white powdery patches turn to brownish-black; the leaves become yellow, coarse and loose their nutritive value.

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Powdery mildew

Factors responsible for spreading of the disease:

  • The disease is air borne spreading by conidia primarily through wind current.
  • Temperature of 24 – 28º C and high relative humidity (75-80 %) are responsible for infection and disease development. 

Control measures to be adopted:  

  • Follow wider spacing of plantation (90 cm x 90 cm) or paired row planting system  [(90 +150) × 60 cm] 
  • Spraying of 0.2 % Karathane (Dinocap 30% EC) / Bavistin on the lower surface of the leaves. Safe period 5 days.
  • Or spray Sulfex (80WP) 0.2%, safe period 15 days.

3. Leaf Rust

Pathogen : Cerotelium fici

Occurrence : The disease is more prevalent during winter and rainy seasons. It starts progressing 45-50 DAP becoming severe on 70th DAP. The mature leaves are more prone to the disease

Crop loss :  10-15%

Symptoms : Initially, circular pinhead sized brown eruptive lesions appear on the leaves and later leaves become yellow and wither off.

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Leaf rust

Factors responsible for spreading of the disease:

  • The disease is air borne dispersing by uredospores through water droplets and wind current.
  • Temperature of 22-26°C and high relative humidity above 70 % are favourable for the disease development.

Control measures to be adopted: 

  • Follow wider spacing of plantation (90 cm x 90 cm) or paired row planting system  [(90+150) × 60 cm] 
  • Avoid delayed leaf harvest
  • Spraying  0.2% Kavach (Chlorothalonil 75 % WP) on the leaves
  • Safe period: 5 days

4. Sooty mould

Pathogen : A group of fungi

Occurrence: The disease is more prevalent during winter (August-December) season.

Crop loss:  10-15%

Symptoms : Thick black coating develops on the upper surface of the leaves.

Factors responsible for spreading of the disease:

  • The disease occurs due to the presence of white flies in the mulberry field.
  • The fungi develop on the honey like substance produced by the whiteflies.
  • Temperature of 20-24° C and high relative humidity above 70 % are favourable for the disease development.

Control measures to be adopted: 

  • Spray 0.2% Indofil-M45 to check growth of saprophytic fungi
  • Foliar spray of 0.02% monocrotophos on 15th and 30th day after pruning to control white fly infestation.
  • Safe period: 15 days.

II. ROOT DISEASES

1. Root knot

Causal organism: Meloidogyne incognita (Nematode)

Occurrence: The disease is out break through out the year and more common in sandy soils under irrigated conditions.

Crop loss: 20 %

Symptoms:

  • Severely affected mulberry plants show stunted growth with low water moisture in leaves, later yellowing of leaf margins. 
  • Formation of knots / galls on roots is the main indicator of the disease symptom. 
  • Galls are spherical and vary in size; young galls are too small and yellowish-white in colour, old galls are big and pale brown.
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Root knot nematode disease

Factors for spreading the disease

  • Disease spreads primarily through contaminated soil, farm implements and run-off irrigation.
  • Planting of infected saplings along with other susceptible crops increases the disease intensity, some susceptible weeds in and around the mulberry gardens act as the secondary sources of infection
  • Temperature between 27-30 ºC, soil moisture of less than 40 % and pH of 5 to 7 are favorable for the development of the root knot disease.

Control measure:

  • Apply neem oil cake @ 800 kg/acre/yr in 4 split doses during intercultural operation or after pruning the plant or after leaf harvest by making the trenches of 10 –15 cm deep near the root zone of plant and cover with soil and irrigate.

2. Root rot

Causal organism : Rhizoctonia bataticola (= Macrophomina phaseolina)

Associated secondary microbes : Fusarium solani/ F. oxysporum/ Botryodiplodia theobromae

Occurrence: Throughout the year in all types of soils especially when the soil moisture and organic matter in soil are low.

Crop loss: 15 % and above depending on the soil health and climate.

Symptoms: Initially the above ground symptom of the disease appears sudden withering of plants and leaves fall off from the bottom of the branches and progressing upwards.

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Above ground symptoms of root rot (yellowing/withering of leaves)

  • The below ground symptoms include decaying of root cortex or skin,  turn black due to fungal spores/ mycelium below the bark (Fig 13).
  • The severely affected plants loose the hold in the soil and can be easily uprooted.
  • On severity, the entire root system gets decayed and plants die.
  • Affected plants after pruning, either fail to sprout or plant sprouted bears small and pale yellow leaves with rough surface.
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Below ground symptoms of root rot (rotting of the roots)

Factors for spreading the disease:

  • The disease occurs in soils of high temperature (28 – 34ºC), low moisture (below 40 %) and low organic matter.
  • The disease spreads primarily through contaminated soil, farm implements and irrigation. The secondary source of infestation is through diseased saplings, irrigation and cultivation practices.

Control measure: A target specific new formulation “Navinya” (herbal 80% & chemicals 20%) is used for the control of root rot disease of mulberry

Method of application : Prune off the dried shoots above 15-30 cm from ground. Make shallow ring around stump and apply the Navinya solution made by adding 10 g of Navinya in 1 liter of water (i.e. 1 kg Navinya in 100 liter water; sufficient for 100 plants @ 1 liter/plant). Pour the solution over the pruned stump to drench completely. Cover with soil around the stump to prevent exposure to sunlight. Treat the surrounding mulberry plants also to prevent spreading of the disease.

Precautions to be taken:
  • Do not irrigate the treated mulberry plants during the first 4-5 days.
  • Remove the dead mulberry plants and burn and expose the soil to sunlight.
  • Plant the new saplings after dipping their roots in 0.2 % Navinya solution for 30 minutes before planting.
  • Maintain optimum organic content >0.5% in soils by applying compost/ manure.
  • During summer months irrigate the garden to keep the soil moisture around 50-60% to prevent the disease.

III. PESTS

1. Pink Mealy bug

Occurrence & Symptom : Pink mealybug, Maconellicoccus hirsutus (Green) causes deformity symptom in mulberry which is popularly called as Tukra. Leaves become dark green, wrinkled & thickened with shortened inter nodal distance resulting in bunchy top appearance/resetting of leaves. It occurs throughout the year, but severe during summer months. Mulberry leaf yield is reduced by 4,500 kg/ha/yr due to this pest.

Control measures

Mechanical control:

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Clip off the infested portion by secateur, collect in a polythene bag and destroy by burning. This will help in reducing the chances of recurrence of pest. This practice may be followed when the silkworms attain 4th age.

Chemical control: Spray 0.2% DDVP 76% EC (@ 2.63 ml/lit water) 15–20 days after pruning. Safety period: 15 days.

Biological control:

Release predatory lady bird beetles Cryptolaemus montrouzieri @ 250 adult beetles or Scymnus coccivora @ 500 adult beetles in two equal splits at an interval of 6 months.

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Availability of predatory lady bird beetles: Pest Management Lab., CSR&TI, Mysore (ph. No.0821-2903285) cost: Rs 120 per unit.

2. Papaya mealy bug
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Occurrence & Symptom: The papaya mealy bug, Paracoccus marginatus is an exotic pest which infest a variety of crops such as papaya, guava, teak, vegetables, Jatropha, and weed plants like Parthenium, Sida, Abutilon etc. In mulberry its infestation causes malformation of affected portion, stunted growth of leaf, presence of red/black ants, honey dew secretion, growth of sooty mould, and outright killing of the plant. At present occurrence of papaya mealy bug is sporadic.

CLASSICAL BIOLOGICAL CONTROL OF PAPAYA MEALYBUG
  • Release exotic parasitoid, Acerophagus papayae @1 vial per acre (1 vial= about 100 adult parasitoids).
  • Do not remove or destroy alternate host plants such as Parthenium, Sida, Abutilon, Jatropha etc., containing mummified mealybugs.
  • Do not spray any insecticide for its control, which may still worsen the situation.
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Note: Exotic parasitoids are available at National Bureau of Agriculturally Important Insects (NBAII), ICAR, Bangalore [opp: CBI, Ganganagar, Bangalore; phone no. 080-23511982/98]

3. Mulberry Leaf roller
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Occurrence & Symptom : Incidence of Leaf roller, Diaphania pulverulentalis in mulberry starts with the onset of monsoon. It occurs from June to February but reaches peak during September – October months. The larva binds mulberry leaf blades by silken thread, stay inside & feed. Its feacal matter can be seen below the infested portion.

Control measures

Mechanical control: Remove the infested portion (along with the larva) by secateur, collect in a polythene bag and destroy by burning.

Chemical control:
  • Spray 0.076% DDVP (@ 1 ml/lit water) 12 to 15 days after pruning. Safety period: 7 days.
  • Second spray of 0.5% commercial neem pesticide (0.03% Azadirachtin) @5ml/Lit water,10 days after first spray. Safety period: 10 days.

Biological control : Release Trichogramma chilonis  egg parasitoid @ 1 Tricho card/week (for 4 weeks). Do not spray any insecticide after the release of trichogramma parasitoids.

(Note: Tricho cards are available on cost basis at Krishi Vigyan Kendra, Suttur, Nanjangud taluk, Mysore dist. or Parasite Breeding Lab., Dept. of Agriculture, [Near DC Office] Mandya)

4. Bihar Hairy Caterpillar

Occurrence & Symptom : Incidence of Bihar hairy caterpillar, Spilarctia obliqua in mulberry starts with the onset of monsoon. It occurs throughout the year and in certain pockets it appears sporadically. Young larvae are gregariously found feeding on the underside of leaf giving an appearance of mesh and one can make out from distance. Grown up ones are solitary, very active, spread throughout the field and feed voraciously on the foliage.

Control measures

Mechanical/Physical control: Collect the egg masses or gregarious young caterpillars and destroy by dipping in 0.5% soap solution or by burning.

Chemical control:

  • Spray 0.076% DDVP (@ 1 ml/lit water) 12 to 15 days after pruning. Safety period: 7 days.
  • Second spray of 0.5% commercial neem pesticide (0.03% Azadirachtin) @5ml/Lit water,10 days after first spray. Safety period: 10 days.
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Biological control: Release egg parasitoids Trichogramma chilonis   @ 1 Tricho card/week for 4 weeks. Do not spray any insecticide after the release of trichogramma parasitoids.

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5. Thrips
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Occurrence & Symptom : Thrips, Pseudodendrothrips mori, is a major pest in Tamil Nadu and minor pest in Karnataka & Andhra Pradesh. It occurs throughout the year and severe during summer (February – April). Both adults and nymphs lacerate the leaf tissues and suck the oozing sap. Affected leaves show streaks in early stages and yellowish/brown blotches in the advanced stage of attack.

Control measures

Mechanical/Physical control : Use sprinkler irrigation to disturb thrips population & eggs on the underside of mulberry leaves.

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Chemical control: Spray 0.1% Rogor (@ 3 ml/lit water) 15 days after pruning. Safety period: 20 days.

Biological control: Release predatory lady bird beetles (Scymnus coccivora @ 500/acre).

6. White fly
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The name white fly is derived from the whiter appearance of the adults and their tendency to fly when disturbed. Adults have a pair of floury wings which are usually white with a few veins. In the recent years outbreak of Dialeuropora decempuncta has occurred on mulberry in southern state of Kerala and now observed to severely infest mulberry in the irrigated belt of Karnataka covering Mysore and Mandya districts.

Occurrence & Symptom : The spiraling of waxy material is the typical symptom of white fly attack. Prolonged dry spell followed by the hot humid weather favours the white fly flare up. Occur during the months March-June; October-December. Both nymphs and adults pierce and suck the sap from foliage and the damaged leaf become unfit for silkworm rearing.

Control measures

Mechanical/Physical control:

  • Use sprinkler irrigation to disturb white fly population.
  • Fix yellow sticky traps @ 75-80 traps/acre to trap the adults.

Chemical control: Spray 0.076% DDVP (@ 1 ml/lit water) 12 days after pruning (safety period: 10 days) and second spray with 0.05% Rogor 30% EC @ 1.5 ml/lit (safety period: 20 days)

Biological control : Release predatory lady bird beetles Cryptolaemus montrouzieri @ 250 adult beetles or Scymnus coccivora @ 500 adult beetles/acre.

Source:

Central Sericulture Research & Training Institute, Mysore, Karnataka

Package of Practices of Mulberry Sericulture for Eastern and North Eastern Region, Central Sericultural Research & Training Institute, Berhampore, West Bengal

Diseases and pests of muga food plants

Leaf blight

Causal organism: Fungal (Pestalotipsis sp)

SILKS

Symptoms
  • Young plants are affected.
  • Both the surfaces of leaf turn yellow or brown with concentric brown zones on lower surface of leaf.
  • Dull green round patch on cotyledons and spreads to the base.
Management
  • Timely pruning,  Spraying 1% Bavistin 3 times  at 15 days interval
Leaf rust

Causal organism: Fungus

Symptoms

  • Yellow postules on the underside of the leaves with dark colour spots on the upper surface.
Management
  • Timely pruning, general cleaning of the plot.
  • Spraying of 1% Bordeaux mixture can control the disease.
Jassids, thrips, aphids

Nature of damage : Browning and curling of tender leaves due to sucking of saps by the insects.

Peak Season: May-June

Management: Collect and destroy the affected leaves/shoots. Spray 0.3% Rogor on the infested leaves 2 to 3 times at 15 days interval.


Leaf Gall ( Pleuropsylla beesoni

Nature of damage: Globular growths on the surface of the leaves

Peak Season: Winter

Management:

Defoliate and destroy the affected leaves. Severely gall infested plants may be pollarded.


Stem borer (Zeuzera indica)

Nature of damage: Young caterpillar bores the basal trunk, makes tunnels by feeding on the tissues inside through the main stem weakening the plants.

Peak Season: Throughout the year

Management:

 Plug the holes with cotton soaked in 1.5% Nuvan solution followed by mud plaster. Cotton soaked in neem extracts found to be effective.

Source
  • Package of Practices of Muga, Eri and Mulberry Sericulture for North Eastern Region of India, 2005, Central Muga Eri Research & Training Institute, Lahdoigarh, Jorhat, Assam.
  • Regional Office, Central Silk Board, Guwahati