Frequently Asked Questions (FAQs):

CENTRAL MUGA ERI RESEARCH & TRAINING INSTITUTE 

Muga Host Plant

What are the primary food plants of muga silkworms?

Som (Persea bombycina) & Soalu (Litsaea monopetala )     

What are the secondary food plants of muga silkworms?

Dighloti (Litsea salicifolia ) and  Mejankari ( Litsea cubeba)

What are the tertiary food plants of muga silkworms?

Gondhsaroi (Cinnamomum glanduliferum); Patihanda (Cinnamomum  obtusifolium) etc.

Is there any polyploidy variety of som?

Yes, there are four polyploidy  varieties of som (PB 009, PB 0010, PB 011 & PB 012)

Which one is the most promising polyploidy variety?

Gadadhar (PB012) is the most promising variety.

What are different genotypes of som?

There are 51 genotypes (PB001-PB051) of Som.                                                                                            Ampotia (PB 001 & 002), Nahorpotia (PB 003), Jampotia (PB 004), Belpotia (PB 005), Kothalpotia (PB 006), are common genotypes of som classified based on leaf shape.

Which are the most preferred genotypes?

Nahorpotia (Acc. PB 003) & Kothalpotia  (Acc. PB 006) are the  most preferred  diploid genotypes

What kind of land is suitable for raising of som plantation?

High slope,  well drained and rich in soil humous

What is the suitable soil pH for som plantation?

Slightly acidic soil (pH range 5.2-6.5)

Which is the planting season for som plantation?

Pre monsoon (April- June) and post monsoon (September)

What is the recommended spacing for som plantation?

3m x 3m spacing

What is the age of planting seedling /sapling?

10-12 months old

What is the pit size for plantation of som seedling/ sapling?

Depth x Breath = 45cmx30cm

What is the gestation period of som for seedling plantation?

4 years

What is the gestation period of som for sapling plantation?

2 years

What is the rate of application of FYM in 1-2 year plantation?

0.5cft/pit

What is the rate of application of FYM in matured plantation?

1cft/pit

What is the rate of application of NPK for 1-2 year of som plantation?

 N:P:K @50:25:25 kg /h/y

What is the rate of application of NPK in som plantation?

N:P:K @100:50:50 kg /h/y from 4th  year onwards

What are the seasons of application of manures and fertilizer?

February- March and August-September

What method is used for application of manures and fertilizer?

Ring method

Is pollarding is applicable?

Yes, pollarding is done after 7 years of plantation

What is the height for pollarding?

Above 1.5m from the ground level

In which season pollarding is done?

June- July and October- November

What is the pruning schedule of som for different muga crops for early instars rearing?

·         1st week of March for Aherua Crop (June-July) rearing.

·         1st week of April for Bhodia Crops (August-September) rearing.

·         1st & 2nd Week of July for Kotia Crops (June-July) rearing.

·         1st week of September for Jarua  Crops (June-July) rearing.

·         1st & 2nd Week of October for Chotua Crops (June-July) rearing.

·         1st week of December for Jethua Crops (June-July) rearing. 

What is the pruning schedule of som for different muga crops for late instar rearing?

·         1st week of February for  Aherua Crop (June-July) rearing

·         1st week of March for Bhodia Crops (August-September) rearing

·         1st & 2nd Week of June for Kotia Crops (June-July) rearing.

·         1st week of August for Jarua Crops (June-July) rearing.

·         1st & 2nd Week of September for Chotua Crops (June-July) rearing.

·         1st week of November for Jethua Crops (June-July) rearing.

What should be the population of som plant in a rearing farm?

1111 plants/h

What is the leaf yield of som?

18-20 MT/h

How som is propagated?

Sexual and asexual methods

What are asexual (vegetative) methods for propagation of som?

Air layering, single leaf bud cutting, grafting, chip budding, cleft grafting and veneer grafting.

What are the most common asexual (vegetative) propagation methods?

Air layering method.

In which season seeds of som become mature?

April/May

Which is the potential period of som seed viability?

Up to 10-20 days after harvesting of seeds.  Viability decreases after 20 days till 45 days.

What is the storage temperature of som seed?

10°C

What is the media for raising som nursery?

Sand: Soil: FYM (1:1:1)

Eri Host Plants

Which are the primary food plants of eri silkworm?

Castor (Ricinus communis L)  and Kesseru (Heteropanax fragrans Roxb.)  are the primary food plants of eri silkworm

What are the secondary food plants of eri silkworms?

Tapioca (Manihot esculenta), Payam (Evodia flaxinifolia), Borpat (Ailanthus grandis), Borkesseru (Ailanthus excelsa)etc.

What are the tertiary food plants of eri silkworm?

Gulancha (Plumeria acutifolia), Gamari (Gmelina arborea) etc.

Is there any preferred variety of castor?

NBR-1 is the most preferred variety of castor.

Are there different variants of castor?

Yes, there are numbers of variants in castor based on stem colour, bloom, seed colour, seed shape etc.

What kind of land is suitable for raising of castor plantation?

Flat and sloppy land rich in humus.

What is the recommended spacing for castor plantation?

1x1m spacing.

What is the method for castor plantation?

Through pit digging method.

What is the pit size for castor plantation?

20 x 25 x 25 cm (LxBxD)

What is the dose of application of FYM/pit?

1 kg/pit

What is the dose of application of NPK/h?

N:P:K @90:40:20 kg/h/y

What is the dose of NPK per plant?

Urea 13 g, SSP 25 g and MOP 3 g per plant.

How many times of leaf harvesting is done in castor?

4 times in a year.

What is the leaf yield of castor/h?

12 MT/h

What is the nursery season of kesseru?

February-March is the nursery season of kesseru.

How kesseru is propagated?

Kesseru is propagated through seeds by sexual means.

What is the kesseru seedling age for plantation?

6 months old

What type of soil is required for keseeru plantation?

High, flat and sloppy land.

What is the spacing of kesseru plantation?

2 x 2 m

What is the pit size for plantation of  kesseru seedling?

25 x 25 x 25cm (L x B X D )

What is the gestation period of kesseru?

2-3 years

What is the dose of application of FYM in 1-2 year kesseru plantation?

0.5cft/pit

What is the dose of application of FYM in kesseru plantation?

1cft/pit (mature plants)

What is the dose of application of NPK in kesseru plantation?

N:P:K @125:75:25 from 2nd   year onwards in two split doses.

What are the season of application manure and chemical fertilizer?

February- March and August-September

What is the method of application manure and chemical fertilizer?

Ring method

How kesseru plant is pollarded?

Kesseru is pollarded at 1.75 height at the age of 3 years (3 years interval following step up and step down method)

How many times kesseru leaf can be harvested in a year?

Kesseru leaf can be harvested 3 times in a year.

What is the leaf yield of kesseru/h?

25 MT/h/y

 

Muga Silkworm Rearing

How many dfls can be reared in one hectare of plantation?

2,000 dfls can be reared in a year in two seasons (1000 dfls in each).

How many dfls can be reared in a plant?

1 to 1.5 dfls can be reared depending upon availability of foliage.

What steps should be taken before rearing (pre-brushing care)?

·         Select rearing plot in shady area during summer and sunny area during winter with plants having quality foliage.
Drain out stagnant water from the plot.

·         Clean individual plant by removing dry twigs and leaves, spider nets, ant’s nest etc.

·         Clean plant basal area and surroundings and dust slaked lime and bleaching powder mixture at the rate of 19: 1 ratio.

·         Erect nylon net over food plants to prevent pests and predators.

·         Disinfect rearing appliances viz. bamboo chalani, rearing net etc. with 5% bleaching powder solution before commencement of rearing.

How seed should be collected for rearing?

Seed should be collected from certified seed producers/ govt. agencies.

What precautions should be taken for transportation and preservation of seeds?

·         Seeds should be transported during cooler hours of the day by wrapping with wet and perforated cotton cloth.

·         Seeds should be preserved in dry and cool place in single layer.

·         Care should be taken to protect the seeds from predators.

·         One day prior to hatching, seeds should be covered with black cloth for uniform hatching.

How larvae should be brushed?

a)   Tender leaves should be spread over the newly hatched larvae to prevent crawling here and there and to settle on the leaves.

b)   Newly hatched larvae along with the tender leaves should be transferred to the food plants early in the morning away from the sunlight during summer and towards the sunlight during winter.

c)   Avoid overcrowding at the time of brushing.

What precautions should be taken at the time of rearing?

a)   Keep one bowl of 5% bleaching powder solution and one bowl of fresh water separately for proper sanitation of hands before and after handling of larvae.

b)   Dig a pit of one and half feet deep away from the rearing field for burial of diseased, dead and unequal larvae and dust mixture of slaked lime and bleaching powder mixture of 9:1 ratio.

c)   Use bamboo forceps for picking up dead and diseased larvae.

d)   Avoid frequent handling of larvae. Transfer the larvae by cutting the twigs as far as possible.

e)   Avoid such activities which may attract pests and predators to the rearing site.

f)    Use smoke in the morning and evening during winter season to avoid insect infestation.

Why box type bamboo mountage should be used instead of jali?

·        To prevent escape of mature larvae

·        Uniform spinning of cocoons

·        Less time requirement for harvesting

·        Less space requirement for accommodation of mountages

·        Durable and can be re-used after proper  disinfection

 

Eri Silkworm Rearing

What are the popular races of eri silkworm?

‘Borduar’, ‘Diphu’, ‘Genung’ and ‘Titabar’ eco-races.

How many crops of eri silkworm can be reared?

4-5 crops can be reared in a year depending upon the availability of food plants.

What is the best season for eri silkworm rearing?

Autumn and Spring is the best season for commercial eri silkworm rearing

What facility is required for eri rearing?

·         Well-ventilated and fly proof rearing room with 1.5 m all round verandah. The plinth area of the room should be 10 m x 5 m for 100 dfls rearing. The site should be 10 to 20 m apart from the living house for better sanitation and easy disinfection.  

·      Rearing appliances like hand sprayer, rearing stands, feeding stands,  rearing trays,  chandrakie, ant wells, disinfection mask, leaf preservation chamber, egg boxes, buckets, wash basins,  basin stands, plastic mug, hygrometer (wet and dry bulb),  maximum and minimum thermometer, foam pad, measuring cylinder, bamboo basket, brooms, paraffin paper etc.  

·         Chemicals like formalin, bleaching powder, slaked lime and other cleaning materials (detergent, soaps, etc.)

How eri silkworm rearing room is disinfected?

Through disinfection of rearing house and appliances before and after each rearing with 2 % formalin solution and 5 % bleaching powder solution.

How eri eggs are sterilized?

Eggs are surface sterilized with 2% formalin solution and dried in room temperature.

How eri eggs are incubated?

Eggs are incubated by spreading eggs uniformly inside the egg boxes in thin layers and keeping inside an incubator in which 24 - 26ºC and 80 – 90 % relative humidity are maintained.  

Why incubation is done?

To facilitate good hatching of eggs

What is Pigmentation stage?

The colour of the egg changes to a dark blue before two days of hatching. This is called pigmentation stage.  It indicates the eggs are ready to hatch

How does hatching occur?

Eggs are hatched out after 10th day of oviposition in suitable climatic condition.

What care should be taken to the worms after hatching?

Tender leaves should be provided on the newly hatched young silkworms for feeding.

What care should be followed during rearing?

Hands should be washed with 2 % formalin solution before starting the rearing operation.  

What is bed cleaning? Why it is needed?

Removal of excreta and left over leaf.

It is needed to ensure hygienic and successful rearing. It helps in keeping the rearing bed dry preventing the occurrence of disease

In what interval, bed cleaning should be done?

Daily basis

What is moulting?

Eri silkworms shed their skin (moult) four times during the entire larval period. This is called moulting.

What is the symptom for moulting?

Worms take rest without taking any food and movement. Occasionally head moves side to side.

What care should be taken during moulting worm?

No bed cleaning should be done during the moult and worms should be undisturbed.

Rearing room should be kept well ventilated and the rearing bed comparatively dry.

When 95 % larvae come out of moulting, fresh feeding should be resumed.

What are different methods of rearing?

Tray  rearing, bunch rearing and platform rearing     

What is tray rearing?

In tray rearing method, the worms are reared providing the leaves on the tray. Trays are made up of either bamboo or wood in different shapes and sizes.

What is the effective size of tray?

For young age (I-III instars) silkworm, size of  the wooden trays should be 50 cm x 60 cm x 5 cm and bamboo tray of 70 cm dia.

What is bunch rearing?

In bunch rearing method, about 10-12 leaves (castor) or branches (of kesseru) are tied together to make a bundle and hung vertically on a horizontal bamboo/wire/string support. Worms are allowed to feed on the tied leaves.  The foliage is changed by keeping fresh bunch near the exhausted one and the worms crawl over the new one. Just below the hanging bunches, bamboo mat or tray is kept on the floor so that the worms which fall down are not contaminated with dust on the floor and can be picked-up and put on the bunches.

What is Platform rearing? When it is recommended?

In Platform rearing method, platform is prepared using wood or bamboo. Shelves are arranged in two tiers with an interval of 30 inches or in three tiers with an interval of 27 inches in between the tiers. The rearing seats of the shelves are prepared by using nylon mesh or bamboo mats. It is generally recommended for mass scale rearing (not less than 100 dfls) of late age eri silkworms. 

What is the ideal size of platform?

The ideal size of the platform is 5’ width and 7’ length. Length can be extended with the availability of the space and rearing capacity

What is the symptom of mature worm?

·         Silkworm body becomes soft as silk glands in the body increase the volume.

·         Intestine of the worms become empty and it become restless for cocooning.

·         May be of various colours like cream, yellow, blue with conspicuous markings like single and double dots, semi-zebra, zebra, etc.

·         Worms become smaller, flabby and hollow sound when rub between finger.

Where cocoons are formed cocooning?

Cocoons are formed in chandrakie or dry leaves

What temperature is preferred for spinning?

A temperature of 25ºC is preferred

What is the time required for cocooning?

3 days in summer and 5 days in winter.

If silkworms are disturbed during cocoon formation, what will happen?

If silkworms are disturbed during cocoon formation, silkworms may stop spinning, producing poor quality cocoon.

How eri cocoons are harvested?

 After completion of pupation, eri cocoons are harvested simply by removing them carefully from chandrakae or dry leaves followed by cleaning.

How cocoons are selected?

Double, melted, flimsy and poor cocoons should be discarded

Good cocoons having compactness, proper shape and size, higher shell content and shell ratio should be selected.

What are the criteria for selecting quality seed cocoon?

Quality seed cocoon should have following criteria 

·         During rearing, larvae should be uniform in size.

·         Cocoon should be selected from the maximum date of ripening i.e. ‘bhor pok’.

·         Cocoon should be compact and uniform.

·         Female cocoon weight should be 6.0 gm and above while male cocoon weight should be 4.0 gm and above in case of muga. In case of eri, Female cocoon weight should be 3.0 gm and above while male cocoon weight should be 2.5 gm and above.

What care should be taken during transportation of quality seed cocoon?

·  Transportation should be in the cooler hours of the day.

·  Cocoon should be packed in bamboo basket with shelves to ensure free aeration, and to avoid damage due to overlapping.

How to preserve seed cocoon?

·  Seed cocoon should be preserved in cocoon cage in single layer or in the form of a garland.

·  The place of preservation should be cooler and well ventilated.

·  The temperature and relative humidity of the cocoon preservation room should be 27-29oC and 70-80%.

How to manage a commercial grainage ?

·         For conducting a commercial grainage two separate room should be arranged, one for cocoon preservation (size- 30 ft X 20 ft) and other for egg laying (size-40 ft X 15 ft).

·         The grainage should be attended in the evening-night hours.

·         The emerged male and female moths should be collected and kept in the moth cages for natural pairing.

·         The paired moths should be collected and tied to khorika (egg laying device) for egg laying.

·        The remaining unpaired moths should be collected and paired mechanically and then tied to the khorika in early morning of the next day for egg laying.

·         Pairing should be allowed at least for six hours and decoupled.

·         In case of shortage of male moths, decoupled male moths may be reused for the 2nd time mating allowing 2-3 hours intermittent rest period.

      The female moths are allowed to lay eggs up to three days.

What is a DFL? Why it is necessary for a successful crop ?

·         DFL means disease-free-laying. Seed is certified as DFL when it is examined by adopting scientific method and found free from pathogen (microsporidian, bacteria and fungal).

·         To get a successful crop, the seed must be free from pathogens.

Why there is shortage of DFLs during commercial seasons?

Muga pre-seed crop (Dec-Jan & June-July) and seed-crop (Feb-Mar & Aug-Sept) falls under adverse climatic conditions as well as natural vagaries often resulting in low cocoon production which leads to seed cocoon shortage for seed preparation for commercial crops. Often the seed crop is contaminated by disease especially by pebrine, In such situation the whole crop is destroyed to check further multiplication. To overcome this, the seed crop rearing during summer seasons should be conducted in cooler areas / under shady condition.

The summer crop of eri falls under high temperature (35-38°C) which causes male sterility in 5th. Stage. This leads to false coupling in seed preparation and lay unfertilized eggs. Hence, hatching is poor.

What is the method of disinfection of grainage hall?

One week prior to start of grainage, the grainage hall along with grainage equipments should be thoroughly cleaned and should be disinfected with 5% bleaching powder solution. The grainage hall should be made free from ants, lizards and uzi maggots. The grainage hall should be closed airtight for 2-3 days and then opened.

Is Disease-free-laying (seed) is solely responsible for a successful muga crop?

Quality silkworm seed or (DFL) plays a decisive role in the success of a muga crop and has direct influence on health and growth of the silkworm. Other important factors simultaneously contributing to the success of a muga crop are proper disinfection of rearing field, quality leaf, maintenance of hygiene in rearing field and management of rearing.

Why hatching is low in Aherua (June-July) and Bhodia crop (Aug-Sept) in muga silkworm?

The seed crops for Aherua and Bhodia crops falls under high temperature (35-38° C) which caused male sterility in 5th. Stage. This leads to false coupling in seed preparation and lay unfertilized eggs. Hence, hatching is poor. To avoid this, the rearing should be conducted in shady place/ areas and spinning of larvae should be allowed in cooler condition.

Why a muga moth always lays less egg retaining a considerable number of eggs as unlaid?

Due to wild nature, muga moth generally laid eggs for 6-7 days. But, scientifically, moths are allowed to lay eggs only for three days to avoid un-uniformity of the hatched larvae as well as to check possibilities of occurrence of different diseases from weak late hatched larvae.

Why the eggs are washed?

Washing of eggs after examination is called surface sterilization, which is generally done by 2% formaldehyde solution followed by washing with soap solution and fresh water.  Such surface sterilization helps to check disease contamination.

What is mother moth examination?

Mother silkmoth examination is a technique to detect a pathogen (microsporidia) present in a mother moth.

Which stage is best for mother moth examination?

Moth stage of silkworm is considered as the best stage for mother moth examination as it is the stage for detection and prevention of pebrine.

What are the methods of mother moth examination?

·         Individual moth is taken in mortar and crushed adding 10 ml of 0.8-1.0% (Muga) and 0.6-0.8% (Eri)  K2CO3 solution.

·         Homogenate is transferred into a test tube preferably of plastic to settle for 3-5 min, so that un-macerated tissue and debris get separated and float above

·        Then the bottom liquid is carefully filtered, through 2-3 thin layers of absorbent cotton and the filtrate should be        centrifuged for 5 min. at 3000 rpm.

·        Then supernatant solution is decanted off and the sediment is dispersed in a few drops of 0.8 % (Muga) and 0.6% (Eri) K2CO3 or 2% potassium hydroxide (KOH) solution, over a cyclomixer or by using a glass rod.

·         Two smears from each sample and five fields per

·        Smear at 600x magnification are examined under a microscope. Examination is done by 2 persons for cross checking

·         The presence of pathogen and the intensity of infection is recorded, if any, based on intensity of spores per field.

 

Pest and Diseases of Muga Host Plants

What are the main factors responsible for qualitative and quantitative characters of muga and eri food plants?

Qualitative and quantitative value of leaf varies greatly owing the numbers of factors, among which diseases and pests play an important role.  

What is disease?

Disease is a condition in which the functions of the organisms are improperly discharged and in other words it threatened the life.

What are the affect of host plant diseases on muga industry?

Diseases make the leaf unpalatable for the silkworms and cause 6 -42% reductions in total leaf yield and ultimately affect on cocoon yield production.

What are the major diseases of muga food plant som ?

The major foliar diseases of muga food plant , som are Leaf spot, Leaf blight, Grey blight  and Red rust

What is the causal organism of leaf spot disease of som  and when it occurres ?

The fungus Phyllosticta perseae is the causative agent of leaf spot disease. The disease appears throughout the year but maximum is during  June-August 

What is the loss caused by leaf spot disease in som plant?

The estimated leaf yield loss is 3214 kg /ha/year ie.16.07% of the total leaf yield.

What are the symptoms of leaf spot disease of som?

Circular or irregular brown spots surrounded by yellow margin. As the disease progresses, the minute spots spread irregularly, become brown in colour, get collapsed and form larger patches causing the drying up of the entire lamina and results in  premature leaf fall.

What are the control measures of leaf spot disease?

Applications of 0.1% Indofil M-45 twice at 15 days interval before the peak season of incidence insignificantly control the disease.

What is the causal organism of anthracnose disease of som and when it occurres?

The Causal organism is Colletotrichum gloeosporioides and July is the peak season .for occurrence of anthracnose disease.

What is the loss cause by anthracnose disease in som plant?

The estimated leaf yield loss due to the disease is 2932 kg/ha/year.

What are the symptoms of anthracnose disease?

The symptom appears in the form of brown colour, round to oval spots irregularly spread to the entire leaf.  The infected areas dry up and become brown to black in colour. The top of the branch or the entire brunch may wither away.

What are the control measures for anthracnose disease of som?

Plucking and burning of infected leaves at the initial stage can minimize the pathogen. Indofil M-45 can be used as a general prophylactic measures to control it.

What is the causal organism of grey blight disease of som and when it occurs?

The fungus Pestalotiopsis desiminata is the causal organism and May to August is the peak season for occurrence of grey blight disease.

What is the loss caused by grey blight disease in som?

The disease causes loss of leaf yield up to 3705 kg/ha/year.

What are the symptoms of grey blight disease?

The “ash” or grey colour spots grow irregularly with increasing of the infection.  As the disease development progresses, the spots get collapsed, malformed and ultimately the entire leaf dries up.

What are the control measures for leaf blight disease?

Foliar spray of 0.1% Bavistin twice in 15 days interval can check the disease.

What is the causal organism of red rust disease of som and when it occurs?

Cephaleuros parasiticus  is the causal organism of the disease. 

What is the loss caused by red rust disease in som?

The estimated leaf yield loss due to red rust disease is 3022 kg /ha/year.

What are the symptoms of red rust disease of som?

Yellow green, orange or gray colour hairy pustules appear on the upper surface of the leaves. The pustules are circular or irregular in shape and surrounded by chlorotic halos. The affected branches become stunted and bear fewer chlorotic leaves.

What are the control measures for red rust disease of som?

Pruning and plucking of infected plant parts and leaves help in reducing the disease spread. Spraying of 1 % Bordeoux mixture is general protective measure.

What are the major diseases of soalu?

The major foliar diseases of soalu are brown blight, Grey blight and Red rust.

What is the causal organism of brown blight disease of soalu and when it occurres?

The causal organism is Colletotrichum gloeosporioides and Sept-Oct. is the peak season for brown blight disease.

What is the loss caused by brown blight disease in soalu ?

The estimated leaf yield loss due to the disease is 3142 kg/h/y.

What are the symptoms of brown blight disease of soalu plant?

The symptom appears roundish to irregular brown spots on leaves in the form of ‘ash’ colour, round to oval spots irregularly spread to the entire leaf. These spots usually appear nearer to the leaf edges. The infected areas dries up and become brown to black in colour. The top of the branch or the entire brunch may wither away

What are the control measures used for brown blight disease of soalu?

Plucking and burning of infected leaves at the initial stage can minimize the pathogen. Spraying of copper oxichloride (Fytolan or Blitox - 50) @ 3gm /L of water at 15 days interval can check the disease.

What is the causal organism of grey blight disease and when it occurres?

Pestalotiopsis spp. is the causal organism of grey blight disease. The peak season for grey blight in soalu is  Feb.-Mar. and Oct-Dec.

What is the loss caused by grey blight disease of soalu plant?

The grey blight disease causes 3801 kg of leaf yield loss per ha/year.

What are the symptoms of grey blight disease of soalu?  

The symptoms appear as round to irregular brown spots on young and mature leaves in the form of ‘ash’ colour, round to oval spots irregularly spread to the entire leaf. As the disease progresses, the spots, turning to grayish colour. These spots usually appear nearer to the leaf edges. The infected area dries up and become brown to black in colour.

What are the control measures of grey blight disease of soalu?

Plucking and burning of infected leaves at the initial stage can minimize the pathogen. Spraying of copper oxichloride (Fytolan or Blitox - 50)  @ 3gm / L of water can be used as a prophylactive measures to control the  disease.

 

Pest and Diseases or Eri Host Plants

What are the major diseases of eri food plants?

Major diseases of eri food plants  are Seedling blight, Alternaria blight and Cercospora leaf spot

What is the causal organism of seedling blight disease of castor and when the disease occurs?

The fungus Phytophthora  parasiticus caused  seedling blight disease in castor. It appears during rainy season, i.e., about the end of June and continues up to September.

What are the symptoms of seedling blight of castor plant?

The first symptom develops as roundish patches of dull green colour on the surface of the leaves. The spots turn yellow or brown with concentric brown zone on the lower surface of the older leaves and also on the stems of the affected plants. The most sever damage occurs with the infection of growing point of leaves with rotting.

What is the control measures used for seedling blight disease of castor?

Spraying of Fytolan or Blitox-50 @ 3gm/L at 15 days interval is recommended for controlling the seedling blight disease. After seven days of spraying the leaves can be utilized for feeding of eri silkworm.

What is the causal organism of Alternaria blight disease of castor and when it appears?

A fungus Alterneria ricini caused the Alternaria blight disease of castor. It occurs through out the rainy season and becomes more extensive during April – July.

What are the symptoms of Alterneria blight of castor?

All the above ground parts of the plants including inflorescence and capsule are affected by the disease. The disease appears in the form of leaf spot. The spots are irregular with gray to brown colour margin in all parts above the ground. The affected capsule  are half matured  under sized  and wrinkled seeds

What are the control measures for Alterneria blight disease of castor?

Spraying of Fytolan or Blitox-50 @ 3gm/ lts.  at 15 days interval is recommended for controlling the seedling blight disease . After seven days of spraying the leaves can be utilized for feeding of eri silkworm.

What is the causal organism of Cercospora leaf spot disease of castor when it occurres?

The fungus Cercospora ricinella is the causal agent of the disease. May to August is the peak season for occurrence of the disease.

What are the symptoms of Cercospora leaf spot of castor?

Diseases first appear as minute water- soaked lesions. It is enlarged and turns brown. Gradually Become irregular in shape with deep colour margin. Several of them may coalescence to form large patches of the leaf blade but checked by the vein.

What are the control measures for Cercospora leaf spot disease of castor?

Spraying of  Dithane Z-78 or Ziram @ 2gm /L is recommended for controlling the Cercospora leaf spot disease of castor

 

Pest and Diseases of Muga and Eri Silkworm

What are the main constrains in muga culture?

Diseases and pests are the main constrains in muga culture.

What are the main diseases of silkworms?

Pebrine, Grasserie, Flacherie , Muscardine  and infectious flacherie are the main diseases.

What is the symptom of pebrine infection?

Irregular growth, moulting and occurrence of black spots on the body surface of infected larva, especially on lateral sides are the main symptoms.

What is the symptom of grasserie infection?

Less feeding, swallowing body, ultimately loss griping, turbid white fluid may occur from the body from the infected larvae

What is the symptoms of flacherie infection?

Less feeding, gradually pale body colour, vomit gut juices and excretes semi-solid faces.

What is the symptom of muscardine infection?

Colour changed to pale, chess the movement, died and whole body covered by white powdery or woody substances i.e. fungus.

What is the symptom of infectious flacherie?

The anal portions of the larvae become swollen and ruptured.

What are the main sources of diseases?

Diseased/ dead silk worm, their fecal matter, contaminated leaves, and rearing appliances are the main sources of diseases.

How to control pebrine disease in muga silkworm?

·        Use of certified & properly  surface sterilized disease  free layings

·       Disinfection of rearing & grainage appliances with 5% bleaching powder solution before and after rearing and grainage operation.

·         Individual mother moth examination.

·        Maintenance of hygenic conditions in rearing and grainage sites. Disinfection of rearing field and grainage hall    with  9 :1 bleaching powder and slaked lime mixture.

How to control grasserie and flacherie diseases ?

·         Proper selection of rearing site as the infections takes place due to fluctuation of temperature and humidity.

·         Identification, peak out and destroy of the early stage infected larvae scientifically.

·         Feeding of quality and stage specific leaves.

·         Dusting of lime in the rearing site to reduce the humidity during monsoon season.

·         Burring of all dead worms and liters in scientific way.

How to control muscardine?

·         Proper disinfection of rearing field.

·         Feeding of quality and stage specific leaves

·         Spraying of .01% ‘LAHDOI’ to the leaves before seven days of brushing.

How to control infectious flacherie?

·         Proper selection of rearing site and feeding of healthy leaves

 

 

 

 

 

 

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