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INTEGRETED MANAGEMENT OF PEST IN SILKWORMS. :- ALEMKUMZUK, Asstt. Sericulture Officer

             The major pest of silkworm is Uzi fly, scientifically known as Exorista sorbillans (Wiedemann) commonly known as Bengal silkworm fly. As Uzi fly has got many alternate hosts in nature, therefore, the Uzi fly can only be managed but not eradicated. The following measures can be practiced as preventive and control measures:-

I. Exclusion Method:-

1. Fixing of fly-proof wire-mesh or nylon nets on ventilators, windows and doors to prevent the entry of Uzi fly into the rearing house.

2. Construction of an ante-chamber at the entrance of the rearing house.

3. Covering the rearing stand, tray separately by fly-proof to exclude the gravid flies from silkworms. This is necessary as in many farmers house there is no separate room for rearing.

4. Keeping of kerosenised water on a pot, tray etc. outside the windows, doors, ventilators so that the female flies is attracted and trapped inside.

II. Physical Method:-

1. Placing of sticky board (yellow colour) near the lamp/light bulb where the flies come there and trapped.

2. Sealing of cracks and crevices in the floor to prevent maggots from getting shelter under the floor for pupation followed by emergence of adult flies inside the rearing room.

3. Dusting of lavigated china clay on the body of the spinning silkworms on the mountage @ 3-4 grams/100 worms and pre sq. ft. of the mountage prevents sticking of Uzi flies eggs laid on the body of the silkworms.

III. Mechanical Method:-

1. Regular collection of maggot infested silkworm larvae, maggots and Uzi puparia from rearing trays and mountages as well as in the cocoon markets and reeling establishments and destroying them immediately by putting them into hot water, formalin water, kerosene, BHC or Chloropicrin mixed water.

2. killing of adult flies at once if found inside the rearing house.

3. Drying of commercial cocoons should be made immediately after harvest on the 5^th day to kill the maggots inside the cocoons.

4. Transport of seed cocoons having Uzi infestation must be stopped immediately to such area where there is no incidence of Uzi infestation.

5. Commercial and Seed zones should be well defined and at quite apart from each other.

6. Do not throw the litter of silkworms indiscriminately.

IV. Chemical Method:-

1. Washing the leaves with 1-3% bleaching powder solution and feed during IV and V instars prevent laying of Uzi eggs on the body of silkworm larvae.

2. 1% Benzoic acid is used for ovicidal. Dipping the egg sheet on the solution kill the body of silkworms.

3. Spraying of 2% bleaching powder solution on the body of silkworm.

V. Genetically Control Method:-

 1. The Chemosterilants such as Thiatepa, Tepa, Apholate can be use to make the flies sterile. 

VI. Biological Method:-

1. So far 18 species of hyper-parasitoids have been collected by Central Sericultural Research & Training Institute.

            Name                                      Nature

i) Nesolynx thymus                               Ecto-pupal parasitoid.

ii) Trichopria sp.                                   Endo- larval- pupal parasitoid.

iii) Exoristobia philippinensis                  Endo- larval- pupal parasitoid.

iv) Dirhinus himalayanus                        Ecto-pupal parasitoid.

v) NST-3 (Bacillus type Bacteria)         Entomopathogen act on pupae/Maggots.

2. House sparrows are known to predate upon the crawling Uzi maggots considerably in the cocoon markets. Hence, attempt may have to be made to encourage the house sparrows in the cocoon yard by providing structure for their nesting.

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