A Survey and Control of Diseases of Silkworm B. Mori in Pakistan and Azad Kashmir

Abstract

Sericulture is a cottage industry in Pakistan and Azad Kashmir. During the last twenty-year, disease of B. mori have caused tremendous economic loss to pool villagers. Keeping in view the national importance of sericulture in the country, Pakistan Science Foundation sanctioned a research project on survey and control of diseases of silkworm in Punjab, N.W.F.P, and Azad Kashmir. The survey of diseases was initiated in February 1975. At first, the rearing period of B. mori was investigated. In Punjab, the rearing period of univoltine races of silkworm starts in the last week of February and continues up to the second week of May. In N.W.F.P. The rearing period of univoltine races of B. mori starts in the first week of march and continues up to the middle of June. In Azad Kashmir, the rearing period of B. mori (univoltine races) starts in the first week of march and continues up to the end of June. There are various ecological zones in each province. There are fluctuations I the rearing period due to variations in temperature and humidity conditions of the areas concerned. The details of Morphology, Biology and Anatomy of B. mori were studied in the laboratory. Biology of B. mori was also studied in the rearing areas. Diseased eggs, larvae, cocoons and moths wore collected from all over the rearing areas. The time table of the appearance of disease was investigated. In Punjab, diseases appeared in various areas (Multan, Pirawala, Chichawatni, Changa manga, Gujranwala, Sialkot, Gujrat, Daffar, Head faqirin, Kahuta, Hasanabdal and Rawalpindi area). The diseases appeared during the first week of march and continues to cause high mortality of larvae up to the beginning of May. In N.W.F.P., disease appeared in various area (Peshawar, Mardan, Haripur, Bannu, Kohat, Parachinar, Miranshah, Swat, Dir, Lower Chitral and upper Chitral). The diseases appeared in epidemic form in the last week of April and outbreak continued up to middle of June. In Azad Kashmir, diseases appeared in various areas (Muzaffarabad, Hajera, Bagh, Kotli, Mirpur, Bhimber, Afzalpur, Khooratta, Panjan, Tattapani, Panjora, Sehansa, Palendri, Tarakhel, Rawalakot, Leepa valley etc.). The diseases appeared in the last week of April and the epidemic continued up to the middle of September. Symptoms of diseases were studied in larvae, pupae and moths. The pathogens were isolated from larvae, pupae cocoons, moths, eggs and rearing areas. Techniques were developed for quick pathological analysis and histopathology. The life cycle and the site of infection of Nosema bombycis was studied. Extracellular stage, intracellular stage, stages in sporulation and the spores in the mid-gut of new host were studied. Nosema Bombycis completed its life cycle in four to seven days after the infection. Histopathological studies of 3rd and 4th instar larvae showed that Nosema Bombycis developed heavily in epithelial cells, adipose tissues silk glands, Malpighian tubules, and hypodermal cells. The hypodermal cells of larvae which were just before spinning, had a large number of Nosema Bombycis. These late instar larvae showed dark pepper like spots on the integument. The pebrinized moths had patches. Discoloration of scales was also visible on the abdominal area of pebrinized moth. The moths, distorted antennae and such moths layed scattered and clumped eggs. The infected larvae either died just before spinning or they span cocoons of very poor quality. Mostly, the cocoons were very thin, abnormal and stained. The fiber of such cocoons was very inferior. The nature and extent of persistence of diseases was studied in various areas. Studies were conducted on the effect of antibiotics, antimicrobial chemicals, vitamins, Unani Medicines and their mixture, on the development of B. mori larvae having Nosema Bombycis infection (transovation). The following antibiotics, chemicals, vitamins and Unani medicines were used: Clioquinol, di-iodoquin, Resochin, Entox, Streptomycin sulphate, Furoxone, Teclozan, Tetracycline, Myambutol, Chiniofon, Nicotinic acid, Cellulose, Ascorbic acid, Sucrose, Arilli acid, Minocin, Paraminobenzoate acid, Kanacin, Salicyl acid, Sulfadiazine, multiple antibiotics, Hareer, Shing Loban, Sulpher, Hena Sandhoor, Gaozoban and Euclyptus. They were used in a low and high concentrations and fed various instars of larvae having Nosema bombycis infect (either transovation or induced in the laboratory conditions. All the above-mentioned antimicrobial agents were fed to larvae on three different patterns, daily, alternate and with three days interval. In general, the larvae treated by antibiotics particularly, Furoxone, Di-iodoquin, Clioquinol and Teclozan were successful in suppressing the disease as the larvae gained weight several times and their life prolonged as compared to the non-treated group. Similarly, Loban, Hareer and shingraf were successful in suppressing the disease in vivo. In case of allopathic medicines, it was observed that antibiotics and chemicals when used in combinations, produced recovery among N. bombycis infected larvae. This was indicated by a gain of weight and development of larvae up to cocoons stage, when the former was treated by the following medicines: Minocin and ascorbic acid; chiniofon and streptomycin; PABA and Ascorbic acid; Kanacin and sucrose; Nicotinic acid. The following Homeopathic medicines were tested for suppressing Nosema bombycis infection in the lab; Arsenicum iodatum, Arsenicum album, Arsenic bromatum, Iodium, Baryta Iodatum, Antimonium iodatum, Antimonium tartaricum, silicea, Mercurius iodatus falavus, Mercurius iodatus rubber, natrum sulphuricum, Calcaren phosphorica. Nosema Bombycis infected larvae showed recovery phenomenon as they gained weight, survived longer and developed up to cocoon stage when they were treated by Natrum sulphuricum and Mercurius iodatus flavus. While studying the site of infection of Nuclear Polyhedrosis virus, histopathology of infected larvae showed that the nuclei of Adipose tissues, tracheal membrane, dermal cells and blood cells developed polyhedral bodies within a week following infection, in general, NPV was a major causal agent of Grasseria. In laboratory, NPV infected larvae were treated by some antimicrobial chemicals (Sodium hypochlorite, Formalin, Folic Acid) and antibiotics (Chiniofon, Kanacin, Rimactane and Virazole). Certain chemicals (as Nicotinic acid, Sodium thiosulphate and Viterra) were used. Among antimicrobial chemicals, Sod. Hypo-chlorite was successful in suppressing NPV infection in the larvae. When treated by nicotinic acid, the larvae were able to spin cocoons. The larvae also showed recovery following treatment by Kanacin, Chinifora, Virazole and a mixture of antibiotics a chemical. In the summer, autumn, and winter rearing, NPV infected larvae were treated by the following homeopathic extracts and homeopathic medicines: AMK extract, PSW extract, MZD extract Influenzinum, sepia, natrum sulphuricum, baryta iodide vaccinium, Mercurius iodatus flavus, Anthraxium, Iodium, Formalin, Staphylococcin, Streptococcin, Pyroginium, Arthritis, Silicea, Mercurius Iodatus ruber, Mercurialis parennis, Mercurius Vivus. Mixture of homeopathic medicines like Kali Suphuricum, natrum sulphuricum and natrum muriaticum, Calearea Phosphorica, and Natrum sulphuricum and kali muriaticum. NPV infected larvae showed recovery and were able to spin cocoons when they were treated by following homeopathic medicines and extracts: Baryta iodide, Vaccinium, Anthraxium, Iodium and Sepin. While conducting the survey of diseases of silkworm in 1975, 1976, 1977, it was found that a number of bacterial pathogens such as Bacillus thuringiensis, staphylococcus, aureus Proteus Vulgari and Aerobacter aerogenesis caused heavy mortality of the larvae in various rearing areas of Pakistan and Azad Kashmir. At first, laboratory studies were initiated to test the sensitivity of antibiotics against bacterial pathogens. The disc of antibiotics was prepared and the zone of inhibition of each bacterial pathogen was observed “in vitro”. Antibiotics were tested in 28 different dilutions ranging from 0.683 to 30000Ugm/ml. Bacillus thuringiensis was sensitive to combiotic, Chloramphenicol and streptomycin sulphate (Conc, 3333.33 and 10,000.0 Ugm/ml), and not sensitive to benzyl penicillin, penicillin V, tetracycline hydrochloride and folic acid (Con.: upto 2500 Ugm/ml). Staphylococcus aureus was sensitive to chloramphenicol and streptomycin sulphate (Con.: above 10,000.0 Ugm/ml), and not sensitive to benzyl penicillin combiotic and tetracycline hydrochloride (Con,: 10,000.00 and 500.0 Ugm/ml, respectively. Proteus vulgaris was resistant to all the antibiotics used (Con.: up to 10,000.00 Ugm/ml). Aerobacter aerogenes was sensitive to chloramphenicol, combiotic and streptomycin sulphate (Con.: 10,000.0 Ugm/ml and above). It was resistant to benzyl penicillin and tetracycline hydrochloride (Con,: 10,000.00 and 500.0 Ugm/ml, respectively. The result of histopathology of B. mori larvae infected by Bacillus Thuringiensis and treated by streptomycin sulphate is discussed in detail. The field studies were initiated from February 1978 and onwards, and were carried out in various ecological zones. The houses of rearers were disinfected by formalin, perchloric acid, lactic acid and resorcinol. The eggs were disinfected by streptomycin and trichloroacetic acid. The rearers were advised to fed the following antimicrobial agents to the larvae: Clioquinol, di-iodoquin, Chloroquin Phosphate, Chloramphenicol, Eurozone, Heteronidazole, Chiniofon combiotic Kanacin, Isoniazid, streptomycin, cicatrin, benzathine penicillin, procain penicillin, erythromycin sulphadiazine, chloromycin, antimony potassium tartrat, formalin, potassium chlorate, septran, sodium chloride, trichroloaecetic acid, citamin B complex, Hareer, Hena and Shingraf. In Daffer (Punjab), the maximum yield of cocoon i.e., 60 seers per ounce of eggs was obtained when diseased larvae were treated by Chiniofon and Antimony potassium tartarate. The larvae recovered when a correct dose of medicine was given for a specific disease.