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ThesisItem Open Access STUDY ON EFFECT OF METHIONINE AND TRYPTOPHAN ON THE LARVAL GROWTH, COCOON CHARACTERS AND REPRODUCTIVE PARAMETERS OF ERI SILKWORM, Samia ricini Donovan(2021) Hazarika, Abhyarthana; Saikia, MonimalaA study on effect of methionine and tryptophan on the larval growth, cocoon characters and reproductive parameters of eri silkworm, Samia ricini Donovan was carried out during the month of December-February, 2020-2021 in the Department of Sericulture, Assam Agricultural University, Jorhat. The study revealed that fortification of castor leaves with methionine and tryptophan significantly improved the larval growth, cocoon characters as well as reproductive parameters of eri silkworm, Samia ricini Donovan. Methionine and tryptophan supplementation especially at 500 ppm concentration found to have more pronounced effect as compared to the remaining concentrations over the control. Fortification of castor leaves with tryptophan at the rate of 500 ppm concentration resulted in maximum increment in respect of larval and cocoon parameters viz., larval weight (both full grown and matured), silk gland weight, Silk Gland Tissue Somatic Index (SGTSI), cocoon yield (g/100 nos. of larvae), cocoon weight, pupal weight, shell weight and shell ratio. Reproductive parameters including total moth emergence, male and female adult longevity, fecundity and hatching percentage also showed a notable influence in larvae fed on 500 ppm tryptophan fortified castor leaves. In case of developmental periods viz., larval (fourth and fifth instar) as well as pupal periods, a significant decrease was observed in amino acid treated batches over control and was more prominent at 500 ppm tryptophan. However, 500 ppm methionine followed by 500 ppm tryptophan reduced the incubation period. The combination treatments of methionine and tryptophan did not express much improvement in respect of these parameters when compared to the individual treatments of methionine and tryptophan. It was observed that fortification of castor leaves with methionine and tryptophan did not have any significant effect on third instar larval duration, Effective Rate of Rearing (ERR), individual male and female moth emergence as well as coupling percentage of eri silkworm. Thus, from the present investigation it can be inferred that fortification of castor leaves with methionine and tryptophan is effective for improvement of larval growth, cocoon characters and reproductive parameters of eri silkworm. Though all the concentrations had positive impact on all the parameters but tryptophan and methionine at a concentration of 500 ppm was more efficient and exert promontory effect than other doses for improving larval growth, cocoon characters and reproductive parameters.ThesisItem Open Access Studies on the production, processing and marketing of sericulture in Dima Hasao District of Assam(2021) Nunisa, Rastra; Hazarika, ChandanSericulture has been practiced in Assam for a long period of time, and the State is proud of traditionally producing Eri, Muga and Mulberry silks. Dima Hasao is one of the important districts of Assam where all four types of silk are available viz. Eri, Muga, Mulberry and Oak Tasar, the prime position occupied by ericulture. The other three silks has lost its competitiveness in recent times but has a scope because of its varying climatic conditions amongst the seri-zone of the district. The study was conducted to analyze “Production, Processing and Marketing of Sericulture in Dima Hasao”, having five development blocks and selecting randomly two villages each from the blocks. A total of 100 respondents were selected randomly for the study. Primary and secondary data collected were edited, scored, systematically tabulated and analyzed by using various statistical tools and techniques such as percentages, compound growth rates, marketing cost and margin analysis, price spread and marketing efficiency, Garrett ranking etc. The study reveals that Dima Hasao is ericulture dominated with an average of 94.03 % families engaged contributing an average production of 3.7 % cocoon and 3.8 % raw silk respectively to the total production of the State. Though negative(–ve) growth rate (-23.72) was observed in Muga, there was significant increase in Eri(15.80) and Mulberry(15.03). Similar trend was also observed in raw silk production in the district. Traditional method of processing of sericulture in the district was still followed by the respondents using Takli and spinning charkhas for yarn production. The main fabric made by eri yarn was a special type of shawl called Rhithap, suitable in winter. Two marketing channels were identified for cocoon marketing and one channel for pupae marketing. Majority (92.37 %) of cocoons were observed to be transacted through channel- I (Rearer - Broker – Consumer). Cocoon price keeps fluctuating, sold for Rs. 600-700 per kg and Rs.500 per kg for pupae. Marketing efficiency was found to be higher in the channel-II in case of cocoon marketing. Shortage of feeds, lack of healthy seeds, lack of information etc were some main constraints encountered during cocoon production. Unavailability of equipments, financial problems, unavailability of proper market structure etc were also identified to be main problems in processing sector. Price fluctuation, middlemen interference, marketing problem etc were also associated in sericulture market channels.ThesisItem Open Access STUDIES ON EPIDEMIOLOGY AND MANAGEMENT OF CERCOSPORA LEAF SPOT OF CASTOR (Ricinus communis L.) IN AGRO-CLIMATIC CONDITION OF ASSAM(2021-11) Narzary, Prety Rekha; Sarmah, D. K.Castor (Ricinus communis L.) is the primary host plant of the eri silkworm Samia ricini Donovan, a domesticated polyphagous multivoltine lepidopteran insect which is responsible for producing the eri silk. The healthy and robust growth of the eri silkworms primarily depends upon the quality and quantity of castor leaves, which ultimately reflects in the qualitative and quantitative parameters of the cocoons produced. Cercospora leaf spot of castor, caused by Cercospora ricinella Sacc. & Berl. is one of the major foliar diseases encountered in the cultivation of castor, causing substantial injury to leaves intended as feed for eri silkworms. Study on occurrence and epidemiology was done during three seasons i.e. pre-monsoon (Mar-May), monsoon (Jun- Aug) and post-monsoon (Sept-Nov) by correlating weather parameters such as, temperature, rainfall, number of rainy days, relative humidity and bright sunshine hours with disease incidence. It was inferred that, disease incidence was prevalent at high levels during the pre-monsoon season (Mar-May) followed by monsoon as compared to post-monsoon season. Disease incidence is positively correlated to maximum temperature (significant), minimum temperature, RH (at P.M.), rainfall and number of rainy days (non-significant) and negatively correlated to RH (at A.M.) and BSSH (nonsignificant). A total of 8 treatments were taken for the experiment of management of the disease in pot condition. The treatments included a phytoextract of Tulsi (Ocimum sanctum) @ 5%, a bio agent (Trichoderma viride) @ 5% and a chemical fungicide (Copper oxychloride) @ 0.2 % and their combinations, applied as foliar spray at 15 days interval. None of the eco-friendly treatments were found superior than chemical fungicide inclusive treatment, Tulsi extract + T. viride + Copper oxychloride, where lowest disease incidence was recorded (7.13%). Among eco-friendly treatments, Tulsi extract + T. viride (12.48 %) was found to be the best. Treatments containing T. viride promoted the growth of plants in terms of leaf area, shoot length, root length, dry and fresh weight of root, thus showing dual roles as bio control agent and plant growth promoter. Biochemical analysis revealed the highest total chlorophyll and flavonoid content in plants treated with Tulsi extract + T. viride + Copper oxychloride whereas, MDA (Malondialdehyde content) in leaf tissues was found to be highest in control and lowest in pots treated with Tulsi extract + T. viride + Copper oxychloride. Another investigation was conducted to find out the effect of treated castor leaves on eri silkworm growth. Silkworms fed with castor leaves treated with T.viride + Tulsi extract showed the best results followed by worms fed with leaves treated with Tulsi extract + T. viride + COC.ThesisItem Open Access MUGA CULTURE IN DHAKUAKHANA: AN ALTERNATIVE FARM-BASED SERICULTURAL ACTIVITY FOR SUSTAINABLE LIVELIHOOD(AAU, Jorhat, 2021) Chamuah, Priyanka; Borah, DebajitThe present study was carried out at Dhakuakhana sub-division of Lakhimpur district, Assam with a sample of 160 respondents by following simple random sampling technique to attain the objectives of the study. Appropriate statistical tools viz., frequency, percentage, mean, standard deviation, weightage mean score, correlation, chi square and multiple regression analysis were employed to analyze the data. The findings revealed that majority (48.75 %) of the respondents were in the age group of 36-56 years with primary school level of education (30.00 %) and were belonged to small sized family consisting of 2-4 members (53.75 %) who considered agriculture as their primary source of income (53.75 %). Most of them (70.00 %) had an average annual income between Rs. 1,00,000 to Rs. 2,77,000; most of the respondents (75.00 %) had 3-5 working members in their household and were small farmers with land holding from 1-2 ha (46.25 %). Moreover, majority (50.62 %) of the respondents were having medium level of farming experience between 10- 20 years, medium level of extension contacts and knowledge level on recommended practices of muga (75.62 %) cultivation. Majority of the respondents (75.00 %) did not have membership in farmers’ organization and utilization of communication channel for collecting information was also low for most (40.78 %) of the respondents. Majority of the respondents (58.75 %) had medium level of training exposure and most of them put in their own finance for investment in cultivating muga (55.63 %). Besides these, majority of the respondents (60.00 %) sell their produce through village traders. Most of the muga rearers (58.75 %) exhibited a medium level of extent of adoption of recommended scientific practices of muga. Through multiple regression analysis it was found that age, education, average annual family income, size of operational land holding, farming experience, extension contact and training exposure were the significant factors that influenced the extent of likelihood of adoption of scientific muga rearing practices. The findings suggested that the government should take proper initiatives to help the muga rearers and proper financial, technical, and other supports should be provided to the rearers by the extension agencies, institutions etc. Periodical need-based training should be provided and timely meetings should be made between the rearers and experts to get proper information and solutions. It is imperative to conclude from the study that muga industry is strong enough to establish a distinctive identity in the study area. Muga culture involves simple scientific technology which is easy to understand and adopt. The rearers need to be encouraged towards the adoption of scientific recommended practices of muga to achieve more production and income generation. Thus, the rearers of Dhakuakhana should be made realized about the economic importance of muga and encourage them to consider it as an alternate farm-based plan for their sustainable livelihood.ThesisItem Open Access A STUDY ON THE EXTENT OF ADOPTION OF SCIENTIFIC MUGA CULTURE TECHNOLOGY BY THE REARERS OF SONITPUR DISTRICT OF ASSAM(AAU, Jorhat, 2021) Saikia, Dababrata; Saikia, MonimalaThe present study was conducted in Sonitpur district of Assam during the year 2020-2021. To attain the objective of the study a multistage sampling design was followed for selection of the respondents and a total of 120 respondents were selected. Appropriate statistical tools viz., frequency, percentage, mean, standard deviation, correlation and chi-square test were applied to analyse the data. The study revealed that majority of the respondents (42.50%) belonged to the middle age group. Most of the respondents (47.50%) belonged to the category OBC (Other Backward Class) and had their (35.00%) education up to middle school. Among the respondents, medium size (50.00%) family was found to be dominant and farming was their primary occupation with medium level of income ranging from Rs. 52,000-1,71,000. Regarding size of operational land holding, majority (40.83%) of the muga farmers owned operational land holding of 1-2 ha. Majority of the respondents (48.33%) had farming experience between 10-20 years. It was also observed that most of the respondents had medium level of extension contact (73.33%), medium risk bearing ability (65.83%), medium decision making ability (60.83%) and medium level of marketing orientation (69.17%). As regards to training exposure, only 27.50 per cent of the respondents had received any training. The study further revealed that 65.83 per cent muga farmers had medium level of extent of adoption. Operational land holding, primary occupation of the family, annual family income, farming experience, risk bearing ability, decision making ability, marketing orientation and training exposure were found to be positively and significantly associated with the extent of adoption. Major problems faced by the muga rearers are lack of self-awareness or interest on adoption of technology, lack of glamour, lack of own land, adverse climatic condition, non-availability of storage facilities for cocoons, lack of adequate knowledge regarding cultivation practices of host plants and rearing practices of muga, non-availability of regulated cocoon market, non-availability of own vehicle and delay in getting loan. Adoption of scientific technologies among the farmers has significant impact on growth and development of muga silk industry as well as economic benefit of the farmer. Effective extension intervention may aid the process of intensification for full scale commercialization of muga silk production by facilitating adoption of scientific package of practices. Suitable and need based training should be organised by the concerned authority for improving knowledge and skills regarding scientific muga rearing and cultivation practices in the study area.ThesisItem Open Access IMPACT OF ENVIRONMENTAL FACTORS ON POPULATION DYNAMICS OF GALL INSECTS INFESTING SOM (Persea bombycina King) AND SOALU (Litsea monopetala Roxb.) PLANT(AAU, Jorhat, 2018) Sahu, Bhupen Kumar; Dutta, L. C.The present study on population dynamics of gall insects infesting Som (Persea bombycina King.) and Soalu (Litsea monopetala Roxb.) plant in relation to the weather factors were carried out in the experimental field of Department of Sericulture, Assam Agricultural University, Jorhat and CMER&TI, Lahdoigarh during 2017-18. Results indicate that the gall insects are host and organ specific and they produce galls on only one species. The gall insect infestation starts with laying of tiny eggs on the upper surface of the leaves in both Som and Soalu plants. On hatching of eggs, the first instar nymphs of Pauropsylla beesoni and maggots of Asphondylia spp. initiate the process of gall formation. The initial gall formation stage is a minute colour change in the infested area which gradually developed into a gall structure. The fully developed gall structures observed on the leaves were light greenish in colour initially and later on changed to purplish red in Som plant and light greenish to dark greenish in Soalu plant. Finally, the adults emerged out from the galls by making tiny holes at the terminal end of the galls. Gall insects appeared throughout the year; however the incidence, population density, extent of damage and intensity of attack of the pest varied during different months of the year and reached a peak in the month of July. Correlation and regression studies were carried out between the incidence, population density, extent of damage and intensity of attack of gall insects with the weather parameters viz., temperature (maximum and minimum), relative humidity (maximum and minimum), total rainfall, number of rainy days and bright sunshine hours. Significant correlation was found with temperature (maximum and minimum), relative humidity (minimum) and total rainfall with gall infestation. Relative humidity (maximum) and bright sunshine hours showed negative relationship with population build-up whereas other environmental parameters showed positive relationship with gall infestation. Thus, it may be concluded that the gall insect, Asphondylia spp. on Som and Pauropsylla beesoni Laing on Soalu plant appeared throughout the year and were largely regulated by meteorological factors viz., temperature, relative humidity and rainfall in different months. Therefore, proper eco-friendly management practices, preferably conservation and inundative release of bio-control agents against the gall insect would be necessary to avoid the probable hazards created by inorganic pesticides. Therefore a detailed study on management of the gall insect population with different bio-control agents is the need of the hour.ThesisItem Open Access Effect of mating duration on reproductive parameters and its impact on larval growth and quality of cocoons of eri silkworm, Samia ricini Donovan(AAU, Jorhat, 2018) Teronpi, Leedarin; Saikia, MonimalaThe current investigation on effect of mating duration on reproductive parameters and its impact on larval growth and quality of cocoons of eri silkworm, Samia ricinia Donovan, was carried out in the laboratory of Department of Sericulture, Assam Agricultural University, Jorhat in autumn and spring season during the year 2017-2018. The findings revealed that mating duration had significant effect on fecundity/ female/ day, total fecundity, weight of eggs, total weight of eggs and average hatchability percentage and non-significant effect on total oviposition duration and incubation period of eri silk moth. In almost all mating durations and seasons the egg laying percentage was maximum in the first day which gradually decreased with succeeding number of ovipositing days. Irrespective of season, five hours of mating duration was found to be better in total fecundity, weight of eggs and total weight of eggs which was at par with four hours mating duration. Four hours of mating duration was found to be better in both fecundity/ female/ day and average hatchability percentage regardless of season. Season also had significant effect on total oviposition duration, fecundity/ female/ day, total fecundity, weight of eggs, incubation period and average hatchability percentage. Total oviposition duration and incubation period of eri silk moth was recorded longer in spring season than autumn season. Fecundity/ female/ day, total fecundity and weight of eggs of eri silk moth were recorded better in autumn season. But, average hatchability percentage was better in spring season. Mating duration had no significant effect on larval growth and cocoon parameters. However, season had significant effect on larval duration, weight of full grown larvae, weight of matured larvae, ERR (%), cocoon weight, shell weight and pupal weight. Larval duration of eri silk moth was recorded shorter in autumn than spring season. Weight of full grown larvae, weight of matured larvae, ERR (%), cocoon weight, shell weight and pupal weight of eri silk moth was recorded better in autumn season than spring season. But, shell ratio (%) was better in spring season. Interaction effect between mating duration and season was significant in total oviposition duration, weight of eggs/ female/ day, larval duration, cocoon weight and pupal weight. Thus, from the present investigation it may be inferred that a period of three to five hours coupling duration is optimum for maximum egg laying of eri silk moth. In addition to this, though the fecundity and weight of eggs was registered better in autumn, with shorter incubation period and hatching percentage of eggs of the silk moth performed better in spring season. Larval and cocoon parameters showed better performance in the autumn season than spring season.ThesisItem Open Access TRADITIONAL KNOWLEDGE AND CULTURAL PRACTICES IN MUGA SILK PRODUCTION IN NORTH LAKHIMPUR DISTRICT OF ASSAM(AAU, Jorhat, 2018) PEGU, KARPUNPULI; Dutta, L. C.Sericulture, or silk farming, is the rearing of silkworms for the production of raw silk. It is an agro based labour intensive industry providing gainful employment mostly for rural people. Sericulture includes cultivation of 4 varieties of silkworm mainly mulberry, eri, muga and tasar. The golden silk muga is the gift of nature to the state and it is the pride of Assam. Muga rearers of Assam have been practicing this culture with traditional indigenous practices. Traditional knowledge is generated by the local people with their own experience and experimentation to meet their needs and these are sustainable in nature. Considering this, the present study was conducted to identify and document various Indigenous Traditional Knowledge in muga silk production, to study the extent of use of Indigenous Traditional Knowledge in relation to the socio-economic profile of the respondents and to find out the problems perceived by the muga rearers in North Lakhimpur district of Assam. A random sampling design was followed to obtain a sample size of 120 respondents. Ten independent and one dependent variable was selected for the study. The statistical techniques used for the analysis of data were frequency, percentage, mean, standard deviation, spearman’s correlation co-efficient and weighted mean score (WMS). The findings revealed that 50 per cent of the muga rearers belonged to age group of 36-50 yrs and 55.80 per cent had their education up to middle school. Moreover, 41.70 per cent of the rearers belonged to Other Backward Class, 52.50 per cent of the respondent had medium family size, 40 per cent of the members had income ranging from Rs.75001-100000 and 40 per cent of the members have small size land holding, whereas 68.40 per cent, 70.83 per cent and 58.40 per cent of the respondents had medium level of extension contact, risk bearing ability and decision making ability and on the other hand 40.80 per cent of the respondents have received training exposure. The study further revealed that 64.17 per cent of the respondent had medium level of extent of use of ITK in the district. It was affirmed from the findings that age, family size and size of operational land holding were found to be positive and significant whereas education, extension contact and training exposure were negative and significantly correlated with the extent of use of ITK. On the other hand caste, annual family income, risk bearing ability and decision making ability were found to be positive and non significant with the extent of use of ITK. Major problems reported by muga rearers included lack of capital, glamour, people are not interested to lease their land for muga rearing, impact of environmental pollution, lack of availability of machinery, inadequate marketing facilities, unaffordable cost of hiring vehicles and lack of need based training.ThesisItem Open Access EFFECT OF FOLIAR SUPPLEMENTATION OF ASCORBIC ACID ON LARVAL GROWTH AND ECONOMIC TRAITS OF MUGA SILKWORM (Antheraea assamensis Helfer.)(AAU, Jorhat, 2017-07) Deori, Manas Jyoti; Dutta, L. C.Muga silk is the product of the silkworm Antheraea assamensis Helfer. endemic to North Eastern India which is prevalent in the Brahmaputra valley and adjoining hills by virtue of its typical agro-climatic condition. Muga silkworm is polyphagous and feeds on the leaves of different plant species. The silkworm is semi-domesticated and multivoltine in nature having 5 to 6 generation in a year. Supplementation or fortification of silkworm host plant leaves is a technique of recent application in sericulture research. A variety of fortification agents such as, proteins, carbohydrates, amino acids, sugars, vitamins, minerals, sterols, hormones, antibiotics, salts and other chemicals have been tested on silkworm larvae (Sundar Raj et al., 2000). The dietary supplements like proteins, vitamins, lipids etc. evincing their specificity at specific dose for various metabolic activities of silkworm (Horie and Watanabe, 1980). Ascorbic acid has many important functions in the animal body (Balasundaram et al., 2013 ). The present investigation is aimed to study the effect of foliar supplementation of ascorbic acid on larval growth and economic parameters of muga silkworm, Antheraea assamensis Helfer. in the Department of Sericulture, Assam Agricultural University, Jorhat during the year 2016-17. The study revealed that supplementation of som leaves with ascorbic acid does not have much impact on the larval growth and cocoon characters of muga silkworm. Application of ascorbic acid in 4th instar larval period with 1.5 % to 3.0% concentration of ascorbic acid increases the larval weight with decrease of larval duration compared to control, while effective rate of rearing was found to be more in 3.0-4.5% concentration of ascorbic acid supplementation during 3rd, 4th and 5th instar larval period. The silk gland weight was 1.8g in control batch and at variation from 1.75g to 2.10g in the treated batches of the silkworm with different concentration of ascorbic acid. The cocoon weight, shell weight, shell ratio, length and size (denier) of cocoon filament found to be increases with application of ascorbic acid with 1.5% concentration at 4th instar larval growth period. Thus, from the present investigation it could be inferred that fortification of host leaves with ascorbic acid does not have much impact on larval growth and economic characters of muga silkworm. However, supplementation of host leaves with lower concentrations of ascorbic acid during 3rd and 4th instar rearing period may be effective at certain levels, for improvement of larval growth and economic traits of muga silkworm.
