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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.ThesisItem Open Access Morphology And Bio-Ecology Of Muga Silkworm (Antheraea Assama Westwood) (Lepidoptera : Saturniidae)(Assam Agricultural University; Jorhat, 2001) Khanikor, Durga Prasad; Dutta, S. K.ThesisItem Open Access Effect Of Castor Varieties On Growth, Nutrition And Cocoon Characters Of Eri Silkworm, Samia Cynthia Ricini Boisduval(Assam Agricultural University; Jorhat, 2000) Dutta, Lohit Chandra; Khaund, J. N.
