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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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Subject: Agricultural Entomology × End date: 2023 × Start date: 2023 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    NUTRITIONAL PROFILING OF SOME EDIBLE SERICIGENOUS INSECTS OF MANIPUR
    (2023) Singha, Th. Aruna; Bhattacharyya, Badal
    Laboratory experiments were carried out to assess the nutritive value of four edible sericigenous insect species viz., Bombyx mori L., Anthrerea proylei J., Antherea frithi M. and Cricula trifenestrata H. based on their proximate & elemental content, amino & fatty acid profiles, antioxidant & anti-nutritional properties as well as their microbial aspects in the Soil Arthropod Pests Laboratory, Department of Entomology, Post Graduate Laboratory, Department of Biochemistry and Agricultural Chemistry, Department of Plant Pathology, Assam Agricultural University, Jorhat during 2019-2022. Edible sericigenous insect species cocoons were collected from various locations covering five districts of Manipur. The powdered samples of the pupae were considered for biochemical and microbial analysis. The proximate analysis of four edible sericigenous insect species had significant variation. The moisture content ranged from 2.038-6.075 per cent and the highest moisture content was observed in A. proylei (6.075%) and A. frithi registered the least moisture content (2.038%) indicating that suitability of sericigenous pupal powder for preservation for a reasonable period of time without any probable risk of any microbial deterioration. The carbohydrate content of the studied species was found maximum (12.130%) in C. trifenestrata and the lowest (2.250%) was recorded in A. proylei. Appreciable amounts of crude protein content were estimated in all the studied species which ranged from 59.315- 69.418 per cent. The highest (69.418%) crude protein was registered in A. frithi and it was found to be significantly superior over the rest of the species. The estimated crude protein content of A. proylei, C. trifenestrata and B. mori were 65.383, 61.463 and 59.315 per cent, respectively. Crude fat content registered in the studied species varied significantly and ranged from 19.213-30.725 per cent. The highest (30.725%) crude fat content was recorded in B. mori followed by A. proylei (29.750%) and C. trifenestrata (28.738%), whereas A. frithi recorded the lowest (19.213%) amount of crude fat content. The crude fibre content varied from 2.213-8.450 per cent and C. trifenestrata registered a significantly high amount of crude fibre (8.450%), whereas the lowest was found in B. mori (2.213%). The highest (5.275%) ash content was observed in A. proylei, whereas the lowest (4.175%) was registered in C. trifenestrata. The ash content of mulberry silkworm B. mori (5.150%) was statistically at par with the A. frithi (5.150%). While analyzing the energy content (kcal/100 g) of all the four species, the maximum energy content (560.205) was estimated in A. proylei followed by C. trifenestrata (556.035) and B. mori (534.885), whereas A. frithi detected the lowest energy content of 465.453 kcal/100 g. Altogether 9 minerals as elemental composition were estimated in all the studied species. The mineral analysis indicated that the concentration of macro elements viz., potassium, calcium and magnesium were significantly higher in A. frithi (70.295, 13.993 & 25.889 mg/100 g), whereas the lowest amount (65.663, 8.790 & 23.526 mg/100 g) potassium, calcium and magnesium were observed in C. trifenestrata. However, the highest sodium and phosphorus content (36.026 & 22.429 mg/100 g) were recorded in B. mori and the least amount of sodium (26.489 mg/100 g) and phosphorus (16.062 mg/100 g) were found in C. trifenestrata. Considerable amounts of micro elements like iron was recorded the highest (26.639 mg/100 g) in B. mori. The lowest iron content was observed in A. proylei (8.315 mg/100 g). Zinc, manganese and copper content (mg/100 g) was estimated to be the highest (21.709, 5.445 and 3.123) in A. frithi which showed statistical superiority over other species whereas C. trifenestrata registered with the lowest zinc (15.381 mg/100 g), manganese (1.209 mg/100 g) and copper (0.997 mg/100 g) content. Among all the amino acids 19 common amino acids, 8 were found essential. Glutamic acid was found to be the most abundant (8.88-7.25%) in all the four species followed by aspartic acid (7.83-5.95%). Among the species, the concentration of glutamic and aspartic content was found to be highest in the A. frithi (8.88 & 7.83%). The range of Essential Amino Acids (EAAs) viz., leucine (3.95-5.76%), valine (3.11-4.22%), isoleucine (2.29-3.29%), lysine (3.65-4.40%), threonine (2.63-3.71%) and phenylalanine (2.90-4.40%) are found in significant amounts. Both the sulphur containing amino acids (methionine and cysteine) were found in relatively low amounts and varied from 1.27-1.95 and 0.35-0.48 per cent. Glycine, alanine and serine were also available in appreciable amounts with values ranging from 3.09-5.87, 3.87-5.48 and 4.52-4.99 per cent, respectively. In case of sweet amino acids (i.e., alanine & glycine), the highest amount was recorded in B. mori (5.48 & 5.87%) but lowest (3.87 & 3.09%) in A. frithi. Most of the amino acid concentration was found to be the highest in A. frithi followed by A. proylei, C. trifenetrata and B. mori, respectively. Total fatty acid analysis revealed that the highest amount of Saturated Fatty Acids (SFA) and Monounsaturated Fatty Acids (MUFA) were recorded in C. trifenestrata (6.69 & 5.26%) followed by A. proylei (4.43 & 4.28%), B. mori (2.38 & 2.70%) while the lowest SFA and MUFA was registered in A. frithi (0.80 & 0.35%). On the contrary, the highest (8.36%) Polyunsaturated Fatty Acids (PUFA) was evaluated in A. proylei followed by C. trifenestrata (7.90%), B. mori (4.36%) and the least amount (0.39%) was recorded in A. frithi. Altogether, 18 fatty acids were registered in A. frithi which was followed by A. proylei and C. trifenestrata (9 nos.) and B. mori (6 nos.). Linoleic and alpha linolenic acid content (2.48 & 5.88%) were found maximum in the A. proylei followed by C. trifenestrata (2.07 & 5.83%) and B. mori (0.78 & 3.58%) while the least linoleic and alpha linoleic acid (0.25 & 0.14%) was observed in A. frithi. In regards of antioxidant properties, phenol (mg catechol equivalent/g), flavonoid (mg quercetin equivalent/100 g) and antioxidant activity (% DPPH inhibition) were found in all the species and varied from 37.261-92.400, 27.223-35.489 and 35.914-74.587, respectively. Cricula trifenestrata showed the highest phenol and flavonoid content (92.400 mg catechol equivalent/g & 35.489 mg quercetin equivalent/100 g) and which was found to be significantly superior over rest of the species. Antioxidant activity was observed to be the highest in A. frithi (74.587% DPPH inhibition) and least in the C. trifenestrata (35.914% DPPH inhibition). The variability in the concentration of tannin, phytic acid and oxalic acid were ranged from 3.280-6.201 mg tannic acid equivalent/100 g, 2.780-5.238 mg/100 g, 1.762-4.138 mg/100 g, respectively. As regards to anti-nutritional compounds, the highest tannin (mg tannic acid equivalent/100 g), phytic acid (mg/100 g) and oxalic acid (mg/100 g) were observed in B. mori (6.201, 5.238 & 4.138) followed by A. proylei (5.702, 4.510 & 3.572), C. trifenestrata (5.468, 3.304 & 2.819) and A. frithi (3.280, 2.780 & 1.762), respectively. However, the presence of anti-nutritional properties in all four edible insect species were detected much more below the recommended range of 250-500 mg/100 g. Microbial enumeration revealed that total viable counts of B. mori, A. proylei and A. frithi silkworm pupal powders stored under ambient temperature (28 to 32°C) had higher bacterial population (3.331, 3.073 & 3.095 log cfu/g), whereas the least bacterial counts (2.639, 2.520 and 2.564 log cfu/g) of B. mori, A. proylei and A. frithi silkworm were observed when they stored under temperature (-16 to -21°C). Cricula trifenestrata recorded the highest population of bacteria (2.870 log cfu/g) under the temperature (15 to 20°C) and least (2.075 log cfu/g) under the temperature (-16 to -21°C). The highest yeast and mould population (3.102, 3.069, 2.855 & 2.714 log cfu/g) was observed when B. mori, A. proylei A. frithi and C. trifenestrata pupal powder were stored at -16 to -21°C. Microbial enumeration showed that B. mori pupal powder had the highest microbial contamination among the other studied sample. Total viable counts were under the advised limit of fresh minced meat (< 6 log cfu/g, TAC). Through microbial test kits, it was further confirmed the absence of two most common food borne pathogens i.e., Escherichia coli and Salmonella sp. in all the studied sericigenous insect samples.
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    ThesisItemOpen Access
    DIVERSITY, POPULATION DYNAMICS AND MANAGEMENT OF INSECT PESTS OF TEA
    (2023) Rabha, Himadri; Dutta, B. C.
    Diversity study of insect pest complex of tea was carried out at three agroclimatic zones of Assam viz.,Upper Brahmaputra Valley Zone (Jorhat) North Bank Plain Zone (Udalguri) and Lower Brahmaputra Valley Zone (Kokrajhar) during 2019-20, 2020-21 and 2021-22, respectively. Laboratory experiments were carried out at Biocontrol laboratory, Department of Entomology, Assam Agricultural University and at laboratory of Krishi Vigyan Kendra, Udalguri. The field experiment was conducted in the tea garden of Udalguri district during 2021-22. Survey results revealed that a total of 4 mites and 22 different insect species belonging to 7 orders and 19 families were found to be associated with tea as recorded from different locations of Assam. In addition, 7 species of insects were found to be as visitors of the tea ecosystem in different period of time. Moreover, 11 different types of natural enemies were also observed. Among the sucking insect pests, per cent infestation of tea mosquito bug was recorded maximum (43.22 per cent) in Jorhat district. Among defoliator pests, per cent infestation of looper caterpillar was recorded maximum (34.23 per cent) in Udalguri district. Among all the insect and mite pests, tea mosquito bug showed highest degree of infestation in Jorhat i.e., 46.21 per cent whereas in case of red spider mite and looper caterpillar, highest degree of infestation was recorded 54.80 and 46.32 per cent in Udalguri district, respectively. Among all the insect and mite pests recorded during the study, tea mosquito bug, red spider mite and looper caterpillar showed moderate (34-66 per cent) degree of infestation, so they are considered as major pests. During 2019-20, the species richness in Jorhat showed maximum value of 1.50 in defoliator pests. The variation of species richness indices indicated a highest value of 1.54 and 1.50 in Udalguri during 2020-21 and 2021-22 in defoliator pests, respectively. Whereas, in Kokrajhar, the highest value was 1.55 in sucking pests (2020-21) and 1.59 in defoliator pests (2021-22). Shannon- Wiener index revealed that the highest value of 2.21 in defoliator pests in Jorhat (2019-20). During 2020-21, in Udalguri, it was found to be highest in sucking pests with value 2.10 and 2.21 in Kokrajhar, respectively. During 2021-22, Shannon- Wiener index showed highest value of 2.10 in Udalguri district and 2.12 in Kokrajhar district in defoliator insect pests. In terms of Simpson’s diversity index, highest value of 0.87 was recorded in defoliator insect pests in Jorhat district (2019-20). Likewise, during 2020-21, in Udalguri and Kokrajhar district, the highest diversity value of 0.82 and 0.87 were recorded in sucking pests, respectively. During 2021-22, the highest diversity values of 0.86 and 0.87 were recorded in defoliator pests in Udalguri and Kokrajhar, respectively. In Jorhat (2019-20), the maximum number of tea mosquito bug was observed to be 5.9 per bush during the first week of September. The highest population indices record of 20.27 mites per leaf was recorded during third week of November. The maximum number of looper caterpillar was observed to be 4.26 per bush during fourth week of February. Correlation studies between weather parameters and population indices of tea mosquito bug showed significant positive correlation with maximum temperature, minimum temperature, evening relative humidity and rainfall whereas, red spider mite showed significant positive correlation with maximum temperature and negative correlation with morning relative humidity, evening relative humidity and total rainfall. The population indices of looper showed significant positive correlation with morning relative humidity. In Udalguri (2020-21), the maximum population indices of tea mosquito bug, red spider mite and looper caterpillar were recorded as 5.12 per bush during the last week of August, 14.78 per leaf during March to April and 5.02 per bush during second week of March, respectively. Correlation studies between weather parameters and population indices of tea mosquito bug showed significant positive correlation with maximum temperature, minimum temperature and evening relative humidity. The population indices of red spider mite showed significant positive correlation with maximum temperature, whereas, it showed negative correlation with morning relative humidity, evening relative humidity and total rainfall. The looper caterpillar population showed negative correlation with maximum temperature, minimum temperature, evening relative humidity and total rainfall. During 2021-22, the maximum population indices of tea mosquito bug, red spider mite and looper caterpillar were recorded to be 5.79 per bush, 28.12 per leaf, 5.23 per bush, respectively. Correlation studies between weather parameters and population indices of tea mosquito bug showed significant positive correlation with maximum temperature, minimum temperature, evening relative humidity and total rainfall. Red spider mite showed significant positive correlation with maximum temperature and negative correlation with total rainfall whereas, looper caterpillar showed significant negative correlation with maximum temperature, minimum temperature and total rainfall. In Kokrajhar (2020-2021), the maximum population indices of tea mosquito bug, red spider mite and looper caterpillar were recorded to be 4.12 per bush, 27.23 per leaf, 4.12 per bush respectively. Correlation studies between weather parameters and population indices of tea mosquito bug showed significant positive correlation with maximum temperature, minimum temperature, evening relative humidity and rainfall, whereas red spider mite showed non-significant positive correlation with maximum temperature and looper showed significant negative correlation with minimum temperature and total rainfall. During 2021-22, the maximum population indices of tea mosquito bug, red spider mite and looper caterpillar were recorded to be 5.30 per bush, 14.52 per leaf and 10.22 per bush, respectively. Correlation studies between weather parameters and population indices of tea mosquito bug showed a negative correlation with morning relative humidity, evening relative humidity and total rainfall. Red spider mite showed significant positive correlation with maximum temperature and negative correlation with morning relative humidity, evening relative humidity and total rainfall whereas looper caterpillar showed significant negative correlation with maximum temperature, minimum temperature, morning relative humidity, evening relative humidity and total rainfall. Laboratory study on efficacy of different plant extracts against tea mosquito bug showed the highest mortality of 80.00 per cent in case of Pongamia pinata in 120 hours after treatment. The results on efficacy of different plant extracts against adult red spider mite showed that the highest mortality was recorded 93.33 per cent in case of both the treatments of Vitex negundo and Azadirachta indica at 120 HAT. Similarly, bio efficacy of different plant extracts against looper caterpillar showed that the larval mortality was highest with value 86.67 per cent at 120 HAT in case of A. indica. The results on efficacy of plant extracts at field condition reveals that at seven days after spraying, P. pinata recorded the least number of populations of tea mosquito bug with 0.67 number per bush. Again, at seven days after spraying, least number of mites was recorded in case of V. negundo with 7.19 mites per leaf. Moreover, the results showed that the maximum reduction of larval population was found in A. indica with 1.72 looper caterpillar population per bush at seven days after spraying.