Central Agricultural University, College of Post Graduate Studies in Agricultural Sciences, Umiam
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ThesisItem Open Access Arthropod diversity in agricultural, horticultural and silvicultural ecosystems with special reference to spiders in mid-hills of Meghalaya /(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019) Gogoi, Jyotim; Ningthoujam, KennedySpiders are Arthropod and belong to the Phylum: Arthropoda, Class: Arachnida, Order: Araneae. Their occurrence worldwide is about 30,000 species belonging to the 60 families. Spiders are the most diverse group of animal on earth, ranked seventh among global diversity. From India 1,685 species belonging 438 genera and 60 families are catalogued. Spiders totally depend on predation of small insects and other animals and have important role in the structure of communities and food webs both as an individual numbers and as an energy consumer. Spiders are the ideal predators because of the number of insects killed per unit of time, good searching ability, wide host range, adaptation to limited food ability, low metabolic rate and poly-phagous nature. Hence, documentation of spiders gives information about biodiversity of ecosystem in a particular geographical area. The collected samples belonged to 2 classes of arthropods viz., Arachnida and Hexapoda (Insecta). The experiment focuses especially on Arachnida and the diversity of class Arachnida. Totally 4023 arthropods were collected from Silvicultural, Horticultural and Agricultural (Maize, Potato and Rice) ecosystem which belonged to 14 orders and 85 Nos. of different families. In familial level maximum diversity was found in class Insecta composed of 66 Nos. of family and 186 Nos. of genera and class Arachnida composed of 19 Nos. of family and 67 Nos. of genera. In ordinal level maximum diversity was found in class Insecta composed of 13 Nos. of orders and class Arachnida composed of 1 Nos. of orders. Among the ecosystem maximum diversity found in Silvicultural, Horticultural and Agricultural ecosystem in terms of alpha diversity such as Shannon Wiener index Simpsons D Species number Margelef D Equitability J Berger Parker index Maclntosch U Brillouin level Fisher Alpha Q Statistic and beta diversity such as Whittaker Bw, Cody Bc, Routledge Br, Routledge Bi, Routledge Be and Wilson & Shmida Bt. Rank abundance and species distribution models also indicating the maximum diversity found in Silvicultural followed by Horticultural and Agricultural ecosystem. PCA, CA, RDA and CCA were evaluated to understand the arthropod population and its association to habitat specific occurrence and environmental parameters. Correlation analysis showed arthropod population positively correlated to maximum and minimum temperature and evening relative humidity and negatively correlated to morning relative humidity and rainfall.ThesisItem Open Access Arthropod diversity in rice ecosystem with special reference to spiders in mid-hills od Meghalaya(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University-Imphal, 2019) Nakambam, Sonali; Ningthoujam, KenedyBiodiversity is essential for sustainability of life on Earth. Terrestrial arthropods represent maximum proportion of all biotic diversity in the world. Spiders are diverse arthropods attaining seventh rank in diversity. In rice ecosystem, spider plays an important role as predators in reducing plant hoppers and leafhoppers. Biological control of insect pests through spiders is gaining importance as they are efficient in reducing pest population and also reduce the use of toxic chemical pesticides. The present study was undertaken to document diversity of arthropods in rice field. A total of 1640 individuals which come under 98 species belonging to 74 genera from 37 families represented by 9 orders falling under 2 classes viz., Arachnida and Insecta were recorded during the study period. Arthropods were collected using various methods viz., visual search, net sweeping, pitfall and rubbish trapping and use of aspirator. Of the total number of individuals collected, class Insecta formed the major group with 909 individuals, while 731 individuals were represented by class Arachnida. Under Arachnida, 41 species from 23 genera and 10 families were identified. Among the Pterygota, Exopterygota formed the largest group with majority of individuals from Hemiptera followed by Orthoptera, Odonata and Dictyoptera. Endopterygota was represented by four orders viz., Lepidoptera, Hymenoptera, Coleoptera and Diptera. In the order Araneae, Araneidae was the most dominant family represented by 6 genera with 16 number of species, followed by the family Lycosidae represented by 2 genera with 4 number of species. Data analysis based on species richness and abundance revealed that October month showed maximum index value in all the indices. A guild structure analysis of spiders revealed six feeding guilds such as orb web weavers, stalkers, ground runners, space web builders, ambushers and foliage runners. Orb weavers guild was shown as the most dominant guild which was abundantly found in the month of October when crop canopy was fully developed. Oxyopes bharatae and Pardosa sumatrana were found throughout the study period. Correlation analysis showed that Araneidae population showed positive correlation with rainfall but negatively correlated with maximum temperature and relative humidity.ThesisItem Open Access Assessment of toxicity of bio-pesticides to the Indian honey bee, Apis cerana indica (Fabricius) in oilseed Brassica(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018-10) Kumar, Challa Girish; Firake, D. M.Rapeseed and Mustard is the second most important edible oilseed crop in India after Soybean and accounts for 27.8 per cent of the total oilseeds produced in the country.The crop shares around one-third of the India's oil production, making it the country’s key edible oilseed crop. It is an open pollinated crop which is heavily pollinated by honey bees. Recently declines of various pollinators have been reported. Biopesticides are the integral part of the organic agriculture and they are considered to be safe to the natural enemies and pollinators. However, several studies indicated that bio-pesticides may also be harmful to the pollinators. It is essential to assess the risk of bio-pesticides to the foraging honey bee in oilseed brassica to promote higher yield with efficient pest control. Therefore, commonly used bio-pesticides were evaluated for their safety to the Indian honey bee, Apis cerana indica (Fabricius). The study was conducted in two tier approach i.e. laboratory and field conditions. For in vitro studies, target insects were collected from entomology farm at ICAR-NEH, Umiam and reared according to standard protocols. LC50, LC90 and LD50 values were determined for the insect pests and honey bees, to assess the risk against honey bees. Laboratory studies showed that LC50’s of pesticides to the honey bee was in the order of Nomuraea rileyi (100) > B. bassiana (4.798) > Bt var k (1.670) > azadirachtin (1.642) > annonin(1.221) > cyantraniliprole (0.056) > spinosad (0.006) > imidacloprid (0.005). Acute toxicity data of insect pests and honey bee were used to determine three essential risk assessment criteria’s viz., selectivity ratio, probit substitution method (%) and hazard ratio/risk quotient. Based on these three risk assessment criteria’s, azadirachtin, annonin, B. bassiana and Bt var kurstaki were found selective, but slightly to moderately toxic to the honeybee; whereas, spinosad, cyantraniliprole and imidacloprid were found non-selective and dangerous to the bees. N. rileyi was found selective and absolutely harmless to the bees. Relative abundance, foraging rate, foraging speed and yield in different treatments were considered to know the influence of biopesticides on foraging activity in vivo. Relative abundance, foraging rate and foraging speed of honey bees were significantly affected in different treatments even up to 2 days of spraying. Among bio-pesticides, deterrence/repellent effect was however severely observed in annonin and spinosad treatments up to 2 days. Significantly higher yield was obtained in azadirachtin (1.43 t/ha) and annonin (1.22 t/ha) treated plots. This study concludes that, except spinosad remaining bio-pesticides were safe to the foraging bees, however considering efficient pest control and higher yield, the neem oil based formulation of azadirachtin and annonin could be efficiently used in Integrated Pest and Pollinator Management Programme (IPPM) in oilseed brassica’s. Owing to its harmful effect on bees, use of spinosad 2.5 SC should be discouraged especially during the flowering period in oilseed brassicaThesisItem Embargo Baseline susceptibility of cabbage butterfly, Pieris brassicae (Linnaeus) to Bacillus thuringiensis (Berliner) cry toxins in Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-10) Saisri, Manchikatla; Ningthoujam, KennedyCabbage, (Brassica oleracea var. capitata) is widely grown as a winter vegetable crop in India and is the second most important crop in Meghalaya after Potato. Cabbage butterfly, Pieris brassicae which is one of the important pests of cabbage and other cruciferous crops, accounts for >40 % yield reduction in the crop. P. brassicae can be effectively controlled by biocontrol agent i.e., Bacillus thuringiensis var. kurstaki and other subspecies of Bt due to the susceptibility showed towards specific delta endo-toxins produced in the larval midgut. Despite the potent action of Bt, many of the insect pests such as Plutella xylostella, Helicoverpa armigera, Spodoptera litura and P. brassicae have also been reported to show resistance to virulent Bt toxins. In the present investigation, the effects of different host plants on the biology of P. brassicae under laboratory conditions and the evaluation of baseline susceptibility of P. brassicae to Bt Cry toxins in Meghalaya were studied. Cabbage, cauliflower and mustard as hosts showed significant difference in certain growth parameters of P. brassicae. Fecundity of P. brassicae on its different hosts ranged from 100.80 eggs (cabbage) to 41.00 eggs (cauliflower). The egg period of P. brassicae was recorded shortest (1.80days) on cabbage and highest on mustard (3.60 days). The average larval (16.40 days) and pupal (12.20 days) period was recorded shortest on cabbage. Longevity of P. brassicae male and female adults varied significantly on its different hosts. The highest male and female longevity of P. brassicae was recorded as 10.60 and 10.40 days on mustard and cabbage respectively. The total life cycle duration of P. brassicae was recorded significantly higher on cauliflower (53.60 days) as compared to lower on cabbage (39.80 days), under laboratory conditions. The studies on the baseline susceptibility of eleven different geographic populations of P. brassicae to Bt Cry toxins (Cry1C and Cry2Ab) in Meghalaya were evaluated using leaf dip bioassay method and significant variation was observed in susceptibility to both the Cry toxins. The median lethal concentrations, LC50 (72 h) varied from 0.535-1.725 μg/mLfor Cry2Ab and from 0.546-1.803 μg/mL for Cry1C. Cry2Ab toxin was found to be more virulent having a lower LC50 value of 0.535 μg/mL (95 % FL, 1.42-1.99) while compared to Cry1C having LC50 value of 0.546 μg/mL (95 % FL, 0.41- 0.71). The most susceptible strains of P. brassicae to Bt Cry1Cand Cry2Ab were found to be from Smit region (LC50, 0.535 μg/mL and 0.546 μg/mL) and the resistant strains belonged to CPGSAS, Umiam (LC50,1.803 μg/mL), Pepbah (LC50, 1.725 μg/mL) regions respectively. The resistant ratio or fold resistance between the most resistant population strain with respect to the most susceptible strain of P. brassicae was found to be 3.3-fold for Cry1C and 3.2-fold for Cry2Ab. The discriminating concentrations were observed to be 24.03 μg/mL (LC99, 95% FL, 12.9-77.0) for Cry2Ab and 19.30 μg/mL (LC99, 95% FL, 11.0-54.3) for Cry1C, on the basis of data for the most resistant CPGS-AS, Umiam and Mookyndur population respectively. The above baseline data will serve as an information to detect changes in the susceptibility status of the P. brassicae due to repeated exposures of Bt toxins either through Bt biopesticides or Bt transgenic crops and in the routine monitoring of resistance to develop an effective pest management programme.ThesisItem Open Access Biodiversity and molecular characterization of insect pests and natural enemies of potato ecosystem in mid hills of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-10) Adhikari, Mounika; Thakur, N. S. AzadPotato is a principal food crop as its greater yield potential along with prominent nutritive significance, it is universally recognized as ‘The king of vegetables’. Major limiting factors for the production and productivity of potato crop include both biotic and abiotic factors. Among biotic factors, Insect pests majorly infest the crop from germination to till harvest. Besides insect pests, several natural enemies and visitors harbour in potato ecosystem. Correct identification of agricultural pests is a prerequisite for the effective control of insect pests. DNA barcoding, a significant device of DNA based taxonomy is used to identify known and unknown species based on the shape of nucleotide positioning in a piece of DNA from marked species. Therefore major work was framed to study the biodiversity and molecular characterization of insect pests and natural enemies of potato ecosystem in mid hills of Meghalaya. A total of 48 insect species and one non insect were recorded. The highest number of species were in the order Coleoptera followed by Hemiptera, Diptera, Lepidoptera, Hymenoptera and Araneae with 43, 31, 12, 10, 2, 2 percent, respectively. A total of 31 insect pests, 14 natural enemies and 4 visitors were recorded. Six major insect specimens viz., Pthorimaea operculella, Thysanoplusia orichalcea, Tuta absoluta, Macrosiphum euphorbiae, Henosepilachna vigintioctopunctata, Anomala sp., were recorded as major pests of potato ecosystem in this region. The remaining 25 insect species were categorized as minor pests which belonged to 3 orders and 11 families. A total of 14 natural enemies of potato crop belonged to 5 orders and 4 families. While the common natural enemies were Chelonus sp., Coccinella septempunctata, Oenopia kirbyi and Micraspis sp. The collected insects were identified based on established taxonomic keys and on molecular basis. DNA was successfully extracted from multiple specimens of 28 insect species and molecular assays were also undertaken for presence of Wolbachia infection. The DNA barcodes were successfully developed for 26 species by sequencing partial Cytochrome oxidase I (COI) gene of mitochondrial DNA. The molecular identity of the insect species was established through NCBI BLAST. The species level identity was developed for 19 species and remaining 7 were identified up to genus level due to absence of matching molecular data at NCBI. All the analyzed sequences were deposited to International Gene Bank (NCBI) with accession numbers MT516413 to MT516440 and MT541891.The comprehensive taxonomical and molecular database developed in this study for a total of 26 species observed in potato ecosystem could be used as diagnostic guide at both morphological and molecular level.ThesisItem Open Access Bioefficacy and dissipation of imidacloprid and thiacloprid in/on chilli (Capsicum annuum L.)(2018-10) Sutnga, Baiamon; Patra, SandipChilli (Capsicum annuum L.) is an important vegetable and spice of India. India is the largest producer of chilli in the world. Although, its share in global production is high, there are still a number of factors that limits its production and productivity and one being infestation by insect pest. In chilli, sucking pests are a major problem and they can cause 60 to 75% loss in yield. Therefore, a study was undertaken to assess the bioefficacy of some new insecticides (imidacloprid and thiacloprid) against chilli aphid, Aphis gossypii Glover. Six treatments (imiacloprid17.8SL @ 25 and 50 g a.i. ha-1, thiacloprid 21.7SL @ 54 and 108 g a.i. ha-1 and dimethoate 30EC @ 300 and 600 g a.i. ha-1) were applied along with control with the initiation of aphid population consisting three replications. Pre-treatment population of aphids was taken one day before the spray and subsequently observation was recorded on 1, 3, 7, 10 and 14 days after insecticide spray. The dissipation pattern of imidacloprid at 25 g a.i. ha-1 and 50 g a.i. ha-1 and thiacloprid at 54 g a.i. ha-1 and 108 ga.i/ha were also studied by collecting chilli fruits and soil samples at 0, 1, 3, 5, 7, 10and 15 DAS. Immediately after collection of samples extraction was done followed by clean up and analysis using High Performance Liquid Chromatography (HPLC). The bioefficacy study revealed that the overall mean reduction of chilli aphid population was highest in imidacloprid at 50 g a.i. ha-1 with 80.33% reduction. The maximum fruit yield was also recorded in imidacloprid @ 50 g a.i. ha-1 with 86.10 q/ha. Dissipation study revealed that the initial deposit of imidacloprid at 25 and 50 g a.i. ha-1 in fruit samples were 1.20±0.102 and 1.74±0.103 mg/kg respectively which dissipated to BDL on 10th DAS. Half-life values of imidaclorid in chilli were 1.75 and 1.87 days at single and double dose, respectively. A waiting period of 4.52 and 5.84 days were calculated for single and double doses, respectively. In thiacloprid, an initial deposit of 1.10±0.036 and 1.84±0.034 mg/kg was observed on chilli fruits at both recommended dose and double the recommended dose, respectively. The residues were dissipated to BDL on7th DAS. The half-life and waiting period of thiacloprid in chilli at single and double doses were worked out to be 1.44 and 1.46 days and 8.33 and 9.53 days, respectively.ThesisItem Embargo Biointensive management of pest complex of Brinjal, Solanum melongena L. in organic environment(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-02) Boruah, Sushruta; Pathak, MaheshIndia is a country with rich biodiversity and with various agro-climatic regions which are conducive for cultivation of a wide range of vegetables throughout the year. Among the various vegetable crops, Brinjal (Solanum melongena L.), is a major vegetable crop with high productivity and high nutritive value. Despite the vegetable's popularity among poor farmers, it requires high inputs, particularly insecticides, because it is infested by a huge number of insect pests. Brinjal is highly prone to damage by insect pests from seedling to harvesting stage. In Meghalaya, Brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) is reported as the major pest. The present study on “Bio-intensive management of pest complex of brinjal, Solanum melongena L. in organic environment” was conducted in experimental farm of College of Post Graduate Studies in Agricultural Sciences (CPGS-AS), Umiam, Meghalaya from April to July, 2021. A total of 22 insect species and 3 non-insects were recorded from the brinjal ecosystem, out of which 15 species were observed as insect pests, 6 species as predators, 1 species as pollinator and 3 species of predatory spiders from the brinjal ecosystem. The Brinjal shoot and fruit borer (BSFB) was found to cause the maximum damage (22.40% shoot infestation and 38.84% fruit infestation). The correlation studies of the major pests (aphids, jassids, hadda beetle and BSFB) with weather parameters (maximum and minimum temperature, maximum and minimum relative humidity and rainfall) revealed that temperature and R.H. had significantly positive relationship with population fluctuation of the pests. The evaluation of bio-pesticide (Um-Comb) and synthetic pesticide showed that Chlorantraniliprole 18.50 SC was most effective against Brinjal shoot and fruit borer and hadda beetle and Dimethoate 30 EC was most effective against sucking pests i.e. aphids and jassids. Seed treatment with Um-Comb gave hundred per cent germination as compared to 84% in untreated seeds. The seed treatment and soil treatment followed by foliar spray with Um-Comb resulted in increased height, no. of branches, length of fruits and yield of the Brinjal crop. Among the different Um-Comb treatments, seed treatment and soil treatment followed by foliar spray was found to be the most effective in managing the major pests. The highest marketable yield was achieved from the chemically treated plots, however the benefit cost ratio was highest (2.74:1) in seed and soil treatment followed by foliar spray with Um-Comb.ThesisItem Open Access Development of DNA barcodes for major insect pests and natural enemies of Cucurbitaceous crops in mid hills of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018) Pongen, Arensungla; Behere, G. T.The cucurbitaceous crops (cucumber, pumpkin, gourds and chow-chow) are of tremendous economic importance and are cultivated throughout the world from tropical to sub-temperate zones. Insect pest infestations in cucurbits bring about heavy losses depending upon species and the season in different parts of the world. Correct identification of insect pest is a prerequisite step before undertaking any control measures. DNA barcoding has appeared to be a useful tool in resolving the issues related to identification of taxonomically difficult insect species. Limited information is available on insect biodiversity and DNA barcodes (insect pest & Natural enemies) in cucurbitaceous crops. Therefore, efforts were made to study the biodiversity of insects and to develop DNA barcodes for major insect pest and natural enemies present in cucurbitaceous crops in mid hills of Meghalaya. A total of 41 insect species belonging to six insect orders viz., Coleoptera (17), Hemiptera (8), Diptera (6), Hymenoptera (5), Lepidoptera (4), and Araneae (1) were collected and identified. There were a total of 31 insect pest and 11 natural enemies recorded. The insect species viz., Aulacophora foveicollis, Aulacophora lewisii, Bactrocera cucurbitae, Bactrocera tau and Henosepilachna pussillanima were found to be major pests of cucurbits in this region while the common natural enemies were Coccinella septempunctata, Micrapis sp. and Oenopia kirbyi. The collected species were identified based on established taxonomic keys, by taxonomists and/or molecular basis. DNA was successfully extracted from multiple specimens of 41 insect species and molecular assays were also undertaken for presence of Wolbachia infection. The DNA barcodes were successfully developed for 33 species by sequencing partial Cytochrome oxidase I (COI) gene of mitochondrial DNA. The molecular identity of the insect species was established through BLAST-n NCBI. The species level identity was developed for 23 species and remaining 10 was identified upto genus level due to absence of matching molecular data at NCBI. All the analyzed sequences have been deposited to International Gene Bank (NCBI) with accession numbers MH198024 to MH198037 and MH395845 to MH395863. The molecular identity of 3 species viz., Malcus sp., Paridea sp. and Coridius sp. were established for the first time and the partial COI sequences of these species were added to the GenBank nucleotide database collection. The insect pests Leptoglossus gonagra, Aulacophora lewisii, Bactrocera carambolae, Arthrotus flavocincta, Spilarctia sp., Spaniocelyphus falcatus, Tiracola plagiata, Kolla paulula, Malcus sp., and Paridea sp., have been reported for the first time in cucurbit crops from Northeastern India; Bactrocera cilifera, a recently discovered fruit fly in India has been reported for the first time in Meghalaya. This study has resulted in 80 percent successful identification of insect pest and its natural enemies. The comprehensive taxonomical and molecular database developed in this study for a total of 33 species observed in cucurbitaceous crop ecosystem could be used as diagnostic guide at both morphological and molecular level.ThesisItem Open Access Dietary influence on the biology and susceptibility of Fall Armyworm, Spodoptera frugiperda (J. E. Smith) to cry toxins from Bacillus thuringiensis(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-12) Karthik K.; Ningthoujam, KennedyFall armyworm, Spodoptera frugiperda an exotic pest native to USA reported in India by Sharanabasappa et al., 2018 and it started migrating all parts of India which is extremely pestiferous and can move 100 to 1000 km during its Pre-ovipositional stage (Kalleshwaraswamy et al., 2018). Rearing of exotic pest using artificial diets under laboratory condition is best option to study about its biology and nutritional requirement. Many researchers attempted to rear Spodoptera frugiperda (Nalim, 1991, and Pinto et al., 2019) under laboratory conditions using synthetic diets. While toxins from Bacillus thuringiensis var kurstaki is effective in causing the septicaemia in lepidopteran larvae Therefore, keeping these points in mind, the present research was done on some of the salient biological parameters of this insect by rearing on the semi-synthetic diets based on four locally available ingredients viz., Kidney bean, Soya meal, Potato and Corn (D1, D2, D3 and D4). The larvae obtained from the culture were used to study the Bioassay, one day old neonates are used against Cry1Ac and Cry1Ab toxin with the concentrations ordering from 0.01 to 5μg/ml were mixed uniformly into artificial diet and mortality values calculated 7 days after treatment. Results disclosed that the fitness index on D1 (955.09) showed the highest followed by D4 (879.62) and the lowest on D3(657.58) and D1 based diet proved to be best for rearing FAW while D4 diet could be good substitute for mass rearing of Spodoptera frugiperda. The 7 days of Median Lethal Concentration (LC50) ranged from minimum of 1.955 μg Cry1Ab/ ml of diet (Fiducial limit values 0.975 to 5.047) to maximum of 2.828 μg Cry1Ac/ ml of diet (Fiducial limit, 1.402 to 7.931). From these values we concluded D1 diet is best for rearing of Spodoptera frugiperda and Cry1Ab toxin found more toxic then Cry1Ac toxin.ThesisItem Embargo Diversity and abundance of fruit fly species by adoption of parapheromonic traps in Ri-Bhoi district of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-01) Chetry, Sunita; Ningthoujam, KennedyFruit fly (Tephritidae: Diptera) is an important insect pest of horticultural crops. The Present study was conducted from October-2020 to July-2021 to analyse the diversity of fruit flies in agri-horticultural and silvicultural ecosystems in Ri-bhoi district of Meghalaya. Parapheromonic traps (Methyl eugenol and Zingerone), food baits (Protein x, Soybean extract and Rotten fruits) and infested fruits and vegetables were used for sampling. A total of 11 species belonging to 3 genera of tephritid fruit flies were recorded from the study area viz., Bactrocera, Dacus and Zeugodacus. The most dominant genus observed was Bactrocera. Two species were recorded for the first time in Meghalaya, of which one is a new record for the country. A total of 11 and 6 species were recorded in Agri-horticultural and silvicultural ecosystem respectively. The most dominant species was Bactrocera dorsalis followed by Bactrocera tuberculata in both the ecosystems. Diversity indices were carried out using PAST software and depicted Species richness (Species number and Margalef’s D) was highest during June in both the ecosystems. Shannon wiener index was highest during July and June in agri-horticultural and silvicultural ecosystem respectively. However, Simpson’s index was highest during January in both the ecosystems. Beta diversity index, Sorenson (0.545) and Jaccard (0.706) showed similarity in both the ecosystems. Correlation study in both the ecosystems revealed that population of Bactrocera genus had a significant positive correlation with maximum, and minimum temperature (r=0.794, 0.688 respectively). Species composition and efficacy evaluation of Methyl eugenol (ME), Zingerone and their mixtures were analysed in horticultural crops by a general linear model (GLM, SPSS). Among the different treatments, 100% ME attracted a significantly greater number of species (five) as compared to the other treatments. In addition, species wise cluster and principal component analysis were carried out. Methyl eugenol attracted more fruit flies from the Bactrocera genus, whereas food baits attracted more fruit flies from the Zeugodacus genus. As a result, it is highly recommended that fruit flies should be monitored and managed using a combination of traps and baits. Therefore, adequate knowledge of the different lures and traps, factors affecting their efficiency etc. is important for successful use of lures and traps as a tool for IPM and ecological studies.ThesisItem Open Access Diversity and morphometric study of termites in mid-hills of Meghalaya.(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-10) Harish. R; Ningthoujam, KennedyMany insects during one or more stages of their life cycle live inside the soil, some in the tunnel made by them for completion of life cycle or consumption of food materials etc. One such group of insects are ‘Termites’ (Blattodea: Insecta), commonly known as ‘White ants’. They are hemimetabolous and belong to an orthopteroid group of insects which are found with greater diversity. Biodiversity of termites in Central region and North-western region of India is relatively poor whereas richness of termite species is more in North-eastern region of India. A comparative study of termite diversity in different ecosystems (agricultural, horticultural and silvicultural ecosystem) was carried out in mid-hills of Meghalaya to understand the species richness and morphological variations between the termite species. A standard transect method and tissue paper bait method were used for sampling the termites and was done at monthly intervals from July-2019 to March-2020. Seven morphometric parameters were selected and measured by using stereozoom binocular microscope. In the study, a total of 10 species were identified which belonged to three subfamilies viz., Macrotermitinae, Amitermitinae and Termitinae. Macrotermitinae was the most presiding subfamily observed in mid-hills of Meghalaya. A total of seven, three and one species were recorded in silvicultural, horticultural and agricultural ecosystem respectively. The most dominant guild was detected in fungus growing wood (or) litter feeders followed by organic rich soil (or) humus feeders. The termite species richness varied across the three ecosystems. The highest species richness was noticed in the month of August and least was recorded in December. The termite diversity was highest in silvicultural ecosystem and lowest in agricultural ecosystem. Shannon Wiener, Margalef’s D, Fisher’s alpha, Simpson’s and McIntosh index in agricultural ecosystem depicted less values compared to horticultural and silvicultural ecosystem. The morphometric variation of termite soldiers were noticed higher in pronotum length and least in head width. In addition, weather parameter studies, principal component analysis and dendrogram studies were worked out on the data collected in a species wise manner. Therefore, proper identification and having knowledge of the termite species are the initial steps which is very crucial for developing environment compatible/sustainable IPM strategies for termite.ThesisItem Embargo Diversity of native Bacillus spp. of mid hills of Meghalaya with special reference to Bacillus thuringiensis (Berliner)(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-11) Reddy, Desam Sainath; Ningthoujam, KennedyBacillus species are ubiquitous gram-positive, rod-shaped cell, aerobic or facultative anaerobic bacteria and are one of the important components of the soil microbial community and many of Bacillus bacteria are reported as beneficial microbes widely used in industry and agriculture that exists in varied ecological niches in many environments. Among the beneficial microbial Bacillus species, Bacillus thuringiensis plays a vital role as biopesticide for the control of insects and the most successfully commercialized bio-control agent worldwide for its high specificity and associated environmental safety. In an effort to understand the diversity and distribution of Bacillus spp. along with Bacillus thuringiensis and its plasmid and cry gene profile variation in a diverse range of environments, the present investigation was undertaken. The isolation protocol was standardized and Enrichment method was chosen as the best method for the isolation of maximum Bacillus species compared to Sodium acetate and Saline methods. A total of 89 putative Bacillus like isolates were isolated using enrichment method from different ecological niches, collected from 12 different locations of Meghalaya. Among them, maximum 36 isolates were obtained from East Khasi Hills followed by Ri Bhoi District (33 isolates) and West Jaintia Hills (20 isolates). Based on Paenibacillus morphological characteristics, biochemical tests and using advance bacteriological identification software (ABIS), the 89 isolates were sorted into two genera (Bacillus and Paenibacillus) with 21 different species. The highest Shannon- Weiner index was recorded in Bhoirymbong (2.043) and the lowest was observed in Jowai (1.099). The highest Margalef index (3.186) and Simsons index value (0.8642) has occurred in Bhoirymbong (3.186), while the lowest in Jowai with value of (1.82) and (0.667) respectively. The Pielou’s evenness index was seen maximum with value of 1 in five locations Nongpoh, Upper Shillong, Nartiang, Jowai, Syndai, Amlarem, while the lowest was observed in Cherrapunji (0.857). Morphological characterization of 89 Bacillus isolates showed that maximum of the isolates had irregular colonies, flat elevation and had dry rough texture with white or cream coloured colonies. Biochemical characterization revealed that majority of the isolates showed positive results for catalase, voges-proskuer, starch hydrolysis and gelatin hydrolysis tests. All the 89 isolates showed negative result for Indole test. All the 89 isolates were found positive for endospore staining and Coomassie Brilliant Blue staining for the B. thuringiensis isolates showed the occurrence of dark blue crystal or staining body in spherical shapes in most of the isolates. Detection of 8 B. thuringiensis isolates (CAU-BT1, CAU-BT2, CAU-BT3, CAU-BT4, CAU-BT5, CAU-BT6, CAU-BT7, CAU-BT8) based on 16s rRNA gene sequencing analysis with a similarity of > 98% with reference Bt. The cry gene profiling for all the eight B. thuringiensis isolates revealed that all the isolates showed the presence of Cry 1 gene. The plasmid profiling revealed that all the 8 B. thuringiensis isolates harboured a single mega plasmid DNA which was above 10000 bp size. The results of the investigation indicate that the soils of Meghalaya are rich in Bacillus-like species with high diversity, which has strong potential for exploitation in the future. There is a substantial number of B. thuringeinsis isolates in this region and the presence of lepidopteran specific cry 1 genes was confirmed which can be potentially used in the integrated pest management for sustainable agriculture.ThesisItem Embargo Diversity of native Bacillus spp. of mid hills of Meghalaya with special reference to Bacillus thuringiensis (Berliner).(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-11) Reddy, Desam Sainath; Ningthoujam, KennedyBacillus species are ubiquitous gram-positive, rod-shaped cell, aerobic or facultative anaerobic bacteria and are one of the important components of the soil microbial community and many of Bacillus bacteria are reported as beneficial microbes widely used in industry and agriculture that exists in varied ecological niches in many environments. Among the beneficial microbial Bacillus species, Bacillus thuringiensis plays a vital role as biopesticide for the control of insects and the most successfully commercialized bio-control agent worldwide for its high specificity and associated environmental safety. In an effort to understand the diversity and distribution of Bacillus spp. along with Bacillus thuringiensis and its plasmid and cry gene profile variation in a diverse range of environments, the present investigation was undertaken. The isolation protocol was standardized and Enrichment method was chosen as the best method for the isolation of maximum Bacillus species compared to Sodium acetate and Saline methods. A total of 89 putative Bacillus like isolates were isolated using enrichment method from different ecological niches, collected from 12 different locations of Meghalaya. Among them, maximum 36 isolates were obtained from East Khasi Hills followed by Ri Bhoi District (33 isolates) and West Jaintia Hills (20 isolates). Based on Paenibacillus morphological characteristics, biochemical tests and using advance bacteriological identification software (ABIS), the 89 isolates were sorted into two genera (Bacillus and Paenibacillus) with 21 different species. The highest Shannon- Weiner index was recorded in Bhoirymbong (2.043) and the lowest was observed in Jowai (1.099). The highest Margalef index (3.186) and Simsons index value (0.8642) has occurred in Bhoirymbong (3.186), while the lowest in Jowai with value of (1.82) and (0.667) respectively. The Pielou’s evenness index was seen maximum with value of 1 in five locations Nongpoh, Upper Shillong, Nartiang, Jowai, Syndai, Amlarem, while the lowest was observed in Cherrapunji (0.857). Morphological characterization of 89 Bacillus isolates showed that maximum of the isolates had irregular colonies, flat elevation and had dry rough texture with white or cream coloured colonies. Biochemical characterization revealed that majority of the isolates showed positive results for catalase, voges-proskuer, starch hydrolysis and gelatin hydrolysis tests. All the 89 isolates showed negative result for Indole test. All the 89 isolates were found positive for endospore staining and Coomassie Brilliant Blue staining for the B. thuringiensis isolates showed the occurrence of dark blue crystal or staining body in spherical shapes in most of the isolates. Detection of 8 B. thuringiensis isolates (CAU-BT1, CAU-BT2, CAU-BT3, CAU-BT4, CAU-BT5, CAU-BT6, CAU-BT7, CAU-BT8) based on 16s rRNA gene sequencing analysis with a similarity of > 98% with reference Bt. The cry gene profiling for all the eight B. thuringiensis isolates revealed that all the isolates showed the presence of Cry 1 gene. The plasmid profiling revealed that all the 8 B. thuringiensis isolates harboured a single mega plasmid DNA which was above 10000 bp size. The results of the investigation indicate that the soils of Meghalaya are rich in Bacillus-like species with high diversity, which has strong potential for exploitation in the future. There is a substantial number of B. thuringeinsis isolates in this region and the presence of lepidopteran specific cry 1 genes was confirmed which can be potentially used in the integrated pest management for sustainable agriculture.ThesisItem Open Access Eco-biology and management of citrus leaf miner: Phyllocnistis Citrella ( Stainton) in Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2009) Syngkon, Shembha; Thakur, N. S. AzadSeasonal incidence of citrus leaf miner (Phyllocnistis citrella) was studied on ten infested citrus plants by recording number of miners on ten infested twigs from each plant, in the citrus orchard during 2008. The incidence of the pest was first noticed in the third week of February (2.67 %) and it reached its peak in the third week of August (31.5%). The pest was not observed from second week of December onwards till second week of February. The biology of P. citrella was carried out under the net house conditions in different months. The duration of various stages of P. citrella was shortest during July 15 to August 15 and longest during November 6 to December 16. The incubation, larval, pupal and total developmental period (egg to adult emergence) ranged from 2-8 days, 4-12 days, and 5-17 days and 11-33 days, respectively. Adult male and female longevity was found to be 3-10 days and 4-12 days, respectively. Fecundity ranged from 27.23 to 47.10 eggs/female, egg hatching from 27.23 to 47.10% and larval mortality from 22.42 to 33.91% in different months. The average sex ratio was found to be 1.37: 1 (female: male). Amongst the abiotic factors, temperature was found to favour the incidence and development of P. citrella. The management with different pesticides along with botanicals revealed that amongst the synthetic insecticides, imidacloprid (0.075 %) was the most effective in reducing larval population and per cent infestation, followed by monochrotophos, spinosad, endosulfan and lamdacyhalothrin in their order of efficacy, whereas amongst the botanicals karanjin (2 %) was found to be the most effective followed by azadirachtin 300 ppm and neem EC, however, prithvi garlic gold was found to be the least effective..ThesisItem Open Access Effect of different temperatures and plant oils on Bruchid, Callosobruchus maculatus (Fab.) and Curculionid, Sitophilus zeamais (Mots.)(2018-07) Sravani, Balguri Lavanya; Thakur, N. S. AzadIn recent times, paramount importance is given on good production practices, efficacious crop protection and handling for higher and better yield, sufficient for meeting the needs of increasing population. But little or no emphasis is given on effective storage requirements with minimum post-harvest losses. One of the crucial reason behind this losses are stored grain insect pests. They are unnoticeable when present in small numbers due to their cryptic behaviour. In congenial conditions, their population can go beyond unmanageable level. Moreover, emerging threats of climate change due to rise in global temperature is a probable reason for aggravating the congenial conditions. Henceforth, there is a need to understand the biology of stored grain pest at different temperatures suitable for development of higher population. Therefore, a study on bruchid, Callosobruchus maculatus (Fab.) and curculionid, Sitophilus zeamais (Mots.) at four different temperatures i.e., 20, 25, 30 and 35 °C was conducted. The duration of development decreased with the increase in temperature. At 20 °C, both the bruchid and curculionid had a longer incubation period (7.01 days; 6.65 days), grub period (21.01 days;35.91 days) and pupal period (6.02 days; 12.03 days), respectively, which was reduced at 35 °C i.e., incubation period (4.35 days; 5.33 days), grub period (12.07 days; 17.95 days) and pupal period (3.41 days, 4.25 days), respectively. The longest longevity period for bruchid and cuculionid male (11.65 days; 93.02 days) was recorded at 20 °C, whereasshortest duration of 7.50 days, 71.65 days, respectively, was recorded at 35 °C. Similarly, female adult longevity of bruchid and curculionid, longest longevity period (13.61 days;125.43 days) was observed at 20 °C, and shortest at 35 °C (8.76 days; 80.42 days), respectively. Bruchid and curculionid had the longest pre-oviposition period of 2.60 hrs and 3.28 days at 20 °C which reduced to 1.33 hrs and 1.87 days, respectively at 35 °C. In case of bruchid, longest oviposition period of 8.61 days was observed at 20 °C and shortest (6.62 days) at 35 °C whereas in curculionid, the longest duration of 80.33 days was recorded at 30 °C and shortest duration (63.93 days) at 20 °C, respectively. However, the fecundity of 103.96 and 90.47 eggs/female was found highest at 30 °C in bruchid and curculionid, respectively. In order to protect the produce from being lost both qualitatively and quantitatively, effective management practices should to be ascertained. Plant oils being one of those, is a boon over pesticides with regard to cost effectiveness, local availability, low persistence, high efficiency, low mammalian toxicity besides environmental safety. Thus, the present investigation was carried out to identify the effective plant oils against C. maculatus and S. zeamais. Eight plant oils i.e., rosemary, blackpepper, sweetflag, sacred tulsi, citronella, peppermint, eucalyptus and pine were evaluated at adose of 2 ml plant oil/kg of seed where seeds without any plant oil served as control. It was observed that the adult mortality of bruchid and curculionid increased with the increase intime period from 24 to 96 hrs. At 96 hrs after treatment, among these oils, rosemary oil and peppermint oil exhibited highest per cent adult mortality by 67.11 % and 69.85 % against bruchid and curculionid, respectively. However, the least mortality of 34.40 % and 11.81 % was yielded by calamus oil and pine oil against bruchid and curculionid, respectively. Plant oil treatments assessed were significantly superior to control. This study concluded that increase in temperature caused higher population build up and greater population dynamics among stored grain pests in shorter duration. Among the plant oils tested, rosemary oil and peppermint oil were highly effective against bruchid and curculionid, respectively, which can be utilized in the stored grain pest management strategies. Further research can be carried out on aspects such as compatibility studies among various plant oils and cost effective technology for incorporating them in storage godowns for safe and longer efficiency.ThesisItem Open Access Effect of plant extracts and essential oils on major Lepidopteran pests of cruciferous crops(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018-10) Devi, Pebam Inija; Firake, D. M.Vegetable production is an important source of income to the farmers of NE region. The lepidopteran pests are one of the most important constraints in vegetable production. Leaf defoliators, Spodoptera litura, Plutella xylostella and Pieris brassicae are three important pests attacking cruciferous plants. Fresh eggs of the major defoliating insect pests on vegetables viz., leaf eating caterpillar, S. Litura (Fabricius), the large cabbage white butterfly, P. brassicae (Linnaeus) and the diamondback moth, Plutella xylostella (Linnaeus) were collected from the unsprayed vegetable field of Division of Crop Protection (Entomology), ICAR Research Complex for NEH Region, Umiam, Meghalaya, during the year 2017-18 and further reared inlaboratory for different experiments on castor, cabbage and knol khol plants, respectively. Plant extracts from different plants viz., Vitex negundo, Curcumaangustifolia, Parkia roxburghii and Fleminga vestita were collected from Division of Crop Protection (Entomology). Essential oils viz., Cymbopogon citratus, Piper nigrum, Mentha piperita, Occimum basilicum and Rosmarinus officinalis were collected from ICAR, Umiam and some are purchased commercially. The test insects were exposed (In contact and oral toxicity) to plant extracts/oils in 2nd instar larval stage (i.e. most active feeding stage). Toxicity test were conducted by standard protocols: Topical application technique: Direct contact (fixed dose) (Mclaughlin et al., 1998) and Leaf dip method: Oral toxicity (Hoskins and Craig., 1962). Concentrations of the extracts were determined on the basis of preliminary experiments on the test insects. Seven concentrations (including control) of each extract were tested against test insects.Overall results revealed that, in topical application technique, LC50 value of O.basilicum was observed to be 0.09 per cent and V. negundo 1.99 per cent, against the caterpillars (2nd instar) of S. litura at 72 hrs; whereas it was found to be 0.28 per cent and 1.59 per cent on P. xylostella, respectively. In case of P. brassicae, LC50 of Pipernigrum oil and V. negundo extract was observed to be 0.02 per cent and 0.71 per cent. When the caterpillars of S. litura, P. brassicae and P. xylostella were topically treated with sub-lethal doses, the significant variation was observed in larval and pupal weight, their duration, per cent pupation and adult emergence. Inverse relationship was found in leaf area consumption by the caterpillars on different extracts. Food consumption was significantly reduced in treated larvae of the two pest species (S. litura and P.brassicae) compared to untreated larvae in control. From the present study, it can be concluded that, n-hexane fraction of Vitex negundo and essential oils of Ocimumbasilicum and Piper nigrum are most effective against major cruciferous defoliators and thus, they can be formulated and further evaluated for their potential under field conditions in organic farming.ThesisItem Embargo Effects of nanoparticles on morpho-histology of eri-silkworm, Samia cynthia ricini (Biosduval)(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-10) Kalita, Hia; Pathak, MaheshSericulture is the rearing of silkworms for the production of raw silk. Silk “the textile Queen” is secreted by the silkworms. Silkworm is an economically important holometabolous insect belonging to the order Lepidoptera. Over the past 50 years, the use of synthetic pesticides for crop protection has rapidly expanded around the world. The need for innovative low-risk control methods and new chemical classes of pesticides has increased as a result of the increasing concern for the environment and human health. In order to protect future agriculture and the environment in India, the post-Green Revolution era calls for a reduction in the use of more fertilizers and pesticides. Recently, nanotechnology being embraces in the world of pest control has the potential to revolutionize modern day agriculture. The rapid development of nanomaterials in various fields of science results in the need of understanding their toxicity on development and physiology of non-target organisms. In the present study, three nanoparticles (NPs) Chitosan, Silver (Ag) and Zinc oxide (ZnO) at seven different concentrations (25, 50, 100, 200, 300, 400, 500 ppm) were used to study their effects on the morphology and histology of Eri silkworm (Samia Cynthia ricini, Boisduval). The nanoparticles were incorporated in their diet by leaf dip method and applied once in each instar. In the larval and pupal stages the length, girth and cocoon weight decreased with increased concentrations of the nanoparticles. At 500 ppm length of larvae treated with Chitosan, Ag and ZnO NPs were 3.99, 4.37 and 5.98 cm as compared to control (7.12 cm), girth of larvae treated with Chitosan, Ag and ZnO NPs were 1.67, 3.31 and 4.49 cm as compared to control (4.78 cm) and cocoon weight of pupae treated with Chitosan, Ag, ZnO NPs were 1.94, 2.03 and 2.83 g/cocoon as compared to control (2.833 g/cocoon). The corrected larval mortality increased with increased concentrations, highest at 500 ppm with 22.18%, 17.73% and 12.18% in Chitosan, Ag and ZnO NPs, respectively. At 500 ppm deformities like absence of silken cocoon in the pupae, failed adult emergence, pupal death and deformed wings in the adults were observed in the morphology of the silkworms. At 500 ppm NPs decreased the fibroin protein content in the cocoons of Chitosan (68.03%), Ag (71.13%) and ZnO (69.49%) as compared to control (77.92%). Defects like split end, slug, bad casting, waste and loop in the silk threads also increased with increased concentration in all the three NPs. The midgut tissues of the dead larvae treated at 500 ppm of the NPs observed under Transmission Electron Microscope (TEM) exhibited alterations in the epithelial layer, basement membrane and muscle layer. In all the three nanoparticles absence of microvilli, empty cell contents and disruption of mitochondria was observed.ThesisItem Embargo Evaluation of synergistic effect of insecticides and Metarhizium anisopliae (Metchnikoff) Sorokin for the management of sucking pests of rice(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-09) Sahoo, Bimal Kumar; Pathak, MaheshRice (Oryza sativa L.) is the world's leading food crop, cultivated over an area of approximately 167.1 million hectares and yielding approximately 782 million tonnes (paddy). In recent years, a number of sucking pests viz., White leafhopper, Green leafhopper, Gundhi bugs have wreaked havoc by causing severe losses on the rice crop in various parts of India. In the present investigation, the compatibility of chemical insecticides with entomopathogen Metarhizium anisopliae was evaluated both in vitro and in vivo for managing sucking pests of rice. Compatibility study was done for six insecticides (Pymetrozyne 50 % WG, Deltamethrin 2.8 % EC, Thiamethoxam 25 % WG, Acephate 75 % SP, Imidacloprid 17.8 % SL and Diafenthiuron 50 % WP) at both lethal doses (LD) and sub-lethal doses (SLD) with M. anisopliae by using standard poisoned food technique. In vitro evaluation of compatibility of six different chemical insecticides with entomopathogen M. anisopliae, revealed that the treatment combination of Imidacloprid (SLD) @ 0.1-0.15 ml/L + M. anisopliae showed effective compatibility with lowest per cent inhibition of radial growth of M. anisopliae (29.70 %), followed by Pymetrozyne (SLD) @ 0.25 g/L + M. anisopliae (31.48 %), Thiamethoxam (SLD) @ 0.125 g/L + M. anisopliae (41.62 %), Diafenthiuron (SLD) @ 0.4-0.5 g/L + M. anisopliae (47.70 %), Acephate (SLD) @ 0.5 g/L + M. anisopliae (59.62 %) and Deltamethrin (SLD) @ 0.75 ml/L + M. anisopliae (62.51 %). In vivo evaluation of synergistic effect of four promising compatible insecticides with M. anisopliae observed in vitro were sprayed on the leaves for managing sucking pests of rice revealed that per cent reduction in WLH, GLH and GB population over control was highest in Imidacloprid (LD) @ 0.2-0.3 ml/L (80.65 %, 50.00 % and 67.51 %) followed by Imidacloprid (SLD) @ 0.1-0.15 ml/L + M. anisopliae (77.11 %, 42.86 % and 63.27 %), respectively. The corrected mortality percentage of WLH, GLH and GB were recorded highest (76.12 %, 50.00 % and 36.99 %) in Imidacloprid (LD) @ 0.2-0.3 ml/L followed by Imidacloprid (SLD) @ 0.1-0.15 ml/L + M. anisopliae (62.69 %, 42.86 % and 28.77 %) in field condition respectively. Highest grain yield was recorded (3.36 t ha-1) in Imidacloprid (LD) @ 0.2-0.3 ml/L followed by Imidacloprid (SLD) @ 0.1-0.15 ml/L + M. anisopliae with 3.14 t ha-1 as superior over control with 2.00 t ha-1. This study concluded that the combined application of four different chemical insecticides with entomopathogen at sub-lethal doses in both in vitro and in vivo showed compatibility with M. anisopliae. Imidacloprid with M. anisopliae was most effective in controlling sucking pests of rice and also recorded highest yield.