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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Novel strains of Metarhizium anisopliae sorokin.(Ascomycota:sordariomycetes) with enhanced abiotic stress tolerance(Department of agricultural entomology, college of agriculture, Vellanikkara, 2023-08-02) Sreelakshmi, U K.; KAU; Deepthy, K BNovel strains of Metarhizium anisopliae Sorokin. (Ascomycota: Sordariomycetes) with enhanced abiotic stress tolerance Abstract The green muscardine fungus, Metarhizium anisopliae Sorokin is widely used in the management of various crop pests. However the efficacy of M. anisopliae in the field is often inconsistent, mainly due to the environmental stresses such as temperature extremes, drought, UV radiation, etc. To circumvent these hurdles, the present study was undertaken to develop novel strains of M. anisopliae with enhanced environmental stress tolerance. The Metarhizium isolates, EKM2, CKD, and M4 were collected from the repository maintained at the Department of Agricultural Entomology and were screened for their temperature and drought tolerance. The isolate EKM2 recorded the highest mycelial weight (6.221g), while the isolate M4 recorded the least mycelial weight (0.328 g) and the least sporulation at the highest temperature of 380C. The screening for drought tolerance was conducted at various levels of Polyethylene glycol (PEG) concentrations in which the isolate CKD has shown higher biomass (2.172 g) with higher sporulation, while isolate M4 recorded the lowest mycelial weight (1.336 g) at the maximum PEG concentration of 39 per cent. The three selected isolates of M. anisopliae (CKD, EKM2 and M4) were subjected to further experiments. The Metarhizium isolates (CKD, EKM2 and M4) selected from the preliminary screening were continuously subjected to temperature stress treatments starting from 35oC to 42oC. At the highest temperature of 41oC, the isolate, EKM2 recorded the highest mycelial weight (1.336 g), number of colonies (18.667103 cfu/ml), number of spores (0.783 X 10 7 /ml), spore size (3.470 µm) and mycelial thickness (3.07 µm). At the same temperature, the isolate, M4 recorded the lowest mycelial weight (0.63g), number of colonies (3 cfu/ml), number of spores (0.217 X 10 7 /ml), spore size (1.637 µm), and mycelial thickness (2.65 µm). Hence EKM2 has been identified as the thermo-tolerant isolate and M4 as the susceptible one. The thermo-tolerant isolate EKM2 was grown continuously for 6 successive generations at the same temperature level of 41oC in order to stabilize the stress tolerance. The Metarhizium isolates (CKD, EKM2, and M4) selected from the preliminary drought screening experiment were also continuously subjected to drought-inducing treatments at PEG concentrations starting from 25 to 40 per cent. At the highest level of PEG concentration (40 %), the isolate CKD showed higher mycelial weight (3.365 g), spore count (0.323X 107 /ml)), number of colonies (4 X 103 colonies/ ml), spore size (3.15 µm), and mycelial thickness (2.723µm). The isolate, M4 recorded the lowest mycelial weight (0.808g), number of colonies (2 cfu/ml), spore count (0.243 spores/ml), spore size (4.493 µm), and mycelial thickness (2.543 µm) at the same PEG concentration. Hence isolate CKD is identified as drought tolerant and M4 as susceptible. The drought-tolerant isolate, CKD was grown continuously for 6 successive generations at the same PEG concentration level of 40 per cent in order to stabilize the stress tolerance. The selected tolerant isolates were evaluated against wax moth larva (Galleria mellonella) to identify their biocontrol efficacy. Isolate EKM2 has shown cent per cent mortality at the dosage of 108 and 109 spores/ml on the 9th day after treatment. At the highest dosage of 1x 109 spores/ ml, the isolate CKD recorded a lower LT50 (5.099 days) value, and isolate M4 recorded the highest LT50 (6.124 days) value. The isolates EKM2 and CKD were found to be more virulent while M4 was less virulent. The thermo-tolerant isolate, EKM2 recorded a total protein content of 0.354 mg/ml, and the drought-tolerant isolate (CKD) recorded a total protein content of 0.373 mg/ml. The thermo-tolerant isolate EKM2 has shown a trehalose content of 1.954 mg/min/g tissue weight which was significantly higher compared to the control (1.074 mg/min/g tissue weight). The trehalose content in the drought-tolerant isolate CKD (1.970 mg/min/g) was also higher when compared to the control (1.224 mg/min/g). The catalase activity ranged between 0.237 EU/min/mg proteins in the control to 0.386 EU/min/mg protein in the thermo-tolerant isolate EKM2, while the catalase activity of the drought-tolerant isolate, CKD was 0.384 c protein which was higher when compared to its control (0.240 EU/min/mg protein). The thermo-tolerant isolate recorded a peroxidase activity of 0.0230 EU/min/g tissue and that of droughttolerant isolate CKD was 0.0236 EU/min/g tissue weight. The protease activity of thermo-tolerant isolate CKD was 0.490 EU/min/mg protein and that of the droughttolerant isolate was 0.621 EU/min/mg protein. At 25 minutes of reaction, the thermo-tolerant and drought-tolerant isolates have shown higher lipase activity (10.000 µmol fatty acid/ml and 11.00 µmol fatty acid/ml respectively) when compared to their respective controls. On the 5th day, both the thermo-tolerant and drought- tolerant isolates recorded significantly higher chitinase activity (1.140 µg of N- acetyl glucose amine/min/ml of broth and 3.062 µg of N- acetyl glucose amine/min/ml of broth respectively) than their controls. The temperature induction had up-regulated heat shock proteins of 25 kDa and 35 kDa in heat-induced isolate EKM2. The isolate also expressed heat shock proteins in the range of 100 kDa molecular weight. Drought tolerant isolate (CKD) on the other hand did not show the presence of any heat shock protein when compared to the control. The study could develop isolates of M. anisopliae which are tolerant to temperature and drought stress, with high virulence as well as higher biochemical activityThesisItem Open Access Bioefficacy of Tagetes minuta L. against Teranychus truncatus ehara (Prostigmata: Tetranychidae) and Aphis craccivora koch (Hemiptera: Aphididae)(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2023-03-25) Ashish V V.; KAU; Haseena, BhaskarThe spider mite, Tetranychus truncatus Ehara and the black cowpea aphid, Aphis craccivora Koch are two predominant sucking pests infesting several vegetable crops in Kerala. Farmers depend heavily on chemical pesticides for the management of these pests. However, due to the adverse effects of synthetic pesticides on environment and non-target organisms, there is a growing need for environmentally benign alternatives. This has generated interest in the development of biopesticides, based on botanicals. Tagetes minuta L., commonly known as Mexican marigold or wild marigold or southern cone marigold is a plant whose pesticidal properties have been well documented. The study was carried out in the Department of Agricultural Entomology, College of Agriculture, KAU, Vellanikkara during 2020-2022. The objectives of the study were to identify the bioactive fractions of T. minuta and to evaluate the bioefficacy of the solvent fractions against T. truncatus and A. craccivora. Tagetes minuta plants cultivated in the Department of Floriculture and Landscaping, were harvested at the flowering stage followed by shade drying and grinding. The powdered botanical was extracted sequentially using hexane (non-polar), chloroform (medium polar) and water (highly polar) as solvents. The hexane, chloroform and aqueous fractions of T. minuta were evaluated for their efficacy against T. truncatus and A. craccivora in the laboratory at five different concentrations viz., 0.025, 0.05, 0.1, 0.15 and 0.2 %. The ovicidal and adulticidal effects of the solvent fractions were evaluated against T. truncatus by topical application method. Considerable ovicidal action was exhibited only by hexane fraction at higher concentrations (0.1, 0.15 and 0.2 %), with cent per cent egg mortality at 0.2 %, after 120 h of treatment. However, all the three solvent fractions caused appreciable mortality of adult mites, in a concentration dependent manner. The hexane fraction at 0.2 % and 0.15 % were significantly superior, causing 91.67 and 90.00 per cent mortality, respectively, followed by 0.2 % chloroform (66.67), 0.15 and 0.10% (56.67), and 0.2 % aqueous fraction (53.33), after 120 h of treatment. The efficacy of the solvent fractions (0.025, 0.05, 0.1, 0.15 and 0.2 %) against A. craccivora was evaluated in the laboratory on cowpea seedlings grown in paper cups. Though the highest reduction in aphid count after 120 h of treatment was recorded in hexane fraction at 0.2 % (90.00 per cent), chloroform (86.67) and aqueous fraction (85.00) also recorded reduction in aphid count on par with it, at the same concentration. Qualitative phytochemical analysis of the hexane and chloroform fractions was carried out by GC-MS/MS to identify the major bio- active constituents. The two compounds, 4-o-methylphorbol 12, 13- didecanoate and milbemycin b were found in both the fractions, while 4α-phorbol 12,13-didecanoate was found in hexane fraction only. The best concentrations of the three botanical fractions of T. minuta were tested for efficacy against T. truncatus on potted plants of amaranthus along with neem oil emulsion (2%) and horticultural mineral oil (2.5%). After 14 days of treatment, the hexane fraction recorded the highest reduction in mite population (88.78 %) followed by chloroform and aqueous fractions which were on par with each other (77.97 and 76.96 %, respectively). Hexane fraction was superior to neem oil emulsion, while chloroform and aqueous fractions were found to be on par with neem oil emulsion (76.44), which is a widely recommended botanical preparation for mite pest management in different crops. The best concentrations of the three solvent fractions of T. minuta identified in the laboratory study were evaluated against A. craccivora on cowpea, in a pot culture experiment. By 10th day of treatment, the field efficacy of hexane fraction (78.95 % reduction) was comparable with that of neem oil emulsion (87.59 %), while chloroform (72.43 %) and aqueous fractions (68.20 %) were comparable with azadirachtin 1 EC (67.97 %). The results of the study indicate that Mexican marigold possess excellent acaricidal and insecticidal properties and that the plant can be explored further, for utilization in the management of spider mites as well as aphids.ThesisItem Open Access Origin and composition of stingless bee propolis(Department of Agricultural Entomology, college of Agriculture , Vellayani, 2023-05-03) Abhijith,R L; KAU; Vijayasree VThe present investigation entitled “Origin and composition of stingless bee propolis” was conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani during 2020-2022. The objective of the study was to assess the resin-foraging behaviour of stingless bees, the origin of the resin, and the characterization of bee propolis. Four locations viz., AICRP on Honey Bees and Pollinators, Vellayani, and apiaries in Nedumangad, Mariapuram, and Navaikulam were selected for the study. Resin sources, foraging rate, physical characteristics, and major components of propolis were studied. The trees and plants were observed within up to a 100m radius of the bee hive for identifying the resin source. Plants identified were Mango tree (Mangifera indica L.), Jack tree (Artocarpus heterophyllus Lam.), Breadfruit tree (Artocarpus altilis Parkinson), Cashew tree (Anacardium occidentale L.), Cambodge tree (Garcinia cambogia Syn.), False mangosteen (Garcinia xanthochymus Hook.), Monkey puzzle tree (Araucaria araucana Molina). Based on the resin flow and wounds present, plants were grouped into 4 grades from 1-4. The number of bees visiting the wound was also counted. M. indica (4) and G. cambogia (3) were recorded with maximum stingless bees foraging per day. A. araucana and G. xanthochymus came under grade 2 with minimum stingless bees foraging per day. Resin foraging activity was found high from 0900h to 1600h in all the locations throughout the observation. Peak foraging activity was noticed from 1100h to 1200h at Vellayani, Mariapuram, and Nedumangad, Navaikulam. There was no significant correlation between weather parameters and resin foraging rate when correlation studies were conducted. Propolis from all the locations possess pleasant aromatic smells and was sticky in texture at normal temperatures and hard at cold temperatures. The colour of propolis from Vellayani and Navaikulam was moderate brown. It was dark grayish-reddish brown and moderate olive brown in Nedumangad and Mariapuram respectively. LC-HRMS and GC-HRMS analysis revealed that the main chemical classes present in the propolis were acids, fatty acids, steroids, alcohols, amines, amino acids, flavonoids, terpenoids, chalcones, aldehydes, ketones, benzene, coumarin, pterocarpan, ether, and ester. The predominant components identified in the propolis of Vellayani and Nedumangad were 20S, 24S-dihydroxy dammer-25-en-3-one, whereas it was Glycyrrhizic acid in Mariapuram and Navaikulam. The various components found common throughout the locations were syringic acid, and ellagic acid (acids), punicic acid, 9,10-dihydroxystearic acid, and phloionolic acid (steroids and fatty acids), thevetiaflavone, luteolin, and quercetin (flavonoids), octadecanamine and oleamide (amines), ursolic acid and oleanolic acid (terpenoids), 5-[(z)-pentadec-8-enyl] benzene1,3-diol (alcohols), dihydrocordoin and orotinichalcone (chalcones). Thus, this study identified different botanical resin sources and found M. indica and G. cambogia with maximum stingless bees foraging. High foraging activity was observed from 0900h to 1600h in all the locations throughout the year. Several components were identified with functional groups like acids, fatty acids, steroids, alcohols, flavonoids, terpenoids, etc. from the propolis when the chemical characterization studies were carried out.ThesisItem Open Access Bioefficacy of Aloe vera (L.) in managing pests of brinjal, Solanum melongena L.(Department of Agricultural Entomology, College of Agriculture,Vellayani, 2023-04-25) Ajay P Kumar; KAU; Malini NilamudeenThe research programme, entitled “Bioefficacy of Aloe vera (L.) in managing pests of brinjal, Solanum melongena L.” was undertaken at the Department of Agricultural Entomology, College of Agriculture, Vellayani during the period 2020 to 2022. The objective of the study was to evaluate the biopesticidal efficacy of A. vera in managing pests of brinjal. Laboratory screenings were conducted to find out the repellent, antifeedant, insecticidal and the effect on fecundity and egg hatchability of aloe leaf extracts viz., crude aloe gel solution, aloe leaf peel aqueous extract and aloe leaf peel powder aqueous extract at three different concentrations (2.50 %, 5.00% and 10.00%) against second instar grubs and adults of Henosepilachna vignitioctopunctata (F.). The highest per cent repellence recorded was 73.33 and 83.33 in aloe leaf peel powder aqueous extract 10 % at 8 h after treatment against the second instar grubs and adults, respectively. Crude aloe gel solution 10 % recorded a per cent repellence of 53.33 against both grubs and adults whereas, aloe leaf peel aqueous extract 10 % recorded 53.33, 30.00 per cent repellence against second instar grubs and adults, respectively. Aloe leaf peel powder aqueous extract 10 % recorded a potential Antifeedant Index (AI), of 99.47 per cent and 100 per cent against the grubs and adults, respectively. Crude aloe gel solution 10 % recorded AI of 88.49 per cent and 99.95 per cent against grubs and adults, respectively whereas, aloe leaf peel aqueous extract 10 % exhibited AI of 70.93 per cent and 90.33 per cent against grubs and adults, respectively. The fecundity of the beetles which were fed on leaves treated with aqueous extract of 10 % leaf peel powder of aloe was reduced to 57.00 per cent and the percentage emergence of grubs was only 82.52. Crude aloe gel solution 10 % recorded a reduction of 45.16 per cent in fecundity and the per cent emergence of grubs was 92.17. Aloe leaf peel aqueous extract 10 % reported only 29.03 per cent reduction in fecundity and 100 per cent emergence of grubs. None of the treatments recorded any mortality on grubs and adults even after eight days of treatment. Based on the results under in vitro experiments, field efficacy of crude aloe gel solution, aloe leaf peel aqueous extract and aloe leaf peel powder aqueous extract at 10.00 % concentrations were evaluated at the Instructional Farm, College of Agriculture, Vellayani in managing the population of Aphis gossypii, Amrasca bigutulla bigutulla, Coccidohystrix insolita, H. vigintioctopunctata and fruit damage caused byLeucinoides orbonalis. At 14 days after treatment, aloe leaf peel powder aqueous extract 10 % recorded a reduction of 56.29, 84.74, 65.18 and 73.50 per cent reduction in the population of aphids, leafhoppers, mealybug and epilachna beetles, respectively. Two weeks after the treatment, aloe leaf peel powder aqueous extract 10 per cent was statistically on par with talc-based formulation of B. bassiana NBAIR Bb5 @ 20 g L-1 in reducing the population of, both aphids and leafhoppers. And it was on par with neem garlic soap formulation-KAU Raksha @ 10 g L-1 in reducing the population of aphids, mealybugs and epilachna beetles. Fifteen days after the treatment, the plots treated with aloe leaf peel powder aqueous extract 10 % recorded a reduction of 39.13 per cent in fruit damage caused by L. orbonalis. At 30 days after treatment, all aloe extract treated plots were on par with talcbased formulation of B. bassiana NBAIR Bb5 @ 20 g L -1 and neem garlic soap formulation-KAU Raksha @ 10 g L -1 in reducing the fruit damage caused by the shoot and fruit borer. All the aloe extracts were found safe to natural enemies, in comparison with the chemical check. Fruit yield from aloe leaf peel powder aqueous extract 10 %, aloe leaf peel aqueous extract 10 % and crude aloe gel solution 10 % treated plots were 0.77, 0.54 and 0.49 kg plant -1 . From the present study, it was clear that the aloe extracts viz., crude aloe gel solution, aloe leaf peel aqueous extract and aloe leaf peel powder aqueous extract at different concentrations exhibited repellent and antifeedant activity in addition to its effect on fecundity and egg hatchability of epilachna beetles. Aloe leaf peel powder aqueous extract 10 % was found more effective compared to 10 % concentrations of crude aloe gel solution and aloe leaf peel aqueous extract in field conditions. Further research to isolate and elucidate the chemical constituents responsible for the effectiveness of aloe leaf peel powder aqueous extract, can pave way for the development of a novel biopesticide.ThesisItem Open Access Susceptibility of Tetranychus okinawanus Ehara (Prostigmata: Tetranychidae) infesting ornamental plants to novel acaricides(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2021) Sreshma, M; KAU; Haseena, BhaskarSpider mites of the family Tetranychidae are well-known agricultural and horticultural pests that feed on a wide variety of plants, including vegetables, fruit trees, and ornamentals. Many traditional insecticides and acaricides have been used to manage mite pests for several decades. The widespread usage of acaricides around the world has facilitated development of resistance in different mite species, making mite management challenging. As a result, many novel acaricides with distinct chemical structures and modes of action have been developed and marketed for mite control. However, after a few years of use, mite populations developed resistance to these newly introduced compounds too. The spider mite species, Tetranychus okinawanus, recently recorded on an ornamental plant Adenium in Thrissur district, for the first time in India, has now emerged as the predominant species of mite infesting ornamental plants in Kerala. Recently, several growers reported inefficacy of the commonly used novel acaricides against mite pests in many ornamental crops, suggesting that the mite populations might have developed resistance to acaricides. Hence a study was carried out to investigate the status of acaricide resistance in Tetranychus okinawanus infesting Adenium in horticultural nurseries and also to elucidate the biochemical mechanism involved in development of resistance. Purposive surveys were conducted in six commercial horticultural nurseries in Thrissur district viz., National Rose Garden, Mangadan Botanical Garden, Ayyappa Nursery, Saranamayyappa Nursery, Pooja Gardens and Nursery, and Manalur Adenium Garden and samples of spider mite infesting Adenium were collected. Mites were maintained as separate isoline cultures assigning unique accession numbers as NrAd1, MgAd2, AyAd3, SyAd4, PjAd5 and MnAd6. Morphological characterisation of the slide mounted mite specimens from the isoline cultures was carried out to confirm the species identity as T. okinawanus. Susceptibility of the six field populations to three acaricides viz., spiromesifen, fenazaquin and dicofol was evaluated in the laboratory, in comparison with the reference susceptible population maintained without exposure to any acaricides in the laboratory, following toxicological bioassay. Susceptibility studies with fenazaquin revealed that the accession NrAd1 recorded the highest LC50 value (27.85 ppm) and has developed moderate level of resistance (14.38-fold) to fenazaquin. This was followed by PjAd5 (9.70-fold), AyAd3 (4.06-fold), MnAd6 (3.78-fold), and SyAd4 (3.23-fold). The lowest resistance ratio was recorded by the accession MgAd2 (1.66). The toxicity studies of spiromesifen also recorded low to moderate levels of resistance in different populations of T. okinawanus. The accession NrAd1 recorded highest resistance ratio of 27.31 followed by PjAd5 (7.18), MnAd6 (3.94), AyAd3 (1.78), MgAd2 (1.42) and SyAd4 (1.06). However, the mite populations showed only low level of resistance to dicofol, recording resistance ratios in the range of 3.65 to 1.22. Biochemical basis of acaricide resistance in different populations of T. okinawanus was investigated by estimating the activity of detoxifying enzymes such as carboxyl-esterase, cytochrome P450 and glutathione S- transferase. Carboxyl-esterase enzyme showed an enhanced activity of 1.03 to 3.52-fold, while cytochrome P450 monooxygenases recorded 1.01 to 2.08-fold higher activity in the field collected populations, compared to the susceptible population. The level of these detoxifying enzymes was found to be higher in the accession NrAd1, which also recorded the highest resistance ratio in the study. However, the activity of glutathione S-transferase (GST) did not differ significantly among the field populations and also with susceptible population, indicating that GST is not a contributing factor in the development of resistance in T. okinawanus against spiromesifen, fenazaquin and dicofol. The study recorded development of resistance in the spider mite, T. okinawanus on Adenium to spiromesifen and fenazaquin, in the horticultural nurseries in Thrissur district, Kerala for the first time in the world. The significant role of the detoxifying enzymes, carboxyl-esterases and cytochrome P450 monooxygenases in imparting resistance in T. okinawanus to the two novel acaricides, fenazaquin and spiromesifen was also confirmed in the study. The study demands formulation of a suitable resistance management strategy in horticultural nurseries in the state for suppressing or delaying resistance development in mite populations.ThesisItem Open Access Microbial diversity in hive-stored pollen of indian honey bee, Apis cerana indica (Fabricius)(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2021) Abhishek, V; KAU; Mani ChellappanHoney bees are eusocial flying insects. Among all insects that pollinate, honeybees are considered to be one of the crucial pollinators. Honey bees represent only a small fraction of the roughly 20,000 known species of bees. Honey bees obtain all of their nutritional requirements from a diverse combination of pollen and nectar. Pollen grains referred to as 'bee bread' or 'bee meat' are the natural sources of proteins, vitamins, fats, lipids and minerals, of which proteins are very much essential for building the body tissues of the bees, especially during the early embryonic growth. Worker bees of Apis cerana indica help in the fermentation of pollen which releases additional nutrients that are used in the production of antibiotics and fatty acids which inhibit spoilage. Pollen analysis of samples provides the information regarding the plants preferred by bees for nectar, as the pollen grains dispersed are mostly collected by bees along with nectar. Honey has two sources of contamination, primary one being the hive stored pollen. Thus, it is very essential to study the microbial diversity of pollen, which may lead to spoilage of pollen and nectar. The present investigation on “Microbial diversity in hive-stored pollen of Indian honey bee, Apis cerana indica (Fabricius)” was conducted at Department of Agricultural Entomology, College of Agriculture, Vellanikkara, Kerala Agricultural University during 2020-2021 in order to study the diversity of hive-stored pollen and associated microbes in A. cerana indica (Fabricius) colonies. Purposive surveys were conducted in six locations at Palakkad and Wayanad district viz., Mannarkkad, Nellipuzha, Nottaamala, Kenichira, Kayakunnu and Cheengode. Hive stored pollen collected were maintained in refrigerated conditions after assigning unique accession numbers as PKD-1, PKD-2, PKD-3, WYD-1, WYD2, WYD-3. Microbial diversity, microbial load of hive stored pollen, identification and characterization of pollen with respect to its nature, size, shape, aperture, exine pattern along with physicochemical properties viz., moisture content, water activity, pH, ash content, total acidity and protein content were studied. Palynological identification plays a crucial role in beekeeping industry. Pollen aids as a food supplement to honeybees for their growth and development. It assists in the identification of geographical and botanical origin of pollen. A total of 21 plants were recorded as pollen sources by bees from the study area (six locations) of two districts. Ten pollen types were identified based on its nature, size, shape, aperture, exine pattern using PalDAT software. Identified plant species were Sphagneticola trilobata (Asteraceae), Caesalpinia pulcherrima (Fabaceae), Zinnia elegans (Asteraceae), Ocimum sanctum (Lamiaceae), Clitoria ternatea (Fabaceae), Biophytum sensitivum (Oxalidaceae), Bauhinia acuminata (Fabaceae), Mimosa pudica (Fabaceae), Tecoma stans (Bignoniaceae), Portulaca grandiflora (Portulacaceae). Characterization of pollen revealed that ten plant species belonging to seven families serve as pollen sources in respective survey locations. Physicochemical properties of hive stored pollen of A. cerana indica collected from six locations were investigated by estimating the moisture content, water activity, pH values, ash content, total acidity and protein content. Moisture content varied from 15.29-15.38 (g/100g). Water activity varied from 0.73 to 0.74 (aw) and the pH varied between 3.77 and 3.83. Ash content varied from 1.87-2.01 (g/100g). Total acidity varied from 9.64-10.13 (mmol/g). Protein content varied from 3.46-3.69 (%). Parameters like moisture content, water activity, protein content were more in the Wayanad sample, it may be because of high humidity and temperature variations. Parameters like pH, total acidity and ash content were more in Palakkad sample, which infers that mineral content might be more. Microbial diversity of hive stored pollen of Apis cerana indica collected from six locations was investigated by identifying the microbes through their morphological, cultural, molecular characterization. Other parameters like microbial diversity, microbial load, microbial load to pollen grain ratio, microbial population were also observed. In total, four bacteria and three fungal species were identified. However, colonies of actinomycetes and yeast were not obtained. Out of four bacteria, B2, B3, B4 – gram positive while B1- gram negative. The shape of all bacterial isolates was rod with change in their colony colour.16s rRNA sequencing of bacterial isolates revealed that B1 as Pseudomonas aeruginosa, B2 as Bacillus megaterium, B3 as Bacillus aryabhattai and B4 as Bacillus megaterium respectively. Out of the three fungi, colony colour of T1 colony colour was green, W1 colony colour was white and A1 colony colour was orange. All isolates have flat elevation with an entire margin. ITS sequencing of fungal isolates revealed that T1 as Trichoderma reesei, W1 as Westerdykella multispora and A1 as Neurospora crassa. Microbial diversity was more in sample collected Wayanad with two fungal and two bacterial colonies whereas, one fungal and two bacterial colonies in sample collected from Palakkad. Microbial load was more in samples from Wayanad (6.6x104 cfu/g) when compared with Palakkad sample (3.3x104 cfu/g). Comparison of microbial load to pollen grain ratio revealed that Wayanad sample recorded highest with 6.6x104 cfu/g to Palakkad sample with 3.3x104 cfu/g. Bacterial and fungal populations were observed more in Wayanad sample when compared to Palakkad sample. The study recorded the pollen sources of different localities in and around the Palakkad and Wayanad districts of Kerala. Moisture content plays a significant role which might be the reason for high microbial diversity and microbial load in Wayanad. The present study demands the investigations of other physicochemical properties like EC, starch content, amino acid composition, microbial spores present in pollen which could be useful for the food preservation industry or potentially hazardous in due course of time.ThesisItem Open Access Insecticide resistance management in Rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2021) Neethu, P; KAU; Thania Sara VargheseThe research work entitled "Insecticide resistance management in rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)" was done at College of Agriculture, Vellayani during 2019 to 2021.The objectives of the study were to assess the resistance levels in rice weevil, biochemical basis of resistance and screening of new molecules for the management of S. oryzae. Different sample populations of S. oryzae were collected from the three godowns of Food Corporation of India (FCI) viz., Kollam, Valiyathura, and Thikkodi, as well as a susceptible lab culture of S. oryzae maintained without pesticide exposure, was obtained from the Division of Entomology, Indian Agricultural Research Institute (IARI). Resistance levels of the commonly used insecticides in FCI viz., malathion and deltamethrin were evaluated in the three populations collected from Kollam, Valiyathura and Thikkodi by film method of bioassay and compared it with the susceptible lab population from IARI. Kollam population showed highest resistance to both malathion and deltamethrin with resistance ratios of 14.94 and 9.03 followed by Valiyathura with resistance ratios of 11.39 and 7.79, respectively. Thikkodi population showed the least resistance to malathion and deltamethrin, with resistance ratios of 8.74 and 5.48, respectively. Malathion resistance was higher in all the three populations than the deltamethrin resistance. The most resistant population selected from the previous experiment i.e., the Kollam population was further assayed for its biochemical basis along with the susceptible IARI lab culture. The Kollam population was found significantly higher in total protein (6 mg ml-1 ) and activity of detoxifying enzymes viz., carboxylesterases (0.65 µmol min-1 mg protein-1 ), glutathioneS-transferases (0.41 µmol min-1 mg protein-1 ) and cytochrome P450 (0.74 p mol min-1mg protein-1 ) than the lab sample. The sample population collected from Kollam was again screened for their susceptibility to new generation insecticides like fipronil, indoxacarb and chlorantraniliprole by film method of bioassay. Fipronil was found to be more toxic with LC50 value of 5.86 ppm followed by indoxacarb (90.57 ppm) and chlorantraniliprole (4041.43 ppm). Fipronil and indoxacarb were 619.8- and 40.13-fold toxic to resistant population of S. oryzae with respect to malathion. The newer insecticides in the previous experiment along with malathion and deltamethrin were further screened simulating the conditions of FCI godown. The insecticides were sprayed on jute bags containing 1 kg of rice grains and 50 adult beetles of Kollam population of S. oryzae. The dosages of newer insecticides were taken 10 times more the LC50 value obtained in the laboratory bioassay and FCI recommended dosage was taken for malathion and deltamethrin. Fipronil 5% SC @ 0.006% recorded significantly higher mortality of 86.5 and 89.5 per cent at 24 and 48 h of treatment followed by indoxacarb 14.5% SC @ 0.09% and chlorantraniliprole 18.5% SC @ 4.04%. The persistence of the most effective insecticide fipronil along with malathion and deltamethrin on rice grains were further studied by recording the residue levels at different time intervals after spraying. Dosages were same as the previous experiment. Insecticides were sprayed on jute bags containing rice grains and residues were analysed at 0 (2 h after spray), 1, 3, 5, 7,10, 15, 20 and 30days intervals using the methods validated prior to residue estimation. Fipronil residues were below the limit of quantification at 2 h after spraying. The residues of deltamethrin and malathion persisted up to 3 and 5 days after spraying with a half-life of 2.48 and 2.71 days, respectively. From the present study it is revealed that S. oryzae collected from Kollam, Valiyathura and Thikkodi were resistant to the commonly used insecticides viz., malathion and deltamethrin and it is confirmed here by the presence of higher levels of detoxifying enzymes in the resistant population. Further screening of newer insecticide molecules against the resistant population of S. oryzae suggested that fipronil 5% SC @ 0.006% is highly effective and less persistent on grains when compared to malathion and deltamethrin.ThesisItem Open Access Field tolerance of chilli varieties against sucking pest complex(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2022) Haritha, N K; KAU; Vijayasree, VThe study on the “Field tolerance of chilli varieties against sucking pest complex”was conducted at Department of Agricultural Entomology, College of Agriculture, Vellayani during 2019-2021 with the objective to evaluate chilli genotypes for field tolerance to sucking pest complex viz; Aphis gossypii Glover, Polyphagotarsonemus latus Banks and Scirtothrips dorsalis Hood. A total of 30 genotypes were screened for the field tolerance to the sucking pests, including indigenous genotypes of Kerala, KAU released varieties and accessions from NBPGR. The mean population count of A. gossypii, P. latus and S. dorsalis on 20, 35, 50 and 65 days after transplanting was recorded and significantly lower mean number of A. gossypii was recorded in L3 (2.83 leaf-1), L9 (4.61 leaf-1) and L14 (5.75 leaf-1). The population of P. latus was observed least in the genotype L5 with a mean number of 1.47 mites leaf-1 which was followed by L14 (2.36 leaf-1) and L3 (2.49 leaf-1). The minimum incidence of S. dorsalis was recorded in the genotype L5 which showed a mean population of 2.25 thrips leaf-1 and it was followed by L14 (3.94 leaf-1) and L3 (4.03 leaf-1). The genotype L11 was found most susceptible with the highest number of A. gossypii (23.72 leaf-1), P. latus (6.30 leaf-1) and S. dorsalis (6.75 leaf-1). The damage assessment was done by observing the leaf damage caused by mites and thrips. When the mean leaf damage was recorded on 20, 35, 50 and 65 days after transplanting, P. latus showed least preference to the genotype L5 with a per cent leaf damage of 14.92 and this was followed by L14 (16.92) and L3 (20.92). The minimum damage by S. dorsalis was observed in the genotype L5 with a leaf damage of 15.08 per cent and was followed by L3 and L14 with a leaf damage of 18.33 and 21.08 per cent respectively. The genotype L11 was severely damaged by P. latus and S. dorsalis with a per cent leaf damage of 76.33 and 74.08 respectively. The Per cent Leaf Curl Index (PLI) was calculated based on the leaf damage, for grouping the chilli genotypes into resistant, moderately resistant, susceptible and highly susceptible categories. Based on the mean PLI due to damage by P. latus the genotypes, L5 and L14 were grouped under moderately resistant category. The genotypes L5 and L3 were grouped as moderately resistant based on mean PLI due to damage by S. dorsalis. The genotypes L11, L4, CF1 and IC284628 were coming under the highly susceptible category due to infestation of P. latus and S. dorsalis. Principal Component Analysis (PCA) was carried out based on the mean population of A. gossypii, P. latus and S. dorsalis to find out the tolerant and susceptible genotypes against the sucking pest complex. The genotypes L5, L3 and L14 were found as the tolerant and L11 as the susceptible genotype for which the analysis of morphological traits, biochemicals and nutrients were carried out. Different morphological traits like plant height, total number of leaves plant-1 and leaf area were highest in L3. The number of branches plant-1 and trichome density was highest in L5 and the length-width ratio of leaves in the genotype L14. However, all these morphological characters were found lowest in the genotype L11. Analysis of biochemicals revealed that the total phenol content and capsaicin content was highest in the genotype L5 (0.290 mg g-1 and 0.016mg g-1 respectively) and lowest in the genotype L11. Total protein and total sugar were highest in L11 (6.169 mg g-1 and 0.216 mg g-1 respectively) and lowest in L14. Total nitrogen and total phosphorus were highest in L11 (0.18% and 0.63% respectively) and lowest in L3. Total potassium was highest in L14 (1.08%) and lowest in L11 (0.46%). Correlation studies were done to find out the relationship between the different traits in chilli genotypes and infestation of A. gossypii, P. latus and S. dorsalis. Among the morphological characters, plant height and leaf area had a significant negative correlation with the population of A. gossypii while number of branches plant-1 had a significant negative correlation with the incidence of all the three sucking pests. The total protein and total sugar had a significant positive correlation with the population of A. gossypii, whereas total phenol had a significant negative correlation with the incidence of P. latus and S. dorsalis. Total nitrogen had a significant positive correlation with the population of A. gossypii whereas total phosphorus had a significant positive correlation with the population of S. dorsalis. Based on the mean population of A. gossypii, P. latus and S. dorsalis and the leaf damage caused by them, the genotypes L5, L3 and L14 were observed as the tolerant whereas the L11 was found as the susceptible genotype to these sucking pest complex.ThesisItem Open Access Quantification and characterization of Indian honey bee (Apis cerana indica Fab.) Venom(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2022) Alen, Joy; KAU; Amritha, V SThe research work entitled “Quantification and characterization of Indian honey bee (Apiscerana indica Fab.) venom” was carried out at College of Agriculture, Vellayani during the year 2019 to 2021. The objective of the study was quantification and characterization of Indian honey bee venom during different seasons. Hives of uniform bee strength maintained in the apiary of AICRP on Honey Bees & Pollinators were selected to identify the peak hour of the day at which maximum bee venom can be collected from a hive using a bee venom collector. Venom was collected from hives at different hours starting from 6 am to 6 pm for three days. The optimum duration at which maximum venom can be collected from the hive with minimum damage to the bees were also assessed. Venom was collected for three different durations viz., 30 minutes, 40 minutes and 60 minutes and the quantity of venom collected and mortality was recorded. Seasonal variation was assessed by collecting venom at the peak hour and optimum duration on all the three seasons viz, brood rearing (September - December), honey flow (January - April) and dearth (May-August). The brood parameters and foraging activity of the hives were also assessed at weekly intervals for a period of one month in order to determine whether the bee venom collection has any impact on these parameters. The venom collected during the three seasons were subjected to characterisation and the proportion of components present in the venom were analysed. Control hives were maintained and the data were subjected to ANOVA and paired t test analysis. Observations on the venom collection at hourly intervals of a day revealed that maximum quantity of venom was collected at 2 pm to 3 pm (52.00 mg per hive) and least venom was collected at 7 am to 8 am. Statistical analysis of the data on optimum duration for venom collection showed that highest quantity of venom was collected at 60 minutes duration (55.34 mg per hive), but the mean mortality was high (5.20 bees per hive). Venom collected at 40 minutes and 30 minutes were 34.14 mg and 25.12 mg per hive which were on par. The optimum duration for placing the bee venom collector was selected as 30 minutes considering the low mortality of bees (0.80 per hive) as compared to 40 minutes (2.00 per hive). Significant variation was not observed in the brood parameters as well as in the foraging activity of the venom collected and control hives. Studies on the seasonal variation in bee venom collected revealed that maximum quantity of venom was collected at honey flow season (55.16 mg per high) followed by dearth season (41.00 mg) and brood rearing season (25.12 mg). Maximum mortality was also recorded at honey flow season followed by dearth season and brood rearing season. Brood parameters as well as the foraging activity of the bees did not vary significantly among the seasons. The quantity of bee venom collected had a non-significant positive correlation with temperature and negative correlation with humidity. The characterisation of bee venom samples collected during the three seasons were carried out at SAIF, IIT Bombay by HR LC-MS (High Resolution Liquid Chromatography-Mass Spectrometry) with database (Plant extract Impurity Profiling and Metabolite Identification). Melittin and apamin were identified as the major components, with melittin showing maximum abundance on all the three seasons. No significant difference was recorded in the abundance of both melittin and apamin among the three seasons. Thus, in the present study, highest quantity of bee venom was collected at 2 pm to 3 pm (52.00 mg per hive) and the optimum duration for collection was 30 minutes, considering the bee mortality factors. Studies on the seasonal variation revealed that significantly high bee venom was collected during the honey flow season (55.16 mg per hive), while no significant variation was observed in the brood parameters among the seasons. Characterisation of the bee venom revealed that melittin and apamin were the major components, of which melittin was 8.5 times abundant than that of apamin with no significant variation among the seasons.
