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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 bioformulations of entomopathogenic fungi and their efficacy aganist banana weevils(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Remya, S; KAU; Reji Rani, O PThe study entitled ‘Novel bioformulations of entomopathogenic fungi and their efficacy against banana weevils’ was carried out at Dept. of Agrl. Entomology, College of Agriculture, Vellayani during 2016-2018, with the objective to develop novel formulations of entomopathogenic fungi, Metarhizium anisopliae (Metch.) Sorokin, Beauveria bassiana (Bals.) Vuillemin and to evaluate their efficacy in managing banana weevils. It was intended to develop capsule and gel formulations. Experiment to standardize a coating material for developing capsules revealed that Hard Gelatin Transparent (HGT), Hard Gelatin Coloured (HGC) and Hydroxy Propyl Methyl Cellulose (HPMC), were equally stable under ambient conditions of storage (26 -33°C and RH 60-80%). On testing their ability to disintegrate under field conditions, it was noted that chitosan filled HGT capsules easily disintegrated at 20% soil moisture after 36 h and after 24 h at 30 % soil moisture. It took 144 h for all capsules to disintegrate in sheath or leaf axil and 24 h in bore holes. Talc and chitosan were superior, in maintaining storage stability as well as degradability. A trial conducted to determine the moisture content of capsules, revealed that 10 % was the ideal moisture level content of the ingredient, to maintain storage stability as well as viability of the formulation. Viability noticed after three months was 2.29 × 107 cfu mL-1 and 2.27 × 107 cfu mL-1 in chitosan based capsules of M. anisopliae and B. bassiana and 2.10 × 107 cfu mL-1 and 0.76 × 107 cfu mL-1 in talc based capsules. Therefore, capsules were developed with HGT coating, with chitosan / talc as carrier at 10 % moisture content. Shelf life studies revealed that chitosan was the best carrier material compared to talc in retaining viability of Metarhizium capsules, with a mean cfu of 2.51 × 107 mL-1 and 1.77× 107 mL-1. During a period of three months of storage, there was no decline in the number of viable colonies, cfu ranging from 1.72 × 107 mL-1 to 2.79 × 107 mL-1. . Storage under refrigeration had better retention of viability (2.63 × 107 cfu mL-1) than at room temperature (1.64× 107 cfu mL-1). In Beauveria capsules, the viability did not differ in both chitosan and talc based capsules. Here also, the number of viable colonies did not decline statistically, till three months of storage, with mean cfu values ranging from 1.85 × 107 mL-1 to 2.36 × 107 mL-1. In general, shelf life of capsules could be extended by two months when chitosan was used as the carrier material. Low temperature storage could also improve the shelf life by two months. Shelf life studies of gel formulations indicated that both Metarhizium and Beauveria gels exhibited high viability in chitosan at room temperature and under refrigeration. The mean number of viable colonies observed was 2.39 × 106 cfu mL-1 in chitosan based gels of Metarhizium and 2.17 × 106 cfu mL-1 in Beauveria gels. The number of viable colonies of Metarhizium and Beauveria observed throughout the experimental period did not vary significantly over three months of storage. The mean number of cfu being 2.26 × 107 mL-1 on the 15th day and 1.41 x 106 mL-1 on the 90th day . It was also inferred that chitosan when used for formulating gels could extend the shelf life of both organisms by one month. Pathogenicity test disclosed the affinity of M. anisopliae to rhizome weevil and B. bassiana to pseudostem weevil. Pot culture studies to evaluate chitosan and talc based capsules of B. bassiana revealed that both the capsules of Beauveria were effective as chlorpyriphos 20 EC 0.05% for pseudostem weevil, in prophylactic and curative methods. The damage index (DI) was one each and reduction in pest population was 91.67 % in prophylactic control and 91.67-100 % in curative control. Metarhizium capsules reduced the damage caused by rhizome significantly, but the reduction in pest population was only to the tune of 47-55 % in prophylactic and 50- 58 % in curative control. Chitosan based gel of Metarhizium tested against rhizome weevil, reduced the damage significantly (DI 46.67 and 30, in prophylactic and curative methods). The pest population was reduced by 61.11 % in prophylactic and 36.11 % in curative methods. The study could standardize the protocol for capsule and gel formulations of entomopathogenic fungi, retaining the viability and infectivity upto three months of storage. It is concluded that placement of Beauveria capsules in leaf axils prophylactically and curatively can effectively control pseudostem weevil and Metarhizium capsules and gels placed in the rhizosphere could manage the rhizome weevil moderately.ThesisItem Open Access Ecological Management of Coconut root grub, Leucopholis coneophora Burm(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Melvin Mohan, S; KAU; SanthoshKumar, TThe study entitled ‘Ecological management of coconut root grub, Leucopholis coneophora Burm.’ was conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani, and College of Agriculture, Padannakkad during 2017 to 2019. The main objectives were to study the efficacy of botanical insecticides and biocontrol agents against coconut root grub, L. coneophora. The entire study consisted of two parts, laboratory evaluation and pot culture experiment. The laboratory experiment was conducted for screening various entomopathogenic fungi (EPF), entomopathogenic nematodes (EPN), botanicals and chemical insecticides against coconut root grub. Metarhizium anisopliae (Ma 4) and Beauveria bassiana (Bb 5) at different concentrations (1 x 108, 1 x 109 and 1 x 1010 spores mL-1) were tested. Entomopathogenic nematodes Steinernema carpocasae and Heterorhabditis bacteriophora at 100, 500 and 1000 IJ mL-1 were used for screening. The botanicals such as Azadirachta indica, Gliricidia maculata, Clerodendron infortunatum and Chromolaena odorata @ 25 g kg-1 of soil were screened for their efficacy against root grub. The chemicals used for the experiment comprised of chlorantraniliprole 0.4% G @ 75g a.i ha-1, fipronil 0.3% G @ 75g a.i ha-1 and spinosad 45% SC @ 73g a.i ha-1. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fifteen kilograms of sterilized moist soil was taken in a plastic basin and fresh potato tubers were given as feed for root grub. Three grubs were released into the basin and treatments were given one week after the release of grubs. The screening experiment using EPF consisted of eight treatments with three replications. The application of M. anisopliae @ 1 x 1010 spores mL-1 was found to be the most effective (100 % mortality) EPF against root grub and was on par with chemical check at 14 days after treatment (DAT). At 21 DAT, B. bassiana @ 1 x 1010 spores mL-1 resulted 100 per cent mortality and was on par with M. anisopliae @ 1 x 1010 spores mL-1 and the chemical check. At 28 DAT, M. anisopliae @ 1 x 1010 spores mL-1 and B. bassiana @ 1 x 1010 spores mL-1 brought about 100 per cent mortality of grubs, which were on par with the chemical check chlorpyriphos 20 % EC @ 225g a.i ha-1 (100 %), followed by M. anisopliae @ 1 x 109 spores mL-1 (92.58 %) and B. bassiana @ 1 x 109 spores mL-1 (85.17 %). The screening experiment with EPN consisted of eight treatments with three replications and the results revealed that all the treatments except chemical check failed to cause infection on grubs upto 10 DAT. Among the botanicals, A. indica application showed 48.14 per cent mortality of root grubs followed by C. infortunatum (37.03 %) at 30 DAT. The effect of chemical insecticides on root grub was conducted with five treatments and four replications. Fipronil 0.3% G @ 75g a.i ha-1 exhibited 97.22 per cent mortality and was on par with the chemical check at nine DAT followed by chlorantraniliprole 0.4% G @ 75g a.i ha-1 (74.99 %). Promising treatments viz. M. anisopliae (1 x 1010 spores mL-1, 1 x 109 spores mL-1), B. bassiana (1 x 1010 spores mL-1, 1 x 109 spores mL-1), chlorantraniliprole 0.4% G @ 75g a.i ha-1, and Fipronil 0.3% G @ 75g a.i ha-1 from laboratory experiments were selected and evaluated in a pot culture experiment and were laid out in CRD with eight treatments and three replications. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fodder grass variety CO-3 was raised in pots and first instar grubs were released after the establishment of the crop. The results of the pot culture experiment indicated that the application of fipronil 0.3% G @ 75g a.i ha-1 resulted in 100 per cent mortality and was on par with the chemical check at 28 DAT followed by M. anisopliae @ 1 x 1010 spores mL-1 (85.17 %). The treatments B. bassiana @ 1 x 1010 spores mL-1 (77.77 %), chlorantraniliprole 0.4 % G @ 75g a.i ha-1 (74.06 %) and M. anisopliae @ 1 x 109 spores mL-1 (74.06 %) were found to be on par at 28 DAT. From the present study, it can be concluded that the application of entomopathogenic fungi M. anisopliae @ 1 x 1010 spores mL-1 is a promising option for the management of first instar grubs of L. coneophora followed by B. bassiana @ 1 x 1010 spores mL-1. Soil application of neem leaves @ 25 g kg-1 of soil can enhance the suppression of root grubs. The results clearly indicate the possibility of reducing the use of chemical insecticides by resorting to botanicals and biocontrol agents.ThesisItem Open Access Biosystematics and barcording of pteromalidae (Hymenoptera:Chalcidoidea) of Kerala(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Manu Govind, K.K.; KAU; Shanas, SThe study entitled " Biosyslematics and barcoding of Pteromalidae (Hymenoptera: Chalcidoidea) of Kerala" was conducted during the 2017-19 at the Department of Agricultural Entomology, College of Agriculture, Vellayani with the objective of identification, morphological and molecular characterization and documentation of parasitoid wasps (Pteromalidae) of Kerala. The base material for study was field collected specimens. Purposive sampling was carried out in 38 locations spread across 14 districts of Kerala. The specimens were collected by random sweep net method. The collections were made in the morning and afternoon when the insect activity was at the peak. The sweep contents were immediately transferred into absolute alcohol and the location and date of collection were recorded on the containers. The field collected specimens were examined under high power stereo microscope and initially all the specimens coming under Chalcidoidea were sorted out based on superfamily characters and stored in labelled vials in absolute alcohol. Pleomalid wasps were separated out from these vials and stored in alcohol in another set of vials according to location. The specimens were card mounted for morphometric analysis and characterization. The study revealed 2 genera and 4 species of Ptcromalids which are new to the World of science. The two new genus fall under the subfamily Miscogasterinae and Pteromalinae respectively. The four new speicies discovered are, Dinarmus sp. nov. 1, Mokrzeckia sp nov. 1, Panstenon sp. nov. 1 and Pansienon sp. nov. 2. The Dinarmus sp. nov. 1 was compared to Dinarmus maculatus^ Mokrzeckia sp. nov. 1 was compared to M pint and Panslenon sp. nov. 1 and P. nov. 2 was compared to P. collareThesisItem Open Access Barcoding and biosystematic studies on Hymenopteran pollinators of cucurbitaceous vegetables(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Erra Harisha; KAU; Shanas, S PThe study entitled “Barcoding and biosystematic studies on hymenopteran pollinators of cucurbitaceous vegetables” was conducted during the year 2017- 2019 at the Department of Agricultural Entomology, College of Agriculture, Vellayani with an objective to study the diurnal activity and dynamics of hymenopteran pollinators of cucurbitaceous vegetables and to explore their morphological and molecular diversity. To determine the composition and relative abundance of different hymenopteran pollinators visiting the flowers of five selected cucurbitaceous vegetables viz., culinary melon (Cucumis melo var. acidulus), bitter gourd (Momordica charantia L.), ash gourd (Benincasa hispida Thunb. and Cogn.), pumpkin (Cucurbita moschata L.) and ridge gourd (Luffa acutangula (Roxb.) L.) collections were made throughout the blooming period in Thiruvananthapuram and four other districts of Kerala viz., Kollam, Pathanamthitta, Alappuzha and Kasaragod from 06:00 h to 18:00 h of the day with a cone type hand net. Among the above mentioned vegetables, culinary melon was selected for detailed study on diurnal activity at College of Agriculture, Vellayani. The study on composition and relative abundance of hymenopteran pollinators revealed that, A. cerana indica was the dominant pollinator in culinary melon (42.51 %), pumpkin (38.76 %) and ridge gourd (35.16 %) whereas, T. travancorica was the dominant pollinator in bitter gourd (31.86 %) and ash gourd (33 %). Observations on diurnal activity were carried out at College of Agriculture, Vellayani in culinary melon during two crop seasons for 3 weeks at weekly intervals. For foraging rate, the number of flowers visited by each bee for 1 minute and for foraging speed, time spent by each bee per flower were observed respectively. During two seasons, the foraging speed of A. cerana indica, T. travancorica and Halictus sp. was found to be highest during 10:00-11:00 h (10.61 and 10.63, 11.23 and 11.46, 10.26 and 10.40 seconds) respectively. The foraging speed of C. hieroglyphica and Lasioglossum sp. was found to be highest during 09:00-10:00 h (9.02 and 9.11, 11.06 and 11.30 seconds) respectively. The foraging rate of T. travancorica, C. hieroglyphica and Lasioglossum sp. was found to be highest during 10:00-11:00 h (9.16 and 9.23, 4.83 and 4.85 flowers/m2/5 min) respectively. The foraging rate of A. cerana indica and Halictus sp. was found to be highest during 11:00-12:00 h and 09:00-10:00 h (10.60 and 10.88, 4.03 and 4.13 flowers/m2/5 min) respectively. Samples which were unidentified through morphological characterization were given for DNA barcoding. The sequence of 2 samples viz., Tetragonula sp. nov.1 and T. travancorica were obtained. Among these, new species (Tetragonula sp. nov.1) of stingless bee, based on adult worker specimen is described. Differences in morphology and genetic analysis based on partial sequences of the mitochondrial COI gene barcode region support the recognition of the new species. The above results revealed that A. cerana indica was dominant in culinary melon, pumpkin, and ridge gourd and T. travancorica was dominant in bitter gourd and ash gourd. The foraging speed during two seasons in the descending order was T. travancorica > Lasioglossum sp. > A. cerana indica > Halictus sp. > C. hieroglyphica. The foraging rate during two seasons in the descending order was A. cerana indica > T. travancorica > C. hieroglyphica > Lasioglossum sp. > Halictus sp. Among the pollinators, five species viz., P. phalerata phalerata, C. annulata annulata from ash gourd, M. disjuncta from bitter gourd, C. simillima, and C. unimaculata javanica from culinary melon were reported for the first time pollinating cucurbitaceous vegetables. Tetragonula sp. nov.1 of stingless bee, collected from pumpkin flower, is the new species report from the study and it is morphologically characterised.ThesisItem Open Access Compactibility and synergism of the entomopathogentic fungus lecanicillium saksenae (Kushwaha ) Kurihara and Sukarno with other crop protectants(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Keerthana, K; KAU; Reji Rani, O PThe study entitled “Compatibility and synergism of the entomopathogenic fungus Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno with other crop protectants” was carried out in College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana during 2017-2019 with the objective to assess the compatibility of L. saksenae with botanical insecticides, chemical insecticides, fungicides other entomopathogenic fungi and to evaluate synergistic insecticidal effect. In vitro studies on compatibility was carried out using poisoned food technique, by assessing radial growth, sporulation and germination of L. saksenae. Botanicals tested were aqueous and solvent extracts of neem seed kernel, neem leaves and neem oil emulsion. Among them, lower dose of neem oil emulsion (NOE) 0.5% did not affect the mycelial growth of the fungus. It was 6.27 cm on 14th day after inoculation which was on par with that of control (6.17 cm). Sporulation of the fungus was affected by all the botanicals, with least inhibition in lower dose of aqueous neem leaf extract (NLE (A)) 1% (4.41 x 107 spores mL-1). The corresponding count in untreated medium was 7.57 x 107 spores mL-1. Viability of the fungus was not affected by the lower dose of neem seed kernel extract (NSKE (A)) 0.5%, when compared to control (97.67 % and 99%). Biological index (BI) indicated that aqueous and solvent extracts of NSKE (0.5%), NSKE (A) 1%, NLE (A) 1% and NOE (0.5%) were compatible with L. saksenae, BI values being 75, 69, 70, 75 and 67, respectively. Among the insecticides tested, flubendiamide 39.35 SC was least inhibitory to the growth of L. saksenae, both at half as well as recommended doses (5.92 cm and 5.88 cm), followed by half the recommended doses of thiamethoxam 25 WG (5.88 cm) and chlorantraniliprole 18.5 SC. (5.78cm). The corresponding growth in untreated medium was 6.10 cm. Sporulation in chlorantraniliprole at the recommended dose and control was same (1.35 x 107 spores mL-1). Spore viability was affected by all the insecticides. Germination in imidacloprid was highest among the treatments (85.67 per cent). BI value indicated that imidacloprid, thiamethoxam, flubendiamide and chlorantraniliprole at recommended and half doses were compatible with L. saksenae. (67-94). None of the fungicides tested, were compatible with L. saksenae. B. bassiana at 108 spores mL-1 was found to be compatible with L. saksenae at 107 spores mL-1 based on mortality of treated rice bugs. Treatments L. saksenae and L. saksenae + B. bassiana caused 100 per cent mortality on fourth and fifth day after spraying in nymphs and adults of rice bug. Synergism studies revealed that, on the first day L. saksenae (107 spores mL-1) and L. saksenae + NSKE (A) 0.5% were equally effective causing 83.33% mortality in nymphs, while in adults L. saksenae was superior to its combination (66.67 and 60%). L. saksenae + thiamethoxam 0.0025% exhibited significantly higher mortality in adults (70%) on the first day while in L. saksenae it was 66.67%. For nymphs, L. saksenae and L. saksenae + thiamethoxam 0.0025% was equally effective (83.33% mortality). In both adults and nymphs, L. saksenae was more effective causing 75 per cent and 85 per cent mortality on the first day, while its combination with B. bassiana caused 65per cent and 80 per cent mortality. L. saksenae and its combinations with botanicals, insecticides and microbials had higher feeding inhibition in rice bugs. Under field conditions, L. saksenae at 107spores mL-1 + thiamethoxam 0.0025% and L. saksenae + B. bassiana at 108 spores mL-1 recorded significantly higher population of 3.5 and 2.75 bugs per plot, compared to that of L. saksenae (2.25 bugs per plot). Population of natural enemies did not vary significantly among the treated and untreated plots. Yield recorded at harvest was higher in plots treated with L. saksenae (1.38 kg plot-1) which was followed by combination spray of L. saksenae and B.bassiana (1.32 kg plot-1) It is concluded that L. saksenae is compatible with the botanicals such as neem seed oil emulsion 0.5% and neem seed kernel extract 0.5%. It was also compatible with the new generation insecticides flubendiamide, chlorantraniliprole, thiamethoxam and imidacloprid. Among the microbials, B. bassiana was not inhibitory. Fungicides such as carbendazim, mancozeb, copper oxychloride, hexaconazole and azoxystrobin were inhibitory to L. saksenae. None of the botanicals, insecticides, fungicides or microbials had synergistic effect with L. saksenae. In the management of rice bug L. saksenae was superior to its combination treatments and it did not affect the natural enemy population in rice ecosystem.ThesisItem Open Access Insecticide resistance in spiralling whitefly,aleurodicus dispersus russell(hemiptera:aleyrodidae) and its management(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Aura Senson; KAU; Ambily PaulA study on “Insecticide resistance in spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) and its management” was done at College of Agriculture, Vellayani and farmer’s field at Kalliyoor during 2018 to 2019. Tokassess thehinsecticide resistance in the fieldhpopulation of spiralling whitefly, A. dispersus and to evaluate the efficacy of new generation insecticides against resistant population of A. dispersus were the objectives of the study. Bioassaykwas carriedLout to assess the insecticideHresistance in field population of A. dispersus collectedUfromHthree different locations (location ISreekaryam, location II-Vellayani and location III-Kalliyoor) based on the intensity of insecticide application. A series of concentrations of three insecticides viz., quinalphos, fenvalerate and imidacloprid were prepared in aqueous solution and leaf dip bioassay was done using the field population of whiteflies collected from three locations. Results revealedDthatkpopulation collected from location-I (Sreekaryam) was foundhto begsusceptible to insecticides with resistance ratio-1 for all three insecticides, which was considered as reference strain. Population collectedgfrom location-II (Vellayani) showed higher resistance with resistance ratio of 2.60, 2.90 and 1.85 and population from location-III (Kalliyoor) was found to be moderately resistant with resistance ratio of 1.14, 1.62 and 1.28 with respect to quinalphos, fenvalerate and imidacloprid respectively. Laboratoryyexperiments were conductedutotevaluateethedefficacy ofdnew generationdinsecticides viz. buprofezin 25% SC @ 75 g.a.i ha-1, clothianidin 50% WDG @ 20 g,a.i ha-1, cynantraniliprole 10.26% OD @ 90 gfa.i ha-1, dinotefuran 20% SG @ 25 g a.i ha-1, flonicamid 50% WG @ 75 g a.i ha-1, thiamethoxam 25%WG @ 50 g a.i ha-1 and thiamethoxamt12.6% + lambdadcyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1against resistant population of A. dispersus in tomato plants. The results revealed that significantly higher mortality was observed in A. dispersus treated with thiamethoxamg12.6% +hlambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 (100%), followed by clothianidin 50% WDG @ 20 g a.i ha-1 (80%) and flonicamid 50% WG @ 75 g a.i ha-1 (66.67%) after 0.75 hours of treatment. Field experiment was conducted by using tomato plants (var. Vellayani Vijay) at Vellayani from where resistant population was collected with three effective insecticides selected from laboratory along with control. No whiteflies were seen in thiamethoxamt12.6% + lambdatcyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 treated plants followed by clothianidin 50% WDG @ 20 g a.i ha-1 (9.20) and flonicamid 50% WG @ 75 g a.i ha-1(11.80) after one day of spraying. Studies on the dissipation of residues of effective insecticides viz., thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1, clothianidin 50% WDG @ 20 g a.i ha-1 and flonicamid 50% WG @ 75 g a.i ha-1 were conducted in tomato plants at farmer’s field at Kalliyoor. Tomato fruits collected at 0,1,3,5,7,10,15 and 30 days after application of insecticides at recommended dose and results showed that insecticides dissipated within 10 days with half- lives of 4.05, 3.42, 8.92 and 7.82 days respectively. The risk assessment studies also proved the safety of insecticides for the end users. The present study revealed the development of insecticide resistance in the field population of A. dispersus against fenvalerate and quinalphos. Thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 followed by clothianidin 50% WDG @ 20 g a.i ha-1 and flonicamid 50% WG @ 75 g a.i ha-1 could be recommended against the resistant population of A. dispersus in tomato. Dissipation and risk assessment studies also supported the result by establishing their safety to consumers. Further studies have to be taken up to develop and popularize Insecticide Resistant Management strategies against A. dispersus by developing Good Agricultural Practices on efficient use of insecticides and to conserve the ecosystem for sustainable pest management.ThesisItem Open Access Insecticide mixtures for the management of pest complex in cowpea(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Banka Kanda, Kishore Reddy; KAU; Ambily PaulA study on “Insecticide mixtures for the management of pest complex in cowpea” was undertaken in College of Agriculture, Vellayani and in the farmers field at Kalliyoor during 2016 to 2018. The main objectives were to evaluate the efficacy of insecticide mixtures having component molecules of different mode of action against pests of cowpea and to study the dissipation pattern of mixtures in cowpea pods. Major pests documented in the experimental field were sucking pests viz., pod bug, Riptortus pedestris Fabricius, cowpea aphid, Aphis craccivora Koch, spotted pod borer, Maruca vitrata Fabricius, and leaf eating caterpillar, Spodoptera litura Fabricius. Experiment was laid out in RBD to study the efficacy of insecticide mixtures viz., chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1, lambda cyhalothrin 4.6 % + chlorantraniliprole 9.3 % ZC @ 30 g a.i ha-1, thiamethoxam 12.6 % + lambda cyhalothrin 9.5 % ZC @ 27.5 g a.i ha-1, beta cyfluthrin 8.49 % + imidacloprid 19.81 % SC 15.75+36.7 g a.i ha-1, flubendiamide 19.92 % + thiacloprid 19.92 % SC @ 48+48 g a.i ha-1, chlorantraniliprole 18.5 % SC +thiamethoxam 25 % WG (hand mixed) @ 1:1 @ 0.30 mL L-1 along with standard checks chlorantraniliprole 18.5 % SC @ 30 g a.i ha-1 and thiamethoxam 25 % WG @ 0.30 g L-1 against cowpea pests (Cowpea variety- Vellayani Jyothika). The results of the study revealed that chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1 was found effective in managing the population of pod bug, R. pedestris, followed by followed by followed by followed by followed by thiamethoxam 12.6 % + lambda cyhalothrin 9.5 % ZC @ 27.5 g a.i ha-1 and beta cyfluthrin 8.49 % + imidacloprid 19.81 % SC @ 15.75+36.7 g a.i ha-1. Less incidence of bug was found in effective treatments after 7 days of spraying. More or less similar result was obtained in the management of cowpea aphid, A. craccivora. Less number of aphid was observed in the plants treated with chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1, thiamethoxam 12.6 % + lambda cyhalothrin 9.5 % ZC @ 27.5 g a.i ha-1, chlorantraniliprole 18.5 % SC + thiamethoxam 25 % WG (hand mixed) @ 1:1 @ 0.30 mL L-1 and thiamethoxam 25 % WG @ 30 g a.i ha-1 against 211.67 aphids plant-1 in control after 15 days of spraying. Significantly higher reduction in leaf damage by S. litura was recorded in plants treated with lambda cyhalothrin 4.6 % + chlorantraniliprole 9.3 % ZC @ 30 g a.i ha-1 (25.03) which was on par with thiamethoxam 12.6 % + lambda cyhalothrin 9.5 % ZC @ 27.5 g a.i ha-1 (26.46) and chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1 (30.20) 10 days after spraying. Whereas, in the management of cowpea pod borer, M. vitrata, less incidence of larvae was found in lambda cyhalothrin 4.6 % + chlorantraniliprole 9.3 % ZC @ 30 g a.i ha-1 and chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1 treated plants after 5 days of spraying against 6.67 larvae in control. Dissipation of residues of these effective insecticide mixtures were studied by analysing the pods collected at 0, 1, 3, 5, 7, 10 and 15 days after treatment and the result showed that both the single insecticides in chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC were dissipated within ten days with half-lives of 5.34 and 3.01 respectively and in lambda cyhalothrin 4.6 % + chlorantraniliprole 9.3 % ZC, lambda cyhalothrin dissipated in five days and chlorantraniliprole dissipated in seven days with half-lives of 5.58 and 13.67 days respectively. The infestation of sucking pests, borers and leaf feeders simultaneously occur in cowpea especially in pod bearing stage. The results of the study revealed that spraying chlorantraniliprole 8.8 % + thiamethoxam 17.5 % SC @ 150 g a.i ha-1, thiamethoxam 12.6 % + lambda cyhalothrin 9.5 % ZC @ 27.5 g a.i ha-1 and lambda cyhalothrin 4.6 % + chlorantraniliprole 9.3 % ZC @ 30 g a.i ha-1 could effectively manage pest complex in cowpea with minimal or no risk to the consumers.ThesisItem Open Access Histomorphology of Indian bee (Apis cerana indica Fab.) supplemented with probiotics(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Akhila Pahee; KAU; Amritha, V SThe study entitled “Histomorphology of Indian bee (Apis cerana indica Fab.) supplemented with probiotics” was undertaken at College of Agriculture, Vellayani, Thiruvananthapuram during 2017- 19. The main objective was to assess the histomorphology of midgut of Indian bee’s (Apis cerana indica Fab.) suffering from various stressors (pathogens and insecticides) and, after being fed with probiotics. Purposive sampling was conducted at Thiruvananthapuram, Kollam, Pathanamthitta and Idukki districts for the present study. Twelve larvae (3 to 4 days old) each from naturally occurring feral colony, domesticated colonies which were fed with and without sugar syrup, naturally infected ones with bacterial brood disease as well as larvae fed with insecticide treated royal jelly (Thiamethoxam 25% WG) were collected and subjected to histomorphological evaluation. Also, the effect of probiotics on larvae under different stress conditions were also evaluated. The study mainly focused on the variations in the midgut histology of the larvae. The midgut of the honey bee larvae from feral colony had high epithelial integrity, well defined brush bordered microvilli which probably helps in the easy absorption of nutrients, prominent regenerative cells that is responsible for epithelial cell replacement and copious secretion of peritrophic membrane that are intented for the protection of the midgut from abrasive food particles, pathogen and toxins. The larvae of the colonies which were not fed with sugar also had similar histology. Histomorphological studies of honey bee larvae fed with sugar syrup, revealed the adverse effect of sugar on midgut cells viz., presence of vacuoles in the epithelium, absence of microvilli, reduced number of regenerative cells and uneven peritrophic membrane secretion. Studies on the midgut histomorphology of bacterial brood disease infected larvae indicated necrosis with picnotic or karyorrhectic nuclei, moderate to severely vacuolated cytoplasm, inconspicuous microvilli and distorted peritrophic membrane. Only occasional regenerative cells were apparent. The midgut epithelial cells of the larvae fed with insecticide, thiamethoxam 25% WG @ 0.05g L-1 exhibited only the presence of vacuoles of variable sizes. The midgut histomorphology of honey bee larvae treated with the probiotic, Darolac (1.25 x 109 cells of Lactobacillus acidophilus, L. rhamnosus, Bifidobacterium longum and Saccharomyces boulardi g -1 @ 1.2 g L-1 of water and sugar syrup) at weekly intervals for a period of four weeks was also evaluated. An increased cell activity which was indicated by the prominent aposematic secretion towards the gut lumen was observed in those larvae supplemented with probiotics when compared with that of the normal larvae from feral colony. Apart from these, enhanced integrity of the epithelial columnar cell, even distribution of microvilli and augmentation in the secretion of peritrophic membrane was also recorded. The present investigation revealed that the larvae fed with sugar syrup or those exposed to various stressors (disease and insecticide) had adverse effect on the midgut where they exhibited necrosis of epithelial cells, broken and unclear microvilli and distorted peritrophic membrane. Thus, the disruption of epithelial cells hindered the absorption of nutrients and water which led to the death of honey bee larvae. When probiotic (Darolac @ 1.2 g L-1) was supplemented to honey bee larvae under different stressors, it helped in mitigating the intensity of cell necrosis by restoration of regenerative cells and the larval health was found to be recovered which was indicated by the even distribution of microvilli.ThesisItem Open Access Endophytic association of entomopathogenic fungi with rice and cowpea(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Divyashree, C; KAU; Reji Rani, O PThe study entitled ‘Endophytic association of entomopathogenic fungi with rice and cowpea’ was carried out in the Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, during the year 2017-19, with the objective to examine the endophytic association of entomopathogenic fungi in rice and cowpea. The entomopathogenic fungi, evaluated were Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Lecanicillium saksenae. They were tested through seven inoculation methods viz., seed coating, seed soaking, radicle dressing, root dipping, soil drenching, foliar spraying and bloom spraying by inoculating the conidial suspension at their effective doses. Among the four entomopathogenic fungi inoculated, B. bassiana, M. anisopliae and L. saksenae were found to colonise rice plants. B. bassiana was found to colonise in stem and roots, while M. anisopliae preferred stem. Both B. bassiana and M. anisopliae colonized effectively by seed soaking method. L. saksenae colonised in the stem and roots in seed soaking, in the roots in soil drenching and in the leaves in foliar spraying method. In plants, B. bassiana and M. anisopliae persisted up to 15th day after inoculation (DAI), while L. saksenae persisted till 45th DAI. In soil, L. saksenae persisted in soil up to 45th day, while other fungi could not be retrieved from soil. L. lecanii could not be retrieved from any of the plant parts or soil up to 45th DAI. Thirteen natural endophytes were isolated from rice, which included growth promoters with nitrogen fixing properties, gibberellic acid production properties, saprophytes and plant pathogens. They were identified with the help of colony and conidial characters. Those fungal endophytes whose identity could not be confirmed were characterised at molecular level through ITS sequencing, and bacterial endophytes through 16S sequencing. The most dominant endophyte in rice was the fungus, Neocomospora rubicola, a known plant pathogen followed by the nitrogen fixing bacterium Burkholderia cepacia. Colonisation of fungal bacterial association Sarocladium oryzae + Kosakonia sacchari was also dominant in the stem. S. oryzae is a known plant pathogen while K. Sacchari is a nitrogen fixing bacterium. The other endophytes with less frequency of occurrence were Pestalotiopsis microspora, Cladosporium sp., Microdochium fisheri, Fusarium solani, Aspergillus and Penicillium. Experiments in cowpea revealed that all the four fungi could successfully colonize different plant parts. Foliar spraying was the best method in cowpea to get endophytic association of all the four fungi, while M. anisopliae could also be retrieved through seed soaking and root dipping methods. B. bassiana, M. anisopliae and L. saksenae were found to colonise leaves, stem and roots, while L. lecanii colonised only on leaves. In cowpea plants, M. anisopliae and L. saksenae were found to be more persistent (up to 45th DAI), while B. bassiana and L. lecanii persisted only up to 30 DAI. Soil samples revealed the presence of B. bassiana, M. anisopliae and L. saksenae up to 15th, 30th and 45th DAI respectively. L. lecanii was not found to colonise soil. Grain samples in rice and bloom samples in cowpea did not reveal the presence of any endophytes. In cowpea, several natural endophytes were found to be stumped upon in different parts, which included four fungi and two bacteria. Apart from this a fungal bacterial association, Fusarium + Ebc 3 (unidentified bacterium) was found to be a dominant endophyte. The bacterium Rhizobium mayense isolated from all plant parts was the most dominant endophyte. The other endophytes isolated were the fungi, Cladosporium sp., Clonostachys rosea, Chaetomium globosum and Cerrena sp. and the bacterium Enterobacter cloacae. Rice plants inoculated by seed soaking, with the conidial suspensions of B. bassiana and M. anisopliae @ 108 spores ml-1 and L. saksenae @ 108 spores mL-1 reflected 28.79, 27.17 and 29.99 per cent increase height, 47.71, 44.75 and 47.92 per cent increase in biomass and 37.73, 36.97 and 39.89 per cent increase in grain yield, the highest values being those of L. saksenae and lowest being those of M. anisopliae. Incidence of rice bug assessed in terms of percentage of chaffy grains per panicle was significantly less in L. saksenae (14.21), while in B. bassiana it was 20.48 and in M. anisopliae, 21.61. There was no disease incidence in treated as well as control plants. It is concluded that B. bassiana, M. anisopliae and L. saksenae has endophytic association with rice and cowpea and L. saksenae is a strong endophyte.
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