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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 Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii(Burgess) (Diptera:Agromyzidae)(Department of agricultural entomology, College of horticulture, Vellanikkara, 2014) Jyothi Sara, Jacob; KAU; Maicykutty P, MathewA study on “Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)” was carried out at the Department of Agricultural Entomology, College of Horticulture, K.A.U., Vellanikkara during 2011-2013 with the objectives of collection and identification of indigenous natural enemies and to assess the pathogenicity of the entomopathogens to explore the feasibility of utilizing them for its management. Surveys were conducted in the vegetable fields for the collection and identification of natural enemies associated with L. trifolii in three districts, namely, Thrissur, Ernakulam and Kottayam from January to March, 2011. The surveys revealed the occurrence of nine species of hymenopteran parasitoids. The per cent parasitism varied from 10.96 to 58.99 per cent among the crops surveyed. Three species of eulophids, namely, Cirrospilus acadius Narendran, C. brevicorpus Shafee & Rizvi and Aprostocetus sp. as well as the braconid, Toxares sp. are new reports for India. Among the parasitoids, Closterocerus spp. were the dominant group followed by Chrysonotomyia sp. All parasitoids were solitary, larval endoparasitoids except Toxares sp. which was larval-pupal in nature. One species each of small ants (Formicidae) and a dipteran fly (Dolichopodidae) were observed as predators on L. trifolii. In the study, no entomopathogens were observed from L. trifolii. Considering the level of pesticide consumption in vegetable crops that undermine the potential of insect parasitoids and also that no entomopathogens could be observed during the survey, it was decided to evaluate entomopathogenic nematodes (EPNs) as biocontrol agents against L. trifolii. Isolation of EPNs from 72 soil samples from Thrissur, Ernakulam and Kottayam districts yielded four isolates of Steinernema carpocapsae. Bioefficacy studies carried out on these four isolates along with Steinernema bicornutum and Heterorhabditis indica showed that S. carpocapsae Isolate - 1 had the lowest LC 50 , LC 90 and LT values indicating their higher effectiveness against the maggots of the pest. 50 Pot culture study conducted to compare the potential of S. carpocapsae Isolate - 1 with other treatments showed that azadirachtin 1 EC at 0.005% was the most effective causing 84.51 per cent mortality to the maggots of L. trifolii. This was followed by the foliar application of H. indica at 32 infective juveniles (IJs)/ maggot which caused 18.98 per cent mortality. Application of Beauveria bassiana at 1×10 7 spores/ ml was not effective. In the field evaluation, fipronil 5 SC at 0.002% was found to be the most effective treatment for controlling L. trifolii followed by azadirachtin 1 EC at 0.005%. Compatibility of the IJs of the S. carpocapsae Isolate - 1, S. bicornutum and H. indica was studied with ten commonly used insecticides in the laboratory by direct exposure method. Chlorantraniliprole 18.5 SC at 0.005% was found to be the most compatible insecticide with S. carpocapsae isolate - 1 causing only 0.17 per cent mortality to IJs at 72 hours after treatment (HAT). Quinalphos 25 EC at 0.05% and chlorpyriphos20 EC at 0.05% were highly incompatible, causing 96.17 and 92.87 per cent mortality of the nematodes. Dimethoate 30 EC at 0.04% was the most compatible insecticide with S. bicornutum and caused only 0.60 per cent mortality at 72 HAT and was followed by azadirachtin 1 EC at 0.005% with 0.78 per cent mortality to the IJs. Quinalphos 25 EC at 0.05% caused 99.93 per cent mortality at 72 HAT. Heterorhabditis indica was compatible with all insecticides except quinalphos 25 EC at 0.05% which was moderately toxic resulting in 39.6 per cent mortality. The virulence, pathogenicity and multiplication of the survived IJs were not affected by the insecticide treatments. Parasitoids and EPNs were observed as potential candidates for the management of L. trifolii. Hence future studies on the bio-ecology and mass production of dominant parasitoids and standardization of methods to improve the efficacy of EPNs are suggested for the successful control of L. trifolii in polyhouses as well as in the field.ThesisItem Open Access Bio-ecology and management of papaya mealybug on mulberry(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Rajan, V P; KAU; Krishnakumar, RThe experiment entitled “Bio-ecology and management of papaya mealybug on mulberry” was carried out at College of Agriculture, Vellayani, Kerala Agricultural University and in farmers’ fields at Agali, Sholayur and Puthur panchayats during October 2009 to July 2012. The main objectives of the study were to identify and assess the extent of infestation of papaya mealybug on mulberry, its role in disease transmission and population dynamics and to evolve an Integrated Pest Management (IPM) strategy to contain the pest. Preliminary survey conducted in sericulture practising districts of Kerala revealed heavy infestation of the pest in three panchayats of Palakkad district in Kerala. The mealybugs identified in the survey were papaya mealybug, Paracoccus marginatus Williams and Granara de Willink, pink hibiscus mealybug, Maconellicoccus hirsutus (Green) and breadfruit mealybug, Icerya aegyptiaca (Douglas). The occurrence of papaya mealybug and its egg masses were found to be high during the period of May to August. The competition between these three mealybugs and also the influence of weather parameters on the population of the papaya mealybug was studied. The mealybug population showed positive correlation with maximum temperature, sunshine and wind speed and negative correlation with minimum temperature, rainfall and humidity. The different plants belonging to families Asteraceae, Euphorbiaceae, Malvaceae and Solanaceae were observed to be the most preferred hosts for papaya mealybug. The highest number of all life stages of papaya mealybug was observed on Parthenium, Parthenium hysterophorus L., which augmented the perpetuation of papaya mealybug in the absence of other crop hosts. Sprouted potatoes were the host material used for studying the biology of the papaya mealybug, pink hibiscus mealybug and breadfruit mealybug. The average number of eggs laid by an adult papaya, pink hibiscus and breadfruit mealybug were 361.50, 281.30 and 141.30 respectively. The mean larval period of papaya, pink hibiscus and bread fruit mealybugs were found to be 16.7, 21.2 and 47.1 days respectively. DAC-ELISA was performed with infected mulberry plants using antibodies of SCBMV and BSV showed the absence of virus in the infected samples collected from the mealybug infested mulberry gardens. The phenol content was also assessed in the infested samples to get an indication of the level of resistance showed by the host plant against mealybug. The level of resistance of the plant found to be increasing with the increase in the per cent damage. The fifth instar larvae of the predator, Spalgis epius was found as the most active feeder with a feeding potential of 21.69, 118.88, 40.88 and 20.49 of ovisacs and first, second and third instars of papaya mealybug respectively. Third instar larvae of green lacewing, Chrysoperla carnea (Stephens) and fourth instar grubs of ladybird predator, Cryptolaemus montrouzieri (Mulsant) were the most voracious feeders and they consumed significantly higher number of ovisacs, first, second and third instar nymphs of papaya mealybug as compared with first and second instar larvae of the predators. Among the different insecticides evaluated in the laboratory against the first instar and adult papaya mealybugs, dimethoate 0.1% was superior followed by imidacloprid 0.01%. Among the combinations, dimethoate 0.05% + econeem plus 2 ml L-1 was found to be superior with the highest per cent mortality of 93.33% and 96.67% for adult and first instar papaya mealybugs respectively. The silkworm larvae fed with the leaves after 15 days of treatment with the combination of dimethoate 0.05% + econeem plus 2 ml L-1 gave the highest yield of (91 /100 larva reared) cocoons with a total larval duration of 576 hours. Single cocoon weight was found to be high (1.56 g) with the highest shell ratio (22.09). The mean larval weight of different instars were 0.54, 0.87, 1.16, 8.80 and 36.61 gram respectively in first, second, third, fourth and fifth. In the above treatment, effective rearing rate (ERR) by number and weight were 9050.00 and 13744.69 g respectively. Field evaluation with the combination of pruning and weeding along with application of dimethoate (0.05%) 1.7 ml + econeem plus 2 ml L-1 and also providing a second spraying with dichlorvos (0.05%) 2 ml + econeem plus 2 ml L-1 was observed to be superior among all the treatments with minimum leaf damage, shoot damage and highest leaf yield per plant. B: C ratio worked out also confirmed the superiority of this treatment. Hence this treatment can be recommended as an IPM strategy for the management of papaya mealybug on mulberry.ThesisItem Open Access Management of banana pseudostem weevil, Odoiporus longicollis (Olivier), using safe chemicals and bio-rational methods(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Sivakumar, T; KAU; Jiji, TA study on ‘Management of banana pseudostem weevil, Odoiporus longicollis (Olivier), using safe chemicals and bio-rational methods’ was conducted at the College of Agriculture, Vellayani and in farmer’s field during 2012-2015. The main objective was to evolve strategies for managing the pest using safe chemicals and bio-rational methods. The study involved documentation of the pest status and farmers’ management practices, evaluation of the efficacy of different insecticides, botanicals and bio-agents under laboratory and field conditions and determination of harvest time insecticide residues in edible parts. Status of pests in banana was documented from Alappuzha, Pathanamthitta, Kollam and Thiruvananthapuram districts during 2013. O. longicollis incidence in banana cv. Nendran varied from 5.36 per cent in Kollam to 7.64 per cent in Pathanamthitta. Erionota sp., Bactrocera dorsalis (Hendel), Polytus mellerborgi (Boheman), Coccus hesperidum L. were observed as the emerging pests from the area. Pest management practices adopted by banana farmers, documented from the above districts, revealed the use of sixteen types of pesticides, including organic preparations. No specific parasite or predator was recorded from field except earwigs and red ants. Efficacy of insecticides, botanicals and bio-agents for the management of O. longicollis was evaluated under laboratory conditions. Thiamethoxam (0.01%), emamectin benzoate (0.002%) and cartap hydrochloride (0.1%) caused 100 per cent mortality of adults and grubs of the pest within 36 h after treatment. Among the botanicals, cassava leaf distillate based formulation, ‘Nanma’ (5%) caused 36.67 per cent mortality of adults and grubs, whereas neem soap caused 36.67 and 16.67 per cent mortality of adults and grubs, respectively. Among the bio agents tested, Metarhizium majus Bisch, Rehner and Humber (ICAR-CPCRI) 2% caused 80 per cent mortality of grubs on the seventh day of inoculation. Compatibility of insecticides, fungicides and botanicals with M. majus was tested using poisoned media technique. The fungicides viz., propiconazole (0.1%), tebuconazole (0.1%), mancozeb (0.3%) and carbendazim (0.1%) resulted in total growth inhibition of M. majus, while thiamethoxam (0.01% and 0.03%), cartap hydrochloride (0.05%) and neem soap (1.0%) were found compatible. Application methods of insecticides, botanicals and bio-agents were standardised through field experiment at the Instructional Farm, College of Agriculture, Vellayani during 2013-2014. Among the application methods, leaf axil filling (LAF) and injection of thiamethoxam (0.01% and 0.03%) recorded a yield of 10.98 and 10.88 kg plant-1, respectively. In the case of biopesticides, the highest yield (6.43 kg plant-1) was recorded with swabbing + LAF application of M. majus (20g l-1), whereas among botanicals, spraying +LAF gave the highest yield (8.8 kg plant-1) for neem soap (1.0%) application. Prophylactic and curative methods for the management of the pest, using thiamethoxam, neem soap, cassava leaf based preparation and M. majus, were tested in farmer’s field at Konni, Pathanamthitta district during 2014-2015. In prophylactic method thiamethoxam injection (0.03%) at 5th and 6th months after planting recorded an yield of 10.67 kg plant-1, followed by thiamethoxam (0.01%) leaf axil filling (10.32 kg plant-1) at 5th and 6th months after planting. Significantly higher value for BC ratio (2.44) was recorded for thiamethoxam (0.03%) injection. The BC ratio was 2.33 for thiamethoxam (0.01%) leaf axil filling. Application of M. majus (2%) at five months after planting, followed by thiamethoxam LAF (0.01%) at 6th month after planting yielded 8.82 kg plant-1. In curative method, plant survival was the highest (80 per cent) for thiamethoxam injection (0.03%). However, a low BC ratio of 0.86 was observed. Thiamethoxam injection (0.03%) and leaf axil filling (0.01%) were on par with chlorpyrifos (0.03%), as curative method. No detectable residue of thiamethoxam on any edible parts of the plant was observed at the time of harvest. To conclude, ‘Nendran’ was found to be the most susceptible banana cultivar to O. longicollis. Thiamethoxam at 0.01 per cent and 0.03 per cent were compatible with the entomopathogen, M. majus. Prophylactic method using thiamethoxam injection @ 0.03% and leaf axil filling @ 0.01%, both at five and six months after planting, were found effective, eco friendly and economical practice for O. longicollis management. The application of entomopathogenic fungi M. majus at five months after planting followed by thiamethoxam (0.03%) injection at six months after planting was also effective for managing the pest.ThesisItem Open Access Efficacy and biosafety of new generation insecticides for the management of fruit borers of cowpea, brinjal and okra(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2013) Vijayasree, V; KAU; Hebsy BaiThe investigation on the “Efficacy and biosafety of new generation insecticides for the management of fruit borers of cowpea, brinjal and okra” was conducted at the College of Agriculture, Vellayani, during 2010-2013. The objectives were to evaluate the efficacy of new generation insecticides against the fruit borers of cowpea, brinjal and okra, assess their safety to entomopathogenic fungi, determine their persistence and degradation and standardize methods to decontaminate the residues on the fruits. The studies were conducted with eight new generation insecticides viz., emamectin benzoate 5SG @10 g a.i. ha-1, spinosad 45 SC @ 75 g a.i. ha-1, novaluron 10 EC @ 100 g a.i. ha-1, chlorantraniliprole 18.5 SC @ 30 g a.i. ha-1, indoxacarb 14.5 SC @ 60 g a.i. ha-1, fipronil 80 WG @ 50 g a.i. ha-1, thiodicarb 75 WP @ 750 g a.i. ha-1 and flubendiamide 480 SC @ 100 g a.i. ha-1 . Two conventional insecticides (carbaryl 50 WP @ 750 g a.i. ha-1 and malathion 50 EC @ 500 g a.i. ha-1) and an untreated control were maintained as check. Laboratory screening of the insecticidesagainst Maruca vitrata, Leucinodes orbonalis and Earias vitella, indicated high mortality of the pests one and three days after treatment with a subsequent decline in the mortality. The insecticides were on par in their efficacy. All the new generation insecticides reduced the pest infestation on the vegetables significantly in the field. The reduction in the flower and pod damages in cowpea ranged from 53.97 to 76.86 and 63.69 to 84.82 per cent, respectively. Damages to brinjal and okra fruits were reduced by 45.96 to 72.21 per cent and 44.34 to 83.26 per cent, respectively. Chlorantraniliprole, indoxacarb and emamectin benzoate which recorded more than 70 and 80 per cent reduction in flower and pod damages in cowpea, chlorantraniliprole, indoxacarb, emamectin benzoate and flubendiamide with more than 60 per cent reduction in fruit damage in brinjal, and chlorantraniliprole, flubendiamide and indoxacarb with more than 70 per cent reduction in fruit damage in okra were superior. The yield was also significantly high in these treatments in the three crops. Prophylactic sprays with neem seed kernel extract 5 % at flower bud initiation and after a fortnight, decreased the population of the pod borer of cowpea remarkably. Subsequently, one spray of the insecticides sufficed to check the pest. All the insecticides were compatible with Beauveria bassiana and Metarrhiziumanisopliae. Flubendiamide and carbaryl inhibited the growth of Lecanicillium lecanii. Chlorantraniliprole with a waiting period of one day in all the three vegetables was the safest insecticide. The other insecticides with waiting periodswithin the harvest intervals of the crops were spinosad (1day), emamectin benzoate (3 days) and flubendiamide (3 days) in cowpea, indoxacarb (1day), spinosad (1day) and emamectin benzoate (4 days) in brinjal and indoxacarb (2 days) and thiodicarb (2 days) in okra. Immersing insecticide treated fruits in slaked lime 2%, turmeric 1 %, vinegar 2% or tamarind 2% solution for twenty minutes followed by washing in water and scrubbing which removed more than 60 per cent residues of most of the insecticides were the effective decontaminating methods for the new generation insecticides. Considering the efficacy of the insecticides against the pests, associated yield increase, benefit cost ratio of the insecticide treatments, waiting period and compatibility with bio agents, chlorantraniliprole 18.5 SC @ 30 g a.i. ha-1, indoxacarb 14.5 SC @ 60 g a.i. ha-1 and emamectin benzoate 5SG @10 g a.i. ha-1 were adjudged as the potential insecticides against the fruit borers of cowpea, brinjal and okra.ThesisItem Open Access Bionomics and management of root mealybug on black pepper(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2016) Najitha, Ummer; KAU; Susannamma, KurienMealybugs are one of the important pests of black pepper and a specific group called as ‘root mealybugs’ are known to infest the underground parts of the crop in Kerala. The infestation was reported to be serious in high altitude region. Hence, an investigation was carried out on the “Bionomics and management of root mealybug on black pepper” with the objectives to document the species of root mealybugs and associated fauna, to study the biology of the dominant species, susceptibility of popular pepper varieties to the pest and management of mealybug on black pepper. The present study was conducted in the College of Horticulture and farmer’s fields at Wayanad and Idukki districts, Kerala. A preliminary survey was conducted during 2013 in different panchayats of Wayanad, Idukki and Kannur districts of Kerala to document the root mealybug species infesting black pepper. No infestation was observed in Kannur district, while three species of mealybugs, namely, Formicococcus polysperes Williams, Dysmicoccus brevipes Cockerell and Pseudococcus sp. were found to be infesting the underground parts of black pepper in Wayanad and Idukki districts.The collateral hosts of F. polysperes, recorded were two intercrops in pepper garden viz., ginger, Zingiber officinale Rose. and elephant foot yam, Amorphophallus paeoniifolius (Dennst.), and weeds, Ageratum conyzoides L., Clerodendron infortunatum L., Cyperus kyllinga L., Phyllanthus niruri L., Physalis minima L., Synedrella nodiflora L.,Urtica parviflora Roxb. and a pepper standard, Erythrina sp. The collateral hosts of D. brevipes were Coffea robusta L., Commelina diffusa L. Cleome rutidosperma (DC.) and C. kyllinga L. The infestation of F. polysperes on ginger is the first report from South India and its other hosts are being reported for the first time globally. During the survey, a coccinellid grub was observed to be predating on the root mealybugs which was identified as Horniolus sp. (Coccinellidae: Coleoptera). Four ant species viz., Anoplolepis gracilipes Smith, Crematogaster rogenhoferi Mayr, Lophomyrmex quadrispinosus Jerdon and Paratrechina sp. were also found to be associated with root mealybug colonies.The study on population dynamics of root mealybugs showed that the highest root mealybug population was in cooler months (November to January) and lowest population in rainy months (June and July). A significant negative correlation existed between root mealybug population and soil temperature. The biology and morphometrics of F. polysperes, were studied in laboratory condition in which females exhibited ovoviviparity mode of reproduction with pre larviposition, larviposition and post larviposition period of 23.65, 9.60 and 4.15 days, respectively. An adult female deposited an average of 136.15 crawlers with a sex ratio of 1: 2.71 (male: female). Life cycle of females consisted of three nymphal instars and adult and that of males had two nymphal, a pre-pupal, a pupal instar and an adult instar. Average duration of first and second nymphal instars was 8.4 and 6.35 days, respectively. Males and females were distinguishable from third instar onwards with a fine silken waxy thread formed by males at the end of second instar. Duration of third female instar was 8.4 days and that of pre-pupa and pupa of male was 1.4 and 7.15 days, respectively. Adult females are apterous with white powdery waxy coating and wax filaments surrounding the body margin are short and thick. Males are winged with a pair of long waxy caudal filaments. Males are short lived with an average life span of 1.8 days and females lived for 37.4 days. The biology of F. polysperes is being reported for the first time. Four popular pepper varieties, namely, Panniyur- 1, Panniyur- 2, Panniyur- 8 and Karimunda were tested for their susceptibility to root mealybugs and Panniyur- 2 was found to be most susceptible and recorded significantly higher number of mealybugs on artificial inoculation. Entomopathogenic fungi (EPF), chemical insecticides and their combinations were evaluated for the management of root mealybugs on black pepper. Four species of entomopathogenic fungi were tested at three different concentrations each and out of which, Lecanicillium lecanii at 2 x 108 spores/ml was found effective under both laboratory and pot experiment. Out of the eight insecticides evaluated against root mealybugs, chlorpyriphos 20 EC at 300 g a.i/ha and imidacloprid 17.8 SL at 25 g a.i/ha were equally superior in laboratory tests whereas, imidacloprid 17.8 SL at 25 g a.i/ha was the most effective in pot culture experiment. Compatibility test of L. lecanii with pesticides indicated that imidacloprid 17.8 SL (25 g a.i/ha) and copper hydroxide 77 WP (1%) was compatible with respect to per cent growth inhibition, sporulation and spore viability. The best treatments of EPF and chemical insecticides were evaluated alone and in combinations, with common farmer’s management practice in pot experiment and the result showed that imidacloprid 17.8 SL at 25 g a.i/ha was effective in managing root mealybugs and the same was evaluated in an infested field at Wayanad and compared with chlorpyriphos 20 EC @ 300 g a.i/ha. The results showed that imidacloprid 17.8 SL @ 25 g a.i/ ha was superior with 97.98 per cent reduction in population at one week after first drenching when compared to that of chlorpyriphos (79.89 per cent).ThesisItem Open Access Entomopathogenic fungi for the management of insect pests in rice ecosystem(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2015) Malini, Nilamudeen; KAU; Sudharma, KThe study entitled “Entomopathogenic fungi for the management of insect pests in rice ecosystem” was carried out during 2011 - 2014 at College of Agriculture, Vellayani. The objectives were to isolate and identify indigenous strains of entomopathogenic fungi, to evaluate the fungal pathogens viz., Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae Metschnikoff (Sorokin) and indigenous fungi against insect pests of rice, to fix their effective dose, to assess the compatibility of the fungal pathogens with new generation pesticides and to develop pesticide tolerant strains of the fungi. Six new isolates of entomopathogenic fungi viz., Aspergillus flavus Link. (Af-m1), B. bassiana (Bb-m2, Bb-m3, Bb-m4 and Bb-m5) and one isolate of M. anisopliae (Ma-m1) were collected and identified on the basis of morphological and molecular characters. The accession numbers obtained for the isolates from National Center for Biotechnology Information (NCBI) were KP 739825, KP 739828, KP 739829, KP 739830, KP 739831 and KP 739826, respectively. The pathogenicity of fungal isolates viz., B. bassiana (Bb 5), M. anisopliae (Ma 4) from NBAIR, B. bassiana (Bb 21) from Department of Microbiology, College of Agriculture, Vellayani and the six new isolates A. flavus (Af-m1), B. bassiana (Bb-m2, Bb-m3, Bb-m4 and Bb-m5) and M. anisopliae (Ma-m1) were evaluated against Cnaphalocrocis medinalis Guen. and Leptocorisa acuta (Thunb). All isolates were pathogenic to larvae of C. medinalis, nymphs and adults of L. acuta. The isolates B. bassiana (Bb 5) and M. anisopliae (Ma 4) were found superior among the fungi evaluated. The bioassay of the potent fungal pathogens viz., B. bassiana (Bb 5, Bb 21), M. anisopliae (Ma 4) and A. flavus (Af-m1) was conducted against C. medinalis larvae and nymphs and adults of L. acuta and field doses were fixed on the basis of LC90 values. Spore concentration dependent mortality of the insects was seen. The LC90 values were 3.50 x 108, 3.40 x 108, 2.25 x 108 and 3.37 x 108 spores ml-1 for B. bassiana (Bb 5, Bb 21), M. anisopliae (Ma 4) and A. flavus (Af-m1) against C. medinalis larvae, 3.92 x 108, 7.55 x 108, 2.96 x 108 and 3.46 x 108 spores ml-1 against L. acuta nymphs and 4.23 x 1010, 4.11 x 1010, 2.85 x 1010 and 8.72 x 1010 spores ml-1 against L. acuta adults. Two field trials carried out at Cropping System Research Centre, Karamana during November 2012 to March 2013 (Puncha) and June 2013 to October 2013 (Virippu) to assess the efficacy of entomopathogens revealed that B. bassiana (Bb 5) @ 1010 spores ml-1 was the best treatment, on the basis of pest population and reduction in damage of pests, population of natural enemies and benefit-cost ratio. This was followed by M. anisopliae (Ma 4) @ 1010 spores ml-1, talc based formulation of Bb 5 @ 20 g l-1, talc based formulation of M. anisopliae (Ma 4) @ 20 g l-1, talc based formulation of Bb 21 @ 20 g l-1 and A. flavus @ 1010 spores ml-1. Among the insecticides evaluated, chlorantraniliprole @ 30 g a.i ha-1 was the best. Assessment of the compatibility of fungal pathogens with insecticides on the basis of the effect of insecticides on the growth, spore count, germination and bioefficacy revealed that, B. bassiana (Bb5 and Bb 21), M. anisopliae (Ma 4) and A. flavus (Af-m1) were compatible with acephate (0.075, 0.150, 0.225 per cent), chlorantraniliprole (0.004, 0.006 and 0.008 per cent) and thiamethoxam (0.003, 0.005 and 0.008 per cent). Investigations on pesticide tolerance of entomopathogens showed that, B. bassiana (Bb 5) and M. anisopliae (Ma 4) tolerated 4.0, 8.0 and 8.0 times higher the field dose of acephate, chlorantraniliprole and thiamethoxam, respectively. The growth, spore count and the bioefficacy of selected cultures (fungi gown initially in media containing highest tolerable dose of insecticide and further grown in poisoned media for 10 passages), relaxed cultures (fungi gown initially in media containing highest tolerable dose of insecticide and further grown in unpoisoned media for 10 passages) and untreated cultures (fungi grown only in unpoisoned media) of B. bassiana (Bb 5) / M. anisopliae (Ma 4) differed significantly. On culturing of the selected, relaxed and untreated cultures of the fungi after 10 passages, in still higher dose of the insecticides i.e., 4.5x, 8.5x and 8.5x times higher the field dose of acephate, chlorantraniliprole and thiamethoxam, respectively, only the selected cultures tolerated the higher doses. Molecular characterisation of the selected, relaxed and untreated cultures of B. bassiana (Bb 5) / M. anisopliae (Ma 4), which were continuously grown for 10 passages in poisoned / unpoisoned media, respectively showed no molecular variations, except a minor polymorphism of 1.61 per cent exhibited in B. bassiana (Bb 5). To conclude, the six new indigenous fungi isolated are pathogenic to C. medinalis and L. acuta. B. bassiana (Bb 5) and M. anisopliae (Ma 4) @ 1010 spores ml-1 are effective and economical for the management of C. medinalis and L. acuta besides being safe to natural enemies. As these fungi are compatible with acephate @ 750 g a.i ha-1, chlorantraniliprole @ 30 g a.i ha-1 and thiamethoxam @ 25 g a.i ha-1, and as they tolerated higher doses of insecticides, without undergoing any genetic variation they are suitable for integration with these insecticides, the best chemical suggested for integration is chlorantraniliprole @ 30 g a.i ha-1 as it is safe to natural enemiesThesisItem Open Access Evaluation of entomopathogenic fungi for the management of coleopteran pests and characterisation of pesticide tolerant strains(Department of agricultural entomology, College of agriculture, Vellayani, 2014) Anis Joseph, R; KAU; Sudharma, KDevelopment of safe and sustainable technologies for pest management is the need of the hour to counter the adversities created by the synthetic pesticides. Considering this, the research on “Evaluation of entomopathogenic fungi for the management of major coleopteran pests and characterisation of pesticide tolerant strains” was carried out in the Department of Agricultural Entomology, College of Agriculture during 2007-2014. The main objectives of the study were to assess the pathogenicity of entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillimen and Metarhizium anisopliae (Metschnikoff) Sorokin against coleopteran pests, determination of LC 50 , LC 90 and LT 50, development of formulations, of field efficacy, compatibility with pesticides and development of pesticide tolerant strains and molecular characterization of the fungi. assessment The isolates PDBC Bb 5 and PDBC Ma 4 were evaluated against nine coleopteran pests viz. Aulacophora foveicollis Lucas, Basilepta fulvicorne Jacoby, Cylas formicarius F., Cosmopolites sordidus Germ., Henosepilachna vigintioctopunctata F., Lanka ramakrishnai Prathapan & Viraktamath, Metriona circumdata H., Oryctes rhinoceros Linn. and Rhynchophorus ferrugineus F. Both the fungi were pathogenic to the grubs as well as adults of all the nine insects tested. Though the symptoms produced in the test insects by both the fungi were more or less the same, differences in the behavior of the infected insects were seen. The period taken for the expression of symptoms also varied. The virulence of these two fungi was determined against these nine coleopterans. Ma 4 was found inferior to Bb 5 in its ability to infect the adults of all the test insects except to that of O. rhinoceros at the comparable dose of 10 8 spores ml -1 . Further, bioassay was conducted against the adults and grubs of all the nine test insects and the LC 50 , LC 90 and LT were worked out. From the probit analysis, it was seen that to achieve fifty per cent mortality of the adult coleopterans 50 with B. bassiana within the shortest periods, spore concentrations of 5. 27 × 10 , 6.53 × 10 8 , 4.24 ×10 9 , 5.62 × 10 7 , 3.99 × 10 8 , 6.76 × 10 8 , 7.26 × 10 9 , 1.56 × 10 and 3.76 × 10 13 spores ml -1 was essential for A. foveicollis, B. fulvicorne, C. sordidus, C. formicarius, H. vigintioctopunctata, L. ramakrishnai, M. circumdata, O. rhinoceros and R. ferrugineus respectively. The LC values were much less for the grubs when compared to the adult coleopterans and the values were 2. 15 × 10 50 , 1.87 × 10 6 , 3.83 × 10 8 , 2.94 × 10 7 , 2.79 × 10 7 , 5.72 × 10 6 , 4.96 × 10 and 4.64 × 10 11 spores ml -1 respectively for the grubs of the above mentioned insects. Corresponding LC values were also worked out. The lethal time to obtain fifty percent mortality also varied with insects. With respect to M. anisopliae 11.42 × 10 10 , 3.99 × 10 8 90 , 8.86 × 10 10 , 6.27 × 10 9 , 6.96 × 10 8 , 3.66 × 10 11 8 8 15 , 6.22 × 10 , 6.13 × 10 , 2.58 × 10 13 and 2.73 × 10 15 spores ml -1 respectively was required for the adult coleopterans and 4.91 × 10 7 , 6.09 × 10 8 , 4.81 × 10 8 , 5.83 × 10 8 , 4.95 × 10 7 , 2.42 × 10 , 4.64 × 10 9 , 3.79 × 10 8 and 10.29 ×10 13 spores ml -1 respectively for the grubs. From the LC 50 and LC values, information on the effective field doses of these two fungi against the nine coleopterans could be garnered. 90 Inorder to identify cost effective materials for the multiplication of the fungus, nine substrates were evaluated. The ideal substrates that maintained the viability of B. bassiana were cow dung, wheat bran, rice bran and neem cake. Cow dung and wheat bran supported maximum cfu of M. anisopliae. The peak sporulation of the fungi was observed in the samples drawn two months after storage. Talc based formulations of both fungi maintained the required standards of colony forming units in the formulation upto three months after storage. The cfu at third month after storage for B. bassiana and M. anisopliae were 0.2 × 10 9 cfu g -1 10 8 and 0. 24 × 10 respectively. The bioefficacy of fungi cultured in different substrates and stored for different months was also evaluated against the grubs and adults of C. formicarius. With respect to bioefficacy also, the fungi cultured in cow dung, wheat bran and neem cake proved better. 7 11 9 The results of the field experiment in banana, variety Nendran to assess the effect of spore suspensions of B. bassiana and M. anisopliae, fungi in cow dung and neem cake substrates and talc based formulations of the fungi in comparison with insecticide revealed that the best treatment was talc based B. bassiana @ 30 g l excepting the insecticide check, chlorpyrifos 0.03 per cent for the management of C. sordidus. In the succeeding crop of banana talc based B. bassiana @ 30 g l was even superior to the insecticide check, chlorpyriphos 0.03 per cent. The least number of galleries (0.63) and the least number of grubs in the rhizomes (0.29) besides the lowest number of adult C. sordidus in soil samples were seen in talc based B. bassiana @ 30 g l -1 . The B : C ratios calculated for the treatments with talc based B. bassiana @ 30 g l -1 in the main crop was 1.57 compared to 1.24 for chlorpyriphos 0.03 per cent. The B : C ratios for the treatments with talc based B. bassiana @ 30 g l -1 and spore suspension of B. bassiana 5 × 10 11 spores ml -1 in the succeeding crop of banana were 1.78 and 1.49 which were higher than that for chlorpyriphos 0.03 per cent. The results from the succeeding crop indicate the ability of these fungi to self perpetuate and bring about long lasting effect in the treated area. Field experiments were also conducted in sweet potato, variety Sree Bhadra to assess the effect of two fungi. Talc based B. bassiana @ 30 g1 was superior treatment excepting imidacloprid 0.006 per cent in reducing the galleries produced by the weevils. A similar trend was evident in the second trial also. The effect of application of B. bassiana and M. anisopliae in cow dung and neem based substrates showed moderate effect with respect to the number of galleries and number of grubs. Drenching of talc based formulation of B. bassiana @ 30 g l -1 was better than its foliar treatment. The compatibility of B. bassiana and M. anisopliae with two fungicides and six insecticides was also evaluated inorder to evaluate the suitability of integrating the fungi with pesticides in pest management programmes. Good compatibility of the insecticide, imidacloprid 0.006 per cent with B. bassiana and M. anisopliae was seen. Bioefficacy of the fungi cultured in this insecticide was also higher. Attempts were -1 -1 -1 also made to develop pesticide tolerant strains of B. bassiana and M. anisopliae. For this they were grown continuously in media with varying doses of pesticides. A total of ten passages through poison food media was made. It was seen that both the fungi tolerated high doses of pesticides though there was inhibition in growth, sporulation and bioefficacy. B. bassiana and M. anisopliae tolerated even 32 times higher the recommended field dose of imidacloprid. Subculturing reduced the spore production of both the fungi and the rate of reduction was higher for B. bassiana. Variations induced in B. bassiana and M. anisopliae after ten passages through poisoned media were analysed. Pesticides varied in their ability to induce such changes in the fungi. Polymorphism was higher for B. bassiana cultured in carbendazim. The polymorphism exhibited in B. bassiana was higher (83.19 per cent) compared to M. anisopliae (38.46 per cent). Among the ten universal fungal primers evaluated, RFu – 10 was found to give maximum polymorphism. To conclude, B.bassiana and M.anisopliae are pathogenic to the grubs and adults of all the nine test insects. Of the two fungi tested Bb 5 was more virulent than Ma 4 except to O. rhinoceros. Talc based formulation of both the fungi maintained the required standards of cfu in the formulations upto three months after storage. Cow dung, wheat bran and neem cake are ideal substrates for the multiplication of the fungi. Soil drenching of talc based formulation of B. bassiana @ 30 g l three months after planting was the best treatment for the management of C. sordidus. For the management of C. formicarius in sweet potato also soil drenching of talc based formulation of B. bassiana @ 30 g l -1 was superior. Compatibility of B. bassiana and M. anisopliae with insecticides and fungicides varied, the most compatible one was imidacloprid. Maximum tolerance to this insecticide, upto 32 times higher than the field dose was shown by B. bassiana and M. anisopliae. Pesticides induced changes in DNA, the polymorphism exhibited was higher for B. bassiana compared to M. anisopliae. Nine isolates of the fungi were also identified through ITS sequencing. The new isolates were Beauveria sp. from C. formicarius, B. bassiana -1 from B. fulvicorne, B. brongniartii from M. circumdata, Metarhizium sp. from B. fulvicorne; Metarhizium sp., Metarhizium album and Metarhizium anisopliae var majus from O. rhinoceros, Fusarium moniliformae from H. vigintioctopunctata and Paecilomyces sp. from C. sordidus and these isolates can be exploited in insect specific biocontrol programmes.ThesisItem Open Access Efficacy of Neoseiulus longispinosus (Evans) (Mesostigmata: Phytoseiidae) for the management of Tetranychus urticae Koch (Prostigmata: Tetranychidae) on Cucumber under protected cultivation(College of Horticulture, Vellanikkara, 2017) Neena, Lenin; KAU; Haseena, BhaskarA study was undertaken at the Acarology laboratory, Department of Agricultural Entomology, College of Horticulture, Vellanikkara during 2013-2016, to investigate the biology, incidence, crop phenology relationship and natural enemies of the two spotted spider mite, Tetranychus urticae Koch infesting cucumber in polyhouse as well as to study the biology, efficacy and prey stage preference of the predator, Neoseiulus ongispinosus (Evans) on T. urticae and standardize the optimum predator: prey ratio of N. longispinosus for biological control of T. urticae in polyhouse. Purposive surveys, conducted in fifteen polyhouses in four districts of Kerala viz., Thrissur, Palakkad, Wayanad and Thiruvananthapuram, revealed the occurrence of four species of tetranychid mites, namely, Tetranychus truncatus Ehara, T. urticae Koch, T. okinawanus Ehara, Eutetranychus orientalis (Klein) and one species of tarsonemid mite, Polyphagotarsonemus latus (Banks) on cucumber. The occurrence of T. truncatus and T. okinawanus is a new report on cucumber in polyhouse. Hence, DNA barcoding was carried out to confirm the species identity of T. truncatus (TOCRF001-15) and T. okinawanus (TOIR001-15). Studies on the relationship of crop stage and mite incidence on cucumber revealed that the population of spider mites was significantly higher during the late fruiting stage of the crop, followed by early vegetative stage. Relatively lower population was recorded at flowering stage and early fruiting stage.Four species of insect predators and six species of mite predators were recorded in association with spider mites on cucumber. The insect predators were Stethorus pauperculus (Weise), Oligota sp., Scolothrips sp. and an unidentified species of Cecidomyiidae. The predatory mite fauna included Agistemus garrulus Chaudhari, Amblyseius paraaerialis (Muma), Cunaxa sp., Cheyletus sp., Neoseiulus longispinosus (Evans) and Tydeus gossabaensis Gupta.Neoseiulus longispinosus was found to be the predominant species of predatory mite on spider mites infesting cucumber. Tetranychus urticae recorded a developmental period of 6.75 days in male and 7.15 days in female. Adult male lived for 8.95 days while mated and unmated female lived for 11.59 days and 13.04 days, respectively. Mated and unmated females recorded a fecundity of 47.91 and 36.08 eggs, respectively. The sex ratio was female biased (1:4.6) in T. urticae. Total developmental period of N. longispinosus was 3.91 and 4.27 days for male and female, respectively. Adult male lived for 19.66 days and the female, for 22.75 days. On an average, a single female laid 31.33 eggs and the progeny consisted of both males and females in the ratio 1:3.31. Parthenogenesis was not observed in N. longispinosus. The adult of N. longispinosus recorded significantly higher predation compared to the nymph. Both nymph and adult, showed preference towards egg compared to active stages of the prey. The time needed to eliminate the available prey population was found to increase with increase in prey density. Studies conducted to identify the optimum predator: prey ratio required for field release of N. longispinosus against T. urticae on cucumber in the laboratory showed that, at ratios of 1:5 and 1:10, the prey population was completely eliminated by tenth day. The prey population recorded in the ratios, 1:20, 1:25 and 1:33 were on par with this. In the polyhouse, the predator: prey ratios of 1:20 and 1:25 were found to significantly reduce the population of T. urticae on cucumber. The present study has revealed the potential of the predatory mite, N. longispinosus as a biocontrol agent of the spider mites. The short life cycle, longer life span of adults, female biased sex ratio and preference for egg stages and above all, the density dependant nature of the prey predator relationship, brought out in the present study could provide a platform for viable biocontrol strategy based on N. longispinosus for management of spider mites under protected cultivation in Kerala.ThesisItem Open Access Identification of Larval morphotypes of Helicoverpa armigera (Hiibner) (Lepidoptera: noctuidae) and their characterization using molecular markers(College of Horticulture, Vellanikkara, 2015) Ranjith, M T; KAU; Mani, ChellappanHelicoverpa armigera (Hübner) is a highly destructive, polyphagous pest inflicting sizeable damage in economically important crops worldwide. Notoriety of H. armigera is characterized by the ability to thrive in different crop ecosystems, high mobility, fecundity and great capacity to develop resistance to synthetic insecticides used in its management. The presence of larval morphotypes in different crop ecosystems is another feature of this pest. Colour morphs reportedly exhibit differential susceptibility against different insecticides indicating the presence of strong genetic variability with an adaptive significance for the insect. Thus, phenotypic and genetic variability studies could yield valuable information on population structure that can be useful in evolving appropriate strategies for management of genetically distinct morphotypes. A study was therefore envisaged to identify larval morphotypes of H. armigera on preferred hosts and to characterize these morphotypes using molecular markers. Surveys were conducted in vegetable growing areas of Palakkad, Thrissur, Kasaragod and Thiruvananthapuram districts in Kerala, as well as flower growing area of Thovalai, Tamil Nadu during the period between 2012 and 14. The larval populations collected from tomato in Palakkad and also from okra, chickpea, amaranthus and tomato in Thrissur were subjected to morphological as well as molecular level studies. Studies on larval prothoracic setal arrangement, structure of male genitalia and DNA barcoding confirmed the identity of the test insect as H. armigera. Twenty two larval morphotypes were identified from four host plants viz., tomato (7), okra (6), amaranthus (5) and chickpea (4) and the frequency of larval morphotypes on each crop were calculated. The dominant morphotypes observed were green on tomato, yellowish green on okra, green with green longitudinal lines on chickpea and green with dark longitudinal lines on amaranthus. Most of the larvae collected from tomato, chickpea and amaranthus possessed continuous pigmentation on lateral bands whereas those collected from okra were without pigmentation on lateral bands. The intensity of black pigmentation on thoracic and last i abdominal segments of morphotypes was worked out based on a standard scale (0-4) and the intensity varied among morphotypes with black pigmentation. The morphometric parameters of larva, pupa and adult were recorded and these showed significant difference among morphotypes on different crops. Further, the morphometric parameters were used for constructing morphocluster based on multivariate analysis techniques and it yielded two major clusters with sixteen morphotypes and six morphotypes in first and second clusters respectively. Genomic DNA was isolated from twenty two larval morphotypes using modified CTAB method, amplified with selected eight H. armigera specific SSR primers, resolved in poly acrylamide gel (10%) and visualized in silver stain (2%). The clear and distinct bands produced were further used for developing DNA fingerprint for individual larval morphotypes. Based on the presence or absence of bands, Dice coefficient of similarity was worked out and the coefficient ranged from 0.55 to 1.00. Dendrogram deduced from similarity coefficient yielded two major clusters and cluster analysis revealed that the morphotypes occurring on vegetables stood together in one cluster, whereas those occurring on chickpea stood out separately in another cluster. Analysis of gut microbiota of larva showed the presence of bacteria belonging to 173 families which helps the insect for its better survival. The twenty two larval morphotypes observed on four host plants were highly specific with respect to body colour and morphometric parameters. Further, molecular level analysis confirmed the existence of genetic difference among the morphotypes. Hence, present findings suggest that even though H. armigera is a polyphagous pest, it could have evolved into different larval morphotypes with great affinity to specific hosts. This could be an adaptive strategy of the pest to reduce intra specific competition and there by ensure better survival on host plants.
