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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 Effect of phorate applied for the control of bunchy top vector of banana Pentalonia nigroneroosa Coq. on the plant and in the soil environment(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Sitarama Rao, D; KAU; Mohandas, NA series of experiments were carried out for ascertaining the basic problems related to the current recommendations for managing bunchytop disease of banana through the application of phorate. The absorption, translocation and metabolism of phorate applied in the soil was influenced more by the condition and age of the plant than by the dose of the insecticide. Since the application of 2.50 g ai/plant did not result in corresponding increase in the residue content or the bioefficacy in the early phases of crop growth, when compared to the 1.25 dose, the latter can be used without significant loss in efficacy. A definite dose-effect relationship existed between the phorate content of plant and the mortality of P.nigronervosa confined at feeding sites. The median lethal doses of the insecticide content of the plant tissue were higher during declining phase of absorption as compared to those obtained during the active absorption phase. The result indicated the lesser toxicity of some components in the total residue during the later phase of the crop. Application of phorate granules in leaf axils was less effective than the treatment done in the soil and hence the current recommendation to use less quantity of insecticide when applied in the leaf axils has to be altered. A simple technique for the separation, identification and quantification of phorate and its metabolites was developed. Phorate and phorate sulfoxide contents of the total residue showed inverse relationship with each other while the other metabolites did not exhibit a clear relationship among them. Phorate and phorate sulfoxide exhibited more positive direct influences on the morality of the vector than the other metabilites. The absorption and toxicity of the insecticide content in plants did not vary significantly up to 174 DAP, when applied @ 2.50 g ai/plant at different intervals after planting. Absorption was very low when the insecticide was applied at 180 and 210 DAP. For ensuring residues within tolerance limits (0.10ppm) in raw fruits, the insecticide treatment has to be limited to 150 DAP and for ripe fruits the limit can be extended up to 180 DAP. The absorption and persistence of phorate and metabolites was significantly higher in plants grown in summer season than in those grown in rainy season. The absorption of insecticide was high in sandy soils and it was lowest in black cotton soils during the active absorption phase. The insecticide persisted at effective levels for 75 days in sandy, 90 days in lateritic upland and 105 days in black cotton soil. Sulfoxidation of the thioether moiety was the dominent metabolic pathway in sandy soil while desulfuration pathway was predominent in the other three soils. Application of phorate at planting, @ 2.50 g ai/plant, did not adversely affect the soil microflora as observed at the time of harvest of the crop.ThesisItem Open Access Bionomics of pareuchaetes pseudoinsulata rego barros (lepidoptera:arctiidae) and its interaction with the siam weed chromolaena odorata king and robinson (asteraceae)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1995) Lyla, K R; KAU; Abraham, C CStudies were undertaken on the biology, morphometrics, feeding habits, factors affecting fecundity and fertility of Pareuchaetes pseudoinsulata King and Robinson (Arctiidae : Lepidoptera) and also the plant response of the weed host Chromolaena odorata L. at the College of Horticulture, Vellanikkara during 1990 – 1993. The morphometrics and morphology of the various immature stages and adults have been described. The total life-cycle of P. pseudoinsulata took a total of 46.75 days and the various developmental stages lasted for 5.5 days in eggs, 21.30 days for larvae (seven instars) 1.5 days for pre-pupa and 10.15 days for pupae at a mean ambient temperature of 28.40 C. In feeding trials to assess the relative preference of tender, mature, semi yellow and yellow leaves of C. odorata, it was found that the I instar larvae showed district preference to tender leaves as compared to mature leaves. The I and II instar larvae did not feed on semi-yellow and yellow leaves and they died of starvation when these types of leaves were offered for feeding. Consumption indices decreased as the age of larvae advanced and thus early instars consuming all the types of leaves recorded high indices. The rate of increase in larval weight gain was higher in later instars (VI and VII). Caterpillars feeding on mature, semi-yellow and yellow leaves showed higher Relative Growth Rate during IV to V stage, but during I to II stage, a high RGR was seen on larvae which fed tender leaves. Yellow. leaf diet for late instar larvae adversely affected their development and adult emergence. Highest fecundity was recorded when the parental sex-ratio of moths was kept at 1:1 level followed by 1:2 ratio and 2:1 in that order. Egg production and viability were significantly higher at 250 C and 75 per cent RH as compared to 300 C and 60 per cent RH. Adult food did not show any influence on fecundity but in respect of improvement of egg viability the treatments were advantageous. Total nitrogen content in leaves was maximum on the sixth day of release of four larvae per cage. Leaf nitrogen showed a declining trend when the larval load per plant was increased from the eighth day of release onwards. Soluble nitrogen content in leaves showed an increasing trend with increase in larval load per plant, but this however failed to reach significant levels. Chlorophyll content in leaves got reduced significantly at increased larval population loads and with passage of time of confinement. The natural enemies of P. pseudoinsulata consisted of avian fauna, spiders and ants and parasitoids. Predatory species of ants recorded in association with the insect included Lioponera sp. Oecophylla smaragdina Fabr. Solenopsis sp.and Monomorium sp. Occasionally NPV infection occurred in the laboratory as well as in field cultures causing substantial mortality. The implications of the various findings in reorienting the biocontrol strategies involving P. pseudoinsulata against C. odorata have been discussed.ThesisItem Open Access Studies on the extent of damages caused by pests of stored copra and controle of the important pests(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Nalina kumari, T; KAU; Mammen, K VThe magnitude and intensity of insect pest attack in stored copra, in the Southern Districts of Kerala, were assessed in an elaborate survey, adopting a random sampling technique for two years. The survey revealed that insects cause significant damage even in well preserved good quality copra stocked for more than five months. N. rufipes, O. surinamensis, A. advena and L. serricorne were the major pests recorded. The immature stages of N. rufipes, adults and immature stages of the other pests were seen inside the tunnels made between the endosperm and testa. N. rufipes and O. surinamensis were distributed widely, while the predominant insects observed at Nedumangad were A. advena and L. serricorne. All the insects were found breeding on copra from June to October. A positive correlation between moisture content of copra and the insect incidence was observed in the studies. The influence of A. flavus on the extent of damage caused by these pests showed that the presence of the mould was not a predisposing factor for insect attack. The extent of damage in copra due to the infestation by N. rufipes was 12.2 per cent at the end of sixth month whereas O. surinamensis caused only three per cent damage. When combind with fungus, the damage caused by N. rufipes was reduced by 50 per cent. This effect was not observed on O. surinamensis. The infection by the fungus adversely affected the oil content of copra and this effect was not altered by the preceeding or succeeding infestation of the insect. The insect attack alone caused significant reduction in oil yield of copra during the sixth month after exposure only. The quality of oil was adversely affected when infested by insects and fungus independently. The infestation of insects preceeding or succeeding fungal infection did not alter the adverse effect caused by them independently. The quantitative loss caused by the attack of N. rufipes and O. surinamensis to copra obtained from different varieties of coconut did not show significant variations. Among the different varieties tested LM and LO were more favourable to N. rufipes and DxT and TxD to O. surinamensis. Two to six fold increase in the longevity of the adults of N. rufipes was observed when they were provided with immature stages in addition to copra for feeding. N. rufipes and O. surinamensis caused significantly greater damage to copra under eight per cent and six per cent moisture levels respectively. The development of N. rufipes was totally arrested in copra with four per cent moisture content. The development of immature stages and adult population of N. rufipes were higher in copra containing eight per cent moisture level and those of O. surinamensis in copra containing six per cent moisture. The response to moisture fluctuations was more conspicuously seen in O. surinamensis than in N. rufipes. Though the population of insects were found to be high in reused gunny bag followed by heap storage, the extent of damage was higher in heap storage than in reused gunny bags. High populations of N. rufipes and O. surinamensis were recorded from heap and reused gunny bags respectively. Low populations of insects were recorded in copra stocked in polythene/alkathene lined gunny bags and netted polythene bags. But the oil extracted from copra stored in these types of bags gave significantly higher acid values. In the trials done to find out a safe prophylactic method of control against pests of copra, malathion and phoxim proved more toxic to N. rufipes and malathion and fenitrothion to O. surinamensis. When these insecticides were evaluated for their persistence on gunny bags, malathion 0.4 per cent gave protection up to five months and fenitrothion 0.8 per cent up to six months. The residues of malathion and fenitrothion came below tolerance limits, 15 and 60 days after treatment respectively . For complete control of the major pests of copra 4.5 g/m (2.5 g ai/m ) of aluminium phosphate with one day exposure period was found adequate. The residue of phosphine in the copra fumigated as above was below tolerance limit.ThesisItem Open Access Resurgens of brown planthopper Nilaparvata Lugens (stal) on rice treated with various insectisides(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1989) Thomas biju, Mathew; KAU; Mohan das, NA series of green house experiments were carried out for screening the insecticides, fungicides and herbicides recommended for the control of pests, diseases and weeds infesting rice in Kerala, for their resurgence inducement in N. lugens. Among the thirteen insecticides screened, each at three doses and applied at three critical growth stages of the crop as well as at their possible combinations, methyl parathion, deltamethrin, fenitrothion, fenthion, quinalphos and carbaryl were identified as resurgence inducing insecticides with no apparent differences among themselves in the intensity of resurgence caused, HCH, dimethoate, monocrotophos, phosphamidon, phorate, BPMC and carbofuran were found to be free from resurgence inducement and some of them even exerted a significant suppressing effect on the progeny production of N. lugens. There was no carry over of resurgence effect over generations. The results of the experiments also revealed that: 1. The manifestation of resurgence inducing property of insecticides was more at the higher doses than at the field doses or lower doses. 2. The frequency of occurrence of resurgence among the different treatments with resurgence inducing insecticides showed that a single application at any of the three critical growth stages of rice and two applications combining any two of the three growth stages were on par while three consecutive treatments covering all the three growth stages was more favourable for manifestation of resurgence. 3. The growth stages of the host plant had significant influence on the manifestation of resurgence inducement of insecticides. It varied with the properties of insecticides used. Some manifested resurgence at tillering, some at panicle initiation and none at booting stage. 4. The resurgence effect induced by the insecticides was found to last in the treated plants for a period of 15 to 20 days after treatment and the results indicated, that there was no cumulative effect by repeated treatments on insect populations. In the light of the above findings the method of screening resurgence inducing insecticides in the green house was standardized as the application of the insecticide at doses higher than the field doses thrice covering the tillering, panicle initiation and booting stages preceeding the exposure of insects for assessment of progeny production which may be done at 15 days after the third application. In further screening adopting the procedure standardized above malathion, methyl demeton, FMC 35001, fenvalerate, permethrin and cypermethrin were found inducing resurgence in N. lugens. The granular insecticides were screened giving two treatments (tillering + panicle initiation) and exposing insects at 30 DAT for egg laying. Results revealed that diazinon, phorate, cartap and carbofuran caused resurgence of N. lugens. Endosulfan, formothion, phosalone, methamidophos, chlorophyriphos, DDVP and their combinations with HCH or carbaryl (liquid formulations), aldicarb, quinalphos and sevidol (granular) were free of resurgence hazard. At the recommended doses and methods of application of fungicides zineb, mancozb, captafol, ediphenphos, kitazin, carbendazim and carboxin and the herbicides 2, 4-D (sodium salt and ester), pendimethalin, fluchloralin, butachlor, propanil and thiobencarb did not post any resurgence problem. The inducement of resurgence by insecticide was seen significantly influenced by the variety of host plants of the insects involved. The levels of plant mediated resurgence inducement and resistance of the plants to insect attack were not mutually related. In screening insecticides for the control of a pest in an agroecosystem, the interaction of the popular varieties of the crop available in the area with resurgence inducement also should be studied. The resurgence inducing mechanism of six identified insecticides was studied in detail. The results of a series of green house and laboratory experiments revealed that : 1. Resurgence inducing insecticides brought about some morphological changes in the crop causing some improvements in the stand but the magnitude of the changes were not adequate to influence the attraction of the insects or build up of the pest population. 2. The application of the insecticides caused significant variations in the nutrient content and biochemical constituents of treated plants causing consistent changes in the total nitrogen, free sugars and free amino acid contents. 3. The feeding of N. lugens on treated plants was significantly higher as indicated by the feeding indices. 4. The correlation studies and path coefficient analysis of the data relating to the magnitude of changes in the above factors caused by the application of insecticides could be attributed as the major cause of plant-mediated resurgence inducement. The direct application of resurgence inducing insecticides revealed that some of the insecticides which showed plant mediated resurgence (methyl parathion, deltamethrin and carbaryl) had direct stimulating effect also on the progeny production of N. lugens at sublethal doses while some (fenthion and fenitrothion) did not show any increase in progeny production and some (quinalphos) showed only marginal effect. While carbaryl and methyl parathion were more stimulatory at lower levels, deltamethrin stimulated reproduction at both the lower and higher levels. The field experiment revealed that the resurgence observed in the field was the added effect of plant-mediated resurgence observed in green house experiments and the direct effect of the pesticides caused by their sublethal doses. In general the conclusions from the green house experiments were in agreement with the results obtained from the field. It was seen that the changes in predatory population in field caused by the application of pesticides did not contribute significantly to the inducement of resurgence in N. lugens. It was also observed that the assessment of plant induced resurgence of insecticides in green house experiments and the direct effects of the toxicants on the insects will serve as an effective alternative elaborate field experiments for evaluating the resurgence effect of insecticides.ThesisItem Open Access Monitoring and management of the pest complex of bitter gourd (Momordica Charantia L.)(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1999) Nandakumar, C; KAU; Saradamma, KSurveys were conducted in 1995-96 among one hundred bitter gourd farmers in Thiruvananthapuram district. Information on the personal and socio- economic characteristics of the farmers was gathered. Field visits indicated that among the pests at flowering, the jassid, H.phycitis and leaf feeder, D. indica were important. At early harvest, the jassid and fruitfly B. cucurbitae were the major pests. Among the natural enemies observed, the potential ones were Cjohnsoni (parasite on Hseptima), I.scutellare, Msexmaculatus and Snubilis . (predators on A.gossypii). Mosaic was severe in 12 per cent of the plots. Sixty two per cent of the farmers used a combination of mechanical, cultural and chemical measures against pests. Most common pesticides used belonged to the organophosphate group. Farmers in general adopted injudicious methods of chemical control. Seventy per cent farmers relied on mass media and interpersonal cosmopolites for information on plant protection. The most important constraint perceived by farmers was the high cost of inputs viz., plant protection chemicals, manures and fertilizers. Monitoring of fruit fly incidence using Biosense stikatrap (lure) indicated the maximum catch at eleven weeks after sowing. Ten carbofuran smeared banana fruit traps (in yellow coloured coconut shell) were found to be more efficient than one Biosense trap in trapping the fruit fly. 2 Studies on seasonal incidence of the pests and their natural enemies from 1995 to 1996 indicated that they were more from November '95 to April '96. In studies on the assessment of potential natural enemies of pests, the biology and efficacy of Cjohnsoni against epilachna beetle was observed. Among the predators viz., Iscutellare, Msexmaculatus and S.nubilis whose biology and feeding potential was studied, Msexmaculatus was observed as the most efficient predator of aphids. In another set of experiments, the effects of botanicals and chemical pesticides on pests and their natural enemies were studied. The antifeedant effect of botanicals on third instar Hseptima grubs indicated that neem seed oil (three per cent) and nimbecidine (0.40 per cent) were effective. Estimation of the comparative effect of chemical pesticides against the fourth instar Hseptima grubs showed that carbaryl and dimethoate were more effective than quinalphos and malathion. Toxicity studies of botanicals and chemical pesticides to Msexmaculatus grubs and Cjohnsoni adults as well as parasite emergence from treated larval! pupal Hseptima hosts indicated that botanicals were safe whereas, the chemicals were toxic to the natural enemies. Based on the above experiments, the botanicals viz., neem seed oil three per cent, nimbecidine 0.40 per cent and the chemical pesticides,carbaryl 0.15 per cent and dimethoate 0.05 per cent were selected for the pest management trial in bitter gourd. The reaction of five bitter gourd varieties viz., Priya, Arka Harit, Preethi, Priyanka and local to pests was tested in a field trial. Based on pest infestation and yield, Preethi was selected for the pest management trial. 3 The pest management trial was conducted for two seasons (January to April, 1996 and 1997). The results indicated that combination of botanical with chemical pesticide was the best in pest control. Based on the results the following recommendations were suggested as part of IPM strategies in bitter gourd. 1. Use variety 'Preethi' (MC-84) for planting 2. Basal drenching of combination of nee m seed oil three per cent soap emulsion with either dimethoate (0.025 per cent) or carbaryl (0.075 per cent) prior to seeding. This is recommended in areas where pests like pumpkin beetles are endemic. 3. Need based application of above till fruit set to control pests. 4. Apply fungicide (Mancozeb) to control foliar disease (downy mildew). 5. Monitor fruit fly incidence using lure trap. Set yellow painted coconut shell trap's containing carbofuran smeared banana (palayankodan) alternated with carbofuran poisoned ocimum I jaggery (2m spacing) at flowering till final harvest. 6. After fruit set, use (need based) a combination of neem seed oil three per cent soap emulsion and dimethoate 0.025 per cent.ThesisItem Open Access Insect pest natural enemy- host plant interaction studies with special reference to the brown planthoper nilaparvata lugens(Stal.)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1999) Haseena, Bhaskar; KAU; Joy, P JField surveys were conducted in Kole land and Kuttanad to assess the population of rice BPH, Nilaparvata lugens (Stal) and its natural enemies. Field investigations on the population dynamics of BPH and its natural enemies were carried out on susceptible (Jaya), moderately resistant (Jyothi) and resistant (Kanakom) rice varieties at the rice fields of Rice Research Station, Moncompu during 1997-98. The influence of these varieties on the biology of the pest, the biocontrol efficiency of the major natural enemies and the biology of the mirid predator Cyrtorhinus lividipennis Reuter was studied in the laboratory. Histological and chemical investigations were undertaken to evaluate the factors that contribute to the resistance/susceptibility in them. Results of field survey in Kole land revealed that the population of BPH was far below the economic threshold level (ETL). In Kuttanad, in kayal area during Rabi season and in karappadam tract during Kharif season outbreaks of BPH occurred in some localities due to the indiscriminate use of insecticides resulting in the mortality of natural enemies. The results of the study on population dynamics revealed that the BPH population was significantly high on the susceptible J aya and low on the resistant Kanakom with the population reaching a peak from February to March. The predatory complex of the BPH comprised of the rnirid Cyrtorhinus lividipennis, Lycosa pseudoannulata, Tetragnatha maxillosa, Atypena formosana, Microvelia douglasi atrolineata, Pseudogonatopus sp. and Ophionea nigrofasciata. C. lividipennis was the most predominant predator regulating the hopper population and there exists a density dependent host-predator relationship. The population of the mirid predator on Jaya and Kanakom did not differ significantly. The prey-predator ratio was lowest on the resistant variety and highest on the susceptible variety. Of the weather parameters studied, the minimum -. temperature showed a highly significant negative correlation with the population of N. lugens in all the varieties. BPH reared on the resistant variety recorded longer nymphal duration, decreased nymphal survival and shorter adult longevity indicating the prevalence of antibiosis in the variety. Lesser number of eggs laid, longer pre-oviposition period and shorter oviposition period recorded on Kanakom indicate the antixenosis factor in it. Macrpterous forms of BPH did not develop on the variety . The predator C. lividipennis and Micraspis sp. fed more BPH when reared on the resistant variety. The veliid bug M. d. atrolineata, the spider L. pseudoannulata and the dryinid Pseudogonatopus sp. predated significantly more BPH nymphs on resistant variety at a higher prey density only. However, the dryinid parasitoid consumed significantly fewer number of hoppers on Kanakom at the higher host density. C. lividipennis recorded longer nymphal duration, shorter adult longevity and low fecundity when fed on BPH reared on Kanakom which can be attributed to the low fecundity of N. lugens on Kanakom leading to less availability of food to the mirid. Nymphal duration and adult longevity of C. lividipennis did not vary between the varieties Jaya and Jyothi. Well developed bundle sheath with more frequently distributed schlerenchyma tissue in the culm of the resistant variety seemed to impart resistance in Kanakom along with thicker cuticle. Higher amounts of silica, Zn and Mn and lower amounts of N, K, Ca and Mg were recorded in the culm of the resistant variety compared to moderately resistant and susceptible varieties. The findings strongly suggest the mechanism of antibiosis and antixenosis in the resistant variety Kanakom.ThesisItem Open Access Population dynamics and management of aphids in vegetable ecosystem(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2009) Thamilvel, D; KAU; Hebsy, BaiEight species of aphids viz., A. gossypii, A. craccivora, A. spiraecola, A. fabae, A. nerii, H. setariae, M. persicae and L. erysimi were recorded from 32 vegetables in a survey conducted in the four taluks of Thiruvananthapuram district of Kerala. Occurrence of A. gossypii on C. grandis, M. oleifera and P. tetragonolobus; A. craccivora on C. gladiata, P. tetragonolobus and S. grandiflora ; A. spiraecola on A. tricolor, C. sativus, C. tetragonoloba, M. oleifera, M. charantia, M. koeingii, P. tetragonolobus and S. androgynus ; M. persicae on A. tricolor and R. sativu; A. nerii on C. annuum and C. frutescens was recorded for the first time from the State and H. setariae on A. tricolor and A. dubius from South India. One hundred and twenty two other plants were identified as host plants of the different aphids. A. gossypii was the dominant species noted, closely followed by A. craccivora, and A. spiraecola. Maximum species of aphids were recorded on amaranthus followed by winged bean. Among the vegetables surveyed, chilli and coccinia were highly susceptible to A. gossypii and winged bean and cowpea to A. craccivora. Mosaic disease incidence was noted in 10 vegetables. Predators were the predominant group of natural enemies associated with the aphids with the coccinellids constituting the major predatory fauna. Twenty species of coccinellids were recorded from different species of aphids on various host plants of which 13 species were new records from Kerala. M. sexmaculatus was the dominant species followed by C. transversalis, S. latemaculatus and C. septempunctata, Four species of syrphids were recorded of which I. scutellaris was predominant. P. yerburiensis and D. aegrota were recorded for the first time from Kerala. Leucopis sp. was the only Chamaemyiid species recorded from the vegetable fields. The chrysopids, C. carneae and A. octopunctata and the hemerobiid, Micromus sp. were the Neuropteran predators of the aphids recorded of which Micromus sp. was dominant. A. octopunctata was recorded for the first time from Kerala. Eleven species of spiders were observed in the vegetable fields among which, O. javanus, T.mandibulata, O. quadridentatus, O. shweta and Phidippus sp. were the frequently encountered species. Aphidius sp. was the most dominant parasitoid in the vegetable ecosystem. Aphelinus sp. and D. rapae were the other parasitoids recorded. Seven species of ants were observed attending the aphids. Studies on the population fluctuation of A. gossypii in chilli and A. craccivora in winged bean during a cropping season indicated that high population was seen during November and December. Correlation studies revealed a significant and positive correlation between the population of both the aphids with the insect predators, spiders and parasitoids. None of the climatic parameters had any significant influence on the aphid population. Excepting, maximum temperature which had a positive influence, all the other weather parameters viz., minimum temperature, relative humidity, rainfall and wind velocity had a negative influence on the population of the predators and parasitoids. Among the botanicals screened in the laboratory, only neem oil- garlic emulsion 2% and NeemAzal T/S 4 ml/l recorded more than 50 per cent mortality of A. gossypii and A. craccivora. Among the insecticides, the neonicotinoids viz., acetamiprid 0.002% imidacloprid, 0.003%, and dimethoate 0.05% proved superior to all other treatments. Dimethoate 0.05% was highly toxic to the coccinellids, syrphids and a hemerobiid (Micromus sp.) predator under laboratory condition. Between the two neonicotinods, acetamiprid 0.002% registered higher mortality than imidacloprid 0.003% whereas NeemAzal T/S 4 ml/l and neem oil + garlic emulsion 2% were safe to the predators. Foliar application of dimethoate 0.05%, acetamiprid 0.002% and imidacloprid 0.003% gave good control of A. gossypii, A. biguttula biguttula, S. dorsalis and A. dispersus in chilli and A. craccivora, A. dispersus, R. pedestris and M. vitrata in winged bean. NeemAzal T/S 4ml/l and neem oil garlic emulsion 2% too checked the population of the pests appreciably. Dimethoate 0.05% was highly toxic to the predators and parasitoids followed by acetamiprid 0.002% both in the chilli and winged bean fields. Comparatively, imidacloprid 0.003% was less toxic. The botanicals were safer to the natural enemies. Dimethoate 0.05% was highly toxic to soil fauna and flora whereas acetamiprid and imidacloprid were less toxic while NeemAzal T/S 4ml/l and neem oil + garlic emulsion 2% were non toxic. In both the trials, significantly higher yield was obtained from all the treatments. However, no significant difference was noted in the yields obtained from acetamiprid 0.002%, imidacloprid 0.003% and dimethoate 0.05% treated plots. Residues of imidacloprid were detected in chilli and winged bean fruits five days after spraying. While on the tenth day after spraying, residues of acetamiprid, and dimethoate were detected in chilli fruits, only residue of acetamiprid was recorded from winged bean pods. Imidacloprid was below detectable level (BDL). Residues of all the three insecticides were below detectable level when estimated fifteen days after spraying. Based on the results of the study, early detection of aphids on weeds and other host through regular monitoring, proper weed and ant management, conservation of the beneficials, application of neem oil + garlic emulsion 2% or NeemAzal T/S 4ml/l during the early stage of infestation and use of imidacloprid 0.003% when needed are suggested for aphid management in vegetables.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.
