1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Bioremediation potential of the entomopathogenic fungus Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno(Department of Entomology, College of Agriculture, Vellayani, 2025) Asna Mol Basheer.The study entitled “Bioremediation potential of the entomopathogenic fungus Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno” was carried out in the Biocontrol Laboratory for Crop Pest Management, Department of Entomology, College of Agriculture, Vellayani, from 2022 to 2024 with objective to evaluate the insecticide, fungicide, nematicide and herbicide degradation potential of the entomopathogenic fungus Lecanicillium saksenae in soil. Tolerance studies were carried out in vitro, using poisoned food technique, in Czapek Dox Agar (CDA) under carbon devoid, nitrogen devoid and phosphorous devoid conditions, to test the ability of the fungus to utilize these molecules from the pesticides. The pesticides selected for the study included the insecticides chlorantraniliprole 18.5% SC, fipronil 80% WG, quinalphos 25% EC, and chlorpyrifos 20% EC, the fungicides hexaconazole 5% EC, tebuconazole 25.9% EC, carbendazim 50% WP, the nematicides carbosulfan 25% EC,fluopyram 34.48% SC and the herbicide pendimethalin 38.7% CS. Tolerance was assessed based on growth and sporulation of the fungus in poisoned media and calculating the Tolerance Index. Among the tested insecticides, highest tolerance was exhibited to chlorantraniliprole 18.5% SC,(nitrogen deprived medium), where the radial growth of mycelia was 4.75 cm by the 21st DAI, which was significantly higher than in fipronil 80% WG (1.30 cm), while quinalphos 25EC and chlorpyriphos 20% EC completely inhibited the fungus. The spore count observed was also highest in chlorantraniliprole poisoned medium (2.09 × 10⁷ spores mL-1), which was on par with that of control (4.27 × 10⁷ spores mL-1).The corresponding spore load in fipronil was 1.51× 10⁷ spores mL-1.In phosphorus-deprived medium, it exhibited moderate tolerance to quinalphos 25% EC and chlorpyrifos 20% EC, radial growth being 1.62 cm and 3.45 cm, respectivelyat 21 DAI and spore counts of 1.109 × 10⁷ spores mL⁻¹and 0.987 × 10⁷ spores mL⁻¹. In the case of the fungicides, hexaconazole 5% EC, tebuconazole 25.9% EC, and carbendazim 50% WP and the nematicides carbosulfan 25% EC and fluopyram 80 34.48% SC, L.saksenae was completely inhibited. So also, the herbicide pendimethalin 38.7% CS completely arrested the fungus in carbon devoid medium but supported its growth in nitrogen devoid medium (6.21 cm) and sporulation (4.26×107spores mL-1). Tolerance Index calculated based on the ratio of colony extension growth rates in the presence and absence of pesticide concluded that,it was highest for pendimethalin 38.7% SC (80.91), followed by chlorantraniliprole 18.5% SC (61.88), chlorpyriphos 20% EC (44.95) and quinalphis 25% EC (21.11). Further, the bioremediation potential of L. saksenae was assessed by inoculating the conidial suspension into pesticide-treated soil. Pesticide degradation was determined by detecting the respective residues using GC-MS and LC-MS for a period of three months. Percentage removal of residues was highest in the case of pendimethalin 38.7% CS (74.2 per cent), followed by chlorantraniliprole 18.5% SC (70 per cent) and fipronil 80% WG (51.67 per cent). Assessment of microbial population in L. saksenae inoculated soil contaminated with tolerant pesticides, revealed that the bacterial, fungal, and actinomycete counts were higher compared to uninoculated soil, indicating the detoxification of toxic molecules in inoculated soil. The bacterial count in inoculated soil after four weeks of treatments was significantly higher in fipronil treated fungus inoculated soil (3.95× 106 CFU g⁻¹) while in the uninoculated soil, it was 2.35× 106 CFU g⁻¹. The actinomycetes count was also highest in fipronil treated soil (5.83× 104 CFU g⁻¹) while in uninoculated it was 2.40× 104 CFU g⁻¹. Soil arthropod population assessed for a period of four weeks indicated that the population of soil mites and collembola was more in inoculated soils (21.90 to17.1) compared to the uninoculated (16.6 to 12). The study highlights the bioremediation potential of L. saksenae as a promising agent for degrading insectides and herbicide in contaminated soils. Its role in sustaining microbial populations further reinforces its applicability in integrated pest management (IPM) and sustainable agriculture. Future research should focus on field-scale validation of these findings and explore potential synergies between L. saksenae and other bioremediation agents.Item Diversity and taxonomy of white grubs in Kasaragod district(Department of Entomology, College of Agriculture,Padannakkad, 2025) Anusree Asokan.The research work “Diversity and taxonomy of white grubs in Kasaragod district” was carried out in the Department of Entomology, College of Agriculture, Padannakkad during the year 2023. The objectives of the research work included survey and collection of white grub adults under the family Scarabaeidae from agro-ecological units of Kasaragod district, taxonomic identification and distribution analysis, redescription and preparation of illustrated key/s of white grub adults under the family Scarabaeidae from Kasaragod district and study of male and female genitalia. Collection surveys were carried out by installing light traps, representing the five agroecological units of Kasaragod district viz., Coastal plain, midland laterites, foothills, high hills and Kaipad lands covering 11 locations viz., Manjeshwar, Vorkady, Chemmanad, Pullur-Periya, West Eleri, Balal, East Eleri, Pilicode, Nileshwar, Padanna and Kayyur-Cheemeni. The adult beetles were collected from light traps at fortnightly interval during 2023. The collected beetles were subjected to wet preservation by storing in 70 percent alcohol and dry preservation. The adults were pinned using number ‘3’ size entomological pins. The pinned specimens were labelled with the following details viz., location, date of collection, name of the collector and its geographical details. These specimens were dried at 45ºC in oven for 15 days and stored for further studies. Very small beetles were mounted onto the narrow end of a triangular white ivory card with fevicol®, later pinned and stored. In order to categorize the stored specimens into subfamilies, they were first grouped based on claws, abdominal sternal lines, antennal insertion, arrangement of metatibial spurs of the beetles. The dissection of the genitalia was done in accordance with standard procedure. Photographs and descriptive studies were conducted on taxonomic features, including the antenna, mouth parts, pronotum, elytra, scutellum, pygidium, legs, tarsal claw, sternum and male genitalia. Descriptions, illustrations and key to species of Scarabaeidae in Kasaragod were prepared. Based on the literature collected and by running taxonomic keys, the identification of the species was done. The total length, total width, and maximum width of adult specimens were measured. Species diversity and distribution map were prepared with the help of PAST software. The study explored 53 species belonging to 25 genera under eight subfamilies viz., Aphodiinae Leach, Cetoniinae Leach, Dynastinae MacLeay, Melolonthinae Leach, Rutelinae MacLeay, Scarabaeinae Latrielle, Sericinae Kirby and Orphninae Erichson. Melolonthid species were recognized under six genera viz., Anomalochela Moser, 1913, Apogonia Kirby, 1818, Holotrichia Hope, 1837, Leucopholis Dejean, 1833, Schizonycha Dejean, 1833 and Sophrops Fairmaire, 1887. The Sericinae species were associated with two genera Maladera Mulsant and Rey, 1871 and Selaserica Brenske, 1897. The Rutelinae species were recognized under five genera viz., Adoretus Laporte, 1840, Anomala Samouelle, 1819, Mimela Kirby, 1823, Parastasia Westwood, 1841, Popillia Serville, 1825. The subfamily Dynastinae is recognized into two genera viz., Alissonotum Arrow, 1908 and Oryctes Hellwig, 1798. The subfamily Scarabaeinae is associated with four genera viz., Catharsius Hope, 1837, Copris Geoffroy, 1762, Digitonthophagus Balthasar, 1959, Onitis Fabricius, 1798, Onthophagus Latreille, 1802. Four genera reported from subfamily Aphodiinae such as Rhyssemus Mulsant, 1842, Chaetopisthes Westwood and Aphodius Illiger, 1798. Single genus were reported from Cetoniinae and Orphniinae, viz., Heterorrhina Schoch, 1894 and Orphnus Macleay, 1819 respectively. Aphodiinae is the most abundant subfamily reported in Kasaragod district with the genus Rhyssemus. Among phytophagous subfamilies, maximum species belonged to the sub-family Melolonthinae. Among the melolonthinae beetles Apogonia ferruginea is reported as the most abundant species in Kasaragod. Based on the comparison of different diversity indices, mid lands exhibited highest genus richness. The value of Simpson-Yule Diversity index (D) was highest for mid lands which indicates mid lands supported maximum genera of white grubs. The value of the Shannon - Weaver Diversity index (H) were found to be highest for foot hills indicating the suitability of the lands to harbour a wide variety of scarab fauna. The highest evenness index (E) found to foot hills followed by high hills, coastal lands and mid lands shows that foot hills are more favoured for a large number of white grub species. The Berger Parker dominance index (d) for the species dominance found to coastal lands showed that coastal lands are less diverse and where one species completely dominated the community. The Kaipad land recorded no scarab beetles. Effect of weather parameters was found to non-significantly correlated with the emergence of white grubs.Item Host suitability and safety evaluation of predominant larval parasitoid of lepidopteran pests in vegetable ecosystem(Department of Entomology, College of Agriculture,Vellayani, 2025) Jyothsna Jose.; Manu, C RThe study entitled ‘Host suitability and safety evaluation of predominant larval parasitoid of lepidopteran pests in vegetable ecosystems’ was carried out in the Department of Entomology, College of Agriculture, Vellayani and farmers’ fields in different districts of Kerala during the period 2022-2024. The main objectives of the study were documentation of larval parasitoids of lepidopteran pests in vegetable ecosystems in southern Kerala and the evaluation of host suitability of the predominant parasitoid and its safety to insecticides and botanicals. Periodical survey was conducted across the various districts of Kerala viz., Thiruvanathapuram, Kollam, Pathanamthitta, Kottayam, Alappuzha, Ernakulam, Kozhikode, Malappuram and Wayanad covering fields of major vegetable crops like cucumber, snakegourd, pumpkin, bhindi, brinjal, and amaranthus. The larvae collected from these fields were reared in the laboratory and observed for parasitisation. Among the lepidopteran pests observed for parasitisation, Diaphania indica Saunders showed maximum susceptibility to parasitoids followed by Sylepta derogate Fabricius with a parasitisation rate of 69.33% and 52.82% respectively. The parasitoids collected were morphologically identified as Bracon hebetor Say, Brachymeria lasus Walker, Apanteles taragamae Viereck and Bracon brevicornis Wesmael. The identification was confirmed with the help of molecular analysis. Out of four parasitoids obtained, B. hebator was designated as the predominant parasitoid since it consistently exhibited highest parasitism in different pests species collected. To identify suitable hosts for the mass production of B. hebetor, a laboratory experiment was conducted using a Completely Randomized Design (CRD) with four treatments and four replications. The hosts selected for the mass production included the rice moth, Corcyra cephalonica Stainton, the greater wax moth Galleria mellonella L, and two natural hosts susceptible to parasitisation, viz., D. indica and S. derogata. The hosts, rice moth and greater wax moth were reared in their respective artificial diet and the natural hosts, cucumber moth and leaf roller were reared in the leaves of respective host plants. The observations on fecundity, emergence period, number of adults emerged, and life stages were recorded. G. mellonella showed significantly higher parasitism (100%), fecundity (20.55), larval emergence (20.55), pupation (20.55), adult emergence (19.66) per host and female progeny (12.6) consistently outperforming C. cephalonica, the common laboratory host for mass production. Contact residual toxicity was assessed using dry film assay to evaluate the safety of B. hebator to insecticides and botanicals. Among the insecticides and botanicals, azadirachtin (5mlL-1) was relatively safer with a maximum parasitoid survival percentage up to 15 HAT followed by KAU Raksha (6gL-1) with survival up to 13 HAT. Although chlorantraniliprole (3ml10L-1) showed survival up to 13 HAT, mortality was observed at 2 HAT. Fenvalarate (2mlL-1) was highly toxic as mortality was observed within 1 HAT. The study identified B. hebetor as the predominant larval parasitoid of various vegetable pests across Kerala. It was also found that D. indica was the most susceptible pest to natural parasitism. B. hebetor was effective against the larvae of other pests viz. Maruca vitrata, Anadevidia peponis, Helicoverpa armigera, Spodoptera litura and Psara basalis under laboratory condition. For mass production of B. hebetor, G. mellonella proved to be the most suitable host followed by C. cephalonica. On safety evaluation, azadirachtin was found to be relatively safer followed by KAU Raksha and chlorantraniliprole.Item Black soldier fly larvae as hosts for entomopathogenic nematodes and its assessment against Odoiporus longicollis (Olivier)(Department of Entomology, College of Agriculture, Vellayani, 2024-04-01) Haripriya, S A; Manu, C RThe study entitled “Black soldier fly larvae as hosts for entomopathogenic nematodes and its assessment against Odoiporus longicollis (Olivier)” was conducted at the Department of Entomology, College of Agriculture, Vellayani during 2021-2023. The main objective of the study was assessment of the pathogenicity of the entomopathogenic nematode, Heterorhabditis bacteriophora (Poinar) multiplied in BSFL against various pests in-vitro and its evaluation against banana pseudostem weevil, O. longicollis. Pathogenicity of H. bacteriophora from BSFL to grubs of banana pseudostem weevil, rhinoceros beetle, hadda beetle and larvae of tobacco caterpillar was assessed with inoculum levels of 10, 50, 100, 200 and 250 IJs per insect. The concentrations viz., 200 and 250 IJs per insect recorded 100 per cent mortality at 60 and 72 hours after treatment (HAT) respectively in pseudostem weevil grubs and at 48 HAT in hadda beetle grub and the highest mortality of 88.89 per cent at 96 HAT in rhinoceros beetle grubs. 100 per cent mortality was observed with concentration of 100 and 250 IJs per insect at 24 HAT in tobacco caterpillar. The mortality percentage increased with increase in infective juvenile concentration and increase in exposure period in all the insects tested. This study systematically assessed the pathogenicity of H. bacteriophora from black soldier fly larvae against various insect pests, offering insights into the potential of these entomopathogenic nematodes for biocontrol purposes in agriculture. Under field evaluation, the cadavers were applied as per schedule of treatments in the outer four leaf axils of plants during 5, 6 and 7 months after planting after inoculation with grubs of pseudostem weevil. During the first application, the bore hole were lowest at 10 and 21 days after treatments in 3 BSFL cadavers (12.08 and 13.17 respectively) and 1 Galleria cadaver per leaf axil (11.92 and 13.08 respectively). Similar trend was observed during the second and third application of treatments wherein 3 BSFL cadavers per leaf axil and 1 Galleria cadaver per leaf axil were recorded least bore holes (21.67 and 22.17 respectively) before application of second treatment and during third application, it was 29.08 and 31.75 respectively. After 10 days and 21 days too these treatments recorded a similar trend after second application and after third application, the lowest bore hole count was with 3 BSFL cadavers per leaf axil, however it was statistically on par with 2 BSFL cadavers and 1 Galleria cadaver per leaf axil. The results of the study suggested that a decrease in borehole counts in banana plants treated with H. bacteriophora infected cadavers compared to control plants, indicating successful pest management. Destructive sampling was carried out seven days after last application and mortality of insect was recorded. The plants treated with 2 BSFL cadavers per leaf axil recorded significantly higher mortality of grubs (72.31%) which was found statistically on par with 3 BSFL cadavers per leaf axil (70.47%) and 1 Galleria cadaver per leaf axil which caused 69.95 per cent mortality of insects. There was no significant difference between the treatments in the biometric observations of plant such as basal girth and girth at 1m height. Highest pseudostem height was observed in the plants treated with, 2 BSFL cadavers per leaf axil (182 cm) followed by 3 BSFL cadavers leaf axil (181 cm) and control plants recorded least pseudostem height (169.50 cm). Leaf length was highest in the plants treated with 1 Galleria cadaver per leaf axil (167 cm) and was on par with 2 and 3 BSFL cadavers per leaf axil and the least in control plants (149.25 cm). The plants treated with 1 BSFL cadaver per leaf axil recorded highest leaf breadth (60.92 cm) which was least in control plants (54.50 cm). Leaf area was also recorded highest in the plants treated with 1 BSFL cadaver per leaf axil (7457.71 cm2) compared to control plants (6149.26 cm2). Biometric observations showed positive effects on plant growth parameters, affirming that the pest control strategy positively influenced overall plant health. The result of the study revealed the potential of utilizing BSFL as hosts for entomopathogenic nematode, H. bacteriophora and the efficacy of these nematodes from BSFL cadaver to cause pathogenicity in the grubs of pseudostem weevil, rhinoceros beetle, hadda beetle and larvae of tobacco caterpillar under in vitro condition. This can be recommended for the management of pseudostem weevil grub as leaf axil application of H. bacteriophora infected BSFL cadaver @ 2 cadavers per leaf axil at 5, 6 and 7 months after planting. The outcomes of this research could contribute to the development of eco friendly strategies for pest management in agriculture.Item Diversity spices richness of pollinators in cashew(Department of Entomology, College of Agriculture, Padannakkad, 2025-03-27) Aparna Krishnan; Nisha Lekshmi, VThe study entitled "Diversity and Species Richness of Pollinators in Cashew" (November 2023–March 2024) conducted at the Regional Agricultural Research Station (RARS), Pilicode, investigated pollinator diversity, species richness, and foraging behaviour in cashew (Anacardium occidentale Linn.), a vital insect-pollinated cash crop. Observations were made on early (Nov–Dec), mid (Dec–Jan), and late (Feb Mar) flowering types through hourly monitoring of 10 inflorescences from 6:00 AM to 5:00 PM. Pollinator species were identified and analysed for abundance, foraging behaviour (peak foraging hours, foraging rate and foraging speed), and correlations with weather conditions. A bagging experiment was done to assess their role in fruit set. Nesting sites and bee pasturage were also documented. The study identified 12 pollinator species, including 11 hymenopterans from Apidae (Apis cerana indica Fabricius, Tetragonula sp., Ceratina hieroglyphica Smith, C. binghami Cockerell), Halictidae (Halictus sp. 1, Halictus sp. 2, Lasioglossum sp., Hoplonomia sp.), and Megachilidae (Megachile cephalotes Smith, M. lanata Fabricius, M. laticeps Smith), along with one dipteran (Mesembrius sp., Syrphidae). Halictidae had the highest distribution (49%). Species abundance varied with flowering type: Tetragonula sp. dominated early flowering (30.435%), A. c. indica Fabricius mid flowering (41.176%), and Lasioglossum sp. late flowering (46.296%). Overall, A. c. indica Fabricius was most abundant (21.85%). It also exhibited the highest foraging rate (15.4 flowers/trip), while Tetragonula sp. had the lowest (2.8 flowers/trip). Tetragonula sp. showed the highest foraging speed (6.19 sec/flower), while Hoplonomia sp. had the lowest (1.49 sec/flower). Peak activity of most pollinators were during the forenoon, aligning with flower anthesis. Diversity indices showed variations in species richness, diversity, and evenness by flowering type and time. Mid-season flowering types displayed the highest richness and diversity, while early types had greater evenness. Highest diversity was recorded between 11:00–12:00 AM. The overall species richness was 12, with high diversity indicated by Shannon-Weiner and Simpson indices. The Berger-Parker index suggested high evenness, with no single species dominating the pollinator population. 101 Weather significantly influenced pollinators. A. c. indica Fabricius and Tetragonula sp. were negatively correlated with maximum temperature and wind speed but positively with relative humidity. Tetragonula sp. also showed a negative correlation with bright sunshine. Halictus sp. 1 and Halictus sp. 2 positively correlated with relative humidity, with Halictus sp. 2 also negatively correlated with wind speed. Mesembrius sp. showed a negative correlation with wind speed, while Lasioglossum sp. positively correlated with maximum temperature, bright sunshine, and wind speed but negatively with relative humidity. Hoplonomia sp. was negatively correlated with relative humidity and positively with wind speed. The bagging experiment underscored essential role of pollinators in fruit set, as open-pollinated inflorescences achieved 7.17% fruit set, while bagged ones had none. This highlights the importance of pollinator conservation for enhancing cashew productivity and sustainability. Nesting sites for C. hieroglyphica Smith and C. binghami Cockerell were found in pruned cashew stumps, with stages separated by powdered wood. Weeds like Stachytarpheta jamaicensis Linn., Mimosa pudica Linn. and Rungia sp. in orchards attracted pollinators, offering crucial bee pasturage. This pioneering study at RARS, Pilicode, provides foundational insights into cashew pollinators, acknowledging variations in pollinator diversity across different locations. It underscores the critical role pollinators’ play in boosting cashew productivity and advocates against using chemical pesticides between 8:00 AM and 3:00 PM to avoid disrupting their activity. Preserving pollinator populations is vital for maintaining cashew production and addressing the increasing demand for cashew nuts.Item Acaricide resistance in spider mites (Acari: Tetranychidae) Infesting major crops of Central Kerala(Agricultural Entomology, College of Agriculture, Vellanikkara,, 2025-08-18) Penuballi Swathi; Haseena BhaskarSpider mites (Acari) inhabit a wide array of environments and pose significant threat to a variety of commercially grown vegetable crops and ornamental plants. Chemical management measures using synthetic acaricides remains the primary means of mite management, globally. However, the repeated use of chemical pesticides has led to the development of resistance in mite populations, including resistance to acaricides with novel modes of action, resulting in control failures. TetranychustruncatusEhara and Tetranychusgloveri Banks are the predominant spider mite pests on vegetable crops and ornamental plants in Kerala. Mite management in vegetable fields and horticultural nurseries of Kerala primarily relies on synthetic acaricides like spiromesifen, fenazaquin and diafenthiuron. Increased instances of control failures, despite the application of recommended doses of these acaricides, have recently been reported by the farmers and nursery owners. Sole dependence on acaricides for a prolonged period might have resulted in the reduced susceptibility of mite populations to commonly used acaricides. Hence, a study was carried out to investigate the susceptibility of the field populations of T. truncatus and T. gloveri to commonly used acaricides, the possible development of cross /multiple resistance and to elucidate the underlying mechanisms of resistance. Purposive sampling surveys were conducted across commercial horticultural nurseries, vegetable fields and tissue culture (TC) hardening units in central Kerala (Thrissur, Ernakulam, Palakkad and Malappuram) to collect spider mite populations. Isoline cultures of eight T. truncatus populations collected on marigold (Mg1Tr) and vegetable crops (Cp1Pt, Cu1Pt, Ok1Pt, Am2Pt, Am3Vt, Cp2Tv and Am4Tv), and nine T. gloveri populations collected on adenium (Ad1Rg and Ad2Sd), gerbera (Gr1Pt), dahlia (Da1Vt), anthurium (An1Bv) and tissue culture banana (Bn3Tr, Bn2Kn, Bn1Gn and Bn4Ak) were maintained in the laboratory with unique accession numbers. The laboratory maintained populations of T. truncatus (SST) for more than 10 years (>300 generations) and T. gloveri (SSO) for more than six years (>180 generations), without exposure to acaricides were designated as susceptible reference populations. The laboratory bioassay of T. truncatus with fenazaquin showed moderate levels of resistance in the populations on amaranthus (Am2Tr- 39.70 folds) and marigold (Mg1Tr- 25.60 folds) populations from Thrissur, cucumber from Pattambi (Cu1Pt- 12.90 folds) and amaranthus from Vyttila (Am3Vt- 10.50 folds). The other populations collected on amaranthus from Tavanur (Am4Tv) and on okra (Ok1Pt), and cowpea (Cp1Pt) from Pattambi, recorded low levels of resistance (RR 3.70- 7.90 folds). Among the T. gloveri populations, adenium population from National Rose Garden, Thrissur (Ad1Rg- 57.20 folds) and TC banana population from Kannara (Bn2Kn- 41.04 folds) recorded high levels of resistance to fenazaquin, while the mite populations collected on TC banana plants from Vyttila (Bn1Gn- 15.72 folds) and Thrissur (Bn3Tr- 15.80 folds), and on dahlia from Vyttila (Da1Vt- 13.31 folds) recorded moderate level of resistance. Other T. gloveri populations collected on gerbera, anthurium and adenium showed only low levels of resistance. Tetranychustruncatus collected on marigold (81.90 folds) and amaranthus (79.75 folds) from Thrissur recorded very high levels of spiromesifen resistance. The amaranthus population from Vyttila (Am3Vt- 33.41 folds); cowpea (Cp1Pt-25.16 folds) and okra (Ok1Pt- 25.83 folds) populations from Pattambi, showed moderate levels of resistance, while populations on cowpea (RR 07.08) and amaranthus (RR 05.90) collected from Tavanur recorded low levels of resistance. Susceptibility studies of T. gloveri with spiromesifen showed that the population on adenium from National Rose Garden (76.33 folds) and on TC banana from Kannara (71.33 folds) exhibited high levels of resistance. Populations collected on TC banana from Vyttila (30.33 folds), Thrissur (28.17 folds) and Anakkayam (13.79 folds) recorded moderate levels of resistance. The populations collected on the ornamental plants viz., dahlia (24.33 folds), anthurium (19.08 folds) and adenium (17.25 folds) also recorded moderate levels of resistance to spiromesifen. Low to moderate levels of resistance to diafenthiuron were recorded in T. truncatus (1.94- 17.56 folds) and T. gloveri (1.95- 15.57 folds), where marigold population from Thrissur (17.56 folds) and adenium population from National Rose Garden (15.57 folds) recorded significantly higher levels of resistance, respectively. Tetranychustruncatus and T. gloveri populations with resistance to fenpyroximate showed moderate levels of cross-resistance to fenazaquin and the propargite resistant populations showed cross resistance to diafenthiuron. However, the field populations recorded only low levels of multiple resistance to chlorfenapyr and hexythiazox (acaricides with different modes of action) in T. truncatus (1.20- 5.40 folds; 1.00- 1.50 folds) and T. gloveri (1.10- 2.35 folds; 2.08- 12.00 folds). Assay of detoxification enzymes in T. truncatus and T. gloveri showed significantly elevated activities of carboxylesterase (CarE) (1.27-2.27fold; 1.59-2.10 folds), cytochrome P450 monooxygenase (CytP450) (1.36- 4.98 folds; 1.08-3.10 folds), and glutathione S-transferase (GST) (1.00- 2.12 folds; 1.09- 1.98 folds) in resistant populations. The highest activity of detoxifying enzyme was recorded in T. truncatus population on marigold for CytP450. The study on differential gene expression and sequence variation of the CYP392E10 gene (encodes CytP450 enzyme) in the spiromesifen and fenazaquin resistant marigold population of T. truncatus showed a lower CT value with 7.61 folds higher gene expression than the susceptible population. Sequence analysis of CYP392E10 gene in the resistant population showed four single nucleotide polymorphisms (SNPs), where T is substituted by A (256th, 676th and 1356th) and A is replaced with G (708th position). The alignment of amino acid sequences of the susceptible and resistant T. truncatus populations showed substitution of Lleucine with methionine at 86th position and phenylalanine with isoleucine and lysine at 226th and 452nd positions, respectively. This study reports alarming levels of acaricide resistance in the spider mites, T. truncatus and T. gloveri in central Kerala, to commonly used acaricides. The mite species were also found to have developed significant levels of cross resistance to many unexposed acaricides. However, significantly low level of multiple resistance to the acaricides, chlorfenapyr and hexythiazox suggests their suitability as alternatives to commonly used acaricides in mite management. The study highlights the role of detoxifying enzymes and the overexpression of the related gene, particularly CytP450 in the development of resistance against commonly used acaricides (fenazaquin, spiromesifen and diafenthiuron). The study also provides new insights into the resistance mechanisms in the mite species in response to sustained acaricide pressure, exhibiting metabolic and target-site insensitivity, which further needs functional validation.Item Endophyte mediated bio-intensive management of pests of cowpea Vigna unguiculata (L.) Walp(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2025-06-28) Rajeshwaran, B; Faizal, M HThe present study entitled “Endophyte mediated bio-intensive management of pests of cowpea Vigna unguiculata (L.) Walp.” was conducted in the Department of Agricultural Entomology, College of Agriculture, Vellayani, during the period 2020 2024. The primary objective of this research was the characterization and utilization of native endospore-forming endophytic bacteria (EEB) for the bio-intensive management of pests in cowpea. This approach aimed to provide an eco-friendly alternative to conventional pest control methods, contributing to sustainable agricultural practices. A total of 54 bacterial endophytes were isolated from vegetable and bush-type cowpea plants, of which 49 were confirmed as endospore-formers using the Schaeffer Fulton method. These endospore-forming bacteria underwent a series of bioassays to assess their pathogenicity and feeding deterrence against the chewing insect Spodopteralitura. The evaluation included direct exposure methods and exposure through primed cowpea seedlings in both choice and no-choice experimental conditions. Among the isolates tested, ten isolates viz., CPB 1a, CPB 2a, CPB 5a, CPB 8b, CPV 06, CPV 08, CPV 14, CPV 18, CPV 21, and CPV 32 were found effective in the in planta choice assessment. These isolates significantly reduced damage with lower damage intensity scores of 1.73 to 2.07 compared to unprimed controls (4.87) and other isolate-primed plants (2.47 - 4.93). The selected ten isolates were further subjected to in planta no-choice conditions, where the fitness of feeding insects was tested using relative growth rates and antifeedant activity of second and fourth instar S. litura. Three isolates, namely CPB 1a, CPV 18, and CPV 14, primed cowpea plants substantially reduced larval relative growth rates for both 2nd instar (0.35 mg/day, 0.46 mg/day, and 0.58 mg/day, respectively) and 4th instar (0.42 mg/day, 0.49 mg/day, and 0.59 mg/day, respectively). Similarly, the antifeedant activity, in terms of percentage weight gain reduction compared to larvae on control plants, was 80.53%, 73.58%, and 65.94% for the 2nd instar and 71%, 65.77%, and 54.44% for the 4th instar in these three isolates. The priming effects of endophytes were prominently observed in cowpea plants treated with CPB 1a and CPV 18 when exposed to S. litura. These plants showedenhanced and sustained production of antioxidants (SOD, CAT, POD, APX, GR) and defense enzymes (PAL, PPO, TP) compared to infested control plants. GC-MS analysis of plant volatiles revealed the release of 1-octen-3-ol and 9-octadecanoic acid, precursors of the plant defense signalling molecule jasmonic acid, in CPB 1a and CPV 18-primed plants, confirming their role in strengthening plant defense against S. litura. The efficacy of these bacterial isolates was evaluated against the sap-sucking insect Aphis craccivora through in-planta choice assays using the Aphid Quantity Ratio (AQR). Isolates CPB 1a, CPV 8, CPV 14, and CPV 18-primed plants demonstrated moderate resistance, with AQR values of 0.5, 0.42, 0.52, and 0.49, respectively, compared to unprimed control plants, which recorded an AQR value of 1.58, classifying them as highly susceptible. Furthermore, in-planta no-choice assays analyzing life table parameters revealed significant impacts of CPV 08- and CPV 18-primed plants on A. craccivora's biological and demographic traits. Relatively shorter oviposition periods of 6.27 and 7.25 days were observed in CPV 8 and CPV 18 treatments, respectively, whereas prolonged oviposition of 11.37 days was noticed in control plants. Consequently, the fecundity of aphids was reduced to 15.42 progeny per aphid for CPV 08 and 19.77 progeny per aphid for CPV 18, compared to 39.8 progeny per aphid in the control. Additionally, the intrinsic rate of population increase was lower for CPV 08 (1.24) and CPV 18 (1.26) than for the control (1.38). The higher production of antioxidants and defense enzymes, along with the release of volatile compounds such as methyl salicylate, betulinaldehyde, and trans-farnesol, confirmed the induction of plant defense responses by these isolates in cowpea plants challenged with A. craccivora. Promising bacterial isolates were identified through 16S rRNA gene sequencing. CPB 1a was identified as Bacillus velezensis, CPV 08 as Bacillus zanthoxyli, and CPV 18 as Bacillus subtilis, with sequence similarity percentages of 100%, 99.13%, and 99.57%, respectively. Comparative studies of potential endophytes such as B. velezensis CPB 1a and B. subtilis CPV 18 for S. litura along with other entomopathogens revealed that, upon seed priming, B. thuringiensis BTG4 and B. velezensis CPB 1a significantly reduced leaf damage to 17.29% and 20.56%, respectively. This was followed by B. subtilis CPV 18-treated plants, which recorded 30.18% leaf damage compared to77.24% in control plants exposed to feeding by S. litura. Additionally, plants primed with these bacteria exhibited enhanced resilience, maintaining better plant biometric characteristics such as increased fresh and dry weight under S. litura feeding conditions. Similarly, the comparative effectiveness of identified potential isolates against A. craccivora, such as B. zanthoxyli CPV 8 and B. subtilis CPV 18, alongside other entomopathogens, demonstrated that the priming effects of these microbes were most pronounced in B. zanthoxyli CPV 8 and B. subtilis CPV 18. These isolates effectively reduced the population build-up of A. craccivora to 29.66 and 32.66 aphids per plant, respectively, compared to 81.66 aphids per plant in the control. Furthermore, plants treated with these isolates showed significant improvements in plant biometric traits, such as improved fresh and dry weight under A. craccivora-infested conditions. All the effective isolates B. velezensis CPB 1a, B. zanthoxyli CPV 8, and B. subtilis CPV 18, including B. thuringiensis BTG4, were successfully reisolated from the primed plants during the observation period of two to four weeks after sowing ensure their effective colonisation as endophytes in cowpea. An in-vitro compatibility study was conducted to assess the potential of integrating these effective endophytic bacteria with entomopathogens. The results indicated that Beauveriabassiana NBAIR 05, Lecanicilliumlecanii NBAIR VL8, and B. subtilis CPV 18 were compatible with one another, enabling the creation of a microbial consortium. Pest incidence in cowpea plants treated with a microbial consortium, along with other promising endophytes and entomopathogens applied singly or in various combinations using different application techniques, was analyzed to assess their pest management potential under natural conditions in a pot culture experiment. Soil drenching with the microbial consortium provided early protection against A. craccivora, reducing populations by 29.45% to 31.28% up to five weeks after sowing (WAS). Foliar applications combining B. bassiana or L. lecanii with the consortium (treatments T18 and T19) yielded results comparable to chemical insecticides by 6 WAS after the first foliar application, with effects sustained until the final observation. Similarly, treatment T18 significantly reduced the incidence of S. litura after the first foliar application by 95%, matching the efficacy of chemical insecticides. T18(Consortium + B. bassiana) also demonstrated enhanced plant biometric characteristics, including increased plant height, number of leaves, number of pods, pod length, and pod yield, while effectively reducing the incidence of Maruca sp. and Riptortus sp. The microbial consortium consisting of Beauveriabassiana NBAIR-05, Lecanicilliumlecanii NBAIR VL-8, and B. subtilis CPV 18 developed in the current study along with foliar application of B. bassiana was proved to be effective in managing major insect pest of cowpea across different feeding guilds and have the potential to be integrated as one of the tactics in integrated pest management in cowpea.Item Diversity and population dynamics of mango fruit fly bactrocera spp (Diptera: Tephritidae)(Department of entomology, college of agriculture, Padannakkad, 2023-08-21) Anagha, K P.; Sreekumar, K MThe study entitled “Diversity and population dynamics of Bactrocera spp. (Diptera: Tephritidae)” was conducted at the Department of Entomology, College of Agriculture, Padannakkad during 2021-2022. The main objective of the study was the documentation of species complex, varietal preference and population dynamics of Bactrocera spp. infesting mango in the Instructional Farm I, College of Agriculture, Padannakkad. Surveillance of fruit flies for a period of one year from 17-09-2021 to 16-09-2022 was carried out using bottle traps with methyl eugenol as the lure. A total of 10,546 individual fruit flies were trapped during the surveillance period of which major percentage was B. dorsalis. Four species of fruit flies viz. Bactrocera dorsalis, B. zonata, Zeugodacus tau and Z. cucurbitae were identified from the population collected in that order of dominance. Out of 10,546 total fruit flies captured 10,332 adults were identified as B. dorsalis, accounting for 97.97% of the population being the dominant fruit fly in the area, 199 number of fruit flies (1.89%) were identified as Zeugodacus cucurbitae, nine fruit flies (0.09%) were identified as B. zonata, and six fruit flies (0.06%) were identified as Z. tau. The highest weekly population of fruit flies was recorded in the 14th Standard Meteorological Week of 2022 (02-04-2022 to 08-04- 2022), with a population of 793 fruit flies and the lowest population in 50th SMW (10- 12-2021 to 16-12-2021), with only one fruit fly. The average monthly population was recorded highest in May with a population of 667.5 flies per month and lowest in December with a population of 16 flies per month. Population parameters of fruit flies such as species richness was found to be 0.32, Simpson dominance index as 0.04, Shannon Weiner diversity index as 0.11 and evenness index as 0.42. Population of fruit flies during the surveillance period of one year had a significant positive correlation with minimum temperature (+0.354). Population of fruit flies during the fruit availability i.e., from April to June had a significant positive correlation with minimum temperature +(0.805), and a significant negative correlation with soil temperature (-0.512). Maximum temperature (-0.329) and wind speed (-0.192) had a negative correlation with population of fruit flies and a positive correlation with rainfall (0.204). Both field and laboratory evaluations were carried out to determine the varietal preference of Bactrocera dorsalis for ten different mango varieties, viz., Phirangiladuva, Kalapady, Neelum, Bangalora, Bennet Alphonso, Mundappa, Banganappalli, Himayuddin × Neelum, Gomanga, and Kuttiattoor mango during the peak period of infestation i.e., from April to June. Natural infestation showed a significantly lower number of egg laying in fruits of Neelum, maggot development in the pulp of Bennet Alphonso and Neelum and adult emergence from the fruits of Himayuddin X Neelum, Kalapady and Bennet Alphonso respectively. Kuttiattoor mango recorded significantly higher number of eggs laid, maggot developed and adult emergence from natural incidence. A total number of 1934 adults emerged from naturally infested varieties were identified as B. dorsalis. Laboratory evaluation of preference of B. dorsalis showed non preference for egg laying, maggot development and adult emergence from mango varieties like Bennet Alphonso, Kalapady, Neelum, Mundappa, Himayuddin X Neelum, and Kuttiattoor mango. Number of eggs laid, maggots developed and adult emergence was significantly higher in Gomanga, Banganappalli, and Gomanga and Bangalora varieties of mango respectively in laboratory condition. Naturally fallen mangoes of six varieties viz., Banganappalli, Phirangiladuva, Kalapady, Neelum, Bangalora and Mundappa collected from IF 1 recorded significantly lower number of maggot development in the Kalapady variety. Phirangiladuva and Banganappalli varieties recorded significantly higher numbers of maggot development. Screening of mango varieties for fruit fly resistance showed that variety Neelum is highly resistant and variety Kalapady is resistant to fruit fly infestation. Correlation between morphological characters of fruit and number of eggs laid in fruits showed that peel thickness had a significant negative correlation (-0.674). Correlation between biochemical characters and maggot population, adult emergence and percent infestation of fruits showed significant negative correlation with ascorbic acid content (-0.67, -0.77, -0.66) and crude fibre content (-0.86, -0.82, -0.59) and significant positive correlation with total sugar content (0.71, 0.70, 0.84). Total phenol content, flavonoid and titrable acidity had a negative correlation. Varietal preference of B. dorsalis suggested that Neelum and Kalapady varieties showed a significant resistance. Morphological and biochemical characters of fruits are significantly related with resistance of mango varieties against B. dorsalis and therefore, can be used as marker traits in further breeding programmes to select resistant varieties.Item Diversity of phytophagous mites and their natural enemies of fruit crops in Kerala(Department of Entomology, College of Agriculture, Vellayani, 2025-03-11) Madhusudhan, M; Neena LeninThe study entitled “Diversity of Phytophagous Mites and their Natural Enemies of Fruit Crops in Kerala” was undertaken in the Department of Entomology, College of Agriculture, Vellayani, during 2022-2024. The major objective of the study was the documentation of the incidence, diversity and natural enemies of phytophagous mites inhabiting fruit crops in Kerala. Purposive sampling was conducted across 14 districts of Kerala, covering orchards, homesteads and other agricultural farms. The mite harbouring leaf samples were collected, labelled separately and transported in airtight polythene bags to the laboratory for further studies. The samples were observed under a stereo-binocular zoom microscope and permanent slides were prepared using Hoyer’s media. Observations of these slides under a phase contrast microscope with image analyser revealed 50 species of mites under 34 genera and 16 families on 27 fruit crops. Out of these 50 mite species, 27 species were phytophagous and 23 were predatory. Out of the 27 fruit crops showing mite presence, banana recorded maximum number of mites (18) including 10 phytophagous and 8 predatory mite species. Phytophagous mite family Tetranychidae was represented by maximum number of species/genera (15/5), followed by Eriophyidae (4/4), Tenuipalpidae (3/2), Tarsonemidae (2/2), Diptilomiopidae (1/1), Acaridae (1/1) and Tydeidae (1/1). The broad mite, Polyphagotarsonemus latus (Banks) was collected from maximum number (16) of fruit crops. Genus Tetranychus Dufour showed the highest diversity with seven species. Banana recorded highest number of phytophagous mites with 10 species. Among predatory mites collected, family Phytoseiidae recorded maximum number of species/genera (10/6) followed by Tydeidae (3/3), Cheyletidae (2/2), Cunaxidae (2/2), Stigmaeidae (2/1), Eupodidae (1/1), Bdellidae (1/1), Erythraeidae (1/1) and Ameroseiidae (1/1). Genus Amblyseius Berlese showed the highest diversity with a record of five species. Maximum number of predatory mite species was recorded on Guava (10). In addition to predatory mites, other natural enemies of phytophagous mites belonging to the Class Insecta were also recorded, representing six families, namely, Coccinellidae, Staphylinidae, Ceciidomyidae, Thripidae, Hemerobiidae and Syrphidae. The study recorded new host plants for phytophagous mites including jackfruit as the new host for Tetranychus macfarlanei Baker and Pritchard, Tetranychus fijiensis Hirst and Eutetranychus orientalis Klein; passion fruit as the new host for Tetranychus truncatus Ehara; banana for Tetranychus udaipurensis Gupta & Gupta and T. macfarlanei; papaya as the new host for T. udaipurensis; sitaphal, peanut butterfruit and hog plum for Brevipalpus phoenicis (Geijskes); peanut butterfruit, hog plum, pomegranate, santol and abiu as the new hosts for Brevipalpus californicus (Banks). Eriophyid mite, Tegolopus indica Chakrabarti & Mondal, and phytoseiid mite Amblyseius tamatavensis Blommers are the new reports from the state. The study highlights the diversity and incidence of phytophagous mites as well as their natural enemies on 27 fruit crops in Kerala. It also sheds light on the host range and specificity of phytophagous mites on fruit crops. The details of new host plants recorded adds to the present knowledge, while, the information on predatory mites and other insect predators can be further explored for building innovative biological control programs against pest mites that have a potential to become possible threat in the future to fruit ecosystem.Item Horticultural mineral oil for the management of pests in mango at the vegetative phase(Department of Entomology, College of Agriculture, Padannakkad, 2025-03-24) Smitha, K VAn experiment was conducted on ‘Horticultural mineral oil for the management of pests in mango during the vegetative phase’ was conducted during 2023-2024 at college of agriculture, Padannakkad and Instructional Farm II, Karuvachery. The objective of the study was to evaluate of Horticultural Mineral Oil (HMO) for the management of mango pests at the vegetative phase. The laboratory experiments were carried out in the Department of Entomology, College of Agriculture, Padannakkad. In the phytotoxicity evaluation, various concentrations of HMO (T1: 3.0%, T2: 3.5%, T3: 4.0%, T4: 4.5%, T5: 5.0%, T6: 5.5%, T7: 6.0%, T8: 6.5%, T9; 7.0%, T10; 8.0%, T11; 9.0% and T12; control) were tested on one year-old mango (Neelum) grafts, revealed that there were no signs of phytotoxicity symptoms up to T8. However, higher concentrations particularly T9, T10 and T11 caused symptoms like necrosis and chlorosis. Based on these findings, four higher concentrations viz., 5.0%, 5.5%, 6.0% and 6.5% were selected for laboratory bioassay. To evaluate the repellency against feeding and oviposition of leaf cutting weevil (Deporaus marginatus), HMO at a concentration of 6.5% effectively reduced feeding, with a recorded feeding area of 3.28 cm² and 63.47% reduction in feeding area compared to the control at 24 hours after treatment (HAT), which was on par with HMO at 6.0%. In all treatments, no oviposition by leaf-cutting weevils was observed. Evaluation of HMO against adults of leaf cutting weevil under laboratory conditions showed that HMO at a concentration of 6.0% and 6.5% caused 64% and 88% mortality of leaf cutting weevil respectively, at 24 HAT in residue film test. In spraying method, HMO at 6.0% and HMO at 6.5% had showed 72% and 76% mortality of leaf cutting weevil respectively, at 24 HAT. When HMO was evaluated against leaf cutting weevil grubs, at a concentration of 6.0% and 6.5% achieved 100% mortality at 24 HAT. Since the results for 6.0% and 6.5% were statistically similar, these two concentrations were selected for field studies. Field evaluation of HMO was carried out at Instructional Farm II, Karuvachery, College of Agriculture, Padannakkad under Randomized Block Design with seven treatments and four replications. The treatments were T1: HMO 6.0%, T2: HMO 6.5%, T3: Pongamia oil soap, T4: Neem oil-garlic soap, T5: Chlorantraniliprole 18.5 % SC, T6: Acephate and T7: Control. Observations on the mean number population of leaf cutting weevil indicated that T6, T3, T5 and T2 were more effective in reducing the mean population during the first application of treatments and it was on par with each other. During the second and third application of treatments, T6, T3 and T5 effectively reduced the mean population of leaf cutting weevils, which were statistically similar with T2 and T1. There was an effective reduction in the mean number of scraped leaves caused by leaf cutting weevil with T6 (3 DAT and 5 DAT in the first application of treatments) and T3 (7 DAT and 9 DAT), which were on par with other treatments. During the second and third application of treatments, T5 and T2 were observed more effective in reducing mean damage and were on par with each other. T1 and T2 were found to be effective in reducing mean number of cut leaves during the first and second application of treatments, which was on par with T3, T5 and T6. There was an effective reduction in mean number of fallen tender leaves from plant base by T3 (9 DAT) and T2 (3 DAT, 5 DAT, 7 DAT and 9 DAT) during the first and second application of treatments, respectively, which were on par with other treatments. For ash weevil (Myllocerus discolor), T6 was found to be effective in controlling the mean number population during the first application of treatments, which is statistically similar with T3 and T2. A similar trend of the population was followed till 9 DAT during the second and third application of treatments, which were on par with T3 and T2. Observations on mean number of damages indicated that T6 was effective in reducing the mean damage during the first (3 DAT, 5 DAT, 7 DAT and 9 DAT) and second (7 DAT and 9 DAT) application of treatments and it was on par with T1, T2 and T3. During the third application of treatments, T2 was effectively reduced the mean number of damaged leaves, which was on par with other treatments. In all three applications of treatments, HMO was effective in controlling the mean number of population and mean number of damages of both leaf cutting weevil and ash weevil and was found to be statistically similar with T6.