1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Effect of insect mediated pollination in culinary melon, Cucumis melo var. acidulus Naudin(Department of Agricultural Entomology, College of Agriculture ,Vellayani, 2025) Vismaya, S A; Amritha, V SThe present study entitled “Effect of insect mediated pollination in culinary melon Cucumis melo var. acidulus Naudin” was conducted at Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala during 2022 to 2024. The objectives of the study were to assess the foraging behaviour of insect visitors, major pollinator-flower interaction and effect of pollination in culinary melon. The popular culinary melon variety, KAU Vishal was used in this study, and the crop was raised both under open field conditions and augmented (bee hive installed) condition. Observations on floral structures viz., flower spread, stamen characters, pistil characters etc., were taken after 10 percentage bloom. Insects visiting culinary melon were documented and the foraging behavior of major pollinator was assessed at weekly intervals for two months. The developmental changes in culinary melon (flower, fruit and seed development) due to bee visits were assessed by installing an Indian bee hive with six frame bee strength among the treatments; augmented, open- pollinated, hand pollinated and in pollinator excluded conditions. Studies on the floral biology of culinary melon revealed that flower bud initiation and anthesis was earlier in male flowers (31.30 days and 32.10 days) when compared to female flowers (38.70 and 49.80 days). Variation in the time of anthesis was also observed among the male (7:45 am) and female flowers (8:04 am). The count as well as the viability of pollen grains on anther and number of pollen grains deposited on the stigma was highest during 1100 -1300 h, which coincided almost with that of the stigma receptivity. A total of 19 insect visitors belonging to 18 genera, 8 families, and 4 orders were recorded, of which 15 species were identified as pollinators in terms of their foraging behaviour. Among them, six were nectar foragers and nine were both nectar and pollen foragers. Based on Shannon-Wiener diversity index, peak pollinator diversity was recorded during 0900-1100 h. Of these pollinators, Apis cerana indica Fab., Nomia 70 strigata Fab. and Ceratina binghami Cockerell recorded highest relative abundance (7.68, 3.70 and 3.04 bees mֿ ² 5 min ⁻¹) and number of loose pollen grains (60,000, 22,000 and 12,500). Thus, A. c. indica was ranked as the efficient pollinator of culinary melon in terms of the pollination efficiency index. Foraging behaviour of A. c. indica exhibited significant temporal variation throughout the day. Peak visitation rates were recorded during 1100-1300 h (11.83 ± 0.68 flowers min⁻¹) when compared to early morning (0700-0900 h: 7.79 ± 0.31 flowers min⁻¹) and late evening (1700-1900 h: 6.16 ± 0.68 flowers min ⁻¹). The number of bees visiting a single bloom was highest during 1100-1300 h (1.92 ± 0.05 bees 5 min⁻¹), followed by 0900 -1100 h (1.76 ± 0.13 bees5 min ⁻¹) and 1300-1500 h (1.62 ± 0.08 bees 5 min ⁻¹). The average time spent by bees on anthers as well as on the stigma was significantly high in the morning hours (0900-1100 h: 11.34 ± 0.84 sec and 0900-1100 h: 65.05 ± 29.65 sec), while, the number of returning foragers was highest during 1300- 1500 h (10.83 ± 0.83 bees 5 min ⁻¹). These findings highlight mid-morning to early afternoon as the optimal period for pollination activity in culinary melon. The impact of bee visits on flower, fruit and seed development under augmented (1-12 visits), open-pollinated, hand pollinated and in pollinator excluded conditions was assessed. Studies on the quantification of endogenous hormone levels such as Auxin (IAA) and Gibberellin (GA₃) revealed that open-pollinated flowers exhibited the highest auxin concentration (19.50 ± 0.20 ppb) which was followed by flowers with seven bee visits (6.32 ± 1.53 ppb). GA₃ was not detected in any treatment, indicating either its negligible role at anthesis in pollination response or due to the concentrations below detection limits. The quantitative and qualitative yield parameters of culinary melon as part of the fruit and seed development among the treatments were also observed. The fruit set percentage (0 to 100%) in culinary melon varied with the number of bee visits, with 100 per cent fruit set both in nine bee visits and open pollinated ones. Though percentage fruit set increased with bee visitation, the percentage of malformed fruits were also found increasing in flowers with 10 visits and beyond. Maximum fruit weight (2.43 ± 0.11 kg), fruit length (46.00 ± 1.00 cm), fruit diameter (11.46 ± 0.41 cm), flesh thickness (3.90 ± 0.10 cm), and TSS content (3.03 ± 0.06 °Brix) were recorded from 71 seven bee visit treatment. The seed quality parameters viz., seed set (1265.67 ± 140.10 seeds per fruit), total seed weight (11.02 ± 0.07 g), 100-seed weight (2.37 ± 0.06 g), and seed germination percentage (97.33 ± 0.57 per cent) were also maximum in the seven bee visits treatment. The present study revealed that A. c. indica was the dominant pollinator in terms of the Pollination efficiency index with peak foraging activity during 0900 to 1300 h. The count as well as viability of pollen grains on anther and number of pollen grains deposited on the stigma coincided almost with that of the stigma receptivity. The syngenesious type of anthers in culinary melon flowers with more than half of them inside the corolla cup and the similarity in length of Indian bee proboscis and stamen, signifies the relevance of bee pollination. Developmental changes in flower, fruit and seed among the pollination treatments indicated that both open-pollinated flowers and those receiving seven bee visits exhibited elevated auxin (IAA) levels, while the treatment, seven bee visits exhibited superior fruit and seed traits. These results highlight the critical role of A. c. indica in pollination, yield and quality of fruits in culinary melon.Item Taxonomy of thrips fauna (Thysanoptera: Terebrantia: Thripidae) on ornamental plants in Kerala(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2024-02-28) Amal Poulose; Haseena BhaskarThis belonging to the order Thysanoptera are considered as one of the most economically important group of insect pests worldwide. Some species of thrips act as vectors by transmitting plant viruses. The order comprises about 6288 species of thrips under two suborders viz., Tubulifera and Terebrantia. The suborder Terebrantia primarily consists of phytophagous species in eight families of which the family Thripidae is the largest. The members of Thripidae are widely reported as serious pests of ornamental plants. However, no systematic study has been conducted so far to document the fauna of Thripidae on ornamental plants in Kerala. The present study entitled “Taxonomy of thrips fauna (Thysanoptera: Terebrantia: Thripidae) on ornamental plants in Kerala” was carried out during the period, 2022-23. The research aimed at studying the taxonomy of thrips species of the family Thripidae infesting ornamental plants of Kerala, preparing an illustrated key for the identification of species of Thripidae and generating DNA barcode for cryptic species of thrips collected during the study. Purposive surveys were undertaken in different localities of Kerala covering 43 geographical locations across 14 districts. Thrips specimens were collected from different ornamental plants including flowering trees and the GPS coordinates of the feographical locations as well as the host plants were recorded. The specimens were assigned unique accession numbers and preserved in AGA mix, and then mounted onto permanent slides as per the standard procedure. The slide mounted specimens were used for morphological characterization, and the illustrations of key taxonomic characters and morphometry were made. The amino acid sequences of mitochondrial cytochrome oxidase subunit I (mtCO-I) were analysed for 13 accessions representing eight species. The study recorded 20 species under 14 genera in three subfamilies (Panchaetothripinae, Sericothripinae and Thripinae) from Kerala. The subfamily Thripinae was the most dominant group with 12 species under six genera. The genus Thrips was more diverse with seven species viz., Thrips andrewsi, T. Flavus, T. florum, T. hawaiiensis, T. orientalis, T. paravispinus and T. simplex. The other species in the subfamily includes Chaetanaphothrips signipennis, Echinothrips americanus, Frankliniella schultzei, Microcephalothrips abdominalis and Scirtothrips dorsali. The subfamily Panchaetothripinae recorded seven species under seven genera viz., Astrothrips tumiceps, Caliothrips indicus, Copidothrips octarticulatus, Heliothrips haemorrhoidalis, Retithrips syriacus, Rhipiphorothrips cruentatus and Selenothrips rubrocinctus. The subfamily Sercicothripinae was represented by a single species, Neohydatothrips samayunkur. An illustrated dichotomous taxonomic key for the identification of subfamilies, genera, and species of thrips collected during the study were prepared. A species distribution map was prepared for the Thripidae infesting ornamental plants of Kerala, using Quantum GIS software. A total of 50 plants under 45 genera in 27 families were recorded as hosts for 20 species of thrips species collected in this study. The predominant families of host plants were Asteracea, Oleaceae, Apocynaceae and Rubiaceae. Thrips parvispinus recorded widest host range of 16 host plants in 11 families followed by Microcephalothrips abdominalis (12 host plants in 3 families), Thrips orientalis (9 host plants in 4 families) and Thrips hawaiiensis (8 host plants in 7 families) from Kerala. The DNA barcodes wre generated for eight species viz., Thrips simplex, T. andrewsi, T. parvispinus, T. hawaiiensis, Astrothrips tumiceps, Selenothrips rubrocinctus, Heliothrips haemorrhoidalis and Neohydatothrips samayunkur. A phylogenetic tree was constructed with 27 sequences of different thrips species (13 sequences in the study plus 14 sequences retrieved from NCBI database) and the sequence of aphid, Aphis gossypii as an outgroup in MEGA 11, using UPGMA method. The sequences were submitted to GenBank (NCBI) and BOLD to generate species-specific barcodes. The study identified Echinothrips americanus as a new distribution record for India. The study also identified six new distribution records of thrips for Kerala viz., Neohydatothrips samayunkur, Chaetanaphothrips signipennis, Microcephalothrips abdominalis, Thrips andrewsi, T. Flavus, and T. simplex. The invasive thrips species, T. parvispinus recorded 11 new host plants viz., Cosmos sulphureus, Tabernaemontana sp., Asystasia gangetica, Hibscus rosa sinensis, Canna indica, Rhododendron spp., Spiraea cantoniensis, Antirrhinum majus, Zephyranthes rosea, Uncaria tomentosa and Justicia carnea, suggesting that the species can pose significant threat to ornamental plants of Kerala. The study indicates the need to explore the potential of the above species to become invasive and establish in new habitats. The biotic and abiotic factors that regulate thrips populations on ornamental plants also have to be investigated. Further, thrips fauna associated with other crops of Kerala need to be explored.Item Baseline susceptibility of rice leaf folder Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Crambidae) to selected insecticides(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2025-08-29) Seena R Subhagan; Berin PathroseWith the rising food production demands, pesticides remain essential for achieving high yields, particularly in staple crops like rice. Despite the known environmental hazards of chemical pesticides, their repeated use has become common practice, often leading to selection pressure and the development of insecticide resistance. This issue is exacerbated when insect pests like the rice leaffolder, Cnaphalocrocis medinalis, which undergoes several generations a year, are exposed to the same insecticide across consecutive generations. Recent failures in controlling rice leaffolder outbreaks in Kerala have raised concerns, though no formal studies have documented insecticide resistance in these populations. This study aimed to address this gap by assessing the susceptibility of rice leaffolder populations to selected insecticides and investigating potential resistance mechanisms. Field populations from five agroecological units (AEUs) in Kerala were assessed for insecticide resistance through laboratory bioassays, with WYD (AEU 20) as a susceptible reference. The PKD (AEU 23), KUD (AEU 4), and TCR (AEU 6) populations experienced significant selection pressure, leading to moderate to high resistance to the tested insecticides, surpassing the resistance observed in the ONT (AEU 3) population. Resistance to acephate (5.07- to 172.53-fold) was identified for the first time in India. High resistance to quinalphos (133.24- to 611.37-fold) and carbosulfan (25.40- to 347.96-fold) were also noted. The observed carbosulfan resistance, despite no prior use, likely stems from cross-resistance due to previous organophosphate exposure, as both target acetylcholinesterase. Continuous exposure intensified resistance to lambda-cyhalothrin (up to 763.66-fold) and fipronil (up to 154.83-fold). Diamide resistance was significant, with chlorantraniliprole (1089.63 fold) and flubendiamide (1572.64-fold), marking the first reported flubendiamide resistance in C. medinalis in India. Cross-resistance to cartap (14.85- to 23.90-fold) and emamectin benzoate (24.97- to 81.09-fold) suggested resistance mechanisms driven by non-specific detoxification pathways. Further, the study aimed to elucidate the biochemical mechanisms of resistance by assessing the activities of detoxification enzymes. Resistant populations exhibited significantly elevated activities of carboxylesterase (CarE) (1.1–1.6-fold), cytochrome P450-dependent monooxygenase CytP450) (1.5–2.5-fold), and glutathione S transferase (GST) (2.3–3.0-fold). These findings underscore the increased activity of detoxifying enzymes as a contributing factor to the resistance observed in C. medinalis further confirmed through synergism bioassays. Bioassays with synergists revealed diverse resistance mechanisms across populations, driven by variations in detoxification enzyme activity. Metabolic resistance to acephate, quinalphos, carbosulfan, and lambda-cyhalothrin was primarily associated with CarE, CytP450, and GST, either individually or in combination. Multiple enzyme involvement was evident in PKD, KUD, and TCR, while CytP450 had a dominant role in ONT, highlighting enzyme-specific contributions to insecticide resistance. However, metabolic detoxification was not the primary driver of chlorantraniliprole and flubendiamide resistance in most populations, suggesting the involvement of alternative mechanisms. Minor contributions from CarE and CytP450 were detected in PKD, while slight synergistic effects in KUD may be linked to endosymbiont mediated resistance. In the case of fipronil, resistance was mediated by CytP450 in PKD, KUD, and ONT, whereas non-metabolic mechanisms likely contributed to the high fipronil resistance observed in TCR. These findings underscore the complexity of resistance mechanisms and highlight the need for further investigation into alternative pathways for diamide and fipronil resistance. This study investigated target site insensitivity as a potential resistance mechanism to diamides and fipronil in C. medinalis by analyzing mutations in the ryanodine receptor (RyR) and resistance to dieldrin (Rdl) genes. Gene duplication and a novel I4712N mutation in transmembrane (TM) domain 3 of RyR were detected in ONT and KUD populations, while PKD and TCR populations had a nonsynonymous mutation (F4691L) and a nonsense mutation (Y4692*) in the TM2-TM3 linker of the RyR gene, which may impact diamide binding. Additionally, a K4885K synonymous mutation was identified in TCR in the TM4-5 linker. As these mutations are newly reported, functional validation is required to confirm their role in resistance. Molecular analysis of the Rdl gene identified an A282S mutation in TM 2 of all populations, including the susceptible WYD, suggesting a limited role in fipronil resistance. Notably, this study reports a novel V457F mutation in TM 4 of the Rdl gene in the resistant TCR population, which may have contributed to high fipronil resistance (154.83-fold) by altering GABA receptor function. The absence of target-site mutations for isoxazoline and meta-diamides suggests their continued efficacy against C. medinalis. Metagenome analysis identified Pantoea sp. and Wolbachia sp. as potential endosymbiont contributors to microbial detoxification of chlorantraniliprole and flubendiamide resistance in KUD. These findings provide new insights into resistance mechanisms and highlight the need for further functional confirmation. Rice leaffolder populations in Kerala have developed diverse resistance mechanisms in response to sustained insecticide pressure, exhibiting metabolic and target-site adaptations. This study presents the first detailed evaluation of insecticide resistance in C. medinalis from Kerala, uncovering alarming resistance levels to multiple insecticides, including newly documented cases for acephate, carbosulfan, lambda-cyhalothrin, and flubendiamide. Metabolic detoxification, primarily through CarE, CytP450, and GST, played a key role in resistance against organophosphates, carbamates, and synthetic pyrethroids, with multiple detoxification pathways raising concerns about cross-resistance. Mutations in the RyR and Rdl genes suggest target site insensitivity for diamides and fipronil (TCR), while the potential involvement of endosymbionts in microbial detoxification (KUD) adds another layer of complexity. These findings highlight the urgent need for proactive resistance management strategies, integrating insecticide rotation, biological control, and molecular monitoring to sustain effective pest management in Kerala’s rice ecosystems.Item Nucleopolyhedrovirus mediated biointensive management of polyphagous pest Spodoptera litura F.(Department of Agricultural Entomology,College of Agriculture,Vellayani, 2025-09-12) Binseena,S R; Faizal,M HThe study entitled ‘Nucleopolyhedrovirus mediated biointensive management of polyphagous pest Spodoptera litura F. was carried out at the Department of Entomology, College of Agriculture, Vellayani, during 2019-2024 with the objective of development and evaluation of liquid and bait formulations of Spodoptera litura nucleopolyhedrovirus (SlNPV) incorporating botanicals and identification of viral gene sequences (iap and egt) of pesticidal relevance in SlNPV genome. Bioassay of botanical oils such as neem, pongam, and cashew nut shell liquid (CNSL) was done against S. litura under laboratory conditions. Cent percentage mortality of larvae was observed for neem oil 4 % and pongam oil 10 % treatments at 144 HAT and CNSL 5 % at 168 HAT. The LT50 values of the botanical oils were computed to 142.45, 146.37, and 176.54 hours for neem oil 4 %, pongam oil 10 %, and CNSL 3 % respectively with corresponding LT90 values of 329.04, 625.90, and 357.84 hours. In the bioassay of SlNPV, 100 % mortality was caused by the treatments with 1010 and 109 POB mL-1 which was at par with the mortality caused by lower concentrations of 108 and 107 POB mL-1 at 192 HAT. The effective doses (ED) of neem oil, pongam oil and CNSL were arrived at as 3.4 %, 4 %, and 2.5 % respectively by critically assessing the three important parameters of mortality, LC50 value and leaf area damage. A combination treatment of SlNPV (107 POB mL-1) and different doses (ED, ¾ ED, ½ ED, and ¼ ED) of botanical oils was attempted with the aim of reducing the lethal time of SlNPV. Significantly high mortality of S. litura (53.33 %) could be achieved in the combination treatments of SlNPV + neem oil 2.5 % as early as 48 HAT. However, at 144 HAT both SlNPV + neem oil 2.5 % and SlNPV + pongam oil 3 % treatments could result in 93.33 % mortality as against 60 % for treatment with SlNPV alone. The development of emulsifiable suspension (ES) formulations of SlNPV was attempted employing different oils as base. Isopropanol was identified as the solvent since it could solubilize all the oils tried at 5 % concentration, with low turbidity and viscosity. Emulsifier combinations of Span 20 + Triton X -100 (29:71) at 5 % for neem oil, sunflower oil, coconut oil, mustard oil, as well as Span 20 + Tween 80 (47:53) at 12 % for pongam oil, all yielding HLB value of 12 produced excellent bloom of Score 5 upon emulsification. SlNPV was dispensed into the oil-solvent-emulsifier combination so as to yield a final concentration of 1010 POBs mL-1. Among the five ES formulations evaluated, neem oil based (ES1) and pongam oil based (ES2) formulations were found to be superior producing significantly high mortality of 100 % and 93.33 % respectively even after 7 months of storage. Boric acid 1 % was selected and added to the formulation since it yielded superior protection of SlNPV with OAR (original activity remaining) value of 65.72 % upon exposure to sunlight. Development of storable ready to use bait formulations containing SlNPV and botanical oils were attempted, utilizing selected combination base matrices containing any two of wheat bran (WB), wheat flour (WF), rice bran (RB), and chickpea flour (CF) along with additives (A) (jaggery, cornstarch, CMC) as well as artificial diet alone. Based on the feeding preference and bait consumption by S. litura in free-choice and no-choice situations respectively three base matrices viz., artificial diet, WF (75 %) + CF (25 %) and WB (65 %) + WF (35 %) + A were selected, into which SlNPV (107 POB g-1) and either neem oil (2.5 %) or pongam oil (3 %) were infused. All three baits thus developed exhibited satisfactory structural integrity upon dehydration and rehydration. WB + WF based two bait formulations B3 and B2 of SlNPV containing pongam oil and neem oil respectively, were found to produce significantly high mortality of S. litura (100 % and 93.33 % respectively). Superior emulsifiable suspension and bait formulations alone and in combinations of the ones having the same botanical oil were evaluated for the management of S. litura in okra under polyhouse conditions. Combined application of an emulsion of ES2 and bait formulation B3 containing both SlNPV and pongam oil produced 96.67 % mortality of S. litura at 7 DAT, an effect on par with the chemical insecticide Flubendiamide 39.35 % SC. Identification of viral genes iap and egt, of pesticidal relevance was attempted in SlNPV for which specific primers with oligonucleotide sequences forward 5' GATTCGATCGCTGTCAACCT-3' reverse 5'-TTTCACTTTGGATGCTGCCT-3' and forward 5'-ATGGACTCGAACATGTTGGAC-3' reverse 5' AAGTCGAACATTGCGTATTTGG-3' respectively were constructed. Amplicons of size 500 bp and 600 bp could be detected in PCR with these primers, indicating the presence of both iap and egt sequences in SlNPV. The combined application of emulsifiable formulation ES2 [containing SlNPV (1010 POB mL-1), pongam oil (82 %), isopropyl alcohol (5 %), Span 20 + Tween 80 in the ratio 47:53 (12 %) and boric acid (1 %)] and bait formulation B3 [containing SlNPV (107 POB g-1 ), pongam oil (3 %), base matrix of WB + WF in the ratio 65:35 (77 %), jaggery (19 %), corn starch (0.3 %) and CMC (0.7 %)], developed in the present study each delivering SlNPV and pongam oil @ 107 POB mL-1/g-1 and 3 % respectively upon application was found effective in managing S. litura and have the potential to be developed as the predominant eco-friendly tactic in its IPM.Item Pests of ornamental plants in commercial horticultural nurseries of Kerala(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2024-03-12) Ardra, S; Deepthy, K BIn Kerala, commercial horticultural nurseries serve as the cradle of ornamental plant trade. The incidence of pests is one of the major challenges faced by ornamental plants in nurseries. However, literature pertaining to pests of ornamental plants in horticultural nurseries of Kerala is scanty. Hence, the present study entitled "Pests of ornamental plants in commercial horticultural nurseries of Kerala", was carried out to document the insects and non-insect pests associated with different ornamental plants. Purposive sampling surveys were carried out in 50 nurseries from 11 districts of Kerala. Insect and non-insect pests infesting 43 flowering ornamentals and 17 ornamental foliage plants were collected. The pests were preserved as per standard protocols and got identified by experts in the relevant taxa. Among the documented pests, sucking pests predominated (69%) followed by defoliators (15%), non-insect pests (11%), flower feeders (4%) and stem borers (1%). The study recorded 50 species of sucking insect pests in two orders viz., Hemiptera and Thysanoptera. Hemipteran pests include 28 species of scale insects (Pseudococcidae- mealybugs (6), Coccidae- soft scales (11), Diaspididae- armoured scales (7), Monophlebidae-giant scales (3), Ortheziidae- ensign scales (1)), eight species of aphids (Aphididae), four species of whiteflies (Aleyrodidae) and one species of lacewing bug (Tingidae). Thysanopteran pests include and nine species of thrips in two families viz., Thripidae (7) and Phlaeothripidae (2). The defoliator pests include five species of caterpillars (Noctuidae (2), Nymphalidae (1), Pyralidae (1), and Sphingidae (1)), three species of leaf-feeding beetles (Curculionidae (2) and Chrysomelidae (1)) and three species of grasshoppers (Acrididae). Three species of flower feeders which includes one species of bud-boring caterpillar (Noctuidae) and two species of flower beetles (Scarabaeidae (1) and Chrysomelidae (1)) as well as one species of stem borer (Cerambycidae) were documented. The non-insect pests documented include six species of mites (Tetranychidae (5) and Eriophyidae (1)) and two species of snails (one Ariophantidae and one unidentified species of aquatic snail) Among the mealybugs documented, Ferrisia virgata recorded a wider host range of seven ornamental plants species, while the highest infestation was recorded by Phenacoccus solenopsis on hibiscus. The scale insect Ceroplastes rubens was recorded on four plant species, while the per cent pest infestation was found to be higher for Coccus viridis on ixora plants. Among aphids, the highest pest infestation was noticed in Aphis gossypii infesting Ixora, while among whiteflies, Bemisia tabaci recorded the highest infestation on Euphorbia pulcherrima. Of the thrips recorded, Thrips florum infesting rose showed the highest infestation percentage in nurseries. Spodoptera litura had been the polyphagous defoliator surveyed and found to infest nine species of ornamental plants. Among the defoliators, higher infestation was recorded by Polytela gloriosa on Hymenocallis littoralis, Myllocerus subfasciatus on Melastoma sp. and Nisotra basselae on hibiscus. The primary polyphagous flower feeder causing severe economic damage to the ornamental plants recorded during this study was Popillia japonica. The stem borer, Cleonaria bicolor, whose grubs hollowed out the tender stems while adults scraped the midribs, veins and stem, had been documented from Ixora coccinea. The mite species Tetranychus gloveri exhibited a wide host range of five ornamental plants. The snail Macrochlamys indica was found to feed on many species of ornamental plants, but the infestation was severe on Canna indica. Even though the nursery owners were reluctant to reveal the pest management strategies, the common cultural practices adopted by them were: cleaning and proper monitoring at timely intervals, greenhouse protective structures to reduce the incidence of pests, intermittent mist irrigation to manage the excess temperature rise under polyhouse conditions, innovative irrigation practices like Ebb and flow system that helped in maintaining the plant's health and soil-less potting media like fibre enriched giffy that reduced the incidence of soil pests. Mechanical measures involved hand-picking in the case of caterpillars and pruning of the old or pest-affected branches to reduce the spread of pests like thrips or whiteflies. Yellow and blue sticky traps were used to manage the population of sucking pests in nurseries. Biological measures involved the use of Neem oil garlic emulsion (2%), Nimbecidine (Azadirachtin 0.03%), entomopathogens like Lecanicillium lecani (Vertilac) against aphids and whiteflies and Beuveria bassiana against lepidopteran pests. The common pesticides used in nurseries include Thiamethoxam (Actara), Fipronil 5% SC (Agadi), Dimethoate 30%EC, Chlorantraniliprole 18.5%SC (Coragen), Bifenthrin 10% EC(Boxer)and Quinalphos 25% EC(Ekalux). Molecular characterization of nine sucking insect pests was performed by isolation of genomic DNA and amplification of mitochondrial cytochrome oxidase one (mtCO1) locus using specific primers. The sequencing of PCR products and in silico analysis of three species of aphids, two species of each of thrips, mealybugs, and scales, were carried out. All the sequences showed a similarity between 95-100 percent with the sequence in the NCBI database and hence agreed with the morphological identification. The sequences were submitted to the NCBI database and uploaded to Barcode of Life Data Systems (BOLD), and specific barcodes were generated. The study documented 73 species of pests infesting 60 species of ornamental plants and the existing pest management practices in horticultural nurseries. Further studies on biology, seasonal incidence, and geographical distribution of major pests of ornamental plants have to be carried out to evolve specific, and environment-friendly pest management strategies for horticultural nurseries in the state.Item Ecological engineering for pest management in rice Oryza Sativa L(Department of Agricultural Entomology, College of Agriculture , Vellanikkara, 2024-03-15) Meera Krishnan; Sreeja, PEcological engineering (EE) for pest management is a strategy to enhance the abundance, diversity, and effectiveness of natural enemies in an agricultural ecosystem. Although EE has gained acceptance as a pest management tactic, there still exist knowledge gaps in the identification of the best floral resources for the population build up and biocontrol potential of natural enemies. Hence, the present study entitled Ecological engineering for pest management in rice Oryza sativa L was carried out during 2022-23 to identify suitable flowering plants for habitat management in rice and evaluate their efficacy for ecological pest management. The olfactory response of predators viz.,lady bird beetle (Micraspis discolor), ground beetle (Ophionea nigrofasciata), green mirid bug (Cyrtorhinus lividipennis) and parasitoids Trichogramma chilonis and T. japonicum to different the flowers was assessed in a six arm olfactometer. In each arm of the olfactometer, ten flowers each of sesame, cowpea and cosmos were individually inserted and for marigold and okra, only one flower was used. The arm without flower served as the control. Ten adults of each predator and twenty adults of each parasitoid were released at the center of the olfactometer. The number of predators and parasitoids settled per arm at 5, 10, 15 and 20 min. after release (MAR) as well as the distance covered per min. was assessed. Micraspis discolor showed the highest attraction towards flowers of cowpea and okra (2.33 each arm-1) at 20 MAR followed by marigold (1.00 arm-1) and sesame and cosmos (0.67 each arm-1). The distance covered towards cowpea was 10.61 cm min-1. and whereas for okra it was 7.37 cm min-1. Similarly, for O. nigrofasciata, the highest response was recorded towards cowpea (2.00 arm-1) followed by marigold (1.67 arm-1) and sesame (1.00 arm-1). The distance covered was also higher in cowpea (3.50 cm min 1 ). Cyrtorhinus lividipennis recorded the highest attraction towards sesame (2.67 arm-1) followed by cowpea (1.33 arm-1) and marigold (1.00 arm-1), which showed significant difference with the control. The distance covered was also high in sesame (4.82 cm min 1 ) followed by cowpea (3.42 cm min-1). As for parasitoids, highest attraction of T. chilonis was found towards cowpea (4.33 arm-1), while that of T. japonicum was towards sesame (2.67 arm-1). Thus, the behavioural response studies of predators and parasitoids revealed a significantly higher preference towards the flowers of cowpea, sesame and marigold. To identify the attractive compounds in the volatiles of flowers, through GCMS analysis, their extraction was conducted through head space method and solvent extraction. The headspace analysis of marigold flowers identified seven major compounds, with insect attractant properties. The compounds were alpha ocimene, myrcene, limonene, cis ocimene, trans ocimene and beta caryophyllene. The attractant compounds of marigold flowers through solvent extraction were caryophyllene, heneicosane, squalene, eicosane, tetrapentacontane, tetracontane, hexatriacontane, heptadecane, octadecane 1-chloro- and dotriacontane and that of cowpea flowers were eicosane, heneicosane, hexadecane, dotriacontane, tetracosane, heptadecane, octadecane 1-chloro- and diisoctyl phthalate. Similarily, the attractant compounds from sesame flowers were eicosane, octacosane, nonacosane, beta-bisabolene, heptadecane, dotriacontane, tetracontane, octadecane 1-chloro- and hexatriacontane. A field experiment was laid out to study the effect of flowering plants in ecological pest management in rice with four treatments: T1- PoP of KAU, T2- PoP in combination with flowering plants, T3- farmers practice and T4- untreated control. The seedlings of best three flowers selected from the olfactometer studies viz., marigold, cowpea and sesame were planted around the rice bunds on the day of transplanting to evaluate their effect on natural enemies and insect pests in rice. The population of major insect pests and natural enemies was recorded at 15,30,45,60,75 and 90 days after transplanting. The extent of damage of stem borers (Scirpophaga incertulus and S. fusciflua) was significantly lower in ecological engineering plot (T2) (2.52 %) followed by the PoP (2.86 %), farmers practice (3.26 %) compared to untreated control (5.39 %). Similarly, the mean damage of leaf folder (Cnaphalocrosis medinalis) was lowest in T2 (1.24 %) which was on par with T1 (1.28 %). The mean population of leafhoppers (Nephotettix nigropictus, N. virescens and Cofana spectra) was lowest in PoP (0.37 m 2 ), while for hispa, Dicladispa armigera, the population in all the treatments was non significant. The population of rice bugs (Leptocorisa spp.) was lowest in PoP (4.43 m 2 ) followed by farmers practice (4.86 m-2), and PoP with flowering plants (7.06 m-2) at 90 DAT. Ecological engineering plot recorded a significantly higher population of all natural enemies as against the control, PoP and farmers practice. Five species of coccinellids were recorded from the ecological engineering plot, viz., M. discolor, Coccinella transversalis, Harmonia octomaculata, Cheilomenes sexmaculatus, and Brumoides suturalis, The highest population of ground beetles (O. nigrofasciata) was recorded in ecological engineering plot (1.60 m-2) followed by control (0.90 m-2). Similarly, significantly higher population of rove beetles and damselflies (2.94 and 1.41 m-2 respectively) were recorded in EE plot. Seven species of spiders viz., Tetragnatha javana, T. mandibulata, Pardosa pseudoannulata, Neoscona theisi, N. elliptica, Argiope catenulate and Oxyopes javanus were documented wherein the population was highest in ecological engineering plot (1.97 m-2). The hymenopteran parasitoids were recorded through sweep netting and significantly higher population was recorded in ecological engineering plot (2.20 /5 sweeps), followed by control (1.06 /5 sweeps). The major parasitoids recorded under Ichneumonidae were Xanthopimpla sp., Trathala flavoorbitalis, Amyosoma sp., Isotima sp., Metopius rufus, Goryphus sp. and Stenobracon nicevelli, whereas Tropobracon sp., and Cardiochiles sp. were documented under Braconidae.The parasitization on stem borer egg mass by Tetrastichus sp. and Telenomus sp. was observed, in which the extent of total parasitism was 92.5 per cent in ecological engineering plot, followed by 72.5 percent in the control. The yield recorded in PoP and ecological engineering plot was 529.73 g m-2 and 513.80 g m-2 respectively and was on par with each other, while the control plot recorded the lowest yield of 263.46 g m-2. The benefit-cost ratio in the ecological engineering plot is 2.16 while the control recorded a ratio of 0.95. The present study identified three flowering plants viz., cowpea, marigold and sesame having the potential to enhance the population of predators and parasitoids in the rice ecosystem. Hence the study will pave the way to develop a habitat management module for pest management in rice. Further studies to identify additional plant species for habitat management are to be carried out. Detailed investigations on the impacts of floral resources on the growth and development of entomophagous insects have to be undertaken to fortify conservation biological control strategiesItem Efficacy and biosafety evaluation of the entomopathogenic fungus Lecanicilliumsaksenae (Kushwaha) Kurihara and Sukarno(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2025-07-17) Karthik, R.S; Reji Rani, O PThe investigation entitled “Efficacy and biosafety evaluation of the entomopathogenic fungus Lecanicilliumsaksenae (Kushwaha) Kurihara and Sukarno” was carried out during 2019 to 2024 at the Department of Entomology, College of Agriculture, Vellayani. The objectives of the study were to evaluate the efficacy of bioformulations of L. saksenae in managing the cowpea pod bug Riptortuspedestris, and to evaluate its biosafety to non-target organisms, including productive insects, pollinators, natural enemies, and mammals. A field experiment conducted in cowpea variety Jyothika, with five treatments viz. (T1) chitin enriched oil formulation of L. saksenae, 108 spores mL-1 @ 10 mL L-1 (T2) talc based formulation of L. saksenae, 108 spores mL -1 @ 20 g L-1 , (T3) L. saksenae spore suspension, 108 spores mL -1 @ 20 mL L-1, (T4) talc formulation of L. lecanii, 108 spores mL-1 @ 20 g L-1 (T5) dimethoate 30 % EC @ 1.5mL L-1. Of these, foliar application of chitin enriched oil formulation of L. saksenae was the superior treatment as it recorded a significantly lower population of the pod bug, R. pedestris. The reduction in population was 34 per cent after the first application and by 21.33 per cent after the second spray, which was equally effective as the insecticide dimethoate 30% EC sprayed at 1.5mL L-1. Population of predators such as the coccinellid beetle, Coccinellatransversalis and spiders Lycosapseudoannulata and Oxyopes sp. did not vary significantly, indicating its safety to natural enemies associated with cowpea ecosystem. Experiment to assess the safety of L. saksenae to non-target organisms was carried out using a concentration that is tenfold higher (109 spores mL-1) than the infective dose to insects. Safety to productive insects was examined using Indian bee, Apisceranaindica and the stingless bee Tetragonulairidipennis. L. saksenae conidial suspension exposed by dry film method did not cause any symptoms of mycosis such as irritability, sluggishness or disoriented movements in adult bees throughout the observation period. Topical application of the conidial suspension did not exhibit any significant difference in the colony strength, brood area (139 to 272.5 cm2) and storage area (31 to 136 cm2) of honey and pollen. There were no behavioural abnormalities nor symptoms of mycosis during the experimental period of ten weeks and the brood development was comparable with that of untreated colonies. The safety test carried out in adult T. iridipennis using the same method, revealed that the fungus was not pathogenic to it, as there were no symptoms of mycosis such as irritability, sluggishness or disoriented movements, till the fourth day post treatment. The colonies treated with conidial suspension did not exhibit symptoms of mycosis or mortality. The coccinellid predator, C. transversalis treated using dry film revealed no symptoms indicative of fungal infection. The cumulative mortality of treated grubs observed for a period of five weeks did not differ significantly with that of untreated (90 and 100 per cent respectively). They pupated normally and the percentage adult emergence was comparable with that of the untreated group (40 per cent each). The larval syrphid predator Dideopsisaegrota tested for its susceptibility to L. saksenae completed its life cycle normally with no symptoms of fungal infection. The mortality recorded four days after treatment was 40 per cent in the treated as well as control group. The larval parasitoidBraconbrevicornis, exposed to the conidial suspension by dry film method did not develop any disease. The cumulative mean mortality of adults did not differ significantly till 12 days of treatment between the treated and untreated (98-100 per cent). Similarly, there was no symptoms of infection in the larval parasitoidGoniozusnephantidis till seven weeks of exposure. The mortality recorded was on par (74 -76 per cent) in both the groups after six weeks of treatment. The egg parasitoidTrichogrammachilonis, emerged normally after treatment and the rate of adult emergence was 11.31 to 94.30 in treated and 14.76 to 98.46 in control, which did not vary significantly from each other. The pollinators Halictus sp. and D. aegrota. topically treated with L. saksenae showed no signs of mycosis, abnormal behavior, or mortality, further validating the safety of L. saksenae to beneficial insects. To evaluate biosafety of L. saksenae in mammals, the experiment was carried out in Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Mannuthy. The acute toxicity studies were conducted on eight weeks old healthy Wistar albino rats (Rattusnorvegicus) weighing 150 – 200 g. The experiment was laid in CRD with three routes of administration viz. oral, dermal, intranasal administration of L. saksenae (6 × 109 spores mL⁻¹) and a control group with six animals per route of adminstraion. Treated animals were observed for clinical, haematological parameters and histopathological changes. The results revealed that there was no variation in body temperature, food and water intake and weight gain during the experimental period. Haematological parameters such as RBC, WBC, haemoglobin, packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), granulocyte count, agranulocyte count, and platelet count were within the normal range in the treated and untreated animals. Serum biochemical analysis of orally treated animals performed to estimate liver function parameters, including alkaline phosphatase (ALP), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), total protein, albumin, and globulin, as well as the renal function parameters, including urea, creatinine, and uric acid. There were no abnormalities in the test results obtained. Euthanized animals exhibited normal gross morphology and histopathological observations did not reveal any significant pathological lesions in the vital organs including brain, liver, kidneys, lungs, spleen, skin and intestines, confirming the non pathogenic nature of L. saksenae to mammals. In conclusion, the chitin enriched oil formulation of L. saksenae offers a viable alternative to chemical pesticides for managing the major sucking pest of cowpea, the pod bug, R. pedestris, without compromising the safety of natural enemies. The fungus also proved safe to productive insects, pollinators and mammals, strongly supporting its candidature in sustainable and ecofriendly pest management programmes.Item Endophytic and growth promoting activities of the entomopathogenic fungus, Lecanicilliumsaksenae (Kushwaha) Kurihara and Sukarno in rice(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2025-07-11) Shree Naveena, PThe study entitled “Endophytic and growth promoting activities of the entomopathogenic fungus, Lecanicilliumsaksenae (Kushwaha) Kurihara and Sukarno in rice” was carried out during 2020-2024 in the Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram. The objective of the study was to establish the entomopathogenic, endophytic and growth promoting attributes of L. saksenae in rice. The infection process of L. saksenae in the rice bug, investigated using Scanning Electron Microscopy (SEM), revealed five step infection processes comprising adhesion, germination, penetration, colonisation/invasion, and conidiation/dissemination at 24, 48, 72, 96 and 120 hours post inoculation (HPI), culminating in dissemination of spores facilitating horizontal transmission and complete mycosis evidenced by mummified appearance, by 144 HPI. Biochemical mechanisms involved in pathogenesis were deciphered using metabolomic analyses of the infected rice bug. Gas Chromatography-Mass Spectrometry (GC-MS) and High-Resolution ORBITRAP Liquid Chromatography Mass Spectrometry (HR-LC-MS) revealed an array of 19 insecticidal compounds, three immunosuppressors, three antimicrobial compounds, and 13 other metabolites related to insect metabolism, highlighting the complex biochemical arsenal employed by L. saksenae in insect pathogenesis. In addition to entomopathogenicity, L. saksenae exhibited significant plant growth-promoting traits. Plate assays and spectrophotometric observations, displayed elevated levels of phytohormones, notably gibberellic acid (GA3: 334.68 µg mL-1) and indole acetic acid (IAA: 30.00 µg mL-1). It also exhibited zinc and phosphate solubilization efficiency (1.15 SE and 1.70 SE), which are related to nutrient assimilation. The siderophore (2.23 AU) and ammonia production (15.42 µmol mL-1) levels which help in nutrient uptake were significant and higher than those in other entomopathogenic fungi. The study further examined endophytic association of L. saksenae upon seed inoculation, in rice through re-isolation, microscopy, and PCR. The fungus could be reisolated from roots, stems, and leaves of the inoculated plants up to 90 days after seed inoculation (DAI) demonstrating its systemic translocation within then plant. Maximum colonisation was noted in roots (72.86 per cent), followed by stem (64.29 per cent) and leaves (40.00 per cent) at 30 DAI, which tapered to 32.86, 17.14 and 11.4 per cent at 90 DAI. SEM observations confirmed internal colonisation of L. saksenae in the leaf stem and root tissues of inoculated rice, which was further established by PCR amplification, that unequivocally matched with the original Accession. MN545844 deposited by Rani et al. (2015). Comparative metabolomic analysis between inoculated and uninoculated plants revealed significant biochemical changes due to L. saksenae colonisation. Significant elevation of proteins, sugars, and phenolic compounds in the inoculated plants indicated a metabolic shift that favours enhanced growth and defence. Untargeted GC-MS analysis revealed predominance of carbohydrates at maximum tillering stage which indicates protection at cellular levels and promotion of plant growth. Untargeted ORBITRAP HR LC-MS detected the presence of 10 insecticidal/insectistatic, one nematicidal, and three antimicrobial compounds, suggesting that L. saksenae induced the defence mechanism in inoculated plants. LC-MS/MS revealed profound modulation of growth and defence related hormones at critical plant growth stages due to fungal inoculation. Inoculated plants showed increased growth related hormones such as indole-3-butyric acid (IBA), IAA, GAs, N6-benzylaminopurine (6-BAP), trans-zeatin (tZ), and trans-zeatin riboside (tZR) at the seedling stage, and IAA, IBA, GA3, GA4, GA7, and tZR at the maximum tillering stage. Defence hormones such as abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), cis-jasmone (CJ), methyl jasmonate (MeJA), epibrassinolide (EBL), and 1 aminocyclopropane-1-carboxylic acid (ACC) were significantly higher in the inoculated plants at the seedling stage and SA, JA, CJ, MeJ, and ACC at the tillering stage, which are related to increased resistance to pest infestation. Inoculated seeds exhibited improved germination (6.38 per cent) and the seedlings exhibited increase in shoot and root length (30.30 per cent, 55.58 per cent), number of leaves and roots (35.29 per cent, 26.58 per cent) and the seedling vigor index (51.46 per cent), compared to the control. Pot culture experiments proved enhancedplant height (25.80 per cent), number of tillers (36.99 per cent), panicle count (30.00 per cent), grain number (24.20 per cent), grain yield (30.00 per cent), and straw yield (28.43 per cent) in the inoculated plants. In L. saksenae colonised, rice bug infested plants, there was a significant reduction in the number of eggs laid (29.40 per cent), number of feeding punctures (32.83 per cent) and grain damage (37.45 per cent) compared to control plants. Gene expression analysis revealed the upregulation of defence related genes, phenyl ammonia lyase (PAL) and lipoxygenase (LOX) in both inoculated and control plants, indicating it as a general stress response to herbivory. However, the pathogenicity related genes of the entomopathogens viz. subtilin like protease (PR1) and chitinase II (CHIT II) were not expressed in the colonised plants, as these genes are typically involved in breaching of insect cuticle. Headspace volatile analysis (GC-MS) of L. saksenae inoculated plants before rice bug infestation revealed the presence of 2-heptanone (natural enemy attractant and insect repellent), and 4-methylbenzaldehyde (oviposition deterrent). L. saksenae inoculated, rice bug infested plants, displayed defence related volatiles, such as S linalool (natural enemy attractant and insect repellent), methyl salicylate (natural enemy attractant), 9-octadecenamide (Z) (insecticidal), N-methyl-1-adamantaneacetamide (insecticidal and repellent). Additionally, there was upregulation of defence related enzymes, PAL, catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), peroxidase (POD), and ascorbate peroxide (APX) in inoculated plants. Temporal profiling revealed a dynamic activation pattern, where PPO, SOD, and APX peaked early at 48 hours after insect release (HAR), followed by a surge in PAL and POD at 72 HAR, and a delayed peak of CAT at 96 HAR. Importantly, L. saksenae inoculated plants displayed earlier and more intense upregulation of SOD and PAL, indicating a primed defence in plants during herbivore attack. These biochemical changes may underlie the observed reduction in pest performance and feeding efficiency. The above findings established the entomopathogenic, endophytic and growth promoting attributes of the indigenous isolate, L. saksenae in rice. By elucidating the tritrophic interactions involving the fungus, plant and insect, the study positions L. saksenae, as a "two-in-one" eco-friendly solution for plant health management in rice.Item Bio -ecology and management of rice caseworm, Paraponyx stagnalis (Zeller) (Lepidoptera : Crambidae)(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2025-02-13) Muhammed Arshad, V; Karthikeyan, KThe rice caseworm, Parapoynx stagnalis (Zeller) (Lepidoptera: Crambidae), has emerged as a serious pest of rice, particularly in South India in recent years. It is reported to cause a reduction in yield by about 30 per cent in rice. Sporadic incidence of the caseworm has been reported recently from many rice growing tracts of Kerala as well. Yet, hardly any study has been conducted either on the biology or management of this pest. The study was conducted at the Department of Agricultural Entomology, Regional Agricultural Research Station, Pattambi during 2023-24. The objectives of the study were to investigate the biology of rice caseworm, the population dynamics of rice caseworm and its natural enemies and to evaluate the bio-efficacy of plant products and insecticides against the pest. The life cycle of P. stagnalis consisted of egg, larva, pre-pupa, pupa, and adult. The caseworm recorded an incubation period of 3.25 days in male and 3.48 days in female. The total larval period was 16.93 and 18.63 days in male and female, respectively. The pre-pupal and pupal duration was 1.30 and 5.4 days in male and 1.58 and 6.18 days in female, respectively. The total duration from egg to adult was shorter for male (30.83 days) as compared to female (34.52 days). The maximum adult emergence was recorded during 6.00 pm to 12.00 am. Pre-oviposition, oviposition and post-oviposition periods of female moth lasted for 1.3, 2.4, and 1.7 days, respectively. The sex ratio was found to be 1:1.43. The female moth laid 45 to 104 eggs, varying in different seasons with 43 to 81 per cent hatchability. The morphometrics study on different stages of caseworm showed that the mean length and width of the egg were 0.65 ± 0.12 and 0.50 ± 0.05 mm. The length and width of 1st, 2nd, 3rd, 4th, and 5th larval instars were 1.95 ± 0.23 and 0.21 ± 0.0 mm, 5.21 ± 0.18 and 0.39 ± 0.09 mm, 6.92 ± 0.13 and 0.65 ± 0.06 mm, 8.95 ± 0.21 and 0.88 ± 0.14 mm, 11.45 ± 0.20 and 1.28 ± 0.14 mm. The pupa measured 7.95 ± 0.34 mm in length and 1.54 ± 0.13 mm in width. In the Rabi season, the highest moth population was recorded in the field after four weeks of transplanting in sweep net catch, viz., 8.5 moths/10 sweeps during 3rd week of January, while in Kharif, the highest catch (7.5 moths/10 sweeps) was recorded during 1st week of September. In light trap, the highest catch was obtained during 3rd week of August in Kharif (7.86) and 2nd week of November (12.14) in Rabi season. The correlation study concluded a significant positive correlation with maximum temperature (0.756) and a significant negative correlation with minimum temperature (-0.88) and relative humidity (-0.778) in the Kharif season. In contrast, no significant correlation was obtained in the Rabi season. The joint effect of weather variables showed a significant negative correlation with minimum temperature and relative humidity (Tmin*RH) in the Kharif season. The highest leaf damage was caused by 4th instar larva with a mean per cent damage of 26.74. The rice field weed, Isachne miliaceae (Naringa) was identified as an alternate host to rice caseworm. In the field, the spider, Plexippus paykulli (Araneae: Salticidae) was recorded as a predator of rice caseworm larvae. A hymenopteran wasp, Apsilops scotinus (Ichneumonidae) was recorded as a larval pupal parasitoid of rice caseworm. The evaluation of oil cakes and bio-pesticides under net house conditions against rice caseworm larva showed that mahua cake at 3 % was the most effective treatment followed by B.t and mahua cake at 2 %. Mahua cake at 3% recorded the lowest leaf damage (7.73 %) followed by mahua cake at 2%, neem cake at 3 %, and B.t. In the field evaluation, Cartap hydrochloride + Emamectin benzoate was found to be the superior treatment recording 100 per cent mortality in Rabi and 95.95 per cent mortality in Kharif. This was followed by Carbosulfan and Fipronil. During Rabi season, significant mortality was observed in the treatment with Bacillus thuringiensis (71.99 %). A higher yield was recorded in the plot treated with Cartap hydrochloride Emamectin benzoate (3344.13 kg/ha in Rabi and 3117.30 kg/ha in Kharif), followed by fipronil and carbosulfan. This study provides valuable insights into the biology, ecology, population dynamics, and management of Parapoynx stagnalis, contributing to the development of effective and sustainable management strategies for rice caseworm, for the enhancement of rice production and food security.Item Radiofrequency heating for the management of rice weevil Sitophilus oryzae (L.)(Coleoptera:Curculionidae) and lesser grain borer Rhyzopertha dominica (Fabricius)(Coleoptera:Bostrichidae)(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2025-03-04) Prashanth PatilIndia is the leading country in the export of rice. The infestation of storage pests, notably the rice weevil, Sitophilus oryzae and lesser grain borer, Rhyzopertha dominica causes a significant loss in the quantity and quality of stored grains. Phosphine use effectively manages stored pests, but insect resistance, residue concerns, strict import regulations, and rising demand for organic products highlight the need for chemical-free alternatives like radiofrequency (RF) heating to protect high-value commodities.. Hence, this study was carried out to assess the effectiveness of RF heating for the management of rice weevil, S. oryzae and lesser grain borer, R. dominica, and to study the impact of RF disinfestation on the quality parameters of rice grains. Eggs, grubs (15 ± 2 day old), pupae, and adults (one week old) of S. oryzae and R. dominica were exposed to RF dryer (40.68 MHz, 10 kW) at three different levels of electrode height (190, 195, and 200 mm) and conveyor speed (6, 8, and 10 m/h) and compared with an untreated control. The order of susceptibility among different life stages of lesser grain borer at 195 mm electrode height and 8 m/h conveyor speed was adult>grub>egg>pupa. S. oryzae was highly susceptible to RF heating, leading to complete mortality of all the stages except pupa at all the treatment combinations. The susceptibility of grubs, eggs, and pupae of R. dominica were comparable, whereas adults were highly vulnerable to RF heating. The mortality of immature stages was assessed based on the per cent decrease in adult emergence over control. Lowering the electrode height of RF dryer increased the mortality of all life stages of S. oryzae and R. dominica. Highest mortality of eggs, larvae, pupae, and adults was obtained at the lowest electrode height of 190 mm. Similarly, the mortality of eggs, larvae, pupae, and adults of S. oryzae and R. dominica increased significantly by decreasing the conveyor speed. The lowest conveyor speed of 6m/h significantly reduced adult emergence and recorded the highest mortality of all the developmental stages of S. oryzae and R. dominica. The analysis of the interaction effect of electrode height and conveyor speed of RF dryer demonstrated that the mortality of different developmental stages of S. oryzae and R. dominica increased with a decrease in electrode height and conveyor speed. There was no adult emergence when the eggs, grubs and pupae of S. oryzae were exposed to RF heating. Meanwhile, the adult emergence of R. dominica was completely inhibited only at the lowest conveyor speed of 6 m/h at all three electrode heights. RF heating resulted in the complete mortality of adults of rice weevil at all the treatment combinations. Lesser grain borer adults were more tolerant to RF heating, with complete mortality observed at all the electrode heights at a conveyor speed of 6 m/h and at the electrode heights of 190 and 195 mm at a conveyor speed of 8 m/h. All other treatment combinations did not cause complete mortality of R. dominica adults. Per cent weight loss was significantly reduced over control when R. dominica and S. oryzae eggs were exposed to RF heating. Meanwhile, weight loss was significantly reduced over control only when S. oryzae grubs were subjected to RF heating. The impact of RF heating on the quality parameters of rice grains was analysed after exposure to RF heating. Moisture, amylose, and cooking time of rice grains decreased with the decrease in electrode height of RF dryer. The moisture content at all the treatment combinations was significantly lower over control. Amylose content and cooking time did not vary significantly over control by RF heating at various combinations of electrode height and conveyor speed. Similarly RF heating did not adversely affect the colour of rice as there was no significant colour change over control after RF heating. Three combinations of electrode height and conveyor speed (190 -6 mm m/h, 195-6 mm-m/h,200- 6mm-m/h) resulted in the complete mortality of all life stages of S. oryzae and R. dominica. Also, there was no significant difference in amylose, cooking time, and colour values of rice grains at these treatment combinations over control. The lowest temperature recorded after RF treatment was 56.9°C in the 200 mm-6 m/h treatment combination. This indicates that a temperature of 56.9°C generated through RF heating can effectively control all life stages of S. oryzae and R. dominica by retaining the quality parameters of the rice grains. Hence, radiofrequency heating at an electrode height of 200 mm and a conveyor speed of 6 m/h can be commercially employed in the complete disinfestation of all the stages of S. oryzae and R. dominica without compromising the quality of rice grains.