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2017 - 201944
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Subject: Agricultural Entomology × End date: 2019 × Start date: 2017 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Morphological variations of root knot nematode in vegetables and banana
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Chinchu, P Babu; KAU; Narayana, R
    The study entitled “Morphological variations of root knot nematode in vegetables and banana” was conducted at College of Agriculture, Vellayani during 2015-17 with the objective to study the morphological and morphometric variations of root-knot nematode in brinjal, okra, tomato and banana in Kerala. Morphological and morphometrical studies of females, perineal pattern, second stage juveniles and males of root knot nematodes collected from Dhanuvachapuram, Kattakada and Vellayani of Thiruvananthapuram district; Balagram, Pampadumpara and Thovalappady of Idukki district; Chazhoor, Thalikulam and Thaniyam of Thrissur district infecting brinjal, okra, tomato and banana were done and the data was analysed to identify the species. M.incognita (Kofoid & White, 1919) Chitwood, 1949, M. javanica (Treub, 1885) Chitwood, 1949, M. arenaria (Neal, 1889) Chitwood, 1949 and M. chitwoodi Golden, O'Bannon, Santo & Finley 1980 were identified from brinjal, okra, tomato and banana in Thiruvananthapuram, Idukki and Thrissur districts of Kerala. The study indicated M. incognita as the major species of root knot nematode in Thiruvananthapuram district (91.66%) with highest percentage of occurrence in brinjal and tomato (27.77). In Idukki district, the major species of root knot nematode was M. javanica (66.66%) with highest percentage of occurrence from brinjal and banana (33.33). In Thrissur district, M. arenaria was found to be the major species (66.66%) with highest percentage of occurrence in okra (37.5). M. incognita was found to be the major species in brinjal (55.55%), okra (44.44%), tomato (55.55%) and banana (44.44%) in Thiruvananthapuram, Idukki and Thrissur districts. The extent of parthenogenesis of root knot nematode was found to be very high (97.22%) in these populations. Intraspecific morphological variations were observed within M. incognita, M. javanica and M. arenaria with respect to shape of females, length and position of neck, perineal pattern morphology, tail characters including rectum dilation. Interpopulation comparison of mature females, perineal pattern and second stage juveniles of M. incognita showed that the characters length, width, neck length, stylet length, LMB, WMB and ratio a of females, LVS, AVS, ATT and IPD of perineal pattern and body length, stylet length, H-MB, ABW, tail length, ratio c and c’ were recorded as stable characters. Interpopulation comparison of mature females, perineal pattern and second stage juveniles of M. javanica showed that all the characters of females, perineal pattern and second stage juveniles were stable characters and in M. arenaria, the characters like body length, width, neck length, stylet length, LMB and WMB of females, LVS, AVS, ATT and IPD of perineal pattern and length, stylet length, H-MB, ABW and tail length were recorded as stable characters and found useful in characterizing species. Intraspecific morphological and morphometric variations of M. incognita, M. javanica, M. arenaria were recorded from four host plants in three districts in Kerala. M. arenaria and M. javanica showed high variability between the populations compared to M. incognita in Kerala. The study indicated that M. incognita, M. javanica and M. arenaria were the major species infesting vegetables and banana in Kerala. Among the sampled populations, M. hapla was not identified which shows that M. hapla is not common in Kerala conditions. The study recorded the first report of species having morphological and morphometrical characters similar to M. chitwoodi from okra in Thiruvananthapuram which opens way to molecular studies in future.
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    ThesisItemOpen Access
    Novel bioformulations of entomopathogenic fungi and their efficacy aganist banana weevils
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Remya, S; KAU; Reji Rani, O P
    The study entitled ‘Novel bioformulations of entomopathogenic fungi and their efficacy against banana weevils’ was carried out at Dept. of Agrl. Entomology, College of Agriculture, Vellayani during 2016-2018, with the objective to develop novel formulations of entomopathogenic fungi, Metarhizium anisopliae (Metch.) Sorokin, Beauveria bassiana (Bals.) Vuillemin and to evaluate their efficacy in managing banana weevils. It was intended to develop capsule and gel formulations. Experiment to standardize a coating material for developing capsules revealed that Hard Gelatin Transparent (HGT), Hard Gelatin Coloured (HGC) and Hydroxy Propyl Methyl Cellulose (HPMC), were equally stable under ambient conditions of storage (26 -33°C and RH 60-80%). On testing their ability to disintegrate under field conditions, it was noted that chitosan filled HGT capsules easily disintegrated at 20% soil moisture after 36 h and after 24 h at 30 % soil moisture. It took 144 h for all capsules to disintegrate in sheath or leaf axil and 24 h in bore holes. Talc and chitosan were superior, in maintaining storage stability as well as degradability. A trial conducted to determine the moisture content of capsules, revealed that 10 % was the ideal moisture level content of the ingredient, to maintain storage stability as well as viability of the formulation. Viability noticed after three months was 2.29 × 107 cfu mL-1 and 2.27 × 107 cfu mL-1 in chitosan based capsules of M. anisopliae and B. bassiana and 2.10 × 107 cfu mL-1 and 0.76 × 107 cfu mL-1 in talc based capsules. Therefore, capsules were developed with HGT coating, with chitosan / talc as carrier at 10 % moisture content. Shelf life studies revealed that chitosan was the best carrier material compared to talc in retaining viability of Metarhizium capsules, with a mean cfu of 2.51 × 107 mL-1 and 1.77× 107 mL-1. During a period of three months of storage, there was no decline in the number of viable colonies, cfu ranging from 1.72 × 107 mL-1 to 2.79 × 107 mL-1. . Storage under refrigeration had better retention of viability (2.63 × 107 cfu mL-1) than at room temperature (1.64× 107 cfu mL-1). In Beauveria capsules, the viability did not differ in both chitosan and talc based capsules. Here also, the number of viable colonies did not decline statistically, till three months of storage, with mean cfu values ranging from 1.85 × 107 mL-1 to 2.36 × 107 mL-1. In general, shelf life of capsules could be extended by two months when chitosan was used as the carrier material. Low temperature storage could also improve the shelf life by two months. Shelf life studies of gel formulations indicated that both Metarhizium and Beauveria gels exhibited high viability in chitosan at room temperature and under refrigeration. The mean number of viable colonies observed was 2.39 × 106 cfu mL-1 in chitosan based gels of Metarhizium and 2.17 × 106 cfu mL-1 in Beauveria gels. The number of viable colonies of Metarhizium and Beauveria observed throughout the experimental period did not vary significantly over three months of storage. The mean number of cfu being 2.26 × 107 mL-1 on the 15th day and 1.41 x 106 mL-1 on the 90th day . It was also inferred that chitosan when used for formulating gels could extend the shelf life of both organisms by one month. Pathogenicity test disclosed the affinity of M. anisopliae to rhizome weevil and B. bassiana to pseudostem weevil. Pot culture studies to evaluate chitosan and talc based capsules of B. bassiana revealed that both the capsules of Beauveria were effective as chlorpyriphos 20 EC 0.05% for pseudostem weevil, in prophylactic and curative methods. The damage index (DI) was one each and reduction in pest population was 91.67 % in prophylactic control and 91.67-100 % in curative control. Metarhizium capsules reduced the damage caused by rhizome significantly, but the reduction in pest population was only to the tune of 47-55 % in prophylactic and 50- 58 % in curative control. Chitosan based gel of Metarhizium tested against rhizome weevil, reduced the damage significantly (DI 46.67 and 30, in prophylactic and curative methods). The pest population was reduced by 61.11 % in prophylactic and 36.11 % in curative methods. The study could standardize the protocol for capsule and gel formulations of entomopathogenic fungi, retaining the viability and infectivity upto three months of storage. It is concluded that placement of Beauveria capsules in leaf axils prophylactically and curatively can effectively control pseudostem weevil and Metarhizium capsules and gels placed in the rhizosphere could manage the rhizome weevil moderately.
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    ThesisItemOpen Access
    Evaluvation of new insecticides against major pests of okra,Abelmoschus esculentus (l))
    (Department of Agriculural Entomology,Padanakkad, 2019) Reshma Chandran, KAU; Ramesha, B
    An experiment was conducted on ‘Evaluation of new insecticides against major pests of okra, Abelmoschus esculentus L.’ at College of Agriculture, Padannakkad and RARS Pilicode sub centre, Karuvachery in two seasons viz., rabi season (September to December 2018) and summer season (January to April 2019).The objective of the study was ‘to study the efficacy of different new insecticides against major pests of okra, viz., shoot and fruit borer, gram pod borer, leaf roller and leafhopper’. The variety selected for the study was Varsha Uphar released by Haryana Agricultural University, Hisar. The experiment was laid out in Randomized Block Design with 8 treatments and 3 replications. The different treatments were; T1: Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC (Voliam flexi®) @ 0.7ml/l; T2: Lambda cyhalothrin 4.6 per cent + Chlorantraniliprole 9.3 per cent ZC (Ampligo®) @ 0.4 ml/l; T3: Thiamethoxam 12.6 per cent + Lambda cyhalothrin 9.5 per cent ZC (Alika®) @ 0.5 ml/l; T4: Flubendiamide 19.92 per cent w/w + Thiacloprid 19.92 per cent w/w (Belt-expert®) @ 0.4ml/l; T5: Novaluron 10 EC @ 2ml/l; T6: Chlorantraniliprole 18.5 SC @ 0.3 ml/l (check); T7: Thiamethoxam 25 WG @ 0.3g/l (check); T8: Absolute control. Treatments were applied one at vegetative and one at reproductive stage after the incidence of pest. The observations like damage symptoms were recorded at seven and fourteen days after treatment and population of jassids were recorded at one, three, five, seven and fourteen days after treatment. Biometric observations and yield parameters were recorded during each harvest. The data recorded from field experiment was tabulated and statistical analysis was performed using analysis of variance (ANOVA). Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC (T1 -Voliam flexi) @ 0.7 ml/l of water significantly reduced the percentage of shoot and fruit damage during both rabi and summer season. No infestation was recorded at seven and fourteen days after treatment. It was on par with the standard check Chlorantraniliprole 18.5 SC. The damage caused by leaf roller was significantly reduced by Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC @ 0.7 ml/l of water. There was no incidence of leaf roller after seven and fourteen days after first spray until the end of the crop period during both rabi and summer season. Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC @ 0.7 ml/l of water was very effective against the population of leafhopper. The population of adults and nymphs of leafhopper was drastically reduced by Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC and three days after spray no hoppers were found on plots treated with Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC. It showed non-significant difference with standard check Thiamethoxam 25 WG @ 0.3 g/l of water. Alika (Thiamethoxam 12.6 per cent + Lamda cyhalothrin 9.5 per cent ZC) @ 0.5ml/l of water significantly reduced the population of leaf hopper after Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC. Hopper population was negligible at fifth and seventh day after treatment while it was increased by fourteenth day. Length of the fruit was inversely proportional to the percentage of damage caused by Earias vitella. Maximum fruit length of 14.85 cm and 15.99 cm was recorded from Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC treated plots during both rabi and summer season respectively. This indicates higher efficacy of Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC against E. vitella. The highest total yield was recorded from Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC treated plots during rabi and summer season with yield of 469.86 and 594.31 g/plant respectively. Chlorantraniliprole 8.8 per cent + Thiamethoxam 17.5 per cent SC also showed high benefit-cost ratio of 2.42 and 3.12during rabi and summer season respectively.
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    ThesisItemOpen Access
    Ecological Management of Coconut root grub, Leucopholis coneophora Burm
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Melvin Mohan, S; KAU; SanthoshKumar, T
    The study entitled ‘Ecological management of coconut root grub, Leucopholis coneophora Burm.’ was conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani, and College of Agriculture, Padannakkad during 2017 to 2019. The main objectives were to study the efficacy of botanical insecticides and biocontrol agents against coconut root grub, L. coneophora. The entire study consisted of two parts, laboratory evaluation and pot culture experiment. The laboratory experiment was conducted for screening various entomopathogenic fungi (EPF), entomopathogenic nematodes (EPN), botanicals and chemical insecticides against coconut root grub. Metarhizium anisopliae (Ma 4) and Beauveria bassiana (Bb 5) at different concentrations (1 x 108, 1 x 109 and 1 x 1010 spores mL-1) were tested. Entomopathogenic nematodes Steinernema carpocasae and Heterorhabditis bacteriophora at 100, 500 and 1000 IJ mL-1 were used for screening. The botanicals such as Azadirachta indica, Gliricidia maculata, Clerodendron infortunatum and Chromolaena odorata @ 25 g kg-1 of soil were screened for their efficacy against root grub. The chemicals used for the experiment comprised of chlorantraniliprole 0.4% G @ 75g a.i ha-1, fipronil 0.3% G @ 75g a.i ha-1 and spinosad 45% SC @ 73g a.i ha-1. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fifteen kilograms of sterilized moist soil was taken in a plastic basin and fresh potato tubers were given as feed for root grub. Three grubs were released into the basin and treatments were given one week after the release of grubs. The screening experiment using EPF consisted of eight treatments with three replications. The application of M. anisopliae @ 1 x 1010 spores mL-1 was found to be the most effective (100 % mortality) EPF against root grub and was on par with chemical check at 14 days after treatment (DAT). At 21 DAT, B. bassiana @ 1 x 1010 spores mL-1 resulted 100 per cent mortality and was on par with M. anisopliae @ 1 x 1010 spores mL-1 and the chemical check. At 28 DAT, M. anisopliae @ 1 x 1010 spores mL-1 and B. bassiana @ 1 x 1010 spores mL-1 brought about 100 per cent mortality of grubs, which were on par with the chemical check chlorpyriphos 20 % EC @ 225g a.i ha-1 (100 %), followed by M. anisopliae @ 1 x 109 spores mL-1 (92.58 %) and B. bassiana @ 1 x 109 spores mL-1 (85.17 %). The screening experiment with EPN consisted of eight treatments with three replications and the results revealed that all the treatments except chemical check failed to cause infection on grubs upto 10 DAT. Among the botanicals, A. indica application showed 48.14 per cent mortality of root grubs followed by C. infortunatum (37.03 %) at 30 DAT. The effect of chemical insecticides on root grub was conducted with five treatments and four replications. Fipronil 0.3% G @ 75g a.i ha-1 exhibited 97.22 per cent mortality and was on par with the chemical check at nine DAT followed by chlorantraniliprole 0.4% G @ 75g a.i ha-1 (74.99 %). Promising treatments viz. M. anisopliae (1 x 1010 spores mL-1, 1 x 109 spores mL-1), B. bassiana (1 x 1010 spores mL-1, 1 x 109 spores mL-1), chlorantraniliprole 0.4% G @ 75g a.i ha-1, and Fipronil 0.3% G @ 75g a.i ha-1 from laboratory experiments were selected and evaluated in a pot culture experiment and were laid out in CRD with eight treatments and three replications. Chlorpyriphos 25 % EC @ 225 g a.i ha-1 was used as a chemical check along with untreated control. Fodder grass variety CO-3 was raised in pots and first instar grubs were released after the establishment of the crop. The results of the pot culture experiment indicated that the application of fipronil 0.3% G @ 75g a.i ha-1 resulted in 100 per cent mortality and was on par with the chemical check at 28 DAT followed by M. anisopliae @ 1 x 1010 spores mL-1 (85.17 %). The treatments B. bassiana @ 1 x 1010 spores mL-1 (77.77 %), chlorantraniliprole 0.4 % G @ 75g a.i ha-1 (74.06 %) and M. anisopliae @ 1 x 109 spores mL-1 (74.06 %) were found to be on par at 28 DAT. From the present study, it can be concluded that the application of entomopathogenic fungi M. anisopliae @ 1 x 1010 spores mL-1 is a promising option for the management of first instar grubs of L. coneophora followed by B. bassiana @ 1 x 1010 spores mL-1. Soil application of neem leaves @ 25 g kg-1 of soil can enhance the suppression of root grubs. The results clearly indicate the possibility of reducing the use of chemical insecticides by resorting to botanicals and biocontrol agents.
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    ThesisItemOpen Access
    Biosystematics and barcording of pteromalidae (Hymenoptera:Chalcidoidea) of Kerala
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Manu Govind, K.K.; KAU; Shanas, S
    The study entitled " Biosyslematics and barcoding of Pteromalidae (Hymenoptera: Chalcidoidea) of Kerala" was conducted during the 2017-19 at the Department of Agricultural Entomology, College of Agriculture, Vellayani with the objective of identification, morphological and molecular characterization and documentation of parasitoid wasps (Pteromalidae) of Kerala. The base material for study was field collected specimens. Purposive sampling was carried out in 38 locations spread across 14 districts of Kerala. The specimens were collected by random sweep net method. The collections were made in the morning and afternoon when the insect activity was at the peak. The sweep contents were immediately transferred into absolute alcohol and the location and date of collection were recorded on the containers. The field collected specimens were examined under high power stereo microscope and initially all the specimens coming under Chalcidoidea were sorted out based on superfamily characters and stored in labelled vials in absolute alcohol. Pleomalid wasps were separated out from these vials and stored in alcohol in another set of vials according to location. The specimens were card mounted for morphometric analysis and characterization. The study revealed 2 genera and 4 species of Ptcromalids which are new to the World of science. The two new genus fall under the subfamily Miscogasterinae and Pteromalinae respectively. The four new speicies discovered are, Dinarmus sp. nov. 1, Mokrzeckia sp nov. 1, Panstenon sp. nov. 1 and Pansienon sp. nov. 2. The Dinarmus sp. nov. 1 was compared to Dinarmus maculatus^ Mokrzeckia sp. nov. 1 was compared to M pint and Panslenon sp. nov. 1 and P. nov. 2 was compared to P. collare
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    ThesisItemOpen Access
    Barcoding and biosystematic studies on Hymenopteran pollinators of cucurbitaceous vegetables
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Erra Harisha; KAU; Shanas, S P
    The study entitled “Barcoding and biosystematic studies on hymenopteran pollinators of cucurbitaceous vegetables” was conducted during the year 2017- 2019 at the Department of Agricultural Entomology, College of Agriculture, Vellayani with an objective to study the diurnal activity and dynamics of hymenopteran pollinators of cucurbitaceous vegetables and to explore their morphological and molecular diversity. To determine the composition and relative abundance of different hymenopteran pollinators visiting the flowers of five selected cucurbitaceous vegetables viz., culinary melon (Cucumis melo var. acidulus), bitter gourd (Momordica charantia L.), ash gourd (Benincasa hispida Thunb. and Cogn.), pumpkin (Cucurbita moschata L.) and ridge gourd (Luffa acutangula (Roxb.) L.) collections were made throughout the blooming period in Thiruvananthapuram and four other districts of Kerala viz., Kollam, Pathanamthitta, Alappuzha and Kasaragod from 06:00 h to 18:00 h of the day with a cone type hand net. Among the above mentioned vegetables, culinary melon was selected for detailed study on diurnal activity at College of Agriculture, Vellayani. The study on composition and relative abundance of hymenopteran pollinators revealed that, A. cerana indica was the dominant pollinator in culinary melon (42.51 %), pumpkin (38.76 %) and ridge gourd (35.16 %) whereas, T. travancorica was the dominant pollinator in bitter gourd (31.86 %) and ash gourd (33 %). Observations on diurnal activity were carried out at College of Agriculture, Vellayani in culinary melon during two crop seasons for 3 weeks at weekly intervals. For foraging rate, the number of flowers visited by each bee for 1 minute and for foraging speed, time spent by each bee per flower were observed respectively. During two seasons, the foraging speed of A. cerana indica, T. travancorica and Halictus sp. was found to be highest during 10:00-11:00 h (10.61 and 10.63, 11.23 and 11.46, 10.26 and 10.40 seconds) respectively. The foraging speed of C. hieroglyphica and Lasioglossum sp. was found to be highest during 09:00-10:00 h (9.02 and 9.11, 11.06 and 11.30 seconds) respectively. The foraging rate of T. travancorica, C. hieroglyphica and Lasioglossum sp. was found to be highest during 10:00-11:00 h (9.16 and 9.23, 4.83 and 4.85 flowers/m2/5 min) respectively. The foraging rate of A. cerana indica and Halictus sp. was found to be highest during 11:00-12:00 h and 09:00-10:00 h (10.60 and 10.88, 4.03 and 4.13 flowers/m2/5 min) respectively. Samples which were unidentified through morphological characterization were given for DNA barcoding. The sequence of 2 samples viz., Tetragonula sp. nov.1 and T. travancorica were obtained. Among these, new species (Tetragonula sp. nov.1) of stingless bee, based on adult worker specimen is described. Differences in morphology and genetic analysis based on partial sequences of the mitochondrial COI gene barcode region support the recognition of the new species. The above results revealed that A. cerana indica was dominant in culinary melon, pumpkin, and ridge gourd and T. travancorica was dominant in bitter gourd and ash gourd. The foraging speed during two seasons in the descending order was T. travancorica > Lasioglossum sp. > A. cerana indica > Halictus sp. > C. hieroglyphica. The foraging rate during two seasons in the descending order was A. cerana indica > T. travancorica > C. hieroglyphica > Lasioglossum sp. > Halictus sp. Among the pollinators, five species viz., P. phalerata phalerata, C. annulata annulata from ash gourd, M. disjuncta from bitter gourd, C. simillima, and C. unimaculata javanica from culinary melon were reported for the first time pollinating cucurbitaceous vegetables. Tetragonula sp. nov.1 of stingless bee, collected from pumpkin flower, is the new species report from the study and it is morphologically characterised.
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    ThesisItemOpen Access
    Compactibility and synergism of the entomopathogentic fungus lecanicillium saksenae (Kushwaha ) Kurihara and Sukarno with other crop protectants
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Keerthana, K; KAU; Reji Rani, O P
    The study entitled “Compatibility and synergism of the entomopathogenic fungus Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno with other crop protectants” was carried out in College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana during 2017-2019 with the objective to assess the compatibility of L. saksenae with botanical insecticides, chemical insecticides, fungicides other entomopathogenic fungi and to evaluate synergistic insecticidal effect. In vitro studies on compatibility was carried out using poisoned food technique, by assessing radial growth, sporulation and germination of L. saksenae. Botanicals tested were aqueous and solvent extracts of neem seed kernel, neem leaves and neem oil emulsion. Among them, lower dose of neem oil emulsion (NOE) 0.5% did not affect the mycelial growth of the fungus. It was 6.27 cm on 14th day after inoculation which was on par with that of control (6.17 cm). Sporulation of the fungus was affected by all the botanicals, with least inhibition in lower dose of aqueous neem leaf extract (NLE (A)) 1% (4.41 x 107 spores mL-1). The corresponding count in untreated medium was 7.57 x 107 spores mL-1. Viability of the fungus was not affected by the lower dose of neem seed kernel extract (NSKE (A)) 0.5%, when compared to control (97.67 % and 99%). Biological index (BI) indicated that aqueous and solvent extracts of NSKE (0.5%), NSKE (A) 1%, NLE (A) 1% and NOE (0.5%) were compatible with L. saksenae, BI values being 75, 69, 70, 75 and 67, respectively. Among the insecticides tested, flubendiamide 39.35 SC was least inhibitory to the growth of L. saksenae, both at half as well as recommended doses (5.92 cm and 5.88 cm), followed by half the recommended doses of thiamethoxam 25 WG (5.88 cm) and chlorantraniliprole 18.5 SC. (5.78cm). The corresponding growth in untreated medium was 6.10 cm. Sporulation in chlorantraniliprole at the recommended dose and control was same (1.35 x 107 spores mL-1). Spore viability was affected by all the insecticides. Germination in imidacloprid was highest among the treatments (85.67 per cent). BI value indicated that imidacloprid, thiamethoxam, flubendiamide and chlorantraniliprole at recommended and half doses were compatible with L. saksenae. (67-94). None of the fungicides tested, were compatible with L. saksenae. B. bassiana at 108 spores mL-1 was found to be compatible with L. saksenae at 107 spores mL-1 based on mortality of treated rice bugs. Treatments L. saksenae and L. saksenae + B. bassiana caused 100 per cent mortality on fourth and fifth day after spraying in nymphs and adults of rice bug. Synergism studies revealed that, on the first day L. saksenae (107 spores mL-1) and L. saksenae + NSKE (A) 0.5% were equally effective causing 83.33% mortality in nymphs, while in adults L. saksenae was superior to its combination (66.67 and 60%). L. saksenae + thiamethoxam 0.0025% exhibited significantly higher mortality in adults (70%) on the first day while in L. saksenae it was 66.67%. For nymphs, L. saksenae and L. saksenae + thiamethoxam 0.0025% was equally effective (83.33% mortality). In both adults and nymphs, L. saksenae was more effective causing 75 per cent and 85 per cent mortality on the first day, while its combination with B. bassiana caused 65per cent and 80 per cent mortality. L. saksenae and its combinations with botanicals, insecticides and microbials had higher feeding inhibition in rice bugs. Under field conditions, L. saksenae at 107spores mL-1 + thiamethoxam 0.0025% and L. saksenae + B. bassiana at 108 spores mL-1 recorded significantly higher population of 3.5 and 2.75 bugs per plot, compared to that of L. saksenae (2.25 bugs per plot). Population of natural enemies did not vary significantly among the treated and untreated plots. Yield recorded at harvest was higher in plots treated with L. saksenae (1.38 kg plot-1) which was followed by combination spray of L. saksenae and B.bassiana (1.32 kg plot-1) It is concluded that L. saksenae is compatible with the botanicals such as neem seed oil emulsion 0.5% and neem seed kernel extract 0.5%. It was also compatible with the new generation insecticides flubendiamide, chlorantraniliprole, thiamethoxam and imidacloprid. Among the microbials, B. bassiana was not inhibitory. Fungicides such as carbendazim, mancozeb, copper oxychloride, hexaconazole and azoxystrobin were inhibitory to L. saksenae. None of the botanicals, insecticides, fungicides or microbials had synergistic effect with L. saksenae. In the management of rice bug L. saksenae was superior to its combination treatments and it did not affect the natural enemy population in rice ecosystem.
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    ThesisItemOpen Access
    Insecticide resistance in spiralling whitefly,aleurodicus dispersus russell(hemiptera:aleyrodidae) and its management
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Aura Senson; KAU; Ambily Paul
    A study on “Insecticide resistance in spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) and its management” was done at College of Agriculture, Vellayani and farmer’s field at Kalliyoor during 2018 to 2019. Tokassess thehinsecticide resistance in the fieldhpopulation of spiralling whitefly, A. dispersus and to evaluate the efficacy of new generation insecticides against resistant population of A. dispersus were the objectives of the study. Bioassaykwas carriedLout to assess the insecticideHresistance in field population of A. dispersus collectedUfromHthree different locations (location ISreekaryam, location II-Vellayani and location III-Kalliyoor) based on the intensity of insecticide application. A series of concentrations of three insecticides viz., quinalphos, fenvalerate and imidacloprid were prepared in aqueous solution and leaf dip bioassay was done using the field population of whiteflies collected from three locations. Results revealedDthatkpopulation collected from location-I (Sreekaryam) was foundhto begsusceptible to insecticides with resistance ratio-1 for all three insecticides, which was considered as reference strain. Population collectedgfrom location-II (Vellayani) showed higher resistance with resistance ratio of 2.60, 2.90 and 1.85 and population from location-III (Kalliyoor) was found to be moderately resistant with resistance ratio of 1.14, 1.62 and 1.28 with respect to quinalphos, fenvalerate and imidacloprid respectively. Laboratoryyexperiments were conductedutotevaluateethedefficacy ofdnew generationdinsecticides viz. buprofezin 25% SC @ 75 g.a.i ha-1, clothianidin 50% WDG @ 20 g,a.i ha-1, cynantraniliprole 10.26% OD @ 90 gfa.i ha-1, dinotefuran 20% SG @ 25 g a.i ha-1, flonicamid 50% WG @ 75 g a.i ha-1, thiamethoxam 25%WG @ 50 g a.i ha-1 and thiamethoxamt12.6% + lambdadcyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1against resistant population of A. dispersus in tomato plants. The results revealed that significantly higher mortality was observed in A. dispersus treated with thiamethoxamg12.6% +hlambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 (100%), followed by clothianidin 50% WDG @ 20 g a.i ha-1 (80%) and flonicamid 50% WG @ 75 g a.i ha-1 (66.67%) after 0.75 hours of treatment. Field experiment was conducted by using tomato plants (var. Vellayani Vijay) at Vellayani from where resistant population was collected with three effective insecticides selected from laboratory along with control. No whiteflies were seen in thiamethoxamt12.6% + lambdatcyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 treated plants followed by clothianidin 50% WDG @ 20 g a.i ha-1 (9.20) and flonicamid 50% WG @ 75 g a.i ha-1(11.80) after one day of spraying. Studies on the dissipation of residues of effective insecticides viz., thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1, clothianidin 50% WDG @ 20 g a.i ha-1 and flonicamid 50% WG @ 75 g a.i ha-1 were conducted in tomato plants at farmer’s field at Kalliyoor. Tomato fruits collected at 0,1,3,5,7,10,15 and 30 days after application of insecticides at recommended dose and results showed that insecticides dissipated within 10 days with half- lives of 4.05, 3.42, 8.92 and 7.82 days respectively. The risk assessment studies also proved the safety of insecticides for the end users. The present study revealed the development of insecticide resistance in the field population of A. dispersus against fenvalerate and quinalphos. Thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha-1 followed by clothianidin 50% WDG @ 20 g a.i ha-1 and flonicamid 50% WG @ 75 g a.i ha-1 could be recommended against the resistant population of A. dispersus in tomato. Dissipation and risk assessment studies also supported the result by establishing their safety to consumers. Further studies have to be taken up to develop and popularize Insecticide Resistant Management strategies against A. dispersus by developing Good Agricultural Practices on efficient use of insecticides and to conserve the ecosystem for sustainable pest management.
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    ThesisItemOpen Access
    Mass trapping of cowpea pod borer maruca vitrata (F.) (lepidoptera; pyralidae) using sex pheromones
    (Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2018) Eurekha Savadatti; Sreekumar, K M
    A study was conducted know the efficacy of synthetic sex pheromone of legume pod borer Maruca vitrata (F.) (Lepidoptera: Pyralidae) at College of Agriculture, Padannakkad. Also investigated the female calling and mating behaviour of the adult moths of M. vitrata. Response of commercial lure to male moths of the test insect was studied in Electroantennogram at NBAIR, Bangalore. The commercial synthetic pheromone lure of legume pod borer M.vitrata from M/s Pest control India (P) Limited, Bangalore was tested and found that it failed to attract not even a single moth. Subsequently, the mating behaviour of the moth was undertaken in detail to investigate whether pheromones are involved in the mating process of the insect. 30 per cent of moths emerged during photophase (6am-5pm) out of which male moths constituted 36.25% and female moths constituted 23.75%. During scotophase (6pm-5am), 69.68% moths emerged, out of which 63.12% was males and 76.25% was females. The emergence found to peak at 5th and 9th hour of scotophase. During calling period female extrudes its pheromone gland beyond the abdominal tip. Female calling behaviour of one to eight day old moths was observed throughout the scotophase. A single calling peak was observed in all aged moths at 6 th hour of scotophase except for three old day moths, which showed additional peaks of calling at fifth, eighth and 9th hour of scotophase. For three-day-old moths, 43.5% was the mean percent of calling at 6th hour of scotophase. The mating behaviour of 1-8 day old M.vitrata moths involving 15 pairs throughout the scotophase showed maximum mating percentage of 26.2 % and 16.6 % for 3 day old and 2 day old moths respectively. Electroantennogram study conducted to know the response of 3-day-old male moths to synthetic lure obtained from PCI, Bangalore showed that response to the stimulus was 0.05mv only, which was the same for the solvent hexane and the air. 75 This showed that there was no distinct physiological response for synthetic pheromone lure. For further confirmation, GC-MS analysis was done and the compound E, E-10, 12-Hexadecadienal was identified at a retention time of 16.42 min. This is the major pheromonally active compound identified in previous studies. In GC- EAD analysis, the response of M.vitrata male moths to E, E-10, 12-Hexadecadienal was checked by matching EAD and FID peaks but without any response. So, the exact reason for the absence of response to commercial synthetic lure is to be elucidated in future studies for developing an effective commercial pheromone for the legume spotted pod borer M. vitrata.