Browsing by Author "Reji Rani, O P"
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ThesisItem Open Access Bioecology and life-tables of the pea aphid (Aphis craccivora koch.) and its natural enemies(Department of Agricultural Entomology, College of Agriculture, Vellayani., 1995) Reji Rani, O P; KAU; Remamony, K SThe seasonal distribution of pea aphid Aphis craccivora and its predators on twigs and pods of cowpea and a perennial alternate host of the insect, glyricidia were assessed during 1993 – 94 at the College of Agriculture, Vellayani, Kerala. On cowpea peak population of the pest during the first season, on twig and pods were noted in January / February while on glyricidia two peaks were noted in the season first from December and early February and the next from February to end to early March. In the second season also one peak period each were seen on twigs and pods of cowpea and on glyricidia, but the three did not coincide in the periods of occurrence. In glyricidia a fourth peak was observed in August / September 1994. Studies thus revealed vital indifference in the trend of population build up on cowpea and glyricidia and even on the twigs and pods of the same plant. The growth stages of the crops and their nutritive status are suggested as the major factor influencing the population build up of A. craccivora than any other factor in the ecosystem. Survey of natural enemies in the region revealed the occurrence of six predators and one insect pathogen. Among them C. sexmaculata and x. scutellare were found to be the important ones. A pest dependent increase in the population of predators were observed but the trends of the population build up of the pest and the natural enemies did not show any effective role of the predators in suppressing the pest population under field condition. The detailed biology of A. oraccivora and the two predators were studied in the laboratory conditions. The duration and percentage survival of each larval instar, adult longevity and fecundity were studied and the data indicated that short duration and higher fecundity od A. craccivora when compared to predators account for the successful establishment of the pest in field even with higher levels of predator population. The parameters of biology in laboratory were found more favourable for the population of X. scutellare than for C. sexmaculata. But in field latter was more successful. Feeding potential of C. sexmaculata ( larvae and adult) was much higher than that X. scutellare (larvae) only. Hence C. sexmaculata was found to be a better bicontrol agent for the control of A. craccivora. The exhaustive information gathered will be useful in cinstructing models for integrated pest control programmes of A. craccivora. Age specific life-tables were consctucted for A. craccivora for assessing the intrinsic rate of increase and germination time of pest and these were found suitable for fast population build up. Life tables were prepared during, December 1993 and January 1994 and the ‘Generation survival’ and ‘Trend Index’ were found increasing in January. The lower mortality percentage of the late instar nymphs were found as the reason for the variations. But the mortality factors could not be precisely determined in the investigations. Series of such life tables developed for different seasons, hosts and different ecosystems may be necessary for constructing suitable models for integrated pest management practices.ThesisItem Open Access Bioefficiency of capsule formulations of Beauveria and Metarhizium managing banana weevils(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2020) Devi, Balakrishnan.; KAU; Reji Rani, O PThe study entitled “Bioefficacy of capsule formulations of Beauveria and Metarhizium in managing banana weevils” was conducted at Instruction Farm, College of Agriculture, Vellayani, Thiruvananathapuram and in the farmers field at Venganoor panchayath, Peringamala, Thiruvananathapuram during 2018-2020. The objective of the study was to validate the efficacy of biocapsules of Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin for the management of banana weevils. The study intended to standardize the dosage and method of application of the Beauveria capsules against the pseudostem weevil, Odoiporus longicollis Oliver and rhizome weevil, Cosmopolites sordidus Germer. The capsules were formulated at a higher spore load of 1010 with HPMC coating and chitosan as carrier following the protocol developed by Remya and Reji (2019). There were three sets of field experiments (1) Efficacy of biocapsules (both Beauveria and Metarhizium) applied as prophylactic treatment against both the weevils (2) Efficacy of Beauveria capsules in curative treatment of pseudostem weevil (3) Efficacy of Metarhizium capsule in curative treatment of rhizome weevil. For prophylactic treatment of pseudostem weevil, two methods of application were tested (1) applying one Beauveria capsule each on all four sides of the outer leaf sheath and (2) applying one capsule each in the outer four leaf axils on all four sides of the plant. The time intervals tested were (1) monthly intervals and (2) bimonthly intervals, starting from fourth month till bunch emergence. Curative management was tested by leaf axil application + bore hole application at two time intervals, weekly and fortnightly. To test the prophylactic treatment against rhizome weevil two methods were tested (1) Plugging the rhizomes at paring on all four sides @ four capsules rhizome-1, followed by pit application @ four plant-1 and (2) pit application alone @ four, plant-1. The time intervals tested were monthly and bimonthly. For curative treatment, the methods tested were pit application at fortnightly, monthly and bimonthly intervals. Results revealed that, placement of Beauveria capsules in the outer leaf sheath @ four, plant-1 at monthly intervals starting from fourth month till bunch emergence was superior with least infestation. Destructive sampling of plants done in the seventh month revealed that there was 90.9 per cent reduction in the population of grubs and adults and 83.33 per cent reduction in the pupal population. The other method, outer leaf axil application @ four, plant-1 at monthly intervals was also found to be effective with a reduction in the population of 72.2 per cent in the case of grubs and adults and 83.33 per cent in pupae. This was on par with single application of chlorpyriphos 20 EC 0.05 % @ 2 mL L-1 as leaf axil filling, where the reduction in population of grubs, pupae and adults was to the tune of 81.81, 50 and 72.72 respectively. Both the methods when applied bimonthly were observed to be less effective. For curative treatment of pseudostem weevil, weekly application of capsules was superior with 51.51, 60.8 and 61.5 per cent reduction in the population of grubs, pupae and adults respectively. This was equally effective as one time application of chlorpyriphos 20 EC 0.05 %@ 2 mL L-1 as leaf axil filling, where the population observed was 54.54, 52.17 and 53.8 per cent of grubs, pupae and adults. Plants in which fortnightly application was done exhibited less control with 24.24, 34.78 and 33.33 per cent reduction of grubs, pupae and adults,respectively. Though there was a marginal increase in yield in the best method, statistically it did not vary from those of others. In the case of rhizome weevil, for prophylactic treatment, placement of four Metarhizium capsules by plugging on the four sides, followed by pit application at monthly intervals was more effective than all other treatments. No tunneling was observed at the time of destructive sampling and the pest stages were totally absent (100 per cent control). When the same method was followed at bimonthly intervals, population reduction was 77.77 and 70 per cent of grubs and adults respectively. Pit application was also effective when applied every month, with 77.77 and 60 per cent reduction of grubs and adults respectively. For curative treatment of rhizome weevil, placement of four capsules in the planting pit at fortnightly intervals was equally effective as one time soil application of Fipronil 0.3 G @ 10g plant-1. Population assessed at the time of harvest revealed that there was 66.65 and 62.5 per cent reduction in the population of grubs and adults, compared to 66.65 and 58.325 per cent in chemical treatment. Analysis of data on yield plant-1 revealed that treatment with capsules at fortnightly and monthly interval were on par with that of chemical treatment and the treatment at bimonthly intervals was equivalent to the yield from untreated plants. It is concluded that for prophylactic management of pseudostem weevil, Beauveria capsules placed in the outer leaf sheath at monthly intervals @ four plant-1, starting from fourth month till bunch emergence is effective, while for curative treatment placement of capsules in the outer four leaf axils @ four plant-1 and one each in the bore hole at weekly intervals is as effective as one time application of chlorpyriphos 20 EC 0.05 % @ 2 mL L-1 treatment. For rhizome weevil, placement of Metarhizium capsules @ four plant-1 by plugging the rhizome at the time of paring, followed by pit application at monthly intervals @ four plant-1 is effective as prophylactic measure and for curative treatment, pit application of capsules at fortnightly intervals @ four plant-1 is effective and equivalent to single application of Fipronil 0.3 G @ 10g plant-1. Therefore the biocapsules of Beauveria can be recommended for the management of pseudostem weevil and those of Metarhizium can be recommended for the management of rhizome weevil.ThesisItem Open 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 PThe 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.ThesisItem Open Access Efficacy of chitin enriched formulations of lecanicillium spp against sucking pests of rice Oryza sativa L.(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Hari Sankar, S S; KAU; Reji Rani, O PThe current study entitled “Efficacy of chitin enriched formulations of Lecanicillium spp against sucking pests of rice Oryza sativa L. was carried out at College of Agriculture, Vellayani and Integrated Farming Systems Research Station, Karamana, Thiruvananthapuram, during 2015-17. The objective was to evaluate the efficacy of chitin enriched formulations of Lecanicillium spp against sucking pests of rice and to assess their impact on natural enemies. The species evaluated were the indigenous isolate Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno (Accession No. LsVs 1 7714) and the NBAIR Isolate of Lecanicillium lecanii (Zimmermann) Zare and Gams, (Vl 8). The indigenous isolate, L. saksenae was found to be infective to rice bug Leptocorisa acuta (Thunberg), brown planthopper Nilaparvata lugens (Stal), green leafhopper Nephotettix nigropictus (Stal), white leafhopper Cofana spectra (Distant), and white winged planthopper Nisia nervosa (Motschulsky). The exotic species L. lecanii was infective to the hoppers but not to rice bug. The pentatomid bugs Scotinophara coarctata (F.) and Menida versicolor (Gmelin) were not susceptible to Lecanicillium spp. Symptoms of mycosis in hoppers which were similar in both the fungi included inactivity, cessation of feeding in dying insects and growth of white fluffy mycelia in the cadaver. The repeated tremors and convulsions were observed in rice bugs treated with L. saksenae within 14 h, which might be due to the action of toxic metabolites. Cross infectivity studies to non target organisms revealed that L. saksenae was found to be safe to the predatory coccinellids viz., Micraspis discolor (F.) and Coccinella transversalis F., the mirid bug, Cyrtorhinus lividipennis Reuter, the carabid beetle, Ophionea nigrofasciata Schmidt-Gobel, and the predatory spiders Tetragnatha maxillosa (Thorell) and Oxyopes shweta Tikader, when treated with spore suspension of 109 spores mL-1. Leaf and soil inoculation of the fungus @ 109 spores mL-1 did not show any cross infectivity to rice plants. Laboratory experiment to determine the effective dose of the selected fungi revealed that, spore suspension @107 and 108 spores mL-1of L. saksenae, caused 100 per cent mortality of L. acuta at 48 - 72 hours after treatment (HAT). Similar trend was observed in the case of the hoppers, N. nigropictus, N. nervosa and C. spectra, but for N. lugens it took 96 - 120 h. In the case of L. lecanii, @ 108 spores mL-1, 100 per cent mortality of N. lugens adults was recorded at 168 HAT, while only 76.67 per cent died in 107 spores mL-1 during the same time period. The time taken was extended upto 168 h for other hoppers. Comparison of median lethal concentration values of L. saksenae and L. lecanii on the sixth day after treatment, revealed that L. lecanii needed a tenfold increase in spore concentration (10 5spores mL-1), in all the susceptible insects, indicating higher virulence of the indigenous isolate. Lethal concentration to cause 90 percent mortality values further substantiates the improved virulence of L. saksenae (105spores mL-1), while for L .lecanii the value was hundred times higher (107spores mL-1). The LT50 of L. saksenae was 18.58 h and 17.58 h for adults and nymphs rice bug. Field evaluation of the bioformulations revealed that, chitin enriched formulation of L. saksenae was superior in terms of population of rice bug (1.33 bugs per five sweeps and five random hills plot-1) and yield (3.25 kg plot-1, plot size 2 x 2 m). Though the talc formulation of Metarhizium anisopliae (Metschnikoff) Sorokin was equally effective in reducing the population (1.67) there was no significant increase in yield (2.17 kg plot-1). Population of insect predators, viz. coccinellids, mirids, and reduviids did not vary significantly on third, seventh and fourteenth day after first spray and third and seventh day after second spray among the treated and untreated plots, the average population ranging from 0.67 to 4.67 per plot,. However, the population was significantly low (1.67, 1.33, and 1.00) in plots treated with Malathion 0.1% on the tenth day after first spay and tenth and fourteenth day after second spray. The count of predatory spiders and hymenopteran parasitoids did not vary significantly among the various plots throughout the experimental period. The study indicated that the indigenous isolate, L. saksenae is more virulent than the exotic isolate L. lecanii. Though L. lecanii could control the hopper pests in rice, it is non infective to the major pest, rice bug, which is effectively managed by chitin enriched formulations of L. saksenae. It is safe to natural enemies of rice ecosystem and non infective to rice plant. Hence, it can be an effective contender and suitable replacement to chemical pesticides for the management of sucking pests in rice.ThesisItem Open Access Endophytic association of entomopathogenic fungi with rice and cowpea(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2019) Divyashree, C; KAU; Reji Rani, O PThe study entitled ‘Endophytic association of entomopathogenic fungi with rice and cowpea’ was carried out in the Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, during the year 2017-19, with the objective to examine the endophytic association of entomopathogenic fungi in rice and cowpea. The entomopathogenic fungi, evaluated were Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Lecanicillium saksenae. They were tested through seven inoculation methods viz., seed coating, seed soaking, radicle dressing, root dipping, soil drenching, foliar spraying and bloom spraying by inoculating the conidial suspension at their effective doses. Among the four entomopathogenic fungi inoculated, B. bassiana, M. anisopliae and L. saksenae were found to colonise rice plants. B. bassiana was found to colonise in stem and roots, while M. anisopliae preferred stem. Both B. bassiana and M. anisopliae colonized effectively by seed soaking method. L. saksenae colonised in the stem and roots in seed soaking, in the roots in soil drenching and in the leaves in foliar spraying method. In plants, B. bassiana and M. anisopliae persisted up to 15th day after inoculation (DAI), while L. saksenae persisted till 45th DAI. In soil, L. saksenae persisted in soil up to 45th day, while other fungi could not be retrieved from soil. L. lecanii could not be retrieved from any of the plant parts or soil up to 45th DAI. Thirteen natural endophytes were isolated from rice, which included growth promoters with nitrogen fixing properties, gibberellic acid production properties, saprophytes and plant pathogens. They were identified with the help of colony and conidial characters. Those fungal endophytes whose identity could not be confirmed were characterised at molecular level through ITS sequencing, and bacterial endophytes through 16S sequencing. The most dominant endophyte in rice was the fungus, Neocomospora rubicola, a known plant pathogen followed by the nitrogen fixing bacterium Burkholderia cepacia. Colonisation of fungal bacterial association Sarocladium oryzae + Kosakonia sacchari was also dominant in the stem. S. oryzae is a known plant pathogen while K. Sacchari is a nitrogen fixing bacterium. The other endophytes with less frequency of occurrence were Pestalotiopsis microspora, Cladosporium sp., Microdochium fisheri, Fusarium solani, Aspergillus and Penicillium. Experiments in cowpea revealed that all the four fungi could successfully colonize different plant parts. Foliar spraying was the best method in cowpea to get endophytic association of all the four fungi, while M. anisopliae could also be retrieved through seed soaking and root dipping methods. B. bassiana, M. anisopliae and L. saksenae were found to colonise leaves, stem and roots, while L. lecanii colonised only on leaves. In cowpea plants, M. anisopliae and L. saksenae were found to be more persistent (up to 45th DAI), while B. bassiana and L. lecanii persisted only up to 30 DAI. Soil samples revealed the presence of B. bassiana, M. anisopliae and L. saksenae up to 15th, 30th and 45th DAI respectively. L. lecanii was not found to colonise soil. Grain samples in rice and bloom samples in cowpea did not reveal the presence of any endophytes. In cowpea, several natural endophytes were found to be stumped upon in different parts, which included four fungi and two bacteria. Apart from this a fungal bacterial association, Fusarium + Ebc 3 (unidentified bacterium) was found to be a dominant endophyte. The bacterium Rhizobium mayense isolated from all plant parts was the most dominant endophyte. The other endophytes isolated were the fungi, Cladosporium sp., Clonostachys rosea, Chaetomium globosum and Cerrena sp. and the bacterium Enterobacter cloacae. Rice plants inoculated by seed soaking, with the conidial suspensions of B. bassiana and M. anisopliae @ 108 spores ml-1 and L. saksenae @ 108 spores mL-1 reflected 28.79, 27.17 and 29.99 per cent increase height, 47.71, 44.75 and 47.92 per cent increase in biomass and 37.73, 36.97 and 39.89 per cent increase in grain yield, the highest values being those of L. saksenae and lowest being those of M. anisopliae. Incidence of rice bug assessed in terms of percentage of chaffy grains per panicle was significantly less in L. saksenae (14.21), while in B. bassiana it was 20.48 and in M. anisopliae, 21.61. There was no disease incidence in treated as well as control plants. It is concluded that B. bassiana, M. anisopliae and L. saksenae has endophytic association with rice and cowpea and L. saksenae is a strong endophyte.ThesisItem Open Access Field efficacy of biocapsules of entomopathogenic fungi for the management of vegetable pests(Department of Agricultural Entomology, College of Agriculture,Vellayani, 2022) Parvathy, Maloth; KAU; Reji Rani, O PThe study entitled “Field efficacy of biocapsules of entomopathogenic fungi for the management of vegetable pests” was conducted at the Biocontrol Laboratory for Crop Pest Management, Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, during the year 2018-2021. The objective of the study was to evaluate the efficacy of biocapsules of Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschnikoff) Sorokin, Lecanicillium lecanii (Zimmermann) Zare and Gams and Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno for the management of major groups of vegetable pests. The study also intended to standardize the dose of biocapsules in managing amaranthus leaf webber Spoladea (Hymenia) recurvalis F., okra shoot and fruit borer Earias vittella F. and cowpea aphid Aphis craccivora Koch. The biocapsules of fungi were formulated at a higher spore load of 1010 with HPMC coating and chitosan as carrier, following the protocol developed by Remya and Reji (2019). In the first field experiment to evaluate the efficacy of biocapsules in managing defoliators in amaranthus, it was revealed that, Metarhizium and Beauveria capsules @ 3 L-1 sprayed twice (at weekly intervals) was effective causing 83.69 and 69.97 per cent reduction in population of S. recurvalis respectively. Lower doses of 2 and 1 capsules L -1 were less effective causing, 47.39 to 66.5 per cent reduction in larval population. Spraying spore suspensions of these fungi @ 108 mL-1 resulted in 91.27 to 100 per cent reduction, while in flubendiamide 39.35 SC, it was 89.84 per cent. Treatment with Metarhizium and Beauveria capsules did not affect the natural enemy population significantly, the mean population being 2.33 to 3.67 plant-1 . The corresponding population was 1.44 in flubendiamide 39.5 SC and 3.67 in untreated control. The yield recorded in the plots treated with Metarhizium and Beauveria capsules @ 3 L -1 was high (2.67 and 2.30 kg plot-1 ) when compared to that in untreated plot 0.80 kg plot-1 . Results of the second experiment to evaluate the efficacy of biocapsules in managing fruit and shoot borer E. vittella in okra concluded that, Beauveria capsule @ 3 L -1 and Metarhizium capsule @ 3 L-1 were equally effective when sprayed at weekly intervals leading to 84.96 and 79.64 per cent reduction in the shoot damage respectively. The percentage reduction in shoot damage was only 65.32 to 73.86 per cent reduction in lower doses of capsules. In plots treated with spore suspensions, the mean shoot damage recorded was 90 to 95 per cent. Percentage reduction in chlorantraniliprole 18.5 SC was 90.71. Considering the fruit damage, Metarhizium capsule @ 3 L-1 was found to be the best treatment causing 100 per cent reduction in damage caused by E. vittella, while it was 89.75 per cent with Beauveria capsule@ 3 L -1 . Reduction in fruit damage ranged from 67.82 to 82.81 per cent in the lower doses of capsules. Highest reduction in the fruit damage observed with spore suspensions of Beauveria and Metarhizium @ 108 mL-1 (93.16 and 100 per cent, respectively). Similar results were obtained in the case of okra leaf roller, Metarhizium @ 2 L-1 and Beauveria capsule @ 3 L -1 were found to be the best treatment causing 96.38 and 85.80 per cent reduction in population of Sylepta derogata F., while it was 80.23 per cent with Metarhizium capsule @ 3 L-1 . Reduction in population ranged from 41.35 - 68.72 per cent in the lower doses of capsules. Highest reduction in the population of S. derogata observed with spore suspensions of Beauveria and Metarhizium @ 108 mL-1 (100 per cent). Percentage reduction in chlorantraniliprole 18.5 % SC was 93.41. Treatment with biocapsules capsules did not cause any adverse affect on natural enemy population, in okra field. The yield obtained from different treatments did not vary significantly. Third experiment in cowpea field revealed that, foliar application of L. saksenae capsule @ 3 L -1 and L. lecanii capsule @ 3 L-1 were equally effective to A. craccivora when sprayed twice (at weekly intervals) causing 94.38 and 92.28 per cent reduction in the population respectively. Reduction in population noted was 57.54 to 63.96 per cent with lower dose @ 2 capsules L-1 while it was least with single capsule treatment (37.51 to 44.73 per cent). The spore suspensions were more effective resulted than the lower doses (78.73 - 83.53 per cent reduction). The chemical check thiamethoxam 25 WG recorded 95.79 per cent reduction in population. Biocapsule treatment did not affect natural enemy population significantly. The yield recorded in the plots with L. saksenae capsules @ 2 and 3 L-1 was high (1.85 and 1.56 kg plot-1 ) when compared to other treated plots and untreated plot (1- 1.45 kg plot-1 ). Therefore, it is concluded that biocapsules of Metarhizium and Beauveria, can effectively manage defoliators in amaranthus and borers in okra and those of L. lecanii and L. saksenae can be recommended for pea aphids, without affecting the natural enemies and yield significantly.ThesisItem Open Access Mycotoxins and enzymes of entomopathogenic fungus lecanicillium saksenae (Kushwaha) kurihara and sukarno and their bioefficacy on crop pests(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2020) Sreeja, P; KAU; Reji Rani, O PLecanicillium saksenae an indigenous isolate from soils of Vellayani isolated by Rani et al. (2015) was reported to have high speed of kill in major hemipteran pests. Its quick insecticidal action prompted to profile its toxic metabolites. Therefore the study entitled ‘Mycotoxins and enzymes of entomopathogenic fungus Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno and their bioefficacy on crop pests” was carried out in the Department of Agrl. Entomology, College of Agriculture, Vellayani and Department of Agrl. Entomology, College of Horticulture, Vellanikkara during2016-2019. The objective of the study was to characterize the cuticle degrading enzymes and mycotoxins produced by L. saksenae and explore their potential for safer pest management. Qualitative assay revealed the presence of different cuticle degrading enzymes viz. chitinase, lipase, protease, chitosanase and amylase, with the Enzyme Indices 1.08, 4.3, 1.1, 1.36, and 1.57 respectively. Qualitative assay using pH indicator medium revealed high activity of chitin deacetylase. Quantitative assay carried out at two day interval for a period of 14 days revealed the peak activity of chitinase to the tune of 1.35 U mL-1 min-1, lipase 0.7 U mL-1 min-1, protease 4.89 U mL-1 min-1, chitosanase 0.26 U mL-1 min-1, amylase 23.42 U mL-1 min-1 and keratinase 73.61 U mL-1 min-1. The activity of Pr1 and Pr2, the key proteolytic enzymes were also detected to the tune of 0.22 U mL-1 min-1 and 0.32 U mL-1 min-1respectively. The peak activity period of these enzymes varied from 4th to 10th day of incubation, whereas the peak activity of Pr2 was on the 2nd day and that of keratinase was on the 40th day, in their respective minimal media with inducing substrates. The biomass reduction of 80.2 per cent in poultry feather substrate due to keratinase activity is notable. Bioefficacy studies of partially purified major cuticle degrading enzymes revealed that protease @ 100 μg mL-1 exhibited 71.79 per cent mortality of brinjal mealybug, Coccidohystrix insolita nymphs, 96 hours after treatment (HAT). The corresponding mortality with chitinase and lipase was 58.10 and 54.23 per cent respectively. These enzymes when applied in combination resulted in 78.79 per cent mortality. However, the efficacy of individual enzymes on adults was meagre and the combined application caused only 40.88 per cent mortality. Bioefficacy studies on the root knot nematode Meloidogyne incognita revealed its inhibitory action in the hatching of eggs. The hatching percentage was drastically reduced in chitinase (18.8%), protease (10.4%) and its combination (7.8 %), as against 70.80 per cent in absolute control. Scanning electron microscopy of the treated eggs exhibited uneven and shrunken surface with distinct lines of breakage on the outer vitelline layer, leading to disintegration of egg mass within five days of treatment. The predominant enzyme, protease was purified through Sephacryl G-100 column and DEAE-cellulose and was characterised with molecular weight 71 kDa by SDS - PAGE analysis. Spectral analysis of crude toxin extracted through standard procedures could detect an array of metabolites, of which the dominant one was purified and characterised. Ethyl acetate extraction of culture filtrate followed by vacuum evaporation and purification yielded 100 mg L-1 of the purified compound. Structural characterisation and identification of the metabolite through UV spectrometry, Fourier Transform Infrared spectrometry (FTIR), High Resolution Liquid Chromatography Mass spectrometry (HR-LCMS) and Nuclear Magnetic Resonance Spectrometry (NMR) unambiguously identified the metabolite as oosporein, the empirical formula of which was confirmed to be C14H10O8 and molecular weight, m/z 306.22. Dipicolinic acid (DPA), another volatile insecticidal metabolite was identified through LC-MS. Bioassay guided fractionation of crude toxin could identify a fraction that caused 64. 23 per cent mortality of C. insolita nymphs at 96 HAT. Spectral data of LC-ESI-MS analysis of this insecticidal fraction showed a strong signal for the ion of m/z 485.6 which was identified as beauverolide. One Strain Many Compounds (OSMAC) technology was carried out to detect multiple metabolites produced by L. saksenae. HR-LCMS and GC-MS analysis of the toxin extracts from various media, identified multiple metabolites whose bioactivity was determined using Dukes phytochemical and ethno botanical and PubChem databases. Of the bioactive metabolites, 22 were insecticidal, seven were nematicidal and 20 were antimicrobial. The dominant insecticidal metabolites other than oosporien, DPA and beauverolide were picolinic acid, cordycepin, anthranilic acid, dibutyl phthalate, hexadecanoic acid, harmine etc. while the major nematicidal metabolites were 2,6, pyridine dicarboxylic acid, 8-hydroxyl quinone, nicotinic acid, hexadecanoic acid, harmine etc. The predominant antimicrobial metabolites were vanillic acid, aminophenol, anthranilic acid, salisylamide, oleamide, terephthalic acid 4-H pyran-4-one, 2, 3, dihydro 3, 5 dihydroxyl 6- methyl, and and Dl-mevalonic acid lactone etc. The volatile compounds detected were hexadecanoic acid, octadecanoic acid, harmine. 2,6, pyridine dicarboxylic acid, 4H pyran-4-one, 2, 3, dihydro 3, 5 dihydroxyl 6- methyl, and Dl-mevalonic acid lactone. Bioefficacy studies of the purified toxin revealed a dose dependent mortality in C. insolita. Toxin at 1000 ppm caused 60.25 per cent mortality in nymphs, 96 HAT, whereas the corresponding mortality in adults was 51.00 per cent. However, the crude toxin caused 100 per cent mortality with the same concentration, justifying the multifaceted properties of the fungus in causing insect diseases. Probit analysis revealed LC50 value of 87.14 ppm in nymphs at 48 h whereas it was higher (193.61 ppm) in adults. Bioefficacy studies on J2 of M. incognita revealed the nematicidal potential of secondary metabolites of L. saksenae. At highest concentration of 250 ppm, mortality of 95.22 per cent was observed at 24 HAT whereas at 48 HAT, mortality was 100 per cent with 50 ppm and above. The study revealed the safety of crude toxin to different life stages of the coccinellid predator Cheilomenes sexmaculata . LC50 value for ovicidal activity was 69 fold higher than that of the pest (51.06 ppm at 96 h) while for grubs it was 79 times higher than that of pest. In silico molecular docking of the metabolites detected from L. saksenae revealed that 18 of them were interacted with acetylcholinesterase (AChE). Among these, 3-Hydroxy-2-methylpyridine exhibited the highest binding energy (-133.24 kcal mol-1) and therefore highest interaction with AChE. Metabolite profiling of L. saksenae revealed its potential entomopathogenic, nematicidal and keratin degrading properties. The study paves way to the possibilities of tapping the potential of the bioactive metabolites for safer pest management. It could be made use in leather industry and keratinous waste management as well.ThesisItem Open 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 PThe 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.ThesisItem Open Access Pests of cabbage (Brassica oleracea L var.capitata) and cauliflower (Brassica oleracea L.var.botrytis) and their management(Department of agricultural entomology, College of agriculture, Vellayani, 2013) Ravi, G B; KAU; Reji Rani, O PInvestigations on “Pests of cabbage (Brassica oleracea L. var. capitata) and cauliflower (Brassica oleracea L. var. botrytis) and their management” were carried out at College of Agriculture, Vellayani during 2011-13. The main objective of the work was to identify the pests and natural enemies associated with cabbage and cauliflower and to evolve pest management strategies. Analysis of pest fauna in cabbage and cauliflower revealed that the crops were attacked by eighteen pest species. The occurrence of pierid butterfly Appias lyncida Cramer on cruciferous crops is reported for the first time. The key pest affecting the crop grown in plains was the cut worm Spodptera litura (Fabricius) and in the hilly tracts it was Plutella xylostella (Linnaeus). Damage caused by S. litura was 30% in cabbage and cauliflower and that by P. xylostella was 38% to heads and 26 % to curds. Two coccinellid predators Chilomenes sexmaculata Fabr. and Coccinella transversallis Fabricius and the syrphid, Ischiodon scutellaris Fabricius were identified from the colonies of aphid, Lipaphis erysimi (Kaltenbach). One parasitoid, Protapanteles sp. was identified from larvae of Plusia signata Fab. Further investigations were focused on S. litura, the major pest in plains. Detailed studies on biology of the pest revealed high fecundity and survival percentage of all the life satges (80 -100), favouring high feeding potential and rapid buildup of population. S. litura incidence in cabbage reached the peak level at head fill stage (13WAP) in cabbage and in cauliflower the peak was observed at curd development stage (12WAP). Correlation studies of the population with weather parameters revealed that the pest and abiotic factors did not show any consistent association. The relative importance of different abiotic factors that acted upon the pest varied during the period. Preliminary screening of entomopathogens, botanicals and new generation insecticides undertaken under laboratory conditions revealed that, GE 2%, NSKE 5 %, SFE 10 % and the synthetic insecticides, indoxacarb 0.008%, and cypermethrin 0.03% were equally effective as the treated check, malathion 0.15%. Field studies conducted using the above selected treatments revealed that the reduction in population of S. litura was maximum with indoxacarb 0.008%, followed by cypermethrin 0.03% and the treated check, malathion 0.15%. Among the botanicals GE 2% was found to be the most effective in reducing the population, followed by 5% NSKE. Management of S. litura had a significant effect on yield of cabbage and cauliflower. Indoxacarb 0.008% resulted in 29.37 per cent increase in net yield of cabbage. The effect of cypermethrin 0.03%, malathion 0.15%, GE 2% and NSKE 5% were also noteworthy in increasing the yield by 23.07 to 28.35 per cent. In cauliflower, there was a yield increase of 53.38 to 60.07 per cent, indoxacarb 0.008%, cypermethrin 0.03%, malathion 0.15%, 10%, NSKE 5% and GE 2%. Samples analysed for residues, at the time of harvest revealed that the mean residue of indoxacarb 0.008%, and cypermethrin 0.03% were below detectable limit. From the above study it is concluded that, the key pest of cabbage and cauliflower grown in hilly tracts was DBM and that in the plains was S. litura. S. litura can effectively be managed by adopting management strategies in the true leaf, cupping and early head formation or curd initiation stages of these crops. Indoxacarb 0.008% and cypermethrin 0.03%, can safely be used as there was no residual problems. Considering the ecological and economic factors, spraying 2 % GE or 5 % NSKE is the safer.ThesisItem Open Access Potential of the narural bio polymers, chitin and chitosan in pest management(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Archana, N H; KAU; Reji Rani, O PThe investigation entitled “Potential of natural bio polymers, chitin and chitosan in pest management” was conducted at College of Agriculture, Vellayani during 2016-17 with an objective to evaluate the insecticidal properties of the natural biopolymers, chitin and chitosan for utilization in crop pest management. Various formulations tested were, chitin (3%, 5%, 7%), chitosan (3%, 5%, 7%), chitosan gel (3%, 5%, 7%), chitin based commercial formulation, Biorakshak 2% and chitosan based commercial formulation, Bioboost 2%. They were tested for their antifeedant, insecticidal, nematicidal and growth promoting properties by leaf dip method and spray methods in laboratory as well as by foliar spray and soil amendments in pot and field studies. Laboratory studies revealed that the pumpkin caterpillar, Diaphania indica Saunders, the leaf beetle Henosepilachna vigintioctopunctata F., pea aphid Aphis craccivora Koch, the root knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood. and the reniform nematode Rotylenchulus reniformis Linford and Oliveira were vulnerable to different chitin and chitosan based formulations whereas, the cut worm Spodoptera litura F. the leaf weevil, Myllocerus viridanus Schoenherr, the pod bug Riptortus pedestris F. and the spiral nematode Helicotylenchus sp. were not. All the formulations tested were safe to the coccinellid predators, Chilomenes sexmaculata F. and Coccinella transversalis F., the syrphid predators, Ischiodon scutellare F. and Xanthogramma scutellare Thorell. and the spiders Tetragnatha mandibulata Walckenaer and Tetragnatha maxillosa Thorell. Antifeedant effect was noticed only D. indica, chitosan 7% being the superior formulation with 43.25 per cent feeding inhibition on first day which decreased to 13.30 per cent on the fourth day. Insecticidal activity was noticed in H. vigintioctopunctata, chitosan gel 7%, being the best treatment causing 100 per cent mortality on seventh day, followed by Bioboost 2% (93.33 per cent mortality). In A. craccivora, chitin 7% caused 100 per cent mortality on fifth day while Biorakshak 2% recorded 91.66 per cent mortality. Nematicidal effect was noticed in M. incognita and R. reniformis. In M. incognita hatching was reduced by 66.6 per cent for chitosan 5% and chitosan 7%, followed by chitin 7% (53.34 per cent). The juveniles (J2) were highly susceptible to all the formulations at 7% causing 100 per cent mortality on second day. Chitin 7% caused 78.54 per cent mortality in R. reniformis on third day. Pot culture studies revealed that, in brinjal, H. vigintioctopunctata population was lowered in plants treated with chitosan gel 7% and chitosan 7%, the population being 2.86 and 4.83 at seven days after treatment (DAT), while in control it was 9.09 per plant. Incidence of M. viridanus and Aphis gossypii Glover was also less in plants treated with chitosan 7% and chitosan gel 7%. The plant height, number of leaves and branches and were also more in the treatment, chitosan gel 7%. Highest yield was recorded in chitosan 7% (149.69 g plant-1 harvest-1). In cowpea, A. craccivora population was significantly reduced (32.97) in plants treated with chitin 7% while in control it was 197.98 at seven DAT. Plants treated with chitin 7%, chitosan gel 7% and Biorakshak 2% showed less damage of mite, Tetranychus sp. Chitin 7% was the best treatment that favored the growth parameters in cowpea. In tomato, M. incognita population in soil was least in plants treated with chitin 7% and chitosan 7% (36 and 52.13) where as in root samples it was least (278.66) in chitin 7% treated plants. Incidence of Liriomyza trifoli Burgess and cercospora leaf spot was also less in these treatments. Field experiment on cowpea revealed that, chitin 7% took seven days to reduce the population of A. craccivora (164.82 plant-1), followed by chitosan 7% and chitosan gel 7% (189.62 and 214.4 respectively), while in plots treated with dimethoate 30EC @ 0.2% there was complete control. Yield plot-1 was 1.76 kg in chitin 7% and it was 1.8 kg in dimethoate 30EC @ 0.2%. In the field trial on tomato, population of nematodes in soil and root sample were less in plots treated with chitin 7% (152.5, 38.75) than in control plots (532.75, 123.75), while in chemical treatment with cartap hydrochloride 4G @ 1 kg a.i.ha-1 it was 72.25 and 5.5 respectively. The incidence of L. trifoli was less in chitin 7% treated plants and that of leaf curl virus was less in treated plants when compared to control. Significantly high yield was noted with crude chitin 7g kg-1 (2.39 kg plot-1) compared to control (1.10 kg plot-1). The study indicated that the potential of natural biopolymers chitin and chitosan can be exploited for the holistic management of crop plants as it has capacity to regulate the population of insect and nematode pests as well as plant diseases. The growth and yield promoting attributes and safety to natural enemies makes them ideal candidates in integrated pests and disease management as well as integrated nematode management programmes.ThesisItem Open Access Tablet formulation of entomopathogenic fungus and its bioefficacy in mosquito control(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2022) Neema, Dileep; KAU; Reji Rani, O PThe research work entitled ―Tablet formulation of entomopathogenic fungus and its bioefficacy in mosquito control‖ was conducted at Biocontrol Laboratory for Crop Pest Management, Department of Agricultural Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, during the year 2019-2021 with an objective to develop water dispersible tablets of entomopathogenic fungus and to test their effectiveness in managing mosquitoes. Pathogenicity studies carried out using 108 spores mL-1 of Metarhizium anisopliae (Metsch.) Sorokin NBAIR isolate Ma4, Beauveria bassiana (Bals.) Vuillemin NBAIR isolate Bb5, B. bassiana KAU isolate ITCC 6063 and 107 spores mL-1 of Lecanicillium lecanii (Zimmerman) Zare and Gams NBAIR isolate Vl 8 and Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno KAU isolate ITCC – 7714, revealed that all the fungi tested were infective to Anopheles, Aedes and Culex at varying levels. Infected larvae were less active at 12 hour after treatment (HAT) with sinking movement and colour change from dark grey to white. Death occurred within 24 h, with degeneration of gut. Copious amount of mucus was noticed around the body, except in L. saksenae. Infected adults were inactive and died within 24 h. The cadavers were mummified and found attached to the walls of the container. In Ma4 treated adults, white mycelial growth which turned green upon sporulation was noted 72 h after death. Observations on mortality taken at 24 h interval revealed that, M. anisopliae was the most effective fungus for mosquito control, followed by B. bassiana isolates. Lecanicillium spp. were less effective to mosquitoes. M. aniospliae was found to be superior to the biocontrol check, Bti and equivalent to the chemical check malathion 50 EC based on larval mortality. Mortality recorded by M. anisopliae was 93.33, 96.66 and 100 per cent in Anopheles, Aedes and Culex respectively, 5 days after treatment (DAT), while in Bti it was 73.33, 66.66 and 70 per cent respectively. The corresponding mortality in malathion 50 EC was 100 per cent. Based on mortality recorded in adults, M. anisopliae (83.33 and 86.66 per cent mortality) was equally effective as Bti to Anopheles and Aedes (66.66 and 76.66 per cent mortality) but inferior to malathion 50 EC that recorded complete mortality. The mortality recorded 112 in Culex was 96.66 per cent, which was on par with that recorded in malathion 50 EC (100 per cent). Dose-mortality studies of M. anisopliae on 4th instar larvae, revealed that 108 spores mL-1 was the effective dose. The LC90 values for M. anisopliae was 106 in Anopheles, Aedes and Culex. The LT90 values were 90.33, 79.46 and 55.9 h on Anopheles, Aedes and Culex, revealing that Culex is the most susceptible species. Larva was found to be the most susceptible stage for Culex, while for Anopheles and Aedes, both larva and adult were equally susceptible, whereas pupa was the least susceptible stage for all the three species. Experiment to standardize the carrier material for M. anisopliae tablets, revealed that talc + chitosan (90:10) was superior to bran, talc and bran + chitosan, as there was 71.16 per cent conidial germination and 95 per cent larval mortality in Culex on the 5th week after storage (WAS). The corresponding viability and virulence in talc were 66.33 per cent and 87.5 per cent respectively, while in bran it was 43.16 and 70 per cent and in bran + chitosan, it was 47.58 and 80 per cent, respectively. Among the binding agents tested, Carboxy Methyl Cellulose (CMC) 7% was superior to Microcrystalline Cellulose (MCC) 7%, Polyvinyl Pyrrolidone (PVP) 5% and Acacia Gum Arabic (AG) 5% as it maintained 62.66 per cent germination and 95 per cent mortality on 5 WAS. The tablets of M. anisopliae @ 1010 spores mL-1, formulated using talc + chitosan + CMC 7% at varying moisture levels of 8, 10 and 15 % when subjected to shelf life studies revealed that tablets formulated at 15 % were superior in viability (65.06 per cent) and virulence (88 per cent mortality) at 8 WAS. Thereafter, though there was a decrease in germination rate below 60 per cent, the virulence could be maintained up to 72 per cent till three months of storage. Extent of contamination noticed was significantly high (105 cfu mL-1) in 15 % moisture compared to 104 in 8 and 10 % moisture levels. However, 105 being the permitted level of contaminants as per CIBRC standards, 15% was fixed as the ideal moisture content for formulating tablets. The effective shelf life was therefore determined as three months under ambient conditions. 113 The tablets when tested for their bioefficacy to Culex larvae revealed that 3 and 4 tablets L-1 were equally effective causing 82 and 83 per cent mortality within 9 DAT, under laboratory conditions. The adult emergence from the treated larvae was 17 and 16 per cent for 3 and 4 tablets L-1, which was significantly lower than that from control (81 per cent). Under field conditions, 9 and 10 tablets 10 L-1 exhibited similar level of mortality (83.97 and 84.1 per cent) compared to 7 and 8 (75.03 and 79.59 per cent). Therefore 9 tablet 10 L-1 was fixed as the effective dosage for treating stagnant water bodies. It is concluded that water dispersible tablets of M. anisopliae formulated at 1010 spores mL-1 with talc + chitosan + CMC (7%) at 15% moisture is effective for the management of mosquito larvae in stagnant water bodies @ 9 tablets 10 L-1. They can be stored effectively for three months with 72 per cent virulence, under ambient conditions.