1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Pellet formulations of entomopathogenic fungi and their bioefficiacy in managing soil inhabiting pests(Department of Entomology, College of Agriculture,Vellayani, 2024-02) Asna Sharin.; Reji Rani, O PThe study entitled “Pellet formulations of entomopathogenic fungi and their bioefficacy in managing soil inhabiting pests” was carried out at Department of Entomology, College of Agriculture, Vellayani during the year 2020-2023 with an objective to develop biopellet formulations of entomopathogenic fungi for the management of soil inhabiting insect pests. Pathogenicity test carried out in soil inhabiting pests such as pepper root mealy bug, Formicoccus polysperes Williams and later stages of cucurbit fruit fly, Bactrocera cucurbitae (Coquillett) using spore suspensions of entomopathogenic fungi such as Metarhizium anisopliae (Metsch.) Sorokin NBAIR isolate Ma4, Beauveria bassiana (Bals.) Vuillemin NBAIR isolate Bb5, B. bassiana KAU isolate ITCC 6063 and Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno KAU isolate ITCC 7714 each at 108 spores mL-1 revealed that all the tested fungi were infective to pepper root mealybug, at varying levels. Apart from the normal symptoms of mycosis, L. saksenae infection resulted in sudden dissolution of the mealy coating, unlike in B. bassiana isolates, indicating its fast action. For the last instar larvae and pupae of cucurbit fruit fly, M.anisopliae was found to be the effective pathogen compared to B.bassiana isolates. Infectivity of L. saksenae was very low in fruit fly. Dose-mortality response of L. saksenae to root mealybug, F. polysperes unveiled that 107 and 108 spores mL-1 were equally effective resulting in 92 and 100 per cent mortality within four days of treatment, hence 107 spores mL-1 was determined as the effective dose. In the case of B. cucurbitae, the effective dose was 108 spores mL-1 for both larvae and pupae causing 77.5 per cent and 55 per cent mortality, respectively. The LC50 and LC90 values of L. saksenae computed on the fourth day after treatment on root mealy bug was 2.2x105 and 2.6x107 spores mL-1, respectively. The lethal time recorded for 50 per cent mortality was 23.13 h and for 90 per cent mortality it was 83.76 h, indicating its high virulence. In fruit fly larvae, for M. anisopliae, the LC50 and LC90 values were 2.5x106 and 6.6x108 spores mL-1, respectively on the 10th day after treatment, indicating a moderate virulence. Experiment to assess the effect of carrier materials on conidial viability and virulence of L. saksenae based on its germination percentage and mortality to test 125 insects revealed the superiority of the talc + chitin in the ratio 95:5 with 78.54 per cent germination and 87.5 per cent mortality of mealybugs even five weeks after storage (WAS). Other carrier materials such as talc + chitosan (90:10), talc alone and chitosan alone, exhibited only 50.62 to 74.58 per cent germination and 55.0 to 67.5 per cent mortality. The spores in chitin exhibited only 33.96 per cent viability and 50 per cent mortality. Based on conidial viability the best carrier material for formulating M. anisopliae pellets was found to be talc + chitosan in the ratio 90:10 as it recorded highest conidial viability (69.75 per cent) 5 WAS and mortality of 32.5 per cent, to the 3rd instar larvae of B. cucurbitae. When talc and talc + chitin (95:5) were used as the carrier materials the corresponding viability and mortality recorded were 61.46 to 65 and 7.5 to 20 per cent. Suitability of binding agents for formulating L. saksenae pellets was tested using various binders such as Carboxy Methyl Cellulose (CMC) 6%, Microcrystalline Cellulose (MCC) 6% and Acacia Gum arabic (AG) 5%. It was found that the combination of talc + chitin (95:5) + the binding agent CMC (6%) was superior for L. saksenae spores compared to its combination with MCC (6%) and AG (5%). CMC maintained 80.63 per cent germination and 92 per cent mortality on five WAS. The corresponding viability and mortality recorded in MCC was 51.5 and 68 per cent and in AG, it was 30.67 and 50 per cent, respectively. CMC was proved to be superior for formulating M. anisopliae pellets also, as it recorded 79.33 per cent germination and 42 per cent mortality on fifth WAS. Pellets formulated at 109 spores mL-1, using a mixture of talc + chitin (95:5) + CMC 6% were tested at varying moisture levels of 8, 10, 12 and 15%. Pellets with 15% moisture content were superior with 67.44 per cent conidial viability and 80 per cent virulence, when observed after two months. Thereafter, though there was a decrease in germination rate below 55 per cent, the virulence could be retained up to 60 per cent till three months after storage. L. saksenae pellets stored for a period of three months under ambient conditions revealed that the shelf life declined gradually after two months. After three months, conidial viability of pellets reduced from 87.25 to 38.74 per cent at 15 % 126 moisture level and from 84.99 to 32.32 per cent at 12% moisture. The mortality decreased from 90 to 60 per cent and 85 to 45 per cent in 15% and 12 % moisture levels, respectively. However, the extent of contamination noted was 2.75x105 cfu mL-1 which was beyond the permissible level as per CIBRC standards. Therefore, the pellets prepared with moisture content between 12 to 15 % where the contaminant count was within the permissible limit, 1.2x104 cfu mL-1 was fixed as ideal for pelleting. Laboratory assay carried out to standardize the dosage of L. saksenae biopellets for managing root mealybugs revealed that, 1.0 (2 pellets), 1.5 (3 pellets), 2.0 (4 pellets) and 2.5 g (5 pellets) biopellets per 100 g of soil were found to be equally effective causing 75 to 82.5 per cent mortality, two WAT. On further evaluation under pot culture, after 4 weeks of treatment the dosage 1.5 g/100g was found to be superior (74.99 per cent mortality). The corresponding mortality in chlorpyriphos 20 EC @ 0.075% was 83.33 per cent. A comparison of population density in different treatments revealed that, L. saksenae was the superior treatment as it was on par with chlorpyriphos 20 EC (0.075%). There was no population buildup upto two weeks after treatment. Hence, the dosage for pot application was fixed as 1.5 g bio pellets for 100 g of soil. The study concluded that L. saksenae biopellets, formulated at 109 spores mL-1 using talc + chitin (95:5) + 6% CMC at 12% to 15% moisture level is effective for the management pepper root mealybugs at 1.5 g of bio pellets (3 pellets) for 100 g of soil. These biopellets can be stored for a period of three months, under ambient conditions.Item Bioefficacy of entomopathogenic fungi against cassava mealybug, phenacoccus manihotti matile-ferrero (Hemiptera: Pseudococcidae)(Department of Agricultural Entomology, College of Agriculture,Vellanikkara, 2024-02-21) Fasna, Sherin, K.; Smitha Ravi; Gowri PriyaCassava mealybug (CMB), Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) is a major insect pest of cassava. It causes severe damage by stunting the growth points of cassava plants, sometimes totally defoliating the plants. Level of infestation and yield loss by cassava mealybug varied from 30 to100 and 30 to 90 per cent respectively. In India, the occurrence of this pest was first noticed on cassava in Thrissur, Kerala during April 2020. Control of mealybugs commonly relies on the use of insecticides. But, it is difficult to control mealybugs using insecticides, due to their cryptic life cycle, presence of waxy coating, and formation of dense colonies. Management of insect pests using entomopathogens has received considerable importance in recent times. As part of AICRP programme of 2020-22, AICRP on BCCP, Thrissur centre conducted survey in cassava growing fields of Thrissur and Palakkad district to assess the species composition of mealybugs, damage intensity and associated natural enemies. During the survey, mycosed cadavers were collected and seven isolates of entomopathogenic fungi were obtained. Out of seven, five entomopathogenic fungal isolates were selected, characterized and evaluated under the present study entitled “Bioefficacy of entomopathogenic fungi against cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae)”. The identity of five isolates was confirmed through morphological, cultural and molecular characterization. The fungal isolates were identified as two isolates of Simplicillium aogashimaense (EPF 2 and EPF 4), two isolates of Purpureocillium lilacinum (EPF 3 and EPF 7) and one isolate of Lecanicillium psallioate (EPF 5). Pathogenicity of these fungal isolates was tested against second instar nymphs of cassava mealybug, P. manihoti in the laboratory. A preliminary screening bioassay was carried out initially, and the superior isolates were subjected to dose-response and exposure-time response bioassay. In the preliminary screening bioassay, P. lilacinum isolates (EPF 7 and EPF 3) recorded more than 90.0 per cent mortality. S. aogashimaense (EPF 4) and L. psalliotae (EPF 5) registered mean mortality of 82.5 and 75.0 per cent respectively. S. aogashimaense (EPF 2) recorded the lowest mortality of 70.0 per cent, which was significantly lower than all other isolates. The best four isolates in the pre-screening were subjected to dose-response and exposure time- response bioassay. Spore suspensions of five different concentrations ranging from109 to 105 spores ml-1 were tested against mealybug. Ten days after treatment, two isolates of P. lilacinum (EPF 7 and EPF 3) recorded more than 80.0 per cent reduction in population of mealybug at the concentration of 109 spores ml-1 . The same isolates showed low LC50 and LT50 values. Efficacy of these two superior isolates of P. lilacinum (EPF 7 and EPF 3) at concentration of 1×108 spores ml-1 was evaluated in a pot culture experiment. The isolates were compared with a standard biocontrol check, NBAIR isolate of Lecanicillium lecanii @ 1×108 spores ml-1 , a botanical insecticide (neem oil emulsion @ 2%) and a chemical insecticide, dimethoate 30 EC @ 1.5 ml L-1 . Maximum reduction in the mealybug population was observed in dimethoate treated plants (99.86%). Even though, the neem oil emulsion (2%) showed significant effect on mealybugs, certain signs of phytotoxicity were observed in treated plants. Among three fungal isolates, significantly higher reduction in population was observed in P. lilacinum, EPF 7 (78.55%) followed by P. lilacinum, EPF 3 (74.92%), and both being on par with each other. In conclusion, the present study revealed that biological control of cassava mealybug, P. manihoti using two promising isolates of P. lilacinum could be a viable component in the integrated pest management. Two rounds of foliar application of any of the two isolates of P. lilacinum (EPF 3 and EPF 7), at 15 days interval at the dosage of 1×108 spores ml-1 was found effective against cassava mealybug, P. manihoti.Item Microbial formulations for the management of spodoptera litura F.(Department of agricultural entomology, college of agriculture , Vellayani, 2023-06-30) Hari Sanker S S.; Faizal, M HThe present study entitled “Microbial formulations for the management of Spodoptera litura F.” was conducted in the Department of Agricultural Entomology, College of Agriculture, Vellayani during 2018-2022 with an objective to develop ecofriendly, biologically based formulations comprising of entomopathogenic fungi (EPF) and nuclear polyhedrosis virus (NPV) in plant derived carrier materials for the management of the polyphagous pest S. litura.Item Field efficacy of biocapsules of entomopathogenic fungi for the management of vegetable pests(Department of Agricultural Entomology, College of Agriculture,Vellayani, 2022) Parvathy Maloth; 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.Item Novel bioformulations of entomopathogenic fungi and their efficacy aganist banana weevils(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Remya, S; Reji Rani, O PItem Management of banana pseudostem weevil, Odoiporus longicollis (Olivier), using safe chemicals and bio-rational methods(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2017) Sivakumar, T; Jiji, TItem 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 t, 2019) Keerthana, K; Reji Rani, O PItem Management of sucking pest complex in chilli using botanical and microbial pesticides(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Priyatha Sundaran, C; Faizal, M HItem Bioefficacy of the acaropathogen, acremonium zeylanicum (petch) gams and evans against the spider mite, tetranychus truncatus ehara (acari: tetranychidae)(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2017) Alka Sherief; Haseena BhaskarItem Population dynamics, biology and management of mealybug, phenacoccus solenopsis tinsley (Hemiptera: pseudococcidae) on okra(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2017) Anusree Padmanabhan, P S; Mani Chellappan