This research was conducted to evaluate biocontrol potential of Isaria fumosorosea, isolated from naturally infected Beauveria bassiana from greeenhouse. Several studies are conducted 1) identification based on morphological characteristics and genetic analysis, 2) host specificity, 3) optimum formu...
This research was conducted to evaluate biocontrol potential of Isaria fumosorosea, isolated from naturally infected Beauveria bassiana from greeenhouse. Several studies are conducted 1) identification based on morphological characteristics and genetic analysis, 2) host specificity, 3) optimum formulation using natural oil based emulsifiable adjuvant oils and their combination, 4) field evaluation for the control of B. tabaci in greenhouse. Entomopathogenic fungal strain I. fumosorosea were isolated from a greenhouse in SeongJu, Gyeonbuk province where adult of B. tabaci were found heavily infested. The cause of massive infection were interpreted as a result of several factors, but mainly in favorable weather conditions, lower temperature(by 5℃), constantly high relative humidity condition(90%), minimal pesticide application. Group of infected B. tabaci were found leaves of oriental melon(Cucumis melo var makuwa), and cansal agent were identified as entomopathogenic fungus, I. fumosorosea. The establish of such a massive infection cold involve number of circumstances, such as weather, greenhouse condition, stage of insect and host creeping crop, host plant, stage of insect, and host specificity. Morphological chararacteristics such as phialade, shape and number of condiospore were the main Key for the identification of this genus along with candelabra typed philalide. All of morphological characteristics based on Humbler’s classification key and analysis of ITS and 5.5S rDNA, indicated the isolated entomopathogenic fungus were Isaria fumosorosea. LC50 values of I. fumosorosea IFs-08 on B. tabaci were 1.0×108conidia/㎖ at 3, 4, 5, and 6 day after inoculation were 2.51×109, 6.31×107, 3.17×105 and 1.26×105conidia/㎖, respectively. Each LT50 value of 1.0×108, 1.0×107, 1.0×106, 1.0×105 and 1.0×104conidia/㎖ spore suspension were 3.2, 4.3, 4.9, 7.0, and 8.9 days confirming high insecticidal efficacy. When spore suspension was applied to different growth stage of B. tabaci, LT50 values were 3.0, 3.0, 3.7 and 16.0 for 1, 2~3, 4th stage nymph, and eggs, respectively. It is suggested that older stage is more resistance to I. fumosorosea IFs-08. And it has hardly effective on eggs. I. fumosorosea IFs-08 was penetrated into epidermis or genital organs with hyphae transformed from germ tube but not with appressorium. The period of spore reproduction from killed B. tabaci was 9.9±0.2 days. Proper temperature of spore germination and hyphal growth was 24~27℃, and showed better growth at high temperature(35℃) than low temperature(15℃) leading to possible of adaptation to high temperature. Infection rate to B. tabaci was increased with period exposed to over 90% relative humid. 90% The mortal rate at 18, 24, 36, 48 hours after inoculation under 90% relative humid was 7, 40, 49, and 64%, respectively. First infection under 90% humid was occurred at 18 hours after inoculation and remarkably increased after 48 hours As a emulsifiable adjuvant oils, which based on oil in water based formulation, emulsifying agent Q2-5211 showed better spore germination than Silwet-L77, Triton X-100 for I. fumosorosea IFs-08 strain. Among natural oil, paraffin and kerosine oil give better spore germination results than other plant oils. Spore germination assay for emulsifiable Adjuvant oils combination, formulation of paraffin 50%+kerosine 50% is 99.5% of spore germination which is similar on positive control, water(Q2 0.02%), and next is kerosine 50%+olive oil 50% and paraffin 50%+olive oils 50%, 97.9% and 96.8% of germination rate, respectively. Lethality for B.t. were higher in all of emulsifiable adjuvant oils formulations than water control treatment. Paraffin+kerosine combination showed 100% of lethality and kerosine+olive is 91.5% and paraffin+olive is 96% of lethality. In preservation test of formulated I. fumosorosea IFs-08 spore, in 25℃ for 1 month conservation, all of combinated formation showed 70% of spore survivability and in 25℃ for 2 month conservation, paraffin+kerosine combination showed a bit of better spore survivability and after 3 month at 25℃ condition, all of combination resulted in lower than 60% of spore survivability. And phytotoxicities were not observed in all of combination. In field assay of formulated I. fumosorosea IFs-08, control value of first spraying treatment is 77 and 71% for paraffin+kerosine form. and kerosine+olive form. respectively and which were 15% higher than Q2 0.02% in water control treatment(54% of control value). And control value of second spraying treatment is 86 and 74% for paraffin+kerosine form. and kerosine+olive form. respectively and which were 20% higher than Q2 0.02% in water control treatment(52% of control value). When comparing control value of the first spraying treatment and second spraying treatment, second spraying treatment increased 5% but, it were not significant statistically.
This research was conducted to evaluate biocontrol potential of Isaria fumosorosea, isolated from naturally infected Beauveria bassiana from greeenhouse. Several studies are conducted 1) identification based on morphological characteristics and genetic analysis, 2) host specificity, 3) optimum formulation using natural oil based emulsifiable adjuvant oils and their combination, 4) field evaluation for the control of B. tabaci in greenhouse. Entomopathogenic fungal strain I. fumosorosea were isolated from a greenhouse in SeongJu, Gyeonbuk province where adult of B. tabaci were found heavily infested. The cause of massive infection were interpreted as a result of several factors, but mainly in favorable weather conditions, lower temperature(by 5℃), constantly high relative humidity condition(90%), minimal pesticide application. Group of infected B. tabaci were found leaves of oriental melon(Cucumis melo var makuwa), and cansal agent were identified as entomopathogenic fungus, I. fumosorosea. The establish of such a massive infection cold involve number of circumstances, such as weather, greenhouse condition, stage of insect and host creeping crop, host plant, stage of insect, and host specificity. Morphological chararacteristics such as phialade, shape and number of condiospore were the main Key for the identification of this genus along with candelabra typed philalide. All of morphological characteristics based on Humbler’s classification key and analysis of ITS and 5.5S rDNA, indicated the isolated entomopathogenic fungus were Isaria fumosorosea. LC50 values of I. fumosorosea IFs-08 on B. tabaci were 1.0×108conidia/㎖ at 3, 4, 5, and 6 day after inoculation were 2.51×109, 6.31×107, 3.17×105 and 1.26×105conidia/㎖, respectively. Each LT50 value of 1.0×108, 1.0×107, 1.0×106, 1.0×105 and 1.0×104conidia/㎖ spore suspension were 3.2, 4.3, 4.9, 7.0, and 8.9 days confirming high insecticidal efficacy. When spore suspension was applied to different growth stage of B. tabaci, LT50 values were 3.0, 3.0, 3.7 and 16.0 for 1, 2~3, 4th stage nymph, and eggs, respectively. It is suggested that older stage is more resistance to I. fumosorosea IFs-08. And it has hardly effective on eggs. I. fumosorosea IFs-08 was penetrated into epidermis or genital organs with hyphae transformed from germ tube but not with appressorium. The period of spore reproduction from killed B. tabaci was 9.9±0.2 days. Proper temperature of spore germination and hyphal growth was 24~27℃, and showed better growth at high temperature(35℃) than low temperature(15℃) leading to possible of adaptation to high temperature. Infection rate to B. tabaci was increased with period exposed to over 90% relative humid. 90% The mortal rate at 18, 24, 36, 48 hours after inoculation under 90% relative humid was 7, 40, 49, and 64%, respectively. First infection under 90% humid was occurred at 18 hours after inoculation and remarkably increased after 48 hours As a emulsifiable adjuvant oils, which based on oil in water based formulation, emulsifying agent Q2-5211 showed better spore germination than Silwet-L77, Triton X-100 for I. fumosorosea IFs-08 strain. Among natural oil, paraffin and kerosine oil give better spore germination results than other plant oils. Spore germination assay for emulsifiable Adjuvant oils combination, formulation of paraffin 50%+kerosine 50% is 99.5% of spore germination which is similar on positive control, water(Q2 0.02%), and next is kerosine 50%+olive oil 50% and paraffin 50%+olive oils 50%, 97.9% and 96.8% of germination rate, respectively. Lethality for B.t. were higher in all of emulsifiable adjuvant oils formulations than water control treatment. Paraffin+kerosine combination showed 100% of lethality and kerosine+olive is 91.5% and paraffin+olive is 96% of lethality. In preservation test of formulated I. fumosorosea IFs-08 spore, in 25℃ for 1 month conservation, all of combinated formation showed 70% of spore survivability and in 25℃ for 2 month conservation, paraffin+kerosine combination showed a bit of better spore survivability and after 3 month at 25℃ condition, all of combination resulted in lower than 60% of spore survivability. And phytotoxicities were not observed in all of combination. In field assay of formulated I. fumosorosea IFs-08, control value of first spraying treatment is 77 and 71% for paraffin+kerosine form. and kerosine+olive form. respectively and which were 15% higher than Q2 0.02% in water control treatment(54% of control value). And control value of second spraying treatment is 86 and 74% for paraffin+kerosine form. and kerosine+olive form. respectively and which were 20% higher than Q2 0.02% in water control treatment(52% of control value). When comparing control value of the first spraying treatment and second spraying treatment, second spraying treatment increased 5% but, it were not significant statistically.
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#곤충병원성 진균 Isaria fumosorosea 담배가루이 생물적 방제원
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