• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.117-125
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• 2023

Outbreaks of Ramulus mikado (Insecta: Phasmatodea: Phasmatidae) in the hilly areas of Mt. Bongsan, Mt. Cheonggye, and elsewhere in Seoul and Gyeonggi occurred from 2020 to 2021, causing serious defoliation. We evaluated the insecticidal effects of six eco-friendly organic materials and the insect-pathogenic fungus Metarhizium anisopliae against R. mikado. The fungus was isolated from naturally dead bodies of R. mikado in forest ecosystems. The results revealed that three eco-friendly organic materials containing azadirachtin or geraniol as active ingredients showed high mortality in the range of 85.2%-100%, which were rates similar to that of the chemical insecticide fenitrothion emulsifiable concentrate. All R. mikado adults that were sprayed with a conidial suspension of M. anisopliae at different concentrations were killed within a few days. In conclusion, three eco-friendly organic materials and M. anisopliae could be good alternatives to chemical insecticides.

• Journal of Sericultural and Entomological Science
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• v.4
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• pp.69-78
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• 1965

1. In younger larval stages, the incubation period of Spicaria pracina was showed to generally last for 8 days after the inoculation of 1st instar, for 11 days after that of 2nd instar, and for 12 days after that of 3rd instar. 2. The more the inoculum of spore is, the more silkworm jundices appear severely throughout all stage except 1st instar. 3. Especially in matured larval stages, more death rate due to silkworm jundice was showed to appear than that due to green muscardine and the more the larvae became mature, the more the loss due to jundice were severe. 4. Among other inoculum, the control by 5 per cent cerisan lime resulted in getting the best economical effect while this chemicals did harm to the silkworms, being of 20.1 per cent death rate.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.73-79
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• 2020

Metarhizium anisopliae is one of the entomopathogenic fungi infecting Protaetia brevitarsis seulensis. Environmental conditions strongly affect the virulence of entomopathogenic fungus. To test the susceptibility of P. brevitarsis seulensis larvae to M. anisopliae, we determined level mortality rates under different rearing conditions: temperatures (20℃, 25℃, 30℃), relative humidities (RH; RH 40%, 50%, 60%, 70%), and water content in sawdust (40%, 50%, 60%). The mortality rate of larvae treated with 5×10⁶ conidia mL^-1 M. anisopliae was not significantly affected by rearing temperature, but was affected by low RH (40%) and low water content in sawdust (40%), both of which resulted in high mortality rates. Mortality rated among M. anisopliae-treated 1^st, 2^nd, and 3^rd instar larvae were highest in 1^st instar larvae.

• Korean Journal of Microbiology
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• v.36 no.2
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• pp.97-102
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• 2000

In order to use Metarhizizmn~ anisopliae as a biological pesticide, effect of envrionmental factors on nlycelial growth, spore formation, and extracellular enzyme activity in culture broth of M. anisopliae DGUM 35001 was determined. Optimal temperature was 26^{\circ}C.$ and optimal pH ranged from 5 to 9. Among the complex media tested, MCM and SDPY media were the most favorable for mycelial growth. When Czapek-Dox agar was used as a mnimal medium, glucose and sucrose among the saccharides were very excellent source of carbohydrate. Among the biopolyners tested. chitin was the most favorable source for mycelial growth and produced high aerial inycelia. Urea and ammonium phosphate as an inorganic nitrogen source and bacto-peptone and soytone as an organic nitrogen source enhanced the mycelial growth When serine as a source of amino acid was supplemented, excellent mycelial growth was shown. Large amount of spores could be obtained from the aerial mycelia of starch medium. When the culture broth was filtrated and then the concentrate with ammonium sulfate was used as a crnde enzyme solution, high enzyme activities of amylase and protease were shown. However, lipase and chitinase activities were comparatively low.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.454-459
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• 2013

Beet armyworm, Spodoptera exigua is difficult to control using chemical insecticides because of the fast development of insecticide resistance. For eco-friendly beet armyworm managements, various control agents are required. Entomopathogenic fungus is one of the promise control agents as an alternative to chemical control agent. We isolated entomopathogenic fungi from soil samples of Yangpyeong, Gyeonggi-do by insect-bait method using Tenebio molitor and conducted bioassay to larva of beet armyworm. The result of bioassay, a selected strain FT83 showed 100% mortality against third instar larva of S. exigua. On the basis of morphological characteristics and analysis of 18srRNA sequence for ITS, the strain FT83 was identified as a Metarhizium anisopliae. The mortality of beet armyworm showed $81.6{\pm}9.3%$ at $1{\times}10^6$ conidia/ml, 100% at $1{\times}10^7$ conidia/ml and 100% at $1{\times}10^8$ conidia/ml respectively. Therefore, we recommend to proper control efficacy against S. exigua in which more than $1{\times}10^7$ conidia/ml suspension of M. anisopliae FT83.