• Korean journal of applied entomology
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• v.55 no.4
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• pp.319-327
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• 2016

Chemical pesticides have been used to control persimmon pests, however the overuse of the pesticides caused insect resistance, followed by failure in pest management and residual problems. Herein we investigate the potential of eco-friendly organic pesticides (EFOP) on the control persimmon pests, Stathmopoda masinissa (persimmon fruit moth) and Riptortus pedestris (bean bug). Ten commercially available plant-derived organic pesticides and one microbial pesticide were sprayed on the target insects in laboratory conditions. The chemical pesticide, buprofezin+dinotefuran wettable powder served as a positive control. In the first bioassay against persimmon fruit moth, alternatively Plutella xylostella larvae were used due to the lack of persimmon fruit moth population from fields, and three organic pesticides showed high control efficacy, such as pyroligneous liquor (EFOP-1), the mixture of Chinese scholar tree extract, goosefoot and subtripinnata extracts (EFOP-2) and Bacillus thuringiensis subsp. aizawai NT0423 (EFOP-11). When the three selected organic pesticides were treated on the persimmon fruit moths, the EFOP-2 treatment showed the highest control efficacy: 27.7% (5 days), 13.3% (7 days) and 6.7% (10 days) of survival rates. In the bioassay against bean bugs, the mixture of Chinese scholar tree, goosefoot and subtripinnata extracts (EFOP-2 and EFOP-9) and the extracts of sophora and derris (EFOP-10) showed high control efficacy, particularly the highest in the treatment of EFOP-2: 20.0% (5 days) and 16.7% (10 days) of survival rates. These results suggest that the mixture of Chinese scholar tree, goosefoot and subtripinnata extracts (EFOP-2) has high and multiple potential in the management of the persimmon pests.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.19-25
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• 2013

This study focused on the usefulness of plant extracts for a city organic farm. Insecticidal activity of 8 plant species, plants crude extracts by ethanol and water, against third instar larvae (susceptible strain) of Plutella xylostella was evaluated in this study. Ethanol(25%) extracts of plant materials had better insecticidal activity than water extracts at the room temperature. Insecticidal activity were investigated by leaf disc spray method. Five plant extracts (Capsicum annuum, Chelidoniun majus, Leonurus sibiricus, Coptis japonica, Mentha piperascens) showed over 50% insecticidal activity to P. xylostella at the concentration of $1500mg{\cdot}L^{-1}$. Extract of C. annuum showed the highest insecticidal activity (83.3%) against P. xylostella. Phytotoxicity was not observed on Raphanus sativus and Brassica campestris with spray application. Seed germination and growth of two plants were not affected. Extract of C. japonica revealed 73.3% control efficacy against P. xylostella of R. sativus and showed 70% control efficacy against those of B. campestris, respectively, in plastic house. Insecticidal activity against various insects was observed in C. japonica extract as 87.4% for R. sativus and 74.3% for B. campestris in the field. These results suggested that extracts of C. annuum, C. japonica showed the highest insecticidal activity, and could be used as city farm insecticides for organic farming.

• Korean journal of applied entomology
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• v.55 no.3
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• pp.277-283
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• 2016

The first occurrence of the tomato russet mite, Aculops lycopersici Massee was in mid-late April, and the maximum occurrence was in mid-late June in 2013 and 2014. However, in 2015, the density of tomato russet mites increased in July. This pattern is thought to be attributed to temperature fluctuations, in which, low temperatures at night promoted their reproduction and long periods of high temperatures during the day promoted their dispersion. Comparison of the use of 11 Eco-friendly organic insecticides (EOIs) showed that, the mortality rates after application of 0.6% matrin(EOIMa) and 10% clove oil (EOICo) were 92.1% and 95.1%, respectively, when administered at 500-fold diluted concentrations. At 1,000-fold and 2,000-fold diluted concentrations, the mortality rates of EOIMa were 90.4% and 88.2%, respectively. In a field test, the mortality rates of EOIMa at the 1,000-fold diluted concentration and of EOICo at the 500-fold diluted concentration were 91.5% and 93.9%, respectively. In conclusion, theses two EOIs are sufficient to replace pesticides, and EOIMa seems to be particularly useful as a prophylactic given that it induced a mortality rate of 88.2% at a 2,000-fold diluted concentration.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.341-345
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• 2019

Ethyl formate (EF) is a rapid kill, environmentally safe, and low mammalian toxicity fumigant, registered to disinfest quarantine insect pests from imported agricultural products. A new concept for controlling insect pests of agricultural crops was tested in a fumigation chamber with EF. Control efficacy of and phyto-toxicity due to EF fumigation were evaluated against four pests (Thrips palmi, Bemisia tabaci, Myzus persicae, and Tetranychus urticae) and on seedlings of four fruit vegetables (FVs; yellow melon, cucumber, tomato, and pepper). Ethyl formate fumigation at a dose of 1.5 g m^-3 for 12 h produced >93.3% mortality in T. palmi, B. tabaci, and M. persicae. However, T. urticae was tolerant to fumigation, showing only 20% mortality at 2.0 g m^-3. In terms of concentration × time (CT) products, at least 8.9 g·h m^-3 CT at 20 ± 1.5℃ was needed to achieve > 90% mortality against the three susceptible insect pests. Fumigation at 1.5 g m^-3 for 12 h caused no phyto-toxicity to any of the four FV seedlings. Ethyl formate application, as a new disinfestation method in greenhouses, could be an alternative to reduce the use of conventional insecticides. However, further studies are needed to determine the efficacy of this method at different pest developmental stages and in different greenhouse environments. Additionally, research is needed to elucidate the phyto-toxicity of EF application at different growing stages of a wide variety of crops.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.27-34
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• 2014

Entomopathogenic fungi were isolated from Bemisia tabaci in an Oriental melon field, and their growth characteristics, factors related to a natural outbreak, and infectivity against Bemisia tabaci, Tetranychus urticae, and Frankliniella intonsa were investigated. The isolates had erect conidiophores bearing whorls of 4-6 phialides with a swollen base where cylindrical conidia of $3.0-3.4{\mu}m$ were attached. The isolates were identified as Isaria fumosorosea on the basis of morphological characteristics and an ITS sequence with 99% similarity. I. fumosorosea IFs-08 grew well on Sabouraud dextrose agar+yeast extract medium(3.2 mm/day/$24^{\circ}C$); it grew better at $35^{\circ}C$ than at $15^{\circ}C$. The isolates of I. fumosorosea-IFs were highly infective and killed 93.9-96.7% B. tabaci, 84.9-92.0% T. urticae, and 81.5-84.4% F. intonsa in bioassay, whereas three isolates (Isaria tenuipes, Isaria farinosa, and Isaria fumosorosea) from KACC showed a low infectivity of 10-20%. To the best of our knowledge, this is the first report of I. fumosorosea isolated from B. tabaci in Korea.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.347-355
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• 1997

For the selection of plants contained pesticidal active conpounds, 31 families 59 species of native plants were collected and biological activites of their crude extracts against brown planthopper (Nilaparvata lugens), Xanthomonas oryzae pv. oryzae and allelopathy were examined. Among the screened plants, the crude extracts from the leaves of Ricinus communis and Sophora angustifolia showed 100% and 82% of mortality on brown planthopper at the concentration of 1% (w/v) respectively. Mixed crude extracts of Sophora angustifolia root and Melia azedarach seed exhibited 128${\sim}$155% of synergistic effects on the mortality of brown planthopper. In case of fungicidal activity, the crude extracts from the leaves of 8 plants including Chrysanthemum indicum were inhibitory of the growth of Xanthomonas oryzae pv. oryzae at 1%(w/v) soluction. Seed germination of radish (Raphanus sativas) and barnyardgrass (Echinochloa crus-galli) was inhibited by 0.5%(w/v) leaf extracts of Pinus densiflora and Quercus acutissima. MeOH extracts of Pinus denislora leaves gave 100% inhibition in seed germintion of radish at 2%(w/v) soluction and showed a complete inhibition in seedling growth of barnyardgrass as well as radish at 5% solution.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.123-127
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• 2012

In order to develop eco-friendly biopesticide, an entomopathogenic bacterium Photorhabdus temperata M1021 has been lyophilized via freeze-drying along with protective agents such as skim milk, starch, sodium alginate, glucose and sodium glutamate to protect cells from lysis. Freeze-drying powder of P. temperata M1021 containing 7% skim milk (w/v) showed highest survival rate of 63% among all the protective agents used in trials. Furthermore, the freeze-dried microbial powder showed 75% of survival rate after stored at $4^{\circ}C$ for 4 weeks at air contact conditions. Injection toxicity of the freeze-dried sample was tested against larvae of Galleria mellonella. A dose of $2.0{\times}10^1$ cells of P. temperata M1021 killed 100% of the G. mellonella larvae within 4 days after injection. Moreover, $2.0{\times}10^0$ cells caused 50% mortality within the 4 days after injection. Freeze-dried P. temperata M1021 strains exhibited effective insecticidal activity and could be a better candidate for being used as a biopesticide.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.241-247
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• 2004

Susceptibility of Blattella germanica male adults to 61 commercial insecticides was evaluated by diet dipping method. Among them three insecticides of dichlorvos, fenitrothion, and fipronil showed over $90\%$ mortality. The insect was more susceptible to dichlorvos and fenitrothion in filter paper contact method than in diet dipping one, but fipronil was vice versa. Toxicities of the three chemicals were evaluated by application parts of the such as head, thorax, abdomen, and legs. Dichlorvos and fenitrothion were more toxic when applied to head, and flpronil was thorax. $LT_{50}$ values by diet dipping method showed that fenitrothion and fipronil acted more rapidly than boric acid and hydramethylnon. The values of the former two were 1.05 and 0.98 days, and those of the latter two were 3.92 and 2.26 days, respectively.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.210-219
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• 2004

Susceptibility of Periplaneta americana male adults to 61 commercial insecticides was evaluated by diet dipping method. Among them eight insecticides of dichlorvos, benfuracarb, cypermethrin, deltamethrin, fenpropathrin, $\zeta$-cypermethrin, $\lambda$-cyhalothrin and fipronil showed 100% mortality. The insect was more susceptible to dichlorvos and fenpropathrin in filter paper contact method than in diet dipping one, but benfuracarb was vice versa. Toxicities of the seven chemicals were evaluated by application parts of the such as head, thorax, abdomen, and legs. Dichlorvos, benfuracarb and $\lambda$-cyhalothrin were more toxic when applied to head, and deltamethrin, fenpropathrin and cypermethrin were abdomen. $LT_{50}$ values by diet dipping method showed that dichlorvos, benfuracarb and $\lambda$-cyhalothrin acted more rapidly than boric acid and hydramethylnon. The values of the former three were 0.10, 0.29 and 0.12 days, and those of the latter two were 6.2 and 4.8 days, respectively.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.452-460
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• 1992

To establish the economical and reliable routine bioassay system for developing new insecticidal compounds, effects of leaf-dipping time, application methods, insect species and their developmental stages on susceptibilities of insects to insecticides were studied. The stable insecticidal activity appeared at the dipping time for 30-60 seconds in leaf-dipping method, and the most effective application methods were leaf-dipping method for apterous green peach aphid adults, and third instars of diamond-back moth and tobacco cutworm, whereas seedling+insect spray method for adults or third instars of brown planthoppers. For two-spotted spider mite, leaf-dipping or intact plant spray method was favorable. In the bioassay for chitin synthesis inhibitors, the inoculation of third instars of brown planthopper, diamond-back moth, tobacco cutworm and green peach aphid, and larvae of two-spotted spider mite to the young host plants treated by spray method were adequate bioassay methods.