• Korean journal of applied entomology
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• v.56 no.3
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• pp.301-308
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• 2017

Locusts, Locusta migratoria (Orthoptera: Acrididae) are periodical unpredictable agricultural pests worldwide and cause serious damage to crop production; however, little consideration has been given to the management of this pest. Herein, we constructed a locust-pathogenic fungal library and confirmed that some fungi could be used as resources for locust management. First, the entomopathogenic fungi were collected from sampled soils using a Tenebrio molitor-based baiting system. For the locust assay, a locust colony was obtained from the National Institute of Agricultural Science and Technology. A total of 34 entomopathogenic fungal granules, which were produced by solid cultures, were placed in the plastic insect-rearing boxes (2 g/box) and nymphs of locust were contained in the box. In 3-7 days, mycosis was observed on the membranous cuticles of the head, abdomen, and legs of locusts. In particular, Metarhizium anisopliae, M. lepidiotae, and Clonostachys rogersoniana exhibited high virulence against the locust. Given that the 34 isolates could be used in field applications, their conidial production and stability (thermotolerance) were further characterized. In the thermotolerance assay, Paecilomyces and Purpureocillium isolates had higher thermotolerance than the other isolates. Most of the fungal isolates produced ca. >$1{\times}10^8conidia/g$ on millet grain medium. In a greenhouse trial, the granular application of M. anisopliae isolate on the soil surface resulted in 85.7% control efficacy. This work suggests that entomopathogenic fungi in a granular form can be effectively used to control the migratory locust.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.54-64
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• 2010

Effects of thirteen essential oils (anise oil, clove oil, marigold, mustard oil, neem oil, quassia, quilaja, rosemary oil, rotenone, tea tree extract, thyme oil, wintergreen oil, and yucca) and caffeine on typical industrial insect, silkworm (Bombyx mori) and two entomopathogenic nematodes, Steinernema carpocapsae GSN-1 strain (Sc) and Heterorhabditis sp. Gyeongsan strain (Hg) were investigated in the laboratory. When 1,000 ppm of each essential oils was treated, neem oil showed the highest insecticidal activity against silkworm. Mortality of silkworm fed on neem oil treated mulberry leaf was 55.3 and 100% 5 and 10 days after treatment, respectively. The silkworm fed on neem oil treated mulberry leaf did not make cocoon and pupa. Weight of cocoon and pupa was low in rotenone treatment showing 0.27 g and 1.01 g, respectively. Mustard oil had the highest nematicidal activity against entomopathogenic nematodes. 20 ppm of mustard oil resulted in 69.0% and 100% mortality of Sc and Hg 3 days after treatment, but 4% and 36% at 5 ppm in X-plate, respectively. Mortality of baited Galleria mellonella larva by Sc was not different from control at the concentration of 100 ppm of mustard oil while 30% lower in Hg in sand barrier. Mean numbers of established infective juveniles of Hg in Galleria larva were lower than Sc in sand barrier. Survival rate of Sc was similar to control at the concentration of <200 ppm of mustard oil in sand barrier.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.33-40
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• 2014

To control Bemisia tabaci on tomato, we applied five different combinations of chemical treatments as below: 1) treatment of combinations of cyantraniliprole on the root area and leaf with the existing registered chemicals three times; 2) treatment of combinations of cyantraniliprole on the root area and dinotefuran + emamectin benzoate on the leaf with the existing registered chemicals three times; 3) treatment of combinations of dinotefuran on the root area and cyantraniliprole on the leaf with the existing registered chemicals three times; 4) treatment of combinations of dinotefuran on the root area and dinotefuran + emamectin benzoate on the leaf with the existing registered chemicals three times; 5) untreated control plot (Table 1). Twenty days after treatment ($17^{th}$ Aug.), the number of population of B. tabaci was zero on the 1, 2, 3, 4 treatments of combinations, and only 2 individuals were found on the 5 treatment of combination per each 20 plant. On $17^{th}$ Sep., in the last observation, the average number of population of B. tabaci was 10.3, 10.3, 10.6 on the 1, 2, 3 treatments of combinations on the 20 plants per each combination, however, the average number of 23.3 and 37.6 were examined on the 4 and 5 treatments of combinations, respectively. TYLCV was not occurring on the 1 and 2 treatments of combinations, and presented only 3% and 17% on the 3 and 4 treatments of combinations, respectively, which indicates that the treatments (1-4) should be effective on TYLCV control as considering that 33% of TYLCV occurred on the untreated control plot. However, after the third flowering period, there is no difference among the five combinations. The amount of products was 9,148g and 9,698g on the 1 and 2 treatments of combinations, respectively, which was the most among the 5 combinations. The number of fallen fruits and the average weight of fruits showed the similar tendency.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.315-324
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• 2009

For the environmental friendly management of diamondback moth, Plutella xylostella (L.), Bacillus thuringiensis subsp. kurstaki ($30{\times}10^8\;cfu/mg$) and neem oil (0.5% azadirachtin) were used as green control agencies with mixed and alternative treatments on the chinese cabbage. When Bacillus thuringiensis subsp. kurstaki was applied to 1st and 2nd larva of P. xylostella with recommended concentration, their mortalities were reached to 100% by 2 days after treatment. In case of azadirachtin, its effect of mortality was continued for 7 days, and reached to 100% mortality. $LC_{50}$ values of Bacillus thuringiensis subsp. kurstaki and azadirachtin against 1st, 2nd, 3rd and 4th larva of P. xylostella were $2.8{\times}10^4$, $3.1{\times}10^4$, $3.4{\times}10^4$ and $1.5{\times}10^5\;cfu/ml$, and 2.7, 3.9, 4.7 and 7.1 ppm, respectively. The number of laid eggs of P. xylostella was reduced to 57.5 at 25 ppm of azadirachtin compared with control treatment. The hatch ratio was not significantly different with Bacillus thuringiensis subsp. kurstaki treatment in comparison with control treatment. However, when azadirachtin was applied, their hatch ratio were reduced to 25.8 and 45.4% at 25 and 50 ppm, respectively. On the other hand, emergence rate of eggs was not different with Bacillus thuringiensis subsp. kurstaki treatment, but 45.4% was shown in azadirachtin treatment with 50 ppm in comparison with control. When the mixture with Bacillus thuringiensis subsp. kurstaki and azadirachtin was applied to adults of P. xylostella, their mortality was higher than Bacillus thuringiensis subsp. kurstaki treatment only. These results are supposed that the mixture of Bacillus thuringiensis subsp. kurstaki and azadirachtin might be used as green control agents for reducing the demage of diamondback moth in the Chinse cabbage.