• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.532-538
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• 1996

GA4/7 spray, injection and several cultural treatments were applied to the greenhouse-grown potted hybrid larch(Larix decidua${\times}$leptolepis) grafts and field-grown European larch seedlings to induce early flowering. A treatment consisting of repeat-ed GA4/7 sprays, alone, was the most effective flower induction treatment for greenhouse-grown, potted larch grafts. Root pruning as a adjunct treatment did not show synergistic effects. Injection for potted grafts with GA4/7 was not useful approach in this study and it resulted in increased mortality. In the field experiment with 10-Year-old larch seedlings, repeated GA4/7 sprays in combination with root pruning or with plastic mulching appears to be useful and practical means for inducing larch flowers:

• Korean journal of applied entomology
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• v.39 no.3
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• pp.199-205
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• 2000

The field control efficacy of entomopathogenic nematode, Steinernema carpocapsae Weiser, was evaluated on the beet armyworm, Spodoptera exigua (Hiibner). The insect pest has been known to be a defoliator at the aerial part of the crop and difficult to be controlled effectively with most commercial chemical insecticides due to its insecticide resistance. To overcome the susceptibility of the nematodes to desiccation when they were applied by leaf spray in field condition, we screened several commercial antidesiccants (alkyl glucoside, CMC, glycerol, Keltrol-F, Kunipia-G, and Laponite LXG) optimal for survival of the nematodes. Keltrol-F (0.1 %) was selected as a candidate supplement for field application of the nematodes. Leaf spray of the nematodes at 5,000 infective juveniles/ml of distilled water containing 0.1 % Keltrol-F resulted in 87.7% control efficacy on the 3rd instar larvae of Sp. exigua.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.51-57
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• 1987

The intent of this research is to acquire some basic informations about formulation of the viral pesticide, Hyphantria cunea nuclear polyhedrosis virus and its virulence under field condition. The nuclear polyhedrosis virus was formulated as wettable powder using spreader, sticker and U.V. protector. The formulated product and aqueous virus were diluted with water at the concentration of 1${\times}$106PIB/ml and sprayed on mulberry leaves in the field. The leaves were fed with 3rd instar larvae of H. cunea to determine the inactivation period of the viral pesticides. The aqueous virus was completely inactivated on 5th day after spray, while the formulated one showed a spare mortality to the larvae even on 20th day after spray. In field application test, The fromulated and aqueous virus were sprayed on individual mulberry tree and 3rd instar laevae of H. cunea were fed on the trees. The mortality of the larvae one day after spray of the formulated and aqueous virus were about 50% and 40%, respectively. The formulated virus exhibited a persistent virulence to the larvae up to 9th day after spray, which the mortality was approximately 30%. The residual virulence of the formulated and aqueous virus was extended up to 4th day and 2nd day after spray, respectively.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.252-256
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• 1990

Viral insecticides were formulated with Spodoptera litura nuclear polyhedrosis virus and different U.V. protectants based on white carbon, molasses, and white carbon and molasses mixture to use as microbial control agents. Effect of rainfall on the attachment of formulated viruses to leaves was no different between the treated and the non-treated experiment. Persistence of the formulations was lated 5 days on the surface-sprayed leaves and 12 days on the under-sprayed leaves which was showing 60% mortality. Total mortality of the viral insecticides was more than 97% with no differences among them. Field evaluation of three viral insecticides in soybean field was very successful then carried out in Chinju, a southern part of Korea. Mortality by the formulation in the field during 14 days was more than 93%, but the formulations contained molasses showed phytotoxicity on soybean leaves. Spray effect of the viral insecticides was begun to appear from 7 days later than that of chemical insecticide.

• The Korean Journal of Pesticide Science
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• v.13 no.1
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• pp.39-44
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• 2009

This study was conducted to evaluate the actual risk of fipronil on worker honey bees (Apis mellifera L.) through acute contact toxicity test, acute oral toxicity test, toxicity of residues on foliage test, and small scale field test. The $48h-LD_{50s}$ of fipronil SC on honeybee were $0.005{\mu}g$ a.i./bee in acute contact toxicity test and $0.004{\mu}g$ a.i./bee in acute oral toxicity test, respectively. In toxicity of residues on foliage test, fipronil showed over 90% of mortality during 28days after treatment at recommended application rate. The $DT_{50}$ of dislodgeable foliar residue was 9 days. Finally, In small scale field test, fipronil showed similar toxicity in the residues on foliage test. It was concluded that fipronil has very high acute toxicity and long residual toxicity to honeybee. Therefore, fipronil is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area. To protect honeybee and wild pollinators from outdoor use of fipronil, ultimately it should need to limit for only indoor use to prevent pollinators from unintentionally exposure of fipronil.

• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.17-29
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• 1989

This study was conducted to evaluate the behavior in the water and the impact on aquatic organisms following aerial application of two insecticides in the forest, cyfluthrin and trichlorfon, to control the alder leaf beetle. As active ingredients, 25g of cyfluthrin and 536g of trichlorfon per ha were diluted seperately into 30L of tap water, and applied with a helicopter to the study areas. A model stream study was also conducted in a stream located adjacent to the study area in order to confirm the impact of insecticides on aquatic invertebrates. Cyfluthrin residues in water were $0.62{\mu}g/L$ (1st. application) and $78{\mu}g/L$ (2nd application) immediately after spraying. and decreased, to a non-detectable level after one day, while trichlorfon residue increased to $30.7{\mu}g/L$ one day after spraying and fluctuated for 22th day depending on precipitation after spraying. Cyfluthrin application rapidly increased the number of some drifting aquatic invertebrates during 24-hour period immediately after spraying, but had no effects on the other aquatic organisms such as fish and zooplankton. The largest increase in the number of drifting organisms following application of cyfluthrin was shown by Ephemeroptera, and followed by Trichoptera, Coleoptera, and Diptera. However, trichlorfon little affected the number of drifting aquatic invertebrates and zooplankton population.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.420-430
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• 2005

As the pine wilt disease spread rapidly over Korea in recent, aerial pesticide spraying to the infected pine stands increased abruptly. The increasing aerial pesticide application for control of the disease would result in disturbance of soil ecosystem in pine stands. This study was conducted to assess the disturbance, using field experiment in pine stands of Hongleong experimental forests in Seoul with BACI experimental design with three sprayed plots and three unsprayed plots of $25m^2$. We sprayed fenitrothion of 0.0335 kg a.i./ha over each of the sprayed plots, being the same as the pesticide residues of litters after aerial spraying. The pesticide had been applied on 4 June, 11 June, and 29 June in 2002, comparable with the dates of the aerial spraying in the previous year in Busan. We monitored population of soil organisms including arthropods, fungi, bacteria, and actinomycetes at two sampling days before pesticide application, at two sampling days during the application season, and at three sampling days after last application for two months since late May in 2002. The pesticide applications did not make any significant effect on the population of arthropods, fungi, bacteria, and actinomycetes in soils and on the structure of soil organism community, showing low probability of significant effects of the aerial pesticide application on soil organisms in pine stands.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.464-471
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• 1996

Trifluralin was selected to study the leaching potentials related to the pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. The batch equilibrium of trifluralin resulted in the Koc value of 875. When the soil columns(5.4 cm i.d. ${\times}$ 26 cm length) were leached with three pore volumes of water, the distributions of trifluralin in soil and leachate were 99.993% and 0.007% of the total recoveries, respectively. When applied at the rate of 1,683 g/ha in the field, the amount of trifluralin within the $0{\sim}10$ cm soil depth was 96.9% of that within the $0{\sim}60cm$ soil depth 31 days after application. The concentrations of trifluralin detected in 1- and 2m- depth wells during 62 days after application ranged from 0.04 ng/mL to 0.08 ng/mL, which were lower than 2.0 ng/mL of the U.S. EPA advisory levels for drinking water. Trifluralin was strongly adsorbed on soil and hardly reached ground water. The leaching properties of trifluralin in the fields were predicted and concurred with those in the columns.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.299-304
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• 2007

Surveying, laboratory and field trial were performed to elucidate the causes of non-spinning syndrome of silkworm, Bombyx mori, abnormal symptoms of silkworm instars observed in certain sericultural fanning region. Mortality and growth of silkworm was still influenced by feeding the mulberry leaves sprayed with 10,000 fold diluted solution of standard spray of diflubenzuron WP (25%). Mortality and growth of silkworm fed with diflubenzuron-sprayed mulberry leaves with recommended spray solution were entirely affected even six weeks after spraying irrespective to the instars. Larval period of 5th instar and cocooning duration of silkworm was not affected in case 50m of buffer zone has maintained in near-by orchard field sprayed with diflubenzuron WP (25%). However, survival rate of pupae was not influenced in case 100 m of buffer zone has kept. Insect growth regulating insecticides were required to keep a certain distance of buffer zone when sprayed with water-diluted solution, 100 m from the application site at least in order to prevent contamination of the spraying drift by the chemicals.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.181-188
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• 2016

BtPlus is a group of biopesticides that are made of Bacillus thuringiensis and immunosuppressant. A new BtPlus that exhibits high insecticidal activity against mosquito larvae has been investigated in control efficacy in field conditions and its environmental safety against aquatic system. This study assessed the control efficacy of BtPlus against mosquito larvae with two different application methods. In aerial spraying application (100 mL per $3.3m^2$), BtPlus was effective at 50% or above formulation concentrations to control mosquito larvae. For a direct application to aqueous mosquito habitat, a semi-field mimicking paddy rice field was constructed. In this condition, BtPlus showed 80% and 100% control efficacies at 0.1% and 0.2% concentrations, respectively. BtPlus also showed 40% mortality against adults at 0.1% concentration in 10% sugar bait. However, its control efficacies against adults were much less than against larvae. Safety assessment of BtPlus against ecosystem was evaluated using young carp (Cyprinus carpio), a water flea (Daphnia magna), and a honey bee (Apis mellifera). BtPlus did not give any adverse effects on these nontarget organisms. Based on these results, BtPlus can be applied to control mosquitoes by direct aqueous application to paddy rice field.