• Korean Journal of Organic Agriculture
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• v.10 no.2
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• pp.111-120
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• 2002

This study was conducted to investigate the effect of foliar application of Chitosan and seedling types on increasing the production of fall-growing potatoes(Solanum tuberosum) at the height of 250m from the sea in Jeju Island. The experiment main-plots consisted of four Chitosan applications, and subplots had three seedling types as cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot. The foliar application of Chitosan of 2000ppm was carried out 0, 1, 3, 5 times at intervals of ten days after ten days of transplanting. Plant height and top dry weight were significantly more vigorous as three to five application of Chitosan. In the small tubers(under 80g), the number of tubers and tuber yield were relatively increased in the seed potatoes planting plot and mine-tuber plug seedling plot, but the large tubers(over 80g) was higher in the cutting plug seedling planting plot. T-N content in leaves was increased as the number of application of Chitosan was increased. A similar tendency was shown in K, P Ca, Mg and Na. The growth and tuber yield in cutting plug seedlings, mine-tuber plug seedling planting plot and seed potatoes planting plot were effectively increased as three to five foliar applications of Chitosan was increased.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.60-67
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• 2021

In this study we investigated pesticide residues on herbs and spices disrtibuted in the Incheon Metropolitan area. A total of 112 samples were purchased from off-line and on-line markets from January to October 2020. In accordance with the implementation of the Positive List System (PLS), the proper usage of pesticides is now being enforced. It is assumed that unregistered pesticides are being used on herbs and spices due to the low number of registered pesticides in the agricultural industry. Pesticide residue levels were not detected in 99 samples but 11 kinds of pesticides in 6 samples (13 times) exceeded the MRLs. The pesticides that were used in accordance with the PLS were Diazinon, Diethofencarb and Pyridalyl. However, unregistered pesticides were on the herbs and spices. Therefore, it is necessary to educate producers of herbs and spices on the appropriate use of pesticides. It is also necessary to establish MRLs on herbs and spices.

• Research in Plant Disease
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• v.20 no.1
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• pp.25-30
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• 2014

Phytophthora infestans was isolated from potato leaves collected from main potato producing areas in Korea during 2009-2011. In 2009, 99 isolates tested were all A1 mating type. Two of 64 isolates in 2010 and two of 78 isolates in 2011 were A2 mating type and they were found only in Miryang area. Among 99 isolates examined in 2009, 13.1% was resistant to metalaxyl, 3.1% was intermediate resistant and 83.8% was sensitive. In 2010, 19.4% of 62 isolates was resistant, 4.8% was intermediate and 75.8% was sensitive. Metalaxyl resistant, intermediate and sensitive isolates collected in 2011 were 23.1%, 9.0% and 67.9%, respectively. Metalaxyl resistant isolates increased mainly in winter cropping areas and seed potato producing areas where fungicides were sprayed more often. Frequencies of isolates showing minimum inhibition concentration of dimethomorph at $1.0-5.0{\mu}g/ml$ were 17.2% in 2009, 19.0% in 2010 and 15.4% in 2011. However, there was no evidence for occurrence of resistant isolate to dimethomorph because no isolate was able to grow at $5.0{\mu}g/ml$.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.101-110
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• 1993

The residues of combined insecticide of polynactin complex(tetranactin) and BPMC were determined to establish an index for the safety use to apple. Evaluation was made on residual concentration of tetranactin and BPMC in apple as a function of application frequency and date when the combined insecticide of tetranactin and BPMC was sprayed into apple. Their persistence in soil were also studied under the field and laboratory conditions. Recovery percentage from apple was ranged from 74.0 to 77.5 in tetranactin, 87.1 to 83.6 in BPMC, those from soil was 82.3 to 88.4 in tetranactin, 83.6 to 887.1 in BPMC. The minimum detectable limits of tetranactin and BPMC were 0.01ppm in apple pulp and 0.03ppm in apple peel and soil. The residue percentage of tetranactin and BPMC in the peel and pulp part of apple was about 96 in peel part by five sprays up to 3th day before harvest. The residues of tetranactin and BPMC in apple are proved to 0.39ppm and 0.75ppm by five sprays up to 30days before harvest. Maximum residue limit(MRL) of BPMC for fruits was established of 0.3ppm in Environment Protection Agency of Korea, and thus it is suggested that the preharvest intervals of combined insecticide for apple could be 30 days with twice spray. The half life of tetranactin in soil under field and laboratory conditions was 6.9 and 24.4 days, and in case of BPMC was 6.3 and 23.2 days, respectively.

• Korean Journal of Environmental Agriculture
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• v.9 no.1
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• pp.15-22
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• 1990

The efects of application time on the persistence of chlorothalonil in sesame plants and its persistence in soil were studied in the field. A procedure was used which permited the analysis of residues of Chlorothalonil (DACONIL 2787) in sesame(Sesamum indicum L.)and soil. The procedure was based on the multiresidue analytical method using an polarized acetonitrile solution or acidified acetone as the extracting solvent. The DACONIL 2787 is separated from the fat in the extracts by using an activated alumina and Florisil chromatogaphic column. Residues of DACONIL 2787 were determined by subjecting the alternate eluate from the Florisil column to gas chromatographic analysis(ECD). Residue of chlorothalonil in sesame are proved to 0.06 ppm for six sprays, 3rd day before harvest The half-life of chlorothalonil in soil proved to be 8.9 days and residues of chlorothalonil was only 0.03 ppm 100 days after application of 15 ppm.

• Research in Plant Disease
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• v.17 no.3
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• pp.295-301
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• 2011

The effect of various fungicides on anthracnose of strawberry, caused by Colletotrichum gloeosporioides, was determined in vitro, and in greenhouse and field trials. The $EC_{50}$ values of benomyl were clearly different between two sensitive and resistant groups of isolates. Iminoctadine tris had lower $EC_{50}$ values than mancozeb and propineb as protective fungicides and the response of mancozeb, propineb and azoxystrobin was variable depending on the isolate. In the greenhouse, pre- and post- inoculation fungicide applications significantly reduced disease compared to the non-treated control. Propineb, mancozeb and azoxystrobin were effective in controlling the disease when applied prior to inoculation. Metconazole and prochloraz-Mn treatments as ergosterol biosynthesis-inhibiting fungicides had the lowest incidence of anthracnose. In the nursery field trials in 2009 and 2010, the reduced fungicide spray program provided similar levels of disease control compared to the calendar-based applications with captan. A reduced spray program based on efficacious fungicides such as prochloraz-Mn will be useful for strawberry growers and provide more options for controlling anthracnose in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.323-330
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• 1994

Benzyladenine(BA) and Diphenylurea(DPU) at 10ppm level were foliar-applied one to three times at an interval of 10 days from heading stage of rice variety, Dongjinbyeo. One time treatment of both cytokinins did not delayed leaf senescence substantially, but consecutive treatments of two to three times markedly retarded leaf senescence. Leaf senescence retarding effects were greater in BA than DPU. Ripened grain ratio, grain weight and grain yield were not improved by the treatments. BA treatments increased the percentage of green and white belly kernels with no effects on opaque and white core kernels. BA and DPU treatments did not altered amylose content, but BA treatments significantly decreased protein content of polished rice. Consecutive treatments of BA and DPU twice or three times at an interval of 10 days from heading increased oil content by 30 to 78% as compared to non-treated control, but one time treatment at any stage did not enhance it of polished rice. Fatty acid composition was slightly altered in favor of unsaturated fatty acid by BA and DPU treatments.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.141-150
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• 2006

To optimise the efficient use of nutrients in pig slurry is to cultivate friendly environmental crops. This field survey is to investigate the actual conditions of pig slurry utilization for cultivation of crops in the agricultural farm, based on the survey for 407 selected farms in 9 provinces included 78 counties in Korea. The results obtained in this survey were summarized as follow ; The motive which came to use pig slurry in the agricultural farm were production of friendly environmental crops (29.7%), economy of chemical fertilizer (25.1%), spontaneously (19.2%), inducement of neighboring farmhouse (16.0%), increase of soil fertility (9.3%), and the others (0.7%), respectively. The proportions of pig slurry application land were 56.5% for.ice paddy, 22.6% for dry field, 13.3% for orchard, 4.4% for controlled agriculture and 3.2% for other, respectively. The number of times of pig slurry utilization per year were once (48.9%), twice (31.9%), thrice (14.0%), and the others (5.2%), respectively. The controversial points of pig slurry utilization were malodor (54.1%), insufficiency of spread equipment (22.1%), inconvenience (14.5%), over application (3.4%), over cost (2.9%), heavy metal (1.7%), sanitation (1.0%) and the other (0.2%), respectively. The results indicated that pig slurry could be used as fertilizer source of friendly environmental crops, but further studies are needed to determine the application method and value of the pig slurry for crop cultivation.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.209-214
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• 1992

Residue of Propineb in Sesame(Sesamum indicum L.) seed was determined to establish an index for the safety use of Propineb to Sesame. Evaluation was made on residual concentration of Propineb in Sesame seed as a function of application frequency and date when the mixed formulations of Propineb(56%), protectant fungicide, and Oxadixyl(8%), contact fungicide, were sprayed into Sesame leaves. Level of Propineb treatment was $0.028g/m^2$ with various combinations of application time from three to sixty days before harvest. Results are summarized as followings. 1. Recovery percentages of Propineb from Sesame seed were ranged from 84 to 96, and the minimum detectable limit of Propineb with the method employed in this experiment was 0.03mg/kg. 2. Residues of Propineb in Sesame seed were in the ranges of 0.14 to 1.38mg/kg, varying with frequency and date of Propineb application. 3. Residues of Propineb increased as increasing application frequency of Propineb or as being application date closer to harvest time. 4. Residue of Propineb in Sesame seed was decreased with time, showing to be fitted to the first-order kinetics. 5. Residues of Propineb in Sesame seen were, irresepective of treatments, lower than 2mg/kg, the Maximum Residue Limit(MRL) established by FAO/WHO. 6. Half-life of Propineb determined in this experiment was ranged from 12 to 16 days.

• Korean Journal of Medicinal Crop Science
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• v.16 no.1
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• pp.33-38
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• 2008

This study was carried out to reduce the number of chemical treatment by optimal apply for the disease and pest and obtain the basal data of environmental-friendly cultivation in Panax ginseng in 2006. The result by checking disease Incidence and pests fried in ginseng field of jeollabuk-Do was as follows. The kind of disease occurred in Jinan was 8 including Rhizoctonia solani, 7 with Botrytis cinerea in Jeongeup, and also 6 with Botrytis cinerea in Kochang within Jeollabuk-Do. It was required thorough disease control before the rainy season because the occurrence time was peaked around July. Also, the most serious disease in Jeollabuk-Do was Alternaria alternata, Botrytis cinerera, and Colletotrichum gloeosporioides. The actual harmful pests in ginseng field were Asusta despecta steboldiana and Holotrichia sp. and in other method using black light trap, Maladera orientalis, Ostrinia furnacalis, and Holotrichia morosa were mainly trapped.