• 한국균학회소식:학술대회논문집
• /
• 2016.05a
• /
• pp.25-25
• /
• 2016

Biological control has many advantages as a disease control method, particularly when compared with pesticides. One of the most important benefits is that biological control is an environmental friendly method and does not introduce pollutants into the environment. Another great advantage of this method is its selectivity. Selectivity is the important factor regarding the balance of agricultural ecosystems because a great damage to non target species can lead to the restriction of natural enemies' populations. The objective of this research was to evaluate the effects of several different bacterial isolates on the efficacy of biological control of soil borne diseases. White rot caused by Sclerotium cepivorum was reported to be severe disease of garlic and chive. The antifungal bacteria Burkholderia pyrrocinia CAB08106-4 was tested in field bioassays for its ability to suppress white rot disease. In field tests, B. pyrrocinia CAB08106-4 isolates suppressed white rot in garlic and chive, with the average control efficacies of 69.6% and 58.9%, respectively. In addition, when a culture filtrate of B. pyrrocinia CAB08106-4 was sprayed onto wounded garlic bulbs after inoculation with a Penicillium hirstum spore suspension in a cold storage room ($-2^{\circ}C$), blue mold disease on garlic bulbs was suppressed, with a control efficacy of 79.2%. These results suggested that B. pyrrocinia CAB08106-4 isolates could be used as effective biological control agents against both soil-borne and post-harvest diseases of Liliaceae. Chinese cabbage clubroot caused by Plasmodiophora brassicae was found to be highly virulent in Chinese cabbage, turnips, and cabbage. In this study, the endophytic bacterium Flavobacterium hercynium EPB-C313, which was isolated from Chinese cabbage tissues, was investigated for its antimicrobial activity by inactivating resting spores and its control effects on clubroot disease using bioassays. The bacterial cells, culture solutions, and culture filtrates of F. hercynium EPB-C313 inactivated the resting spores of P. brassicae, with the control efficacies of 90.4%, 36.8%, and 26.0%, respectively. Complex treatments greatly enhanced the control efficacy by 63.7% in a field of 50% diseased plants by incorporating pellets containing organic matter and F. hercynium EPB-C313 in soil, drenching seedlings with a culture solution of F. hercynium EPB-C313, and drenching soil for 10 days after planting. Soft rot caused by Pectobacterium carotovorum subsp. carotovorum was reported to be severe disease to Chinese cabbage in spring seasons. The antifungal bacterium, Bacillus sp. CAB12243-2 suppresses the soft rot disease on Chinese cabbage with 73.0% control efficacy in greenhouse assay. This isolate will increase the utilization of rhizobacteria species as biocontrol agents against soft rot disease of vegetable crops. Sclerotinia rot caused by Sclerotinia sclerotiorum has been reported on lettuce during winter. An antifungal isolate of Pseudomonas corrugata CAB07024-3 was tested in field bioassays for its ability to suppress scleritinia rot. This antagonistic microorganism showed four-year average effects of 63.1% of the control in the same field. Furthermore, P. corrugata CAB07024-3 has a wide antifungal spectrum against plant pathogens, including Sclerotinia sclerotiorum, Sclerotium cepivorum, Botrytis cinerea, Colletotrichum gloeosporioides, Phytophotra capsici, and Pythium myriotylum.

• Korean Journal of Plant Resources
• /
• v.21 no.4
• /
• pp.304-309
• /
• 2008

All the seeds of rape (Brassica napus) sprout vegetables were germinated within three days after seeding irrelevant to the light colors. The total fresh weight of rape sprout vegetables at 6 days after seeding have been increased when grown under green and white color lights by 0.339g/10plants and 0.339g/10plants compared with the control. The total flavonoid contents in rape sprouts were increased under red and blue lights by 72.5 and 70.9mg${\cdot}L^{-1}$. Those DPPH radical scavenging activities at 2,000mg${\cdot}L^{-1}$ were increased by 90.0 and 90.3% which were sprouted and grown under blue and white lights. Nitrite radical scavenging activity of sprouts were most decreased compared with the control when grown under the red light by 57.4mg${\cdot}L^{-1}$. And mushroom tyrosinase inhibition activity of rape sprouts was extremely increased under the green light by 22.5mg${\cdot}L^{-1}$.

• The Korean Journal of Pesticide Science
• /
• v.17 no.4
• /
• pp.237-243
• /
• 2013

Pesticides were sprayed on perilla leaf and leafy lettuce in a greenhouse and the reduction rate of pesticide residues on each vegetable by washing were tested. The reduction rate of pesticide residues by washing for 30 sec~3 min on perilla leaf were 3~63% in tap water, 2~58% in salt water, 6~74% in green tea water, and 8~86% in detergent solution. The detergent solution only showed significant difference in reduction rates compared to the tab water washing. Considering reduction effects of the washing duration, it was showed that the reduction rates were a pattern of inclining as the duration of washing process increased, but there was no significant difference in the reduction rates except the reduction rates between washing in the detergent solution for 1 min and 3 min. Comparing washing in flowing tab water and in stagnant tab water with leafy lettuce, the reduction rate by one time washing were 8~68% in flowing tab water and 7~64% in stagnant tab water. The water and the time used in this experiment were 17.5 L, 2.9 min with flowing tab water and 4 L, 1 min with stagnant tab water. The reduction rate by 3 times washing in stagnant tab water were 16.5~76.6%, and the water and the time used were 12 L, 3 min. Therefore, when the water and the time used to wash vegetables were considered, washing two or three times in stagnant tab water could be more effective than washing one time in flowing tab water.

• Korean Journal of Plant Resources
• /
• v.30 no.4
• /
• pp.475-480
• /
• 2017

A new Gomchwi cultivar 'Damogy ' was bred by crossing between Gomchwi (Ligularia fischeri (Ledeb.) Turcz.) and Handaeri-gomchwi (Ligularia fischeri var. spiciformis Nakai). The selection and investigation of growth and yield characteristics were conducted from 2006 to 2011 in field and greenhouse of Highland Agriculture Research Institute, NICS, Rural Development Administration, Korea. On a newly developed cultivar 'Damogy', Color of petiole ear was purple, petiole trichome was exist, light of leaf back was not exist, and density of leaf vein was degree 4. Plant height, leaf length, leaf width and petiole length were 45.9, 16.9, 21.1 and 29.0 cm, respectively in the $3^{rd}$ year in growth characteristics. Plant size was also higher than that of Gondalbi. Bolting and flowering time were Aug. $23^{th}$ and Sept. $10^{th}$, respectively. In contrast, Gondalbi showed quite earlier bolting time more than 38 days compared with 'Damogy' and consequently earlier flowering time more than 26 day. 'Damogy' showed similar leaf number (129) per plant compared to 'Gondalbi' (130). Furthermore, yield was higher 'Damogy' (1,889 g/plant) than in 'Gondalbi' (798 g/plant). 'Damogy' showed higher leaf thickness (0.71 mm) than 'Gonalbi' (0.46 mm), and consequently showed more hardness in leaf characteristics ($28.3kg/cm^2$) compared with 'Gondalbi' ($23.0kg/cm^2$). 'Damogy' showed higher resistance in the susceptibility of powdery mildew disease compared to 'Gondalbi'. 'Damogy' variety was registered plant variety protection right as a No. 89 on December 2015.

• Journal of Bio-Environment Control
• /
• v.20 no.2
• /
• pp.93-100
• /
• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.

• Journal of the Korean association of regional geographers
• /
• v.4 no.2
• /
• pp.31-47
• /
• 1998

This paper deals with the historical geography of land-use and agriculture along the Lower Nam-River floodplains. The reclamation process of the river floodplains, the cultivation methods on the reclaimed lands, and the land-use patterns and processes are investigated. The Nam River, one of the major tributaries of the Nakdong River, flows through the boundary between Ham-An and Eu-Ryong Guns. Larger floodplains are located in Ham-An Gun. The floodplains of Ham-An Gun have been surveyed intensively in this study. In South Korea, the alluvial plains, mostly located along the river valleys, have been reclaimed to provide fertile agricultural lands. Those along the upper river valleys were reclaimed before those along the lower river valleys. The flood-plains of Han-An Gun were reclaimed to be the largest agricultural lands of the Gun. The natural levees along the Lower Nam-River Valley were identified before the reclamation processes but now hardly identified. Relatively larger floodplains are located along the tributary streams of the Nam River. Often there are low-lying back swamps between the natural levees and the hills/mountains that rise above the floodplains. The back swamps, called 'natural bog lands' in this region, have been reduced in size and in number through reclamation for the purpose of agricultural and industrial land-uses. Now about ten 'natural bog lands' are found in the Ham-An floodplains, and some of them are being reclaimed for the industrial land-use. This study suggests the emergent need of conservation for the remaining 'natural bog lands' in terms of ecology. Seven agricultural fields of large size, originated from the Nam-River floodplains, are identified in this study: Kun(큰들), Chung-Am(정암들), Chang-chi(장지들), Baek-San(백산들), Ha-Ki(하기들), Gu-Hae(구혜들), and Chang-Po(장포들) fields. The Kun field was reclaimed during the Japanese control and the Gu-Hae, in the 1950s. All of those except the above two fields were reclaimed after the mid-1960s. The Nam-River Dam in Chinju, completed in 1969, contributed the reclamation processes along the Lower Nam-River floodplains. The rice acreage of the region has been reduced slowly since 1970 but the rice production of the region has been relatively stable (Table 4). Rice culture had been the most important agriculture on the reclaimed lands for decades before the greenhouse vegetable cultivation became more important in the 1980s. Among the vegetables cultivated in the greenhouse, the watermelon is the dominantly leading one. Watermelons are usually harvested two or three times in a year though it is possible to harvest four times in one year. The rotation of watermelons and rice is common in the region. It is known the physical conditions of the Nam-River floodplains in Ham-An Gun is the most suitable for watermelon cultivation in South Korea.

• Research in Plant Disease
• /
• v.26 no.4
• /
• pp.272-278
• /
• 2020

The severe lettuce damage caused by Paratylenchus projectus was first reported in 2019 in Korea. To find high-value rotation crops for the control of P. projectus, nine vegetables, Brassica juncea (leaf mustard), B. rapa subsp. nipposinica (kyona), B. oleracea var. italica (broccoli), B. rapa subsp. chinensis (bok choy), B. oleracea var. viridis (kale), B. oleracea var. gongylodes (kohlrabi), Cichorium endivia (endive), C. intybus (chicory), Ipomoea aquatica (morning glory) were planted in d-10-cm clay pots in greenhouse. The growth of vegetables was compared between inoculated with 3,000 P. projectus per 100 ㎤ of soil and non-inoculated. Treatments were replicated 10 times. After 100 days, the reduction of fresh top weight was 30.4% in C. intybus, 35.1% in I. aquatica, 36.9% in B. oleracea var. acephala, 40.5% in C. endivia, 42.1% in B. rapa, 47.5% in B. rapa subsp. nipposinica, 50.4% in B. oleracea var. gonglodes, 56.3% in B. oleracea var. italica, and 66.0% in B. juncea. Nematode multiplication rates (Pf/Pi) were lower in I. aquatica (0.64) and C. endivia (1.1), but higher in B. oleracea var. gongylodes (2.54). Considering these results, I. aquatica is suitable for the rotation crop with lettuce until better rotation crops developed.

• Korean journal of applied entomology
• /
• v.46 no.1 s.145
• /
• pp.63-69
• /
• 2007

This study was conducted to examine the problems that would arise in our cropping systems when introducing Gain Threshold (GT) which is an important element in determining Economic Injury Level (EIL). Cain Threshold (GT) can be defined as the amount of damage (=yield loss) to justify management, and calculated by dividing the management costs by the market crop price. GTs for some pests in rice, soybean, and greenhouse vegetable crops cultivation were estimated and also compared with those in foreign countries. GTs and percentage of yield loss equivalent to them were estimated to be 4.6-6.1kg/10a/season and 1.0-1.3% for brown planthopper, white-backed planthopper, rice water weevil, and sheath blight, whereas for rice blast in rice cultivation were 12.7kg/10a/season and 2.7%. In soybean cultivation, the values for bean bug were 6.2 kg/10a/season and 3.6%. GTs and percentage of yield loss estimated for melon thrips, whitefly, and downy mildew in cucumber cultivation were 10.0-12.6kg/10a/week, 1.4-1.7%, and the values for two spotted mite and gray mildew in strawberry cultivation were 3.1-3.5kg/10a/week, 1.3-1.5%, and the values for American leaf minor, whitefly, and gray mold in tomato were 8.4-9.7kg/10a/week, 1.7-1.9%. Overall GTs in our cropping systems were so low compared to those in foreign countries, which meant that the low GTs might yield the low EILs. Therefore, we could suggest that prior to direct introduction of GTs calculated from current cultivation systems in developing EILs it is necessary to seriously consider reasonable values of GTs or the yield loss equivalents to them.

• Horticultural Science & Technology
• /
• v.33 no.2
• /
• pp.177-185
• /
• 2015

The aim of this study was to investigate the amounts of glucosinolates (GSL) in kale at various development stages. Kale varieties 'Manchoo Collard' and 'TBC' were cultivated from 20 February 2012 to 3 July 2013 in the greenhouse at Chungnam National University. During the cultivation periods, samples were harvested at 35, 63, 91, 105, 119, and 133 days after sowing (DAS) and the amount of GSL quantified by HPLC. Ten types of GSL (progoitrin, sinigrin, glucoalyssin, gluconapin, glucoiberverin, 4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin, gluconasturtiin, and neoglucobrassicin) were observed in 'TBC', whereas nine types of GSL (the same as above, except glucoiberverin) were identified in 'Manchoo Collard'. The amount of total GSL in 'Manchoo Collard' was comparatively higher at 133 DAS (mean $8.64{\mu}mol{\cdot}g^{-1}$) and lower at 35 DAS ($1.16{\mu}mol{\cdot}g^{-1}$ dry weight, DW) of cultivation. In the case of 'TBC', the amount of GSL was higher at 91 DAS (mean $13.41{\mu}mol{\cdot}g^{-1}$) and lower at 35 DAS ($0.31{\mu}mol{\cdot}g^{-1}$ dry weight, DW). Sinigrin was the most abundant GSL (57% of total GSL) in 'Manchoo Collard' at 133 DAS and was also highest (44%) in 'TBC' at 91 DAS. Together, progoitrin, sinigrin, glucobrassicin, and gluconasturtiin, the precursor of crambene, allylisothiocyanate, indol-3-cabinol, and phenethylisothiocyanate accounted for 94 and 78% of GSL in 'Manchoo Collard' and 'TBC', respectively. Our results demonstrate that the amounts of GSL, which have potential anti-carcinogenic activity, change during development in kale.

• The Korean Journal of Pesticide Science
• /
• v.10 no.2
• /
• pp.99-106
• /
• 2006

Chlorothalonil and imidacloprid sprayed onto the green peppers were degraded more faster at outdoor than in greenhouse. These results were affected by dew and photodegration, considering no rain during the experimental period. Chlorothalonil, esfenvalerate and imidacloprid in green pepper, green twist pepper and sweet pepper did not show any residual pattern, because green peppers are one of the continuous harvesting crops and pesticides could not be sprayed homogeneously on them. When green peppers were pickled with soy sauce and green twist peppers were fried with vegetable oil, the amounts of pesticides such as alpha-cypermethrin, bifenthrin, chlorfenapyr, esfenvalerate and imidacloprid were diminished to the levels of about $30{\sim}71$ and $20{\sim}41%$, respectively. Esfenvalerate and imidacloprid could not be detected in 2 month-old hot pepper paste. The removal rates of pesticide residues in leaves of green peppers were about $22{\sim}37%$ by washing, about $74{\sim}95%$ by parboiling, and about $17{\sim}55%$ by drying after parboiling.