• Research in Plant Disease
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• v.14 no.2
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• pp.112-116
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• 2008

Powdery mildew of Paprika caused by Leveillula taurica has been a serious problem in greenhouse. It is an unusual endophytic powdery mildew because the mycelia grow inside the leaf, such that the pale yellow lesions on adaxial surfaces appear first and the white powdery lesion/signs develop later on the corresponding to the spots of the abaxial leaf surface, where the conidiophores are typically emerge through the stomatal opening. Although one foliar application of cooking oil and yolk mixture(COY) to the foliage was not practically effective enough, two or three, weekly application of COY to the foliage at either 0.3 or 0.5% concentration resulted in excellent control against powdery mildew with disease index less/lower than 1, respectively. This treatment could provide protection for three weeks, which, we believe, is not only cost-effective, but also environment-friendly. Powdery mildew fungus was affected by COY treatment quickly which is recognizable in three days. Net photosynthesis and evapotranspiration was remarkably reduced by powdery mildew infection compared to healthy leaves, suggesting that prevention and early protection is the most critical strategy for peak paprika fruit yield. Moreover, COY treatment did not adversely affect the photosynthesis and evapotranspiration of foliages.

• Journal of Mushroom
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• v.3 no.3
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• pp.95-99
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• 2005

Carbon dioxide($CO_2$) promotes development of primordia and depress differentiation of sporophore and gill containing basidia, have an effect on quality. This experiments were conducted to elucidate optimal level of $CO_2$ for king oyster mushroom(Pleurotus eryngii). King oyster mushroom was cultivated under 1,600, 2,400, and 3,200ppm $CO_2$. Harvest ratio in normal plot were 98.6, 99.3, and 93.8% at 1,600, 2,400, 3,200ppm, respectively, so 2,400ppm is optimal. The yield per bottle was 102.5g at 2,400ppm, better than 99.7g at 1,600ppm, The $CO_2$ concentration of 2,400ppm was also the best condition for quality, 6.1 at 2,400ppm was 115% of 1,600ppm's. In thinning treatment plot, quality at 2,400ppm was 9.5 better than 1,600ppm whose quality was 9.4. The yields per bottle were 90.7, 98.2, 77.3g at 1,600, 2,400, 3,200ppm respectively. These results show that 2,400ppm was optimal $CO_2$ concentration for quantity of King Oyster mushroom as well as quality.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.187-197
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• 1987

Bacteria and fungi antagonistic to Fusarium oxysporum f. sp. cucumerinum Owen were effectively isolated with each of modified Triple Layer Agar (TLA) technique from rhizosphere soil where cucumber had been grown healthily in plastic film house. Three predominant bacterial isolates selected were identified as Pseudomonas fluorescens, and P. putida, Serratia sp. and three fungal isolates were Gliocladium sp. Trichoderma harzianum, and T. viride. Antagonistic bacteria inhibited $26-45\%$ of germination and $41-56\%$ of germ tube elongation of microconidia of F. oxysporum f. sp. cucumerinum on Water Agar (WA). P. fluorescens was the strongest inhibitor. Several my co parasitisms were observed on dual culture of WA between antagonistic fungi and F. oxysporum f. sp. cucumerinum such as coiling, penetration, overgrowing, and lysis. Mycelial lysis of the pathogen was the most severe at pH 4.6, followed by 3.6, 5.6 and 6.6 of the medium in decreasing order. At pH 6.6, mycelia of the pathogen were not conspicuously damaged, however, the antagonistic fungi formed abundant chlamydospores especially Gliocladium sp. T. harzianum revealed the most excellent antagonism in vitro.

• Research in Plant Disease
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• v.26 no.1
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• pp.8-18
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• 2020

Red pepper, one of the major economic crops in Korea, is being affected by anthracnose disease caused by Colletotrichum acutatum. To control this disease, an antagonistic bacterial strain, Bacillus subtilis YGB36 identified by 16S rDNA sequencing, physiological and biochemical analyses is used as a biological control agent. In vitro screening revealed that the strain YGB36 possess strong antifungal activity against the pathogen Cylindrocarpon destructans. The strain exhibited cellulase, protease, amylase, siderophore production and phosphate solubility. In vitro conidial germination of C. acutatum was most drastically inhibited by YGB36 cell suspensions (10⁶ cfu/ml) or culture filtrate. Development of anthracnose symptoms was reduced on detached immature green pepper fruits by treatment with cell suspensions, and its control value was recorded as 65.7%. The YGB36 bacterial suspension treatment enhanced the germination rate of red pepper seeds and promoted root development and growth under greenhouse conditions. The in vitro screening of fungicide and insecticide sensitivity test against YGB36 revealed that the bacterial growth was not affected by any of the insecticides, and 11 fungicides out of 21 used. Collectively, our results clearly suggest that the strain YGB36 is considered as one of the potential biocontrol agents against anthracnose disease in red pepper.

• Research in Plant Disease
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• v.26 no.2
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• pp.72-78
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• 2020

Clover cyst nematode, Heterodera trifolii, is one of the most important plant-parasitic nematode on Kimchi-cabbage in highland in Korea. Recently, a demand of soil disinfection machine for fumigants is increasing. This study was conducted to assess the control effects of a newly developed prototype soil disinfection machine to the cyst nematode. Two fumigants, dimethyl disulfide (DMDS) and metam sodium (MNa), were treated using the machine in a field, which was infected with the cyst nematode. After 4 weeks, control effects of fumigants were assessed as eggs hatching rates inside of cysts extracted from the soil, and as a number of females reproduced in roots of Kimchi-cabbage. DMDS (39 l/10 a) suppressed over 99.0% of the eggs hatching rate and the number of females reproduced. On the other hand, MNa (29 l/10 a) controlled the egg hatching rates from minimum 78.3% to maximum 99.4%, and the number of females from 34.7% to 49.3%. The control effects of two fumigants to clover cyst nematode by treated depth were no significant differences statistically. These results showed that DMDS treatment using the soil disinfection machine was expected to have the control effects for the clover cyst nematode.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.107-114
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• 2012

This study was conducted to evaluate the weed suppressing effects of different cropping system including hairy vetch (Vicia villosa) and rye (Secale cereale) cover crops, polyethylene plastic film, and transplanting film mulching in direct sowing and transplanted sorghum field in 2011. Crop growth and development and weed occurrences in the fields were examined to know the efficiency of proposed cropping system. In polyethylene film mulching treatment, heading date of sorghum was earlier by 3 days than control, on the other hands, rye cover crop mulching delayed heading date by 11 days. Besides the effect of cover crop on the heading of sorghum, the residues changed growth characteristics. Plant height of sorghum was increased by 27.3% at hairy vetch treatment although it was reduced by 47.5% in the rye cover crop treatment. Hairy vetch treatment showed beneficial effects on sorghum growth reduced the occurrences of grasses and broadleaf weeds to 84% and 96%, respectively, as compared to control in sorghum fields. While rye cover crop treatment showed poor sorghum growth reduced less strongly grasses and broadleaf weeds by 35% and 71%, respectively. At harvest, yield of sorghum was greater in order of hairy vetch cover crop > polyethylene film mulching > rye cover crop ${\fallingdotseq}$ control in both transplanted and direct sown fields.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.49-55
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• 2017

The objective of this research was to investigate the effects of planting date, root pruning and uprooting on growth, yield and budding ratio of 'Seolhyang' strawberry (Fragaria${\times}$ananassa Duch.). Planting dates of plantlets with 60 ~ 70 days old were September 7th, September 14th and September 21th. Root pruning rates were controlled to 25% (RP 25) or 50% (RP 50) before transplanting. In the uprooting treatments, the plantlets were pulled out on root media and were replanted into same bed at 10 days (UR 10) and 20 days (UR 20) after transplanting. The delayed planting dates of plantlet resulted in the suppressed growth of plant, reduced yield, and slight earlier appearance of flower buds. The RP 50 treatment showed the lowest value among root pruning treatments in growth and yield, but appearance of flower buds slightly fall behinds. The UR 20 treatment only made flower budding earlier by 6 days than non-treatment. All of root stress treatment was appeared to decrease vegetative growth and yield except the RP 25 treatment. Above results imply that strong root stress was required to emerge second flower bud earlier but which reduced overall growth and yield in 'Seolhyang' strawberry.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.332-337
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• 2004

A suspected biotype of Scirpus planiculmis to be resistant to sulfonylurea(SU) herbicides was identified in Seosan reclaimed paddy fields in Korea, in 2004. The fields have been cultivated for monocultural rice production with wet-direct seeding method and continuously treated with SU-based herbicide mixtures for thirteen years since 1990. In greenhouse studies, 6 different SU herbicides, such as azimsulfuron, bensulfuron-methyl, cinosulfuron, ethoxysulfuron imazosulfuron and pyrazosulfuron-ethyl, completely controlled the Musan assession of Scirpus planiculmis at the recommended dose of each herbicide, however, the Seosan accession of S. planiculmis biotype was survived 20 to 45% even treated with 5 times higher dose of each recommended rate of all herbicides treated. The $GR_{50}$ values of 6 SU herbicides for Seosan accession of S. planiculmis were 47 to 100 times higher than those for Musan accession of S. planiculmis. The $I_{50}$ values pyrazosulfuron-ethyl to acetolactate synthase(ALS) extracted from Sesan and Muan accession of S. planiculmis were 409 nM and 0.8 nM, respectively. The $I_{50}$ value of Seosan was 511 times higher than that of Muan accession. These results suggested that the Seosan accession of S. planiculmis have strong resistant characteristics to 6 SU herbicides, respectively, indicating that resistance might be due to the alteration in the target site of ALS.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.301-301
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• 2009

겨울철 농경지 이용율 제고 및 자연경관 조성을 위하여 녹비작물을 재배하는 면적이 지속적으로 증가하고 있는 추세이다. 그 동안 녹비작물에 대한 연구는 주로 파종적기, 작물에 대한 양분공급효과 및 타감 효과 등에 집중되어왔다. 본 연구에서는 토양 중 양분공급 및 미생물활성의 경시적 변화, 잡초억제 및 작물생육에 대한 녹비작물의 투입효과를 알아보기 위하여 수행하였다. 국립농업과학원 구내포장에서 2007년 9월 하순에 헤어리베치(8kg/10a)와 호밀(10kg/10a) 종자를 파종한 후, 이듬해 4월 하순에 수확하여 토양에 환원하였다. 질소공급량은 화학비료(15.2kgN/10a) 대비 헤어리베치(32.2kg/10a, 212%), 호밀(9.2kg/10a, 60%) 및 헤어리베치+호밀(15.5kg/10a, 102%)로 헤어리베치의 질소공급효과가 매우 높았다. 토양 무기태질소 함량은 녹비 처리 후 30일경에 최대에 도달하였으나, 호밀 처리구는 조사기간 동안 큰 변화가 없었다. 토양 유기물 함량의 변화는 시험 전(10DBI)과 비교하여 큰 차이를 보이지 않았으나, 녹비환원 후 10일경에 일시적으로 감소하는 경향을 보였는데 이는 녹비환원 후 토양경운에 의한 영향으로 판단되며, 무기태질소와는 달리 호밀처리구의 유기물함량이 지속적으로 증가하는 경향을 보였다. 토양 탄수화물(수용성 당)은 시험 전에 가장 높았으며, 시간의 경과와 함께 서서히 감소되는 양상을 보였으며 토양 미생물탄소 및 미생물질소의 양은 녹비처리구가 화학비료 처리구에 비해 높았으며 녹비환원 후 50일 까지는 증가하다가 그 이후에 감소하는 경향을 보였는데 이는 토양의 무기태질소 및 탄수화물과 밀접한 관계가 있는 것으로 판단되었다. 녹비처리 후 85일경에 잡초발생량을 조사한 결과, 화학비료 처리구에 비하여 헤어리베치 처리구는 40%, 호밀 처리구는 68%, 헤어리베치+호밀 처리구는 40%의 잡초억제효과가 있었다. 고추과의 수량은 화학비료 처리구(702kg/10a)>헤어리베치(694kg>10a)>헤어리베치+호밀(361kg/10a)>호밀(179kg/10a)의 순으로 나타났다.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.219-236
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• 1988

Bensulfuron concentrations of $10^{-7}$, $10^{-6}$, $10^{-5}$ and $10^{-4}M$ were applied to agar medium on susceptible (cv. KH 17854 and cv. IR 1846) and tolerant (cv. Chinsurah Boro II and IR 14252) rice cultivars were grown for microscopic inspection. Susceptible cultivars showed the decrease in shoot and root growth at the concentration of $10^{-5}M$ while ones showed no difference. Such a tendency was also observed from microscopic inspection in the elongation zone of shoot meristematic tissue. Seedlings grown in soil for 10 days were transfered to distilled water containing only bensulfuron solutions. There were significant differences between cultivars in terms of supression of shoot meristematic activity and swelling of cell volume. Observations of those cells made it clear that especially susceptible cultivars showed the irregular cell layering, vacuolation, cell swelling and partial damage in membrane of shoot tissue. The major response of root tips of susceptible cultivars showed the disorganization of cortex, rupture and contraction of membrane, inhibition of cell division, swelling and emergence of lateral root while tolerant ones showed no such responses.