Chemical Control of Rice Brown Spot

Wan Hae Yeh,Yong Ki Kim,Hong Sik Shim,Choong Hoe Kim,Byung Youl Oh 한국농약과학회 2003 한국농약과학회 학술발표대회 논문집 Vol.- No.-

Bacillus vallismortis EXTN-1-Mediated Growth Promotion and DiseaseSuppression in Rice

Kyungseok Park,DIBY PAUL,Wan-Hae Yeh 한국식물병리학회 2006 Plant Pathology Journal Vol.22 No.3

Bacillus vallismortis EXTN-1, a biocontrol agent in cucumber, tomato and potato was tested in rice pathosystem against rice fungal pathogens viz. Magnaporthe grisea, Rhizoctonia solani and Cochliobolus miyabeanus. Apart from increasing the yield in the bacterized plants (11.6-12.6% over control), the study showed that EXTN- 1 is effective in bringing about disease suppression against all the tested fungal pathogens. EXTN-1 treatment resulted in 52.11% reduction in rice blast, 83.02% reduction in sheath blight and 11.54% decrease in brown spot symptoms. As the strain is proven as an inducer for systemic resistance based on PR gene expression in Arabidopsis and tobacco models, it is supposed that a similar mechanism works in rice, bringing about disease suppression. The strain could be used as a potent biocontrol and growth-promoting agent in rice cropping system.

A New Method for Sclerotial Isolation of Two Species of Sclerotium from Infested Soils

Kwon, Mi-Kyung,Shim, Hong-Sik,Yeh, Wan-Hae,Kim, Taek-Soo,Cho, Weon-Dae,Kim, Choong-Hoe,Kim, Yong-Ki The Korean Society of Plant Pathology 2004 Plant Pathology Journal Vol.20 No.4

White rot on Allium crops recently had a high incidence with incrensed cultivating areas of tropical garlic types in Korea. Two types of Sclerotium have known as causal agents that produce different size and shapes of sclerotia in infested fields. Therefore, we developed a new method for isolation of sclerotia from infested field soils that can be used for ecological study of Sclerotium spp. and establishment of control strategy. Soil samples collected from heavily infested fields were evenly mixed and placed on a automatic sieve shaker connected with tap water, After 10 min of shaking, residues on 0.5 mm and 0.25 mm sieves were separately collected and suspended with 70% sugar solution, which method floats sclerotia in aqueous layer, Then, floated fraction was carefully separated and mixed with a same volume of 1% sodium hypochlorite solution to differentiate with organic materials. This method provides a direct count of sclerotia under a dissecting microscopy.

Bacillus vallismortis EXTN-1-Mediated Growth Promotion and Disease Suppression in Rice

Park Kyung-Seok,Paul Diby,Yeh Wan-Hae The Korean Society of Plant Pathology 2006 Plant Pathology Journal Vol.22 No.3

Bacillus vallismortis EXTN-1, a biocontrol agent in cucumber, tomato and potato was tested in rice pathosystem against rice fungal pathogens viz. Magnaporthe grisea, Rhizoctonia solani and Cochliobolus miyabeanus. Apart from increasing the yield in the bacterized plants (11.6-12.6% over control), the study showed that EXTN1 is effective in bringing about disease suppression against all the tested fungal pathogens. EXTN-l treatment resulted in 52.11% reduction in rice blast, 83.02% reduction in sheath blight and 11.54% decrease in brown spot symptoms. As the strain is proven as an inducer for systemic resistance based on PR gene expression in Arabidopsis and tobacco models, it is supposed that a similar mechanism works in rice, bringing about disease suppression. The strain could be used as a potent biocontrol and growth-promoting agent in rice cropping system.

Damage Analysis of Rice Panicle Blast on Disease Occurrence Time and Severity

Shim, Hong-Sik,Hong, Sung-Jun,Yeh, Wan-Hae,Han, Seong-Sook,Sung, Jae-Mo The Korean Society of Plant Pathology 2005 Plant Pathology Journal Vol.21 No.2

The structural differences between healthy and diseasedpanicle necks caused by Pyricularia oryzae were observed using electron-microscope. In the diseased panicle neck, the infection hyphae of the rice blast pathogen grew through the sclerenchymatous fiber tissue and reached to the central internal lacuna. Since the pathogen grew through the sclerenchymatous fiber tissues, the vascular bundle composed with xylem and phloem had been destroyed and finally the nutrients from the leaf and stem were not able to be transported into the grains. Infection of panicle base by the blast pathogen until 20 days after heading caused more than 50% of yield loss in both Jinmibyeo and Chucheongbyeo. There was a positive correlation between incidence of the panicle blast and rice yield losses. The regression equations between incidence of the panicle blast and yield losses were y= -3.61+496.7 ($R^2$=0.70) in Jinmibyeoand y=-3.93+520.2 ($R^2$=0.82) in Juanbyeo. The panicleblast caused deterioration of grain quality. Healthy grain rate was reduced by increase of panicle blast infection.

주요 작물 몇 가지 병해충에 대한 수익역치 추정

박홍현,예완해,박형만,Park, Hong-Hyun,Yeh, Wan-Hae,Park, Hyung-Man 한국응용곤충학회 2007 한국응용곤충학회지 Vol.46 No.1

본 연구는 경제적피해수준 설정시 병해충 방제의 경제성을 결정하는 수익역치 개념을 우리나라 농업생산환경에서 적용함에 있어서 일어날 수 있는 문제점들을 검토해 보고자 수행되었다. 수익역치는 방제를 정당화할 수 있는 손실량을 의미하며, 병해충 방제에 소요되는 비용을 농산물 가격으로 나눈 값이다. 본 연구는 우리나라의 벼, 콩, 시설 채소작물의 몇몇 병해충을 대상으로 수익역치를 계산하고, 외국 문헌들에서 보고된 값들과 비교하였다. 벼에 있어서 벼멸구, 흰등멸구, 혹명나방, 벼물바구미, 잎집무늬마름병의 GT값과 그에 상응하는 수량감소율은 4.6-6.1kg/10a/작기, 1.0-1.3%, 도열병은 12.7kg/10a, 2.7% 수준이었다. 콩의 톱다리개미허리노린재는 6.2kg/10a/작기, 3.6% 수준이었다. 시설재배 채소의 경우, 오이의 오이총채벌레, 온실가루이, 노균병은 10.0-12.6kg/10a/주, 1.4-1.7%, 딸기의 점박이응애, 잿빛곰팡이병은 3.1-3.5 kg/10a/주, 1.3-1.5%, 토마토의 아메리카잎굴파리, 온실가루이, 잿빛곰팡이는 8.4-9.7 kg/10a/주, 17-1.9% 수준이었다. 우리나라 환경에서 추정된 GT값들이 전반적으로 외국에서 보고된 값들과 비교했을 때 낮은 수준이었다. 낮은 GT값들은 EIL을 낮게 설정 되도록 한다. 따라서 EIL 설정시 현재의 재배환경에서 계산된 GT 값들을 바로 도입하기 전에, 이 값들이 합리적인가에 대해 진지하게 고려해야 한다는 것을 제안한다. 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.

Responses of Korean Isolates of Phytophthora capsici to Several Chemicals

Hyeong-Jin Jee,Ki-Woong Nam,Wan-Hae Yeh 한국농약과학회 2002 한국농약과학회 학술발표대회 논문집 Vol.- No.-

Leaf blight of welsh onion caused by Phytophthora nicotianae.

Jee, Hyeong-Jin,Kweon, Jin-Hyuek,Yeh, Wan-Hae,Kim, Choong-Hoe The Korean Society of Plant Pathology 2001 Plant Pathology Journal Vol.17 No.6

pBRG-4를 이용한 Metarhizium anisopliae의 형질전환

이동규,예완해,황철원,권석태,강선철,Lee, Dong-Gyu,Yeh, Wan-Hae,Hwang, Cher-Won,Kwon, Suk-Tae,Kang, Sun-Chul 한국응용생명화학회 1998 Applied Biological Chemistry (Appl Biol Chem) Vol.33 No.2

작물 병해충에 대한 무공해 미생물 농약 개발의 일환으로 곤충 병원성 곰팡이 Metarhizium anisopliae의 분자생물학적 육종을 위해 이 균주의 형질전환계를 확립하였다. M. anisopliae의 원형질체를 제작하여 benomyl 약제에 대하여 저항성을 나타내는 Aspergillus flavus 유래의 ${\beta}-tubulin$ 유전자를 갖는 pBRG-4 plasmid DNA를 polyethylene glycol 방법으로 형질 전환하였다. 이 형질전환은 pBRG-4 DNA $50\;{\mu}g$당 10개의 효율로 이루어졌으며, 그 결과 야생형 균주들의 $2.5\;{\mu}g/ml$ 농도의 benomyl 존재 하에서도 성장이 억제되는데 반하여 선발된 형질전환체들은 $5.0\;{\mu}g/ml$ 농도의 benomyl 함유 배지에서도 잘 성장하였다. 또한 이 형질전환체들의 chromosomal DNA를 분리하여 Southern 분석한 결과 ${\beta}-tubulin$ 유전자가 homologous recombination에 의하여 M. anisopliae의 genome속에 삽입 되었음을 확인하였다. We have established a transformation system for entomopathogenic fungus, Metarhizium anisopliae, in order to develop mycoinsecticide by recombinant DNA techniques. Protoplasts of M. anisopliae would be transformed to a benomyl-resistant by introducing pBRG-4 plasmid DNA, which contains a ${\beta}-tubulin$ gene of Aspergillus flavus conferring resistance to benomyl and a pyr4 gene of Neurospora crassa, in the presence of 5% polyethylene glycol and 10 mM calcium chloride. Transformants occuring at a frequency of 10 colonies per $50\;{\mu}g$ pBRG-4 DNA grew on the $5\;{\mu}g/ml$ concentrations of benamyl, while the wild type was inhibited by $2.5\;{\mu}g/ml$. From the Southern analysis using genomic DNAs isolated from M. anisopliae transformants, the positive signals suggested that the ${\beta}-tubulin$ gene had integrated in the M. anisopliae genome by homologous recombination.

pBRG-4 를 이용한 Metarhizium anisopliae 의 형질전환

이동규,예완해,황철원,권석태,강선철 ( Dong Gyu Lee,Wan Hae Yeh,Cher Won Hwang,Suk Tae Kwon,Sun Chul Kang ) 한국응용생명화학회 1998 Applied Biological Chemistry (Appl Biol Chem) Vol.41 No.3

We have established a transformation system for entomopathogenic fungus, Metarhizium anisopliae, in order to develop mycoinsecticide by recombinant DNA techniques. Protoplasts of M. anisopliae would be transformed to a benomyl-resistant by introducing pBRG-4 plasmid DNA, which contains a β-tubulin gene of Aspergillus flavus conferring resistance to benomyl and a pyr4 gene of Neurospora crassa, in the presence of 5% polyethylene glycol and 10 mM calcium chloride. Transformants occuring at a frequency of 10 colonies per 50 ㎍ pBRG-4 DNA grew on the 5 ㎍/㎖ concentrations, of benamyl, while the wild type was inhibited by 2.5 ㎍/㎖. From the Southern analysis using genomic DNAs isolated from M. anisopliae transformants, the positive signals suggested that the β-tubulin gene had integrated in the M. anisopliae genome by homologous recombination.