• The Plant Pathology Journal
• /
• 제17권5호
• /
• pp.264-270
• /
• 2001

The effects of leaf extracts of 14 different non-host plant species on in vitro conidial germination of Phaeoisariopsis personata, the causal organism of late leaf spot(LLS) of groundnut were evaluated. Aqueous and ethanol leaf extracts of Datura metel, Lawsonia inermis and aqueous leaf extracts of Sphaeranthus indicus at 25%(w/v) concentration completely inhibited the conidial germination of P. personata both at 24h and 48h after incubation. Aqueous leaf extracts of Blumea bifoliata, Eucalyptus globules, Ocimum sanctum and Pongamia pinnata, and ethanol leaf extracts of Azadirachta indica and S. indicus inhibited the conidial germination by >90%. Aqueous and ethanol leaf extract of L. inermis and S. indicus were highly inhibitory to conidial germination up to 1% concentration. Aqueous and ethanol leaf extracts of D. metel and ethanol leaf extract of A. indica were highly inhibitory to P. personata even at 0.01% (100 ppm) concentration. Ethanol leaf extract of A. indica up to $80^{\circ}$, aqueous leaf extracts of D. metel and S. indicus up to $100^{\circ}$, and L. inermis up to $60^{\circ}$, were highly stable and retained their fungitoxic effects. Extract of D. metel was antifungal even after 180 days when it was stored both at room temperature and $4^{\circ}$. Aqueous leaf extract of D. metel at 2% concentration effectively reduced the development of LLS by >60%, under greenhouse conditions both in prophylactic and simultaneous applications. Extracts of D. metel could be a potential economical and an eco-frendly alternative for control of late leaf spot, and its efficacy under field conditions is further being evaluated.

• 한국식물병리학회지
• /
• 제10권3호
• /
• pp.169-174
• /
• 1994

A new unidentified pear leaf spot disease presumed to first occur in the late 1970's has recently become prevalent over the pear growing areas, and caused the greatest problem for pear production in Korea. The disease began to develop on pear leaves at mid- to late May, peaked at mid- to late une, but stopped further development until September in cool climate. Leaf lesions are 0.9∼2.5 mm in diam., oval or irregular to rectangular in shape, first appeared reddish purple, later changed to dark brown, and to whitish grey in the late season. Lesions were limited to appear only on the mature, hardened leaves, initially from leaf margin or near the leaf veins, and later scattered over the leaf surface. Individual lesions usually did not enlarge, but often coalesced each other, commonly causing shot holes and eventual early falling. The disease was most severe on the major pear cultivars Niitaka and Okusankichi ranged with 4 to 100% infections in trees, depending on the orchards, but not on the cultivar Chojuro. Damages from the disease included lower fruit weight, and higher acid and less sugar content in fruits, resulting in lowering the overall fruit quality. Etiology of the disease including identification of the causal organism is in a separate paper.

• 한국식물병리학회지
• /
• 제14권6호
• /
• pp.676-681
• /
• 1998

Disease incidence of Codonopsis lanceolata was surveyed at the major cultivating fields in Chonbuk province in 1996 to 1997. The main diseases of Codonopsis lanceolata were ovserved as leaf spot caused by Septoria codonopsis, anthracnose by Glomerella cingulata, brown leaf spot by Cercospora sp., rust by Coleosporium koreanum, powdery mildew by Erysiphe sp., Fusarium wilt caused by Fusarium oxyporum, and white root rot by Sclerotium rolfsii. Anthracnose, leaf spot and brown leaf spot occurred severely on leaves from early July to late August. They were caused early fallen leaves. Fusarium wilt and white root rot occurred severely on stem and below the soil line in late August. They resulted in withering to death or chlorosis and fallen of leaves. Disease incidence of Codonopsis lanceolata was also substantially different in occurrence with a method of cultivation in late growth stage. Fusarium wilt and white root rot were more severe with a method of no support cultivation than those with a method of support cultivation with a stick. Fusarium wilt occurred 48.8% in a method of no support cultivation but 3.1% in a method of support cultivation with a stick. And white root rot occurred 18.9% in a method of no support cultivation but 0.3% in a method of no support cultivation with a stick. Thus, it proved that soil-borne diseases could be controlled support cultivation with a stick.

• The Plant Pathology Journal
• /
• 제33권4호
• /
• pp.434-439
• /
• 2017

Incidence rates of diseases in kiwiberry orchards were investigated monthly from late June to late September in Gwangyang and Boseong in 2015 and 2016. The impact of postharvest fruit rot was investigated during ripening after harvest. Bacterial canker was only observed on one single tree in 2015, but black rot, powdery mildew, leaf spot and blight, and postharvest fruit rot diseases were problematic throughout the study period in both 2015 and 2016. Incidence rates of the diseases varied with kiwiberry cultivar, region and sampling time. Incidence rates of powdery mildew, leaf spot and blight diseases increased significantly during the late growing stages near fruit harvest, while black rot peaked in late August. Incidence rate of postharvest fruit rot on fruit without fruit stalks was less than half of fruit with fruit stalks, regardless of kiwiberry cultivars. Among the four cultivars, Mansu was relatively resistant to black rot and postharvest fruit rot diseases. In our knowledge, this is the first report of various potential pathogens of kiwiberry in Korea.

• The Plant Pathology Journal
• /
• 제20권1호
• /
• pp.67-74
• /
• 2004

A complete understanding of the epidemiological factors required for optimum for disease development facilitates the design of effective and reliable screening techniques and also disease prediction models. An attempt was made to study the effects of different temperatures ($15-35^{\circ}C$) and leaf wetness periods (4-24 h) on the development of late leaf spot (LLS) in three groundnut genotypes differing in their susceptibility to LLS infection. Irrespective of the genotype, the disease progress evaluated based on different components of resistance was maximum between $15-20^{\circ}C$ and minimum between $20-25^{\circ}C$. At temperatures $\geq$$30^{\circ}C$, LLS development was insignificant. The overall severity of LLS increased with an increase in the leaf wetness period from 4 h to 12 h a day. Further increase of wetness period to 16 h resulted in a rapid increase in the severity. Thereafter, the disease severity gradually decreased with an increase in the wetness period. The effect of temperature and wetness periods on the individual component of disease quantification was not uniform compared between genotypes with different levels of susceptibility/resistance to LLS infection. The results of this study indicate that temperature and leaf wetness period are critical in late leaf spot screening programs since the expression of disease symptoms measured from disease initiation till defoliation, varied differently in the test genotypes with respect to change in these two parameters.

• 식물병연구
• /
• 제10권4호
• /
• pp.209-216
• /
• 2004

The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.

• 식물병연구
• /
• 제17권3호
• /
• pp.410-412
• /
• 2011

2000년대 후반부터 고흥지역의 비파나무(Eriobotrya japonica)와 제주지역의 홍가시나무(Photinia glabra)에 Entomosporium mespili에 의한 극심한 점무늬병이 발생하기 시작하였다. 따라서 방제효과가 높은 살균제를 선발하기 위하여 이 연구를 수행하였다. 효과를 검정한 3개의 농약 중 비파나무 점무늬병에는 propiconazole 처리가 방제가 64.1%로 가장 높게 나타났고, 홍가시나무 점무늬병에는 chlorothalonil 처리가 방제가 87.6%로 가장 높게 나타났다. Thiopanate-methyl 처리는 방제가가 비교적 낮게 나타났고, propiconazole은 홍가시나무에 약해를 나타내었다.

• 한국약용작물학회지
• /
• 제5권3호
• /
• pp.206-210
• /
• 1997

6월 하순부터 1개월 간격으로 작약의 잎과 줄기에 인위적 고사를 유도하여 지상부 고사가 뿌리의 발달, 수량, 상품성에 미치는 영향을 구명코자 시험한 결과는 다음과 같다. 1. 작약의 잎과 줄기를 고사시키는 주 병원균은 점무늬병균, 녹병균, 흰가루병균, 검은무늬병균, 탄저병균, 갈색점무늬병원균이었다. 2. 점무늬병과 흰가루병은 4월 하순에서 5월 중순경에 발병되었고, 녹병은 6월 상 순부터 발생되어 시일이 경과할수록 발생율이 증가하였다. 3. 작약 지상부의 고사는 5월 하순부터 시작되어 8월 하순경에는 50% 이상의 고사율을 보였다. 4. 수량은 정상주에 비해 6월 하순 및 7월 하순 고사가 $31{\sim}35%$ 감수되었고, 8월 하순과 9월 하순 고사가 $7{\sim}12%$의 감수를 보였다. 5. 직경 10mm이상 상품성이 있는 뿌리수는 6월과 7월 고사가 8월이후 고사에 비해 적었고 주성분 Paeoniflorin 함량은 조기에 고사된 작약 뿌리 가 오히려 높았다.

• 한국약용작물학회지
• /
• 제4권3호
• /
• pp.236-240
• /
• 1996

1. 작약(芍藥)의 지상부(地上部)에 기생(寄生)하는 주요 병원균(病原菌)은 점무늬병균 등 7종(種)이었으며 점 무늬병은 잎, 검은무늬병은 줄기, 흰가루병은 잎과 줄기 등 지상부 전체에 발생이 심하였다. 2. 작약(芍藥)에는 점무늬병과 흰가루병이 우점종(優占種)이었고, 각각 4월 하순, 5월 중순부터 발생되기 시작하여 5월 하순 이후는 급격히 증가하였으며 의성작약(義城芍藥)이 영천종(永川種)보다 발병율이 높았다. 3. 시기별(時期別) 작약(芍藥) 지상부(地上部) 고사율(枯死率)은 95년의 경우 5월 하순부터 고사(枯死)하기 시작하여 6월 하순에 15.3%로 그 이후부터는 급격히 증가하여 8월 상순에는 50.6%가 고사(枯死)하였으며 5, 6월의 조기고사(早期枯死)는 주로 흰가루병 때문이었다.

• 한국유기농업학회지
• /
• 제24권4호
• /
• pp.773-786
• /
• 2016

포도 캠벨얼리품종은 우리나라 포도재배면적의 70%를 차지하고 있으며 다른 품종에 비해서 갈색무늬병에 대해서 감수성으로 병 발생이 심할 경우 과실당도의 저하를 가져와 품질하락과 생육불량 등의 문제점을 발생시킨다. 이러한 켐벨얼리 포도품종에서의 갈색무늬병에 의한 생육피해 해석을 위해서 7년생의 유기재배 켐벨얼리 품종대상으로 2015년 8월에 갈색무늬병이 발병된 포도나무를 대상으로 광합성 효율 특성, 엽록소함량 및 감염잎의 화학성분 등을 비교분석하였다. 갈색무늬병 감염면적이 증가함에 따라서 $CO_2$ differential value (기준기와 분석기 $CO_2$ 농도차이), WUE value (광합성수분사용효율)와 A value ($CO_2$의 흡수율/호흡률) 등은 크게 감소하는 경향이었으며 stomatal conductance value (기공전도도)은 큰 영향이 없는 것으로 조사되었다. 총 엽록소의 함량은 병징이 심할 경우 50% 이상 감소하여 엽록소 함량의 감소가 포도갈색무늬병 발병잎의 광합성 효율 저하에 큰 영향을 끼치는 것으로 생각되며 병반면적률에 따른 화학성분을 조사한 결과 병반면적률이 증가할수록 잎의 질소, 인산, 칼륨 함량은 감소하였으며 반면에 총탄소, 칼슘 그리고 마그네슘의 함량은 병반면적률에 비례해서 증가하였다.