• Mycobiology
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• 제39권3호
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• pp.200-205
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• 2011

Marssonina coronaria associated with apple blotch disease causes severe premature defoliation, and is widely distributed in Korea. Thirteen isolates were collected from orchards located in Gyeongbuk Province from 2005~2007. All isolates displayed over 99.6% and 99.2% sequence similarity to each other in internal transcribed spacer regions and partial sequences of 28S rDNA, respectively. The isolates were phylogenetically closely related to Chinese isolates. Selected isolates did not differ in their pathogenicity. The optimum conditions for fungal growth were $20^{\circ}C$ and pH 6 on peptone potato dextrose agar (PPDA). Peptone and mannose were the best nitrogen and carbon source, respectively. Fungal growth was better on PPDA than on common potato dextrose agar. This study provides valuable information for integrated disease management program and facilitates the routine culturing of M. coronaria.

• Journal of Plant Biotechnology
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• 제42권3호
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• pp.271-276
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• 2015

Crab apple cultivars, 'Maypole', 'Tuscan', and 'Manchurian', were evaluated as potential pollinizers of major apple cultivars, 'Fuji', 'Hongro', and 'Tsugaru', cultivated in high-density apple orchard systems. Numerous cultivar characteristics, including blooming time, pollen germination, fruit set, disease and pest resistance, and self-incompatibility, were examined. The blooming times of both 'Maypole' and 'Tuscan' ranged from April 19 to May 5, which was 2-4 days earlier than those of the major commercial apple cultivars. PCR analysis did not reveal the presence of any of the S-alleles (S1, S3, S7, or S9) identified in major commercial apple cultivars. In addition, the percentage of the fruit set was high after trees were artificially fertilized with crab apple pollen. Artificially cross-pollinated fruits were of similar or higher quality than open-pollinated fruits. They also demonstrated resistance to apple blotch, sooty blotch, and fly speck. The results indicate that the two crab apples, 'Maypole' and 'Tuscan' would be potential candidates for pollinizers of major apple cultivars in Korea. Use of the pollen of these crap apples in commercial production will improve fruit quality and promote sustainable and robust fruit production.

• The Plant Pathology Journal
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• 제35권6호
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• pp.585-597
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• 2019

A disease forecast model for Marssonina blotch of apple was developed based on field observations on airborne spore catches, weather conditions, and disease incidence in 2013 and 2015. The model consisted of the airborne spore model (ASM) and the daily infection rate model (IRM). It was found that more than 80% of airborne spore catches for the experiment period was made during the spore liberation period (SLP), which is the period of days of a rain event plus the following 2 days. Of 13 rain-related weather variables, number of rainy days with rainfall ≥ 0.5 mm per day (L_day), maximum hourly rainfall (P_max) and average daily maximum wind speed (W_avg) during a rain event were most appropriate in describing variations in airborne spore catches during SLP (S_i) in 2013. The ASM, Ŝ_i = 30.280+5.860×L_day×P_max-2.123×L_day×P_max×W_avg was statistically significant and capable of predicting the amount of airborne spore catches during SLP in 2015. Assuming that airborne conidia liberated during SLP cause leaf infections resulting in symptom appearance after 21 days of incubation period, there was highly significant correlation between the estimated amount of airborne spore catches (Ŝ_i) and the daily infection rate (R_i). The IRM, ${\hat{R}}_i$ = 0.039+0.041×Ŝ_i, was statistically significant but was not able to predict the daily infection rate in 2015. No weather variables showed statistical significance in explaining variations of the daily infection rate in 2013.

• 한국식물병리학회지
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• 제11권1호
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• pp.17-29
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• 1995

This study was conducted from 1991 to 1993 to develop a fungicidal spray program for the apples exportable to the United States of America, in which quarantine and pesticide residue in agricultural products are strictly regulated. In 1991, 2 spray schedules were applied to an orchard, in one of which the 7 fungicides registered for apple both in Korea and U.S. were used, and in the other of which the Bordeaux mixture for which the tolerance was exempted in U.S. was used 2 times along with those 7 fungicides. The apple white rot and fruit infection by Alternaria mali were not effectively controlled by the 7 fungicides alone; however, the control efficacy was raised by adding the Bordeaux mixture to the spray schedule. In 1992, 4 spray schedules were applied in which the kinds of fungicides and spray intervals were different one another. The results suggested that an effective spray program can be developed by adopting the Bordeaux mixture for 3 times or adopting the imminoctadine-triacetate which has not tolerance level in U.S. for same times in the vulnerable stage of apple white rot and alternaria blotch. In spite of the high efficacies against major apple diseases, the Bordeaux mixture could not be recommended to the apple growers due to the various defects such as restrictions in compatibility with insecticides and acaricides, troublesomeness in preparation and spray, especially the harmful effect on the finish of Fuji apples. In 1993, a spray program adopting 3 times of imminoctadine-triacetate during the growing season of apple was developed, which not only can effectively control the major apple diseases but also avoid the pesticide residue problems if it was sprayed 2 or 3 times after bagging. On the basis of the 3 years results, a basic fungicide spray program was formulated in which 1~3 times of imminoctadine-triacetate and 1~2 times of bitertanol were adopted in addition of the 7 common fungicides registered in both countries. In the results of application of the spray schedule to the actual farming in the 4 areas of Kyungpook Province in 1994, no noticeable defects were detected at the first year trial. However, this spray program will be continuously evaluated and modified to obtain better control efficacies against major apple diseases.

• The Plant Pathology Journal
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• 제25권3호
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• pp.270-279
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• 2009

During the course of a study to develop a spraying program at 15-day spray intervals, two important findings were identified allowing for further reduction of spray frequency by increasing the spray interval. In evaluating the contribution of fungicides from a 15-day spray interval program, control of white rot, which is of prime importance in Korea, was not affected, in spite of the extended spray interval caused by omitting the fungicides during the season. In another experiment assessing the duration of the protective activities of several key fungicides used in the 15-day spray interval program, infection control was maintained for almost 30 days for some fungicide. Based on these two findings, a basic spraying program with a 25-day spray interval was developed. This program was modified for four successive years to improve the control efficacy against bitter rot and Marssonina blotch, which sometimes causes as much damage as white rot.

• The Plant Pathology Journal
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• 제22권4호
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• pp.375-380
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• 2006

In the survey from 1992 to 2000, twenty-eight parasitic diseases were observed in major apple producing areas in Korea. The predominant apple diseases were white rot(Botryosphaeria dothidea), Marssonina blotch(Marssonina mali), Valsa canker(Valsa ceratosperma), Alternaria leaf spot(Alternaria mali), and bitter rot(Collectotrichum gloeosporioides and C. acutatum). Apple scab that reappeared in 1990 after disappearance for 15 years was disappeared again since 1997. A viroid disease(caused by apple scar skin viroid) was newly found in this survey. The five diseases, fire blight(Erwinia amylovora), black rot(Botryosphaeria obtusa), scab(Cladosporium carpophilum), Monochaetia twig blight(Monochaetia sp.), and brown leaf spot(Hendersonia mali), which had once described in 1928 but no further reports on their occurrence, were not found in this survey. However, blossom blight(Monilinia mali), brown rot(Monilinia fructigena), and pink rot(Trichothecium roseum), which did not occur on apple after mid 1970s, were found in this survey.

• 원예과학기술지
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• 제19권3호
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• pp.362-366
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• 2001

1998년 8월 중순 경북 북부지역에 있었던 집중호우에 의한 하천 범람으로 침수된 과수원을 군위, 의성, 안동에서 지역별 6개 과수원씩, 총 18개 과수원을 대상으로 '후지' 사과나무의 생육 상황과 주요 병해 이병률을 조사하였다. 조사 과수원의 침수 깊이는 70cm-350cm였고, 침수 기간은 6시간-72시간이었다. 침수 피해 사과원의 낙엽률, 발아율 및 이상개화 현상은 침수 깊이가 깊을수록, 침수 기간이 길어질수록 증가하였다. 새 뿌리 발생은 침수 기간이 길어질수록 급격히 감소하였고, 침수로 인한 뿌리 고사율은 16.2%로 나타났다. 잎의 갈색무늬병, 과실의 부패병, 역병 발생이 무침수 과원에 비해 크게 증가하였고, 조사 항목 간 상관분석 결과, 침수에 의한 이상 생육과 발병 증가가 침수 깊이보다는 침수 기간에 더 큰 영향을 받는 것으로 조사되었다.

• The Plant Pathology Journal
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• 제17권6호
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• pp.368.4-369
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• 2001

• 한국식물병리학회지
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• 제10권4호
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• pp.284-291
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• 1994

In order to establish an appropriate spray schedule to reduce the infection, 11 kinds of chemicals were tested for their properties on the inhibition of spore germination at the surface of apple fruits and the duration of the inhibitory effect after spray of each chemical was examined from late June to early September with basically 10 day intervals. Actual control efficacy of each chemical by the 8 successive spray and the patterns of waterborne spore dispersals during that periods were also examined. Combining those results with the meteorological observation data, actual control efficacy of each chemical in the given periods could be estimated. It was revealed that folpet, Brodeaux mixture, mancozeb, oxine copper and imminoctadine-triacetate could be used at any time during the possible infection periods. Captan and dithianon could also be used except the rainy season due to the short duration of inhibitory efficacy against spore germination under heavy rain. However, the usefulness of propineb, benomyl and chlorothalonil against the apple white rot could not be demonstrated in this experiment. Thiram, even though has not been used for apple white rot, can also be used before or after the rainy season to control not only white rot but also alternaria blotch.

• 한국유기농업학회지
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• 제18권2호
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• pp.221-232
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• 2010

본 연구에서는 2005년부터 2008년에 걸쳐 무농약 유기농산물 인증을 받은 사과원의 변동 상황을 조사하였고, 무농약 유기재배 사과원에서 병해충 발생과 관리 실태 파악을 목적으로, 2006년에는 17명, 2009년에는 13명을 대상으로 심각한 피해를 야기하는 문제병해충과 병해충 관리를 위해서 사용한 친환경 농자재에 대해서 설문조사를 실시하였다. 2007년에는 무농약 유기농산물 인증을 받은 음성 무주 장성 영주 의성 청송 칠곡 지역의 10개 사과원을 대상으로, 2009년에는 충주 예산 영덕 지역의 3개 사과원을 추가한 13개 사과원을 대상으로 피해가 많았던 병해충의 발생상황과 병해충 관리를 위해서 사용한 친환경 농자재에 대해 방문조사를 실시하여 다음과 같은 결과를 얻었다. 2005~2008년에 걸쳐 사과에 무농약농산물 인증을 받은 농가는 각각 9, 24, 42, 48농가였으며, 유기농산물(전환기 유기농산물 포함) 인증을 받은 농가는 각각 5, 4, 11, 30농가로서, 2005년 대비 2008년에 무농약농산물은 5.3배, 유기농산물은 6배가 증가하였다. 무농약 유기농산물 인증 사과원에서 문제된 병해는 갈색무늬병, 탄저병, 겹무늬썩음병, 그을음(점무늬)병이었는데, 석회유황합제와 석회보르도액을 사용하는 사과원의 경우에 2006년과 2007년에 비하여 2009년에는 갈색무늬병, 탄저병, 겹무늬썩음병의 피해가 적었고, 그을음(점무늬)병은 심하지는 않았지만 문제가 되었다. 문제된 해충으로는 2006년과 2007년에는 사과혹진딧물, 복숭아순나방, 복숭아심식나방이었으나, 2009년에는 교미교란제, 난황유, 기계유유제를 사용하는 사과원의 경우에 이들 해충의 피해는 크게 적어진 반면에, 일부 사과원에서 사과유리나방과 사과면충으로 인해 새로운 문제가 야기되었다.