• Plant Disease and Agriculture
• /
• v.5 no.1
• /
• pp.50-54
• /
• 1999

Leaf blight outbreak was investigated in sweet persimmon tree orchards in Korea during a three-year period from 1995 to 1997. The man percentage of sweet perismmon leaves blighted by Pestalotiopsis theae was 15.9%. The highest disease incidence was surveyed to 20% in Milryang. The disease began from early June to late October, and peaked in September and October. The lesion size on leaf ranged mainly 1-3 cm. The typical symptoms were large grayish concentric lesions of oval patterns of either mesophyll or margin of the leaf, and olde trees were more susceptible than younger ones.

• Korean Journal Plant Pathology
• /
• v.14 no.2
• /
• pp.120-124
• /
• 1998

The conidial germination of Pestaotiopsis theae was occurred in cells attched with pedicels, the inferior cell of conidium. The cells were swollen like a ball, and then germinated in 4 hours under favorable conditions. Generally, it was considered that fifty percent of whole conidia was germinated in the range 6~12 hours. The optimum temperature and pH for conidial germination of P. theae (SP-3) causing leaf blight on sweet persimmon was $25^{\circ}C$ and pH 5, respectively. Conidial germination rate was higher than 90% at 100% relative humidity, but never germinated at a relative humidity lower than 88.5%. Conidial germination was highest at the concentration of 1~4$\times$104 conidia/ml. In case of cultural media, the conidial germination was higher than 90% on PDA, PSA, OME and Leonian agar. There was no relationship between light and conidial germination. It was concluded that the key environmental factors affecting conidial germination of the fungus (SP-3) were temperature and moisture.

• The Korean Journal of Mycology
• /
• v.32 no.2
• /
• pp.130-133
• /
• 2004

Leaf blight and fruit rot of sweet persimmon (cv. Fuyu) caused by Pestalotia diospyri were observed during the growing season and postharvest such as storage and transport, respectively. Typical symptoms on leaves developed with small brown spots and were later reddish brown colors. In the storage fruit, the white mycelial mats formed between fruit and calyx. The pathogenic fungus was isolated from infected fruits and cultured on potato dextrose agar (PDA). Colony color of the fungus was white at first on PDA. Conidia were ovoid or fusiform, 5 cells, middle 3 cells were olive, upper and lower 2 cells were colorless, and their size were $16{\sim}22\;{\times}\;6{\sim}8\;{\mu}m$. They had were $2{\sim}3$ appendage at basal cell and size $9{\sim}18\;{\mu}m$. Based on the cultural and mycological characteristics and pathogenicity test on host plants and fruits, the fungus was identified as Pestalotia diospyri Syd.&P. Syd. This is the first report on the leaf blight and fruit rot of sweet persimmon caused by Pestalotia diospyri in Korea.

• Korean Journal Plant Pathology
• /
• v.12 no.3
• /
• pp.377-379
• /
• 1996

1990이래 단감재배 면적이 확대되고 있는 경주 및 그 인근의 포장으로부터 이미 알려진 병징과는 전혀 다른 병징을 나타내는 병을 단감의 주요 품종인 부유의 이병 잎과 신초로부터 병원균을 분리하고 그 병원 곰팡이의 병원학적 특징을 조사하였다. 이 병은 신초선단부 잎에서 발생하여 아래잎으로 진전되며, 잎에는 잎가장자리나, 중앙부 등 일정한 부위가 없이 발병하여 회갈색의 둥근 무늬가 확대되기도 하고, 심하면 잎이 고사탈락하기도 한다. 심한 경우 병반의 크기가 전체 잎의 1/3이상을 차지할 정도로 크게 확대되었다. 신초는 병의 진전이 심해지면 고사함으로서 나무 생육이 급격히 중지되거나, 나무 수세가 떨어져 수확에도 지장을 주고 있다. 발생시기는 6월 중.하순~7월, 9~10월 초순까지 발병하며, 병든 잎과 가지를 채집하여 병원균을 순수 분리하여 Guba(1949년), Sutton(1969)와 Steyaert(1971)의 분류기준에 따라 동정한 결과는 다음과 같았다. 병원균의 분생포자의 크기는 23.1$\times$7.1 $\mu\textrm{m}$, color cell의 크기와 수는 15.65 $\mu\textrm{m}$, 3개이었고, 포자의 윗부분은 다갈색이었으며 아래부분은 올리브색이었다. Setrlae의 크기와 개수는 23.6 $\mu\textrm{m}$, 2~4(3)개이고, pedicle의 길이는 5.17 $\mu\textrm{m}$였다. 이상의 결과에 근거하여 이 병원균을 Pestalotiopsis theae로 동정하고 국내미기록병으로 보고한다.

• The Korean Journal of Pesticide Science
• /
• v.5 no.4
• /
• pp.50-56
• /
• 2001

In vitro experiments, several fungicides including prochloraz, tebuconazole, fluazinam, fludioxonil, and iminoctadine-triacetate showed more than 85% inhibition of mycelial growth of Pestalotiopsis theae (SP-3). Dichlofluanid and chlorothalonil inhibited mycelial growth at the rate of 10 and 33%, however benomyl did not inhibit mycelial growth of the fungus. Minimum inhibitory concentration(MICs) of iminictadine-triacetate on the mycelial growth of SP-3 isolate was $10{\mu}g/m{\ell}$, but that of P. theae $\underline{MAFF}$ 752002 and P. longiseta $\underline{MAFF}$ 752001 was $1{\mu}g/m{\ell}$. MIC of benomyl, chlorothalonil, dichlorofluanid was $1,000{\mu}g/m{\ell}$, and that of fludioxonil, fluazinam, tebuconazole was $10{\mu}g/m{\ell}$. Conidial germination was inhibited more than 80% in tile medium which contained $1{\mu}g/m{\ell}$ of prochloraz, tebuconazole, fluazinam, fludioxonil, and minoctadine-triacetate. Control values of benomyl, chlorothalonil and dichlofluanid were 40, 60 and 30%, respectively. The controlling effect of iminoctadine-triacetate ($10{\mu}g/m{\ell}$) aganist P. theae (SP-3) in leaf disc test was more than 93%, but benomyl and dichlofluanid could not control leaf blight disease caused by P. theae (SP-3). Tebuconazole, fluazinam, fludioxonil, and iminoctadine-triacetate showed more than 94% of protective and curative effect of leaf blight of sweet persimmon, while, benomyl and dichlofluanid did not show any control effect of the disease.

• Korean Journal Plant Pathology
• /
• v.14 no.5
• /
• pp.502-506
• /
• 1998

In this study, we calculated the genetic relationships of Pestalotiopsis species collected from various places in southern part of Korea through isozyme analyses. As a result, EST showed the largest number of band, and the number of bands were ranged from 5 to 7 on the average. All the isozymes used in this study showed distinctive band patterns for each isolates. Similarities among the compared isolates ranged from 48 to 93%. Isolates SP7, SP19 and SP23 showed more than 90% similarities, and most isolates showed similarities ranging from 65 to 82%.