• The Plant Pathology Journal
• /
• v.33 no.4
• /
• 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.

• Research in Plant Disease
• /
• v.24 no.2
• /
• pp.113-122
• /
• 2018

Ripe rot, Botrytis storage rot and Sclerotinia rot are major fungal diseases that lead to deterioration of fruit quality in Korea. Ripe rot, which is caused by Botryosphaeria dothidea, affects harvested fruits during post-storage ripening, while Botrytis storage rot, caused by Botrytis cinerea, affects harvested fruits during cold storage, and Sclerotinia rot, caused by Sclerotinia sclerotiorum, mainly affects immature fruits on the trees. Major fungal fruit rots tend to affect yellow- and red-fleshed cultivars of kiwifruit more severely because of the sharp increase in their cultivation acreage in recent years in Korea. In this review, we summarize symptoms and epidemiological characteristics of the major fungal fruit rots and propose integrated management methods of the diseases that can be practically utilized at the farmers' orchards in order to prevent the diseases based on our research works and field experiences and the research works of others conducted during the last three decades worldwide.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.1
• /
• pp.79-82
• /
• 2012

Blossom-end rot is probably the most recognizable Ca deficiency that affects fruit production including pepper. We investigated the induction of blossom-end rot during the period of rapid vegetative growth and fruit setting, and the effect of Ca fertilization on the suppression of blossom-end rot in pepper plants grown in a plastic-film house. During the first fruit setting period, more than 60% of pepper fruits larger than 8 cm showed the symptoms of blossom-end rot. Under the condition of transpiration occurring at a much faster rate, growing leaves of pepper plants could be the greater sinks for Ca than developing fruits. The incidence of blossom-end rot was significantly decreased after two weeks of Ca fertigation. Calcium application during the rapid vegetative growth and fruit setting period could be suggested as a preventive step to overcome the local Ca deficiency inducing blossom-end rot of pepper fruits.

• Research in Plant Disease
• /
• v.26 no.1
• /
• pp.48-52
• /
• 2020

In July 2019, typical rot symptom was observed on peach fruits harvested from the fields at Andong, Korea. As the disease progressed, white and purple colored mycelial mat developed on the surface of the infected fruits. A causal pathogen was isolated from the infected fruit and cultured on potato dextrose agar media for identification. Fungal colonies on potato dextrose agar produced 3 pigments, including purple, yellow, and white colors. The isolate incited fruit rot symptoms on artificially inoculated peach fruits, from which the same fungus was isolated, fulfilling Koch's postulates. Based on the morphological characteristics and sequence analysis of rDNA internal transcribed spacer, translation elongation factor 1-alpha, and β-tubulin, the causal agent of the disease was identified as Fusarium avenaceum. This study is the first report of fruit rot of peach fruits caused by Fusarium avenaceum in Korea.

• The Korean Journal of Mycology
• /
• v.42 no.4
• /
• pp.353-356
• /
• 2014

In August 2013, brown rot was observed on cherry fruits (Prunus avium L.) in Hwaseong city, Korea. Fruit rot first appears as small, circular brown spots that increase rapidly in size causing the entire fruit to rot. Grayish spores appear in tufts on rotted areas. Based on these morphological characteristics, the two isolates were identified as Monilinia fructicola. Molecular analysis of 5.8S subunit and flanking internal transcribed spacers (ITS1 and ITS2) was performed to confirm the identification. The ITS sequences had 100% identity with those of other reference M. fructicola isolates of NCBI GenBank. Pathogenicity was tested using spore suspension inoculation on wounded or unwounded cherry fruits. The lesions were observed on wounded and unwounded fruits after inoculation for 7 days. This is the first report on M. fructicola causing brown rot on cherry fruits in Korea.

• Journal of Bio-Environment Control
• /
• v.17 no.2
• /
• pp.143-149
• /
• 2008

The effects of fruit bagging time, bag kinds, and plant oil treatment on fruit cracking, pathogenic decay, and quality in grapevines were studied. The occurrence of cracking fruit was not affect by bag kinds in 'Campbell Early'. But, bitter rot occurrence in 'Campbell Early' and occurrence of cracking fruit and bitter rot in 'Wase Campbell Early' decreased effectively compared the ones of conventional bag, window bag, calcium coated bag to non-bagging. The cracking fruit occurrence of and 'Kyoho' decreased significantly by bagging to each before July 5 of 'Campbell Early' and before June 29 and July 5 of 'Kyoho' grapevines. The cracking fruit and bitter rot occurrence by plant oil treatment decreased significantly in 'Wase Campbell Early', and increased calcium of fruit skin in 'Campbell Early'. The soluble solids in fruits were much reduced by window bag and the Hunter b value in fruit skin was reduced by calcium coated bag. Accordingly, treatment of Ca-coated bag and plant oil was become judgment to reduction effect of cracking fruit.

• The Plant Pathology Journal
• /
• v.17 no.2
• /
• pp.110-113
• /
• 2001

Post-harvest diseases of kiwifruit caused severe damages on the fruits during storage, transportation, marketing and consumption. Phomopsis sp. was reported to be one of the major causal organisms of post-harvest fruit rots of kiwifruit. Symptoms of stem-end rot caused by Phomopsis sp. appeared at the stem-end area of the fruit as it ripened. The brown pubescent skin at the area became soft and lighter in color than the adjacent firm healthy tissues. A watery exudate and white mycelial mats were frequently visible at the stem-end area forming a water-drop stain down the sides on the dry brown healthy skin. When the skin was peeled back, the affected flesh tissue was usually watersoaked, disorganized, soft and lighter green than the healthy tissue. Phomopsis sp. was consistently isolated from the diseased fruits, and its pathogenicity was confirmed by an artificial inoculation test on healthy fruit of kiwifruits. The mycological characteristics of the telemorph state of the fungus produced on potato-dextrose agar were in accordance with those of Diaporthe actinidiae. This is the first report on the occurrence of a telemorph state of D. actinidiae as the causal organism of stem-end rot of kiwifruit in Korea.

• The Plant Pathology Journal
• /
• v.19 no.5
• /
• pp.227-230
• /
• 2003

Ripe rot was commonly found in overripe kiwifruits (Actinidia deliciosa) during a disease survey conducted in Jeju and Jeonnam provinces in Korea in 1999. While the disease did not manifest any clear external symptoms on kiwifruits, it caused portion of the fruit surface to collapse. Watersoaked flesh tissue could be seen on the sunken part when the skin of the collapsed portion was peeled off. The milky internal symptom with dark green margin developed concentrically as the fruit ripened. A species of Botryosphaeria was consistently isolated from lesions showing typical symptoms of ripe rot on kiwifruit, and its pathogenicity was confirmed by artificial inoculation test on healthy kiwifruits. The fungus was also pathogenic to apple and pear. The mycological characteristics of the fungus were consistent with those of Botryosphaeria dothidea. This is the first report on the detailed mycological characteristics of the causal organism of post-harvest ripe rot of kiwifruit in Korea.

• The Plant Pathology Journal
• /
• v.35 no.5
• /
• pp.530-537
• /
• 2019

Fuji, a major apple cultivar in Korea, is susceptible to white rot. Apple white rot disease appears on the stem and fruit; the development of which deteriorates fruit quality, resulting in decreases in farmers' income. Thus, it is necessary to characterize molecular markers related to apple white rot resistance. In this study, we screened for differentially expressed genes between uninfected apple fruits and those infected with Botryosphaeria dothidea, the fungal pathogen that causes white rot. Antimicrobial tests suggest that a gene expression involved in the synthesis of the substance inhibiting the growth of B. dothidea in apples was induced by pathogen infection. We identified seven transcripts induced by the infection. The seven transcripts were homologous to genes encoding a flavonoid glucosyltransferase, a metallothionein-like protein, a senescence-induced protein, a chitinase, a wound-induced protein, and proteins of unknown function. These genes have functions related to responses to environmental stresses, including pathogen infections. Our results can be useful for the development of molecular markers for early detection of the disease or for use in breeding white rotresistant cultivars.

• Korean journal of applied entomology
• /
• v.25 no.2 s.67
• /
• pp.63-70
• /
• 1986

Severity of incidence of white rot on apple fruit ranged from 5 to 16% and averaged 9% over major apple growing area in 1981. An isolate of Botryosphaeria ribis obtained from rotted apples developed lesions on leaves, branches and fruits of apple, pear, peach and grape in a series of wound inoculation test. B. ribis grew well on both potato sucrose agar and oatmeal agar. The best condition for vegetative growth on these two media was at $25{\sim}30^{\circ}C$ pH 4 and $10{\sim}15%$ sucrose content under light illumination. Rot development on fruit was first observed in the orchard at early August when sugar content in fruit reached 9.0%. Thereafter, number of rotted apples increased as sugar content increased. There was no correlation between the pH of juice of fruit and rot incidence. Infection on fruit began to occur as early as mid-June when young fruits were formed and infections were continued until harvest. When apple fruits were collected at 10-day intervals from the orchard beginning from early June and were wound-inoculated with B. ribis, rot lesion developed regardless of the stage of fruit growth. Incidence of white rot in the orchard was severe on Golden-delicious and Yukou, intermediate on Aoli, Fugi and Indo, and least on Jonathan and Red-delicious.