• Research in Plant Disease
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• v.29 no.2
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• pp.145-157
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• 2023

Apple grower in the Cheongsong region, Korea has reported the increased loss of apple yield due to severe bitter rot incidence. We noticed that this indience is because the Colletotrichum population has developed resistance to commonly used fungicides. We isolated 39 Colletotrichum isolates from 13 orchards in Cheongsong, and all the isolated Colletotrichum species were identified as C. siamense or C. fructicola. These 39 strains were tested for mycelial growth and conidial germination against 12 fungicides. trifloxystrobin (30-55% in recommended concentrations) was shown lower inhibitory effect on mycelial growth. However, the inhibition of conidial germination was shown higher than mycelial growth (62-100%). Kresoxim-methyl was shown lower inhibitory effect on mycelial growth (29-55%). conidial germination inhibitory effect was shown 51% to 96%. dithianon was shown diversity response to inhibition of mycelial growth (43-100%). Tebuconazole was shown high inhibitory effect on mycelial growth (84-100%) and conidial germination inhibitory effect was shown to be 64 to 100%. metconazole has been found to display with high inhibitory effect on mycelial growth (79-100%) and conidial germination (70-80%). fluazinam was shown to possess high inhibitory effect on mycelial growth (87-100%) and conidial germination (94-100%). This study provides basic information for the effective management of apple bitter rot.

• Korean journal of applied entomology
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• v.9 no.2
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• pp.75-80
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• 1970

1. Retention of fungicides and efect of the mixing of spreaders and insecticides with fungicides in control of apple bitter rot were evaluated by 'the assay of inhibition zones with apple exocarp disks:' 2. The effectiveness of chemicals was reduced gradually as the time after treatment increased. Of all the chemicals tested, Difolatan retained approximately 60 percent of the original activity even after IS days. Difolatan had the highest followed by Tuzet, Phaltan, Bordeaux mixture, and Delan, in that order. 3. The fungicidal acivity of Tuzet decreased with increasing application of simulated rain. The wash-offf of Tuzet was reduced by adding spreaders. Dry skim milk and soybean extract were better than commercial chemicals such as Lino No. 1,2 and Tween 20. 4. The mixing of insecticides such as EPN, Folithion, Parathion and Lebaycid with Phaltan resulted in no significant differences in fungicidal effect even after 12 days of storage at room temperature.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.99-106
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• 1999

In order to acquire microbial agents that can be utilized for biological control of bitter rot(Glomerella cingulata), the major airborne disease to apple, the effective microorganisms were isolated, tested for antagonistic activity to the pathogen. Through the screening of more than 1,000 species of microorganisms collected in nature, 11 species of antagonists were selected. On of the 11 species, one species designated as CH141 demonstrated outstanding activity. The bacterial strain, CH1141 exerted antagonistic efficiency of 65% on Glomerella cingulata. The CH1141 was identified as a bacterial strain to Bacillus subtilis based on morphology, culture conditions, and physiobiochemical characteristics.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.109.2-109
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• 2003

A basic spray program for apple in which fungicides are scheduled to spray at 15-day interval from petal fall to late August was formulated on the properties of several selected fungicides. In order to improve it, experimental plots, completely randomized block with 3 replications, were prepared in an orchard of 15 years old Fuji cultivar, and the spray programs in which only one chemical in the basic spray program was substituted with others were applied to each plot. It was revealed that only single substitution of the fungicide in the basic spray program makes a great differences in the control of white rot and bitter rot, and that the control property of the fungicides against the two diseases was quite variable even by the time of application. A simila! ! r trial was conducted in 2002 with a new basic spray program that was formulated with fungicides that have shown best control in each spraying time in the previous trial, similar results were obtained. Applying this method, the usefulness of certain fungicide in the spray program for apple could be properly assessed. Anthracnose of Robinia pseudo-acacia L. caused by Collectotrichum spp.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.708-718
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• 2016

Two different pest control programs were applied on 8-year-old 'Ryoka'/M.26 apple trees (Malus domestica Borkh.). Lime sulfur or Bordeaux mixture with emulsified oil were applied 12 times from late March to mid-September as organic treatment, and synthetic chemicals were 7 times applied as control treatment. Over the entire apple-growing season, photosynthesis rates of apple trees were significantly lower in the organic treatment than in the control, and this photosynthetic differences were larger in July and August. Photosynthesis-related parameters such as stomatal conductance and transpiration behaved similarly to photosynthesis. The leaf area in the organic treatment was significantly smaller ($24.7cm^2$) than that in the control treatment ($30.7cm^2$). Organic leaves contained significantly less Chl. a ($15.5mg{\cdot}g^{-1}$) than did control leaves ($17.6mg{\cdot}g^{-1}$). Fruit yield per tree was significantly lower in the organic treatment (18.8 kg) than in the control (24.5 kg), because organic fruits experienced a higher rate of disease infection such as white rot (Botryosphaeria dothidae) and bitter rot (Glomerella cingulata) than did control fruits. Organic fruits had high flesh firmness but less color development (lower Hunter's a values). In this experiment, the pest control program with frequent applications of organic fungicides showed negative effects on photosynthesis and disease infection on leaves and fruits, and thus reduce the fruit quality and yield in 'Ryoka'/M.26 apple trees.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2000.10a
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• pp.37.2-37
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• 2000

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.37-37
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• 2014

Glomerella leaf spot pathogens can infect apple leaves, causing extensive necrosis and premature defoliation, as well as necrotic spots on fruit. In recent years, the disease has been reported with increasing frequency in China, and appears to be spreading rapidly in some apple-producing areas. In this study, fungal isolates from diseased apples leaves collected in Henan and Shaanxi provinces were analyzed based on morphology, cultural characters, pathogenicity and molecular phylogenetics. It was found that Glomerella leaf spot of apple was caused by two pathogens, Colletotrichum fructicola and C. aenigma. Pathogenicity tests showed that C. fructicola and C. aenigma could infect apple leaves of cultivar Golden Delicious, as well as Gala, Qinguan, Pink Lady, Pacific Rose, Golden Century and Honeycrisp, all of which include Golden Delicious in their parentage. In wound inoculation experiments, C. fructicola and C. aenigma were pathogenic to fruit of Gala, Qinguan, Golden Delicious, Pacific Rose, Starkrimson and Fuji. With non-wounded fruit, C. fructicola was pathogenic to Gala and Golden Delicious, and C. aenigma was pathogenic to Gala. It is concluded that the two pathogens could be differentiated according to pathogenicity to leaves and fruits of different apple cultivars.

• Korean Journal of Organic Agriculture
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• v.18 no.2
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• pp.221-232
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• 2010

During 2005~2009, current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the non-chemical or organic cultured apple orchards in Korea. Numbers of certified organic or non-chemical apple orchards increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits were caused by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests, respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective under the adequate conditions.

• Research in Plant Disease
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• v.12 no.3
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• pp.153-157
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• 2006

In 2005, average temperature was lower, and average rainfall was less than those of previous year. The diseases of rice, barley, pepper, chinese melon, apple and oriental pear were surveyed. Bacterial blight, bacterial grain rot, and panicle disease of rice, black rot of pear, and white rot and bitter rot of apple were severe. Especially, brown rot of rice occurred four times higher than those of previous year. Panicle blight of rice increased about 3 times, compared with the previous year, presumed that the higher rainy days, rainfall and RH promoted spread of the fungal pathogens to panicles of rice. The diseases of rice leaf blast, sudden wilt syndrome, downy mildew and powdery mildew of chinese melon in plastic greenhouse, and virus diseases of hot pepper occurred distinctly less than those of the previous year. Another diseases surveyed occurred similar or less.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.45-56
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• 2009

Current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the organic or non-chemical pest control orchards from 2005 to 2009. Numbers of certified organic or non-chemical apple orchards were increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits occurred by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective to control under the adequate conditions. At present, it is extremely difficult to produce organic apples in Korea. Growers must consider about and solve so many conditions on the cultivar, weather, local site, marketing and so on, before when they decide to change from conventional or IPM(Integrated Pest Management) to organic or non-chemical pest control orchards.