• Horticultural Science & Technology
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• v.33 no.3
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• pp.429-434
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• 2015

Apple blotch-like symptoms (ABLS) were observed on 'Fuji' apple leaves in Cheongsong, Gunwi and Yeongcheon apple orchards located in Gyeongbuk Province during 2010-2014. Characteristics of ABLS were yellowing, brown spots on leaves, and defoliation, similar to apple blotch diseased (ABD) leaves, which are infected with Marssonina coronaria. It is difficult to differentiate by eye between ABLS and ABD, which has led to misdiagnosis and overuse of fungicides. The present study was conducted to investigate the cause of ABLS using stereomicroscopy, culture isolation, cross-sectional analysis of leaves, and PCR. No acervuli were found on the surface of ABLS leaves and no growth was observed on potato dextrose agar (PDA) plates in culture. Furthermore, cross-sectional analysis revealed similar results, and mycelia were absent in ABLS leaves. By contrast, all these characteristics were present in ABD leaves. Furthermore, no fungi or viruses were detected in ABLS leaves by PCR, suggesting that the disease is not caused by these agents. These findings suggest that ABLS might be a physiological disorder in plants that is distinct from ABD.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.324-330
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• 2021

Agriculture is one of the essential needs of human life on planet Earth. It is the source of food and earnings for many individuals around the world. The economy of many countries is associated with the agriculture sector. Lots of diseases exist that attack various fruits and crops. Apple Tree Leaves also suffer different types of pathological conditions that affect their production. These pathological conditions include apple scab, cedar apple rust, or multiple diseases, etc. In this paper, an automatic detection framework based on deep learning is investigated for apple leaves disease classification. Different pre-trained models, VGG16, ResNetV2, InceptionV3, and MobileNetV2, are considered for transfer learning. A combination of parameters like learning rate, batch size, and optimizer is analyzed, and the best combination of ResNetV2 with Adam optimizer provided the best classification accuracy of 94%.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.371-381
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• 2023

The effectiveness of plant-based attractants was studied using large traps, which attracted relatively more snails in agricultural water drainage ditches and rice-cultivating environments, although their effectiveness in rice fields and lakes was limited. The rate began to rise after three hours of observation. Watermelon peel exhibited the highest apple snail attraction rate (13.8%), followed by potatoes (10.0%), and apple peel (8.8%). These values significantly differed from the attraction rate attributed to papaya leaves (F=3.84; P=0.0387). After 24 h, watermelon peel and apple peel indicated a higher rate of attraction (23.4% and 21.7%, respectively), which were significantly different compared with those of papaya leaves and potatoes (F=9.94; P=0.00455). Large bait traps outperformed funnel traps in capturing golden apple snails and trapped a significant number of snails measuring over 1 cm in size. Watermelon peel was the most effective attractant for a large bait trap, followed by apple peel, potatoes, and papaya leaves. On average, 110 snails were captured in the lure net. However, potatoes, apple peels, and papaya leaves caught an average of 93, 80, and 79 snails, respectively. Among the attractants, the lure effect of the snails was not significantly different. The efficiency of large bait traps in capturing snails, regardless of the plant attractant employed, followed the order: apple peel > watermelon peel and potatoes > papaya leaves > melon > Korean melon. Watermelon peel is highly recommended for farmer use, as well as apple peel and potatoes. Utilizing these snail attractants may contribute positively to developing a safe and environment-friendly integrated pest management strategy.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.133-140
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• 2012

In this study we investigate the use of 2D and 3D scanning optical coherence tomography (OCT) technology for use in apple blotch diagnosis. In order to test the possible application of OCT as a detection tool for apple trees affected by Marssonina coronaria, we conducted several experiments and compared the results from both healthy and infected leaves. Using OCT, we found several distinctive features in the subsurface boundary regions of both the diseased and healthy leaves. Our results indicate that leaves from diseased trees, while still appearing healthy, can be affected by M. coronaria. The A-scan analysis method confirmed that the boundaries found under the subsurface layers can be faint. This shows that M. coronaria can exert its influence on entire apple trees (as opposed to only on leaves with lesions) once it infects healthy trees. Our results indicate that OCT can be used as a noninvasive tool for the diagnosis of fungal disease in apple trees. Microscopic imaging results, performed as a histological study for comparison, correlated well with the OCT results.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.36-36
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• 2014

Apple blotch, caused by Marssonina coronaria, induce early defoliation in apple and leading to critical economic losses in apple orchards in Korea. Since M. coronaria is difficult to culture, we developed isolation and cultural method. We collected M. coronaria isolates from Gyeongbuk Province and then constructed phylogentic tree based on ITS regions. As the results, phylogenetic relationship indicated that all Korean isolates formed a same cluster and closely related to Chinese isolates [1]. Ecological characteristic of M. coronaria have been observed in apple orchards which located in Gyeongbuk Province from 2011 to present. As the results, the typical apple blotch symptoms were observed from July, and then the infected leaves were discolored and formed acervuli on the leaves. After rainfall, severe infection of symptoms such as discoloration and early defoliation were continuously observed until October. Also overwintered conidia were observed in next March on the fallen diseased leaves [2]. In the last 5 years, ascopores of M. coronaria were not observed in apple orchards which were severely infected by M. coronaria in Korea. Thus, it is assumed that overwintered conidia could be a primary inoculum of M. coronaria. Meanwhile, apple blotch has long latent periods compare to other apple disease. During the latent period, early diagnosis of apple blotch is the most important to control the disease by spray fungicide. In this reason, we developed novel diagnostic method to detect M. coronaria during latent period using optical coherence tomography (OCT) and Loop-mediated isothermal amplification (LAMP) method [2, 3]. In this presentation, it will introduce ecological characterization of M. coronaria in Korea and unique detection technique of M. coronaria in apple. It will be helpful to develop new strategies to control apple blotch in Korea.

• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.1-6
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• 1989

This study was performed to reveal the heavy metal contents in apple leaves, and to estimate the correlation between contents of heavy metals of orchard lands and those of apple leaves. For this experiment, the apple leaves were collected from 58 apple orchards in Korea. The results were as follows ; 1. The average heavy metal contents in apple leaves were 26.44(6,23-182,85) ppm in Cu, 0.34 (0.07-0,61) ppm in Cd and 9.47 (0.00-225.50) ppm in Pb. 2. On the simple correlation coefficients between contents of heavy metals of orchard lands and those of apple leaves, all three copper cadmium and lead were positive but cadmium was insignificanfly, correlated. There was no difference among varieties (Ralls, Jonathan, etc) in these results. 3. The 0.1N HCl extraetion proved, was more suitable than the $IN-NH_4OAC$ extraction for describing the relation-Ship between heavy metal contents of apple leaves and those of orchard lands.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.17-18
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• 1974

The outbreak of apple scab was found on the apple seedlings growing in Korea which were imported from Marylang, U.S.A. in 1972. Symptom of apple scab is much similar with pear scab caused by Venturia pirina except that the round spot on leaves, more lesions on upper side of leaves and much severe symptoms appeared on both side of leaves. About $14\%\; and \;12\%$ of plants were infected in 1972 and 1973, respectively.

• Research in Plant Disease
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• v.27 no.2
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• pp.79-83
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• 2021

The aim of the present study was to develop a sensitive and specific detection method for the rapid detection of apple scar skin viroid (ASSVd) in apple leaves. The resulting reverse transcription recombinase polymerase amplification (RT-RPA) assay can be completed in 10 min at 42℃, is 10 times more sensitive than conventional reverse transcription polymerase chain reaction, and can specifically amplify ASSVd without any cross-reactivity with other common apple viruses, including apple stem grooving virus, apple stem pitting virus, and apple chlorotic leaf spot virus. The reliability of the RT-RPA assay was assessed, and the findings suggested that it can be successfully utilized to detect ASSVd in field-collected samples. The RT-RPA assay developed in the present study provides a potentially valuable means for improving the detection of ASSVd in viroid-free certification programs, especially in resource-limited conditions.

• Korean Journal of Plant Resources
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• v.32 no.6
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• pp.677-682
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• 2019

Hand leaf thinning for improvement of fruit coloration and quality is one of the most labor-consuming works in Korean apple cultivation. The study was aimed at investigating whether foliar application of two chelate compounds (Cu-EDTA, Fe-EDTA) could defoliate effectively 'Hongro'/M.9 apple leaves and enhance fruit coloration and quality. At 30 days before harvest, foliar spray with two chelate compounds defoliated significantly the apple leaves. Chelate treatments did not affect the leaf chlorophyll content. High concentration of chelates decreased drastically photosynthetic rate of true leaves, and then it stayed in low levels, whereas low levels of chelates reduced sharply the photosynthetic rate but it was gradually restored over time. Cu-EDTA regardless of its concentration triggered higher defoliation compared to Fe-EDTA. Consequently, higher defoliation improved light interception of fruits and accumulated more anthocyanin. Particularly, Cu-EDTA could target mainly fruit cluster leaves which affect directly light interception of the fruits, i.e. more selective defoliants compared to Fe-EDTA. However, 3% Cu-EDTA rather defoliated excessively, accompanying with reduction of fruit weight and soluble solids. Therefore, our results suggest that 1% Cu-EDTA which defoliates properly the fruit cluster leaves could improve coloration and quality of 'Hongro'/M.9 apple fruits.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.46-49
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• 1999

Bacterial blight occurred on the flowers, leaves, twigs and branches of apple trees (Malus domestica Borkh) in Chunchon, Kangwon-Do. Infected flowers and leaves turned brownish black, and they were fallen down or remained hanging in the trees. Under humid conditions during postblossom period, the casual bacterium spreaded along twigs and killed them. However, killing of branches was very rare. The symptoms on apple trees were very similar to symptoms of fire blight. But the causal organism isolated from the lesions was identified as Pseudomonas syringae based on physiological and chemical characteristics. This is the first described bacterium that causes apple shoot blight in Korea.