• Research in Plant Disease
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• v.9 no.4
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• pp.196-200
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• 2003

Sixteen hundred fruits were randomly collected from 16 kiwifruit (Actinidia deliciosa) orchards in Jeonnam, Gyeongnam and Jejn provinces in Korea in 2000 and incidences of postharvest fruit rots were examined. The overall disease incidence was 32% and varied much with locations of orchards ranging from 5 to 68%. The percentages of kiwifruits showing internal, external, and both internal and external symptoms were 21.9%, 4.9%, and 5.2%, respectively. Several fungi were isolated from rotten fruits; Botryosphaeria dothidea, Diaporthe actinidiae and Botrytis cinerea were the major pathogens with the average isolation rates of 83.3%, 11.9% and 1.4%, respectively. Based on the symptoms on kiwifruits and the characteristics, the postharvest fruit rots caused by B. dothidea and D. actinidiae are suggested to be named as ripe rots and stem-end rots, respectively.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.105-110
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• 2000

Sex pheromone composition was analyzed for Dichocrocis punctiferalis, which attacksapple, peach, chestnut fruits, etc., and its behavioral and field trapping studies were conducted to developa monitoring system with its sex pheromone. Virgin females showed maximum mating behavior andhairpencil extrusion behavior between 4-5 hrs after lights-off under 16L18D photoperiod and 26rf 1 "C.During this period, two sex pheromone components, ElO-hexadecenal and ZlO-hexadecenal, weredetected by GC analysis in the hexane extract of abdominal tips of virgin females. The best attraction ofmales to various synthetic sex pheromone blends was obtained at the 70 : 30 ratio of ElO-hexadecenal andZ10-hexadecenal for hair pencil extrusion and at the 80 : 20 ratio for flying upwind response. The highestattractiveness in fields was obtained between 70 : 30 and 80 : 20 from several tests in apple, peach andchestnut orchards.and chestnut orchards.

• Journal of Forest and Environmental Science
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• v.25 no.1
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• pp.1-24
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• 2009

Teak (Tectona grandis) is one of the most valuable timber yielding species in the world, with predominant distribution in tropical or sub-tropical countries. However, natural teak available only in few countries like India, Myanmar, Laos People's Democratic Republic and Thailand. Teak grows well in deep, well-drained alluvial soils, fairly moist, warm, tropical climate with pH ranges from 6.5-7.5. Teak is cultivated in many Asian, African and South American countries for timber production. The global teak plantations are estimated to be three million hectare with major share in India (44%) followed by Indonesia (33%). India is considered as richest genetic resources of teak with large areas of natural teak bearing forests (8.9 million ha), plantations (1.5 million ha), clonal seed orchards (1000 ha) and seed production areas (5000 ha). The studies on diversity of teak populations showed that teak is an out crossing species with major portion of diversity present within the populations. The productivity and quality of teak timber varies depending upon the site and environmental conditions. Teak wood is moderately heavy, strong and tough,straight grained, coarse textured and ring porous with specific gravity varies from 0.55 to 0.70. The sapwood is white to pale yellow in colour and clearly demarcated while heartwood is dark brown or dark golden yellow in colour. Teak is one of the most durable timbers in the world, practically, impervious to fungus and white ant attack and resistant to decay. Teak wood is used in ship and boat constructions, furnitures and aesthetic needs. Genetic improvement programmes have been undertaken in countries like Thailand, India, Malaysia and Indonesia. The programme includes provenance identification and testing, plus tree selection and clonal multiplication, establishment of seed orchards and controlled hybridization. Several aspects like phenology, reproductive biology, fruit characteristics, silvicultural practices for cultivation, pest and diseases problems, production of improved planting stock, harvesting and marketing, wood properties and future tree improvement strategy to enhance productivity have been discussed in this paper.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.255-262
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• 2016

Purpose: Fuji apples are one of the top selling exports for South Korea bringing in over $233.4 million in 2013. However, during the last few decades, about half of the Fuji apple orchards have been infected by Apple Marssonina Blotch disease (AMB), a fungal disease caused by Diplocarpon mali., which takes about 40 days to exhibit obvious visible symptoms. Infected leaves turn yellow and begin growing brown lesions. AMB promotes early defoliation and reduces the quality and quantity of apples an infected tree can produce. Currently, there is no prediction model for AMB on the market. Methods: The Precision Agriculture Laboratory (PAL) at the University of Florida (UF) has been working with the National Academy of Agricultural Science, Rural Development Administration, South Korea to investigate the use of hyperspectral data in creating an early detection method for AMB. The RDA has been researching hyperspectral techniques for disease detection at their Apple Research Station in Gunwi since 2012 and disseminates its findings to the local farmers. These farmers were surveyed to assess the state of knowledge of AMB in the area. Out of a population of about 750 growers, 111 surveys were completed (confidence interval of +/- 8.59%, confidence level of 95%, p-value of 0.05). Results: The survey revealed 32% of the farmers did not know what AMB was, but 45% of farmers have had their orchards infected by AMB. Twenty-five percent could not distinguish AMB from other symptoms. Overwhelmingly, 80% of farmers strongly believed an early detection method for AMB was necessary. Conclusions: The results of the survey will help to evaluate the outreach programs of the RDA so they can more effectively educate farmers on the identifying, treating, and mediating AMB.

• Research in Plant Disease
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• v.23 no.1
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• pp.1-18
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• 2017

Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker, is currently causing severe economic losses to kiwifruit production worldwide. The pathogen has affected green-fleshed kiwifruit cutlivars and yellow-fleshed kiwifruit cultivars since 1988 and 2006 in Korea, respectively. In recent years, the biovar 3 strains of P. syringae pv. actinidiae were introduced through imported contaminated pollens and have rapidly spread to neighboring kiwiruit orchards by secondary infection, leading to outbreaks of bacterial canker and tremendous damages on yellow- and red-fleshed kiwifruit cultivars. In this review, we summarize the various management practices of bacterial canker of kiwifruit such as disease escaping, cultural practices, blocking of dissemination, early diagnosis, eradication of inoculum sources, chemical control, and trunk injection on the basis of our research works and field experiences and important research products conducted during the last three decades in the world. Finally, we propose a manual for the efficient management of the disease that can be practically utilized at the farmers' orchards in order to keep kiwifruit vines healthy in the future.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.567-575
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• 2009

Organic pear (Pyrus pyriforia) fruits have remarkably increased in Korea since year 2000 due to increase consumer's demand for the fruit, and the farmers are keep trying to change their cultivation system that is replaced from conventional farming to organic-base farming for the fruit. However, there is little information for the soil properties, tree nutrition, and tree growth at organic orchards in Korea. Therefore, this study was established to investigate for the chemical properties of soils and leaf and bud characteristics of a conventional and organic pear trees in experimental orchards for two years. Commercial (Sanwool, YoungHwa Co., Korea) compost was applied to the orchard soils with conventional farming systems for two years for pear trees (10 to 15 year old trees) in KyungSan, Korea. The compost application increased pH, organic matter content, cation exchange capacity (CEC), and, microbial biomass in the soil. The compost treatment also increased specific leaf weight and foliar $P_2O_5$ concentration as well as leaf and floral bud sizes.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.235-241
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• 2017

Purpose: It is to develop an agricultural three-directional dumping vehicle that can help farmers reduce intensive labor when carrying heavy loads and for easy dumping. In addition, a novel mechanism was applied for controlling the direction of the tilting cargo box by using a single hydraulic cylinder and simple apparatus. The overturning safety was analyzed to provide safe-use ground slope region of the vehicle to be used at upland fields and orchards. Methods: The developed three-directional dumping vehicle was constructed using a cargo box, vehicle frame, driving components, lifting components, and controller. The novel mechanism of controlling the dumping direction involves the operation of two latching bars, which selectively release or collapse the connecting edge between the vehicle frame and cargo box. A multibody dynamics analysis software (RecurDynV8R5) was used to determine the safe-use ground slope area when tilting the cargo box at slopes. A computer analysis was conducted by increasing the ground slope while rotating the vehicle when the cargo box comprised loads of 300 and 500 kg and stacking heights of 40 and 80 cm, respectively. Results: The three-directional dumping vehicle was successfully manufactured, and the cargo box was tilted at $37^{\circ}$ and $35^{\circ}$ for dumping forward and sideways. The latching bars were manually and selectively collapsed with the vehicle frame to control the dumping direction. When forward dumping, the safe-use ground slope was over $20^{\circ}$ in all vehicle directions and loaded conditions. Conclusions: A three-directional dumping vehicle was developed to reduce labor-intensive work in the farming environment. The user can easily control the dumping direction by using the control panel. The vehicle was safe to be used in most of the Korean upland fields and orchards (area over 96%) for the forward dumping.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.24-29
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• 2014

BACKGROUND: Recently, as the consumption of fresh jujube is increased, fertilizer in jujube cultivation is excessively used to supply nutrient for large fruit produce. This study was conducted to obtain the useful data related to optimum nutrient management technique for fresh jujube cultivation. METHODS AND RESULTS: Nutrient contents of the jujube orchard soils were investigated at 30 different jujube orchards in Boeun, Chungbuk. Soil samples were collected from the different orchards in June, both 2012 and 2013. Soil chemical properties such as pH, organic matter, available phosphate, and exchangeable potassium, calcium, and magnesium were analyzed. Soil available phosphates in optimum level for jujube cultivation were 7% and 13% of total samples in the 2011 and 2012 respectively, and 73% and 57% were higher than optimum level. In Exchangeable K, 37%, 30% were optimum level, 63%, 67% were higher in the year 2011 and 2012 respectively. CONCLUSION: These results showed that nutrient contents of soils were accumulated in jujube orchard of Boeun area. Especially, available phosphate and exchangeable potassium were greatly higher than their optimum level for jujube cultivation respectively.

• Korean journal of applied entomology
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• v.29 no.1
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• pp.20-24
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• 1990

Studies were carried out to investigate the overwintering densities of spider mites, hatching rate and time of P. ulmi eggs, and seasonal occurrences of spider mites (P. ulmi and T. urticae) in apple orchards of Kyungpook province from 1987 to 1989. Overwintering density of P. ulmi eggs was higher in Kunwi, Andong, Chilgok but lower in Kyungju. Overovintering densities of T. urticae were high in all the regions. With the hatching time and rate for P. ulmi eggs, the first hatching ate was April 14, and the last was May 3, and the average hatching rate was 89.3%. The density of P. ulmi was high from early May to middle July and T. urticae begin to increase rapidly from middle June and then was continuously high upto fruit harvesting time.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.235-240
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• 2006

Efficacies of two commercial mating distruptor (SPLAT$^{(R)}$ and Isomate$^{(R)}$-ROSSO) were evaluated on field overwintering populations of Oriental fruit moth, Grapholita molesta (Busck), in four apple orchards. Based on the monitoring with sex pheromone traps, all the orchards (Youngchun, Kyungsan, Chungsong, and Youngju in Korea) exhibited significant overwintering populations from late April to late May. Both mating disruptors that were applied 10 days before the monitoring period significantly inhibited the male orientation to the monitoring lures, in which SPLAT type was more effective than Isomate type in the disrupting efficacy. The disruption of male orientation was highly correlated with the reduction in the early leaf damage caused mostly by G. molesta.