• Korean journal of applied entomology
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• v.58 no.4
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• pp.271-280
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• 2019

We investigated the control efficacy and phytotoxicity of unmanned aerial vehicle-applied pesticides against the insect Spodoptera exigua, a major emerging pest in Chinese cabbage. Phytotoxicity was investigated in cabbage and 7 crops cultivated in the perconducted on 8 surrounding crops including Chinese cabbage at 1 to 2 times the recommended pesticide dosage. We treated cabbage fields with spinetoram suspension concentrate (16×), methoxyfenozide, sulfoxaflor suspension concentrate (16×). Then, we used water-sensitive paper to measure the distribution pattern of falling pesticide particles and the degree of coverage. Two of the pesticides showed 97% control efficacy, however, control efficacy might differ in resistant populations. Phytotoxicity was not observed in Chinese cabbage and the 7 surrounding crops treated with 1 to 2 times the recommended pesticide dosage. Analysis of the distribution pattern of falling pesticide particles revealed that breeze caused particle diffusion. Thus, wind is an important factor affecting the uniform treatment and diffusion of multicopter-applied pesticides. It follows that setting optimal conditions is necessary for effective control and treatment.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.229-236
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• 2011

This study was carried out to provide recent information on zoysiagrass (Zoysia spp.) sod production in Japan. Total zoysiagrass sod production acreage in Japan was 6,623 ha. The acreage by prefecture was 3,900 ha (58.9%) in Ibalaki, 779 ha (11.8%) in Tostoli, 609 ha (9.2%) in Kagosima, and 550 ha (8.3%) in Sijeumoka, respectively. Sod was harvested by 1.5 cm sod thickness. Mowing height of Goraisiba (Zoysia matrella) and Nosiba (Zoysia japonica) cultivars was cut by 10 mm and 25 mm height, respectively. Japan agricultural cooperative issued a warranty of sod production quality to zoysiagrass consumers. A quality evaluation for sod production was carried out continuously to maintain a reasonable degree of uniformity and hight quality of sod production three times a year. Also, zosiagrass sod production was rotated with Chinese cabbage (Brassica rapa var. glabra Regel) for improving fertility of soil every five to six years. Patented cultivars for promoting bland in Ibaraki prefecture of Japan were 'Tsukuba himae', 'Tsukuba kagayaki', 'Tsukuba Talou' and 'Tsukuba green'.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.246-254
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• 1996

Since the mid of 1980's, cultivation area and production of Ganoderma lucidum have been increased annually in Korea. However, the presence of a fungal disease has become a major limiting factor in the cultivation of Ganoderma lucidum, causing a serious economic loss. The present study was carried out to isolate and identify the pathogenic fungus to Ganoderma lucidum. Several fungi isolated from the wood logs showing typical symptoms were tested whether they are pathogenic to Ganoderma lucidum or not by cross-pairing culture method, flask inoculation method, and wood log inoculation method. The pathogenic fungus produced ascomata. Mature ascomata was spherical, dark, thick-walled, $45{\sim}95\;{\mu}m$ diameter. Asci were thin-walled, evanescent when mature, disintegrate early. Ascospores were spherical, hyaline, glaborous, thick-walled, refractive, $3.6{\sim}4.3\;{\mu}m$ in size. Conidiophores soon became abundantly septate and broke up into arthrospores, which are cylindrical, $3{\sim}6\;{\mu}m$ long and $3{\sim}4\;{\mu}m$ wide. Based on the observations under dissecting microscope, light microscope and scanning electron microscope, teleomorph and anamorph of the pathogenic fungus were identified as Xylogone sphaerospora Von Arx & Nilsson and Sporendonema purpurascens (Bonordon) Mason & Hughes, respectively. X. sphaerospora is first reported as a pathogenic fungus of Ganoderma lucidum.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.183-187
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• 1995

The germination characteristics of Diplachne fusca (L.) P. Beauv. seeds were investigated under different seed storage conditions to find out reliable system for maintaining the seeds with high and uniform germination rate and thus for possible use of the seeds in herbicide screening with a continuous seed supply. When the seeds were stored under wet-low temperature($4^{\circ}C$) condition, the germination rate was 88% after 4-week-storage. The germination rate slightly declined after the storage for longer than 3 months. Dry seeds stored at room temperature exhibited very low germination rate. The wet-low temperature treatment was effective for inducing the germination of the seeds which had been stored under dry-room temperature condition for 4 months. The germination rate was 70% after 2-week- storage under the wet-low temperature condition. The germination rate was much higher under an alternate temperature condition than under a continuous temperature condition. The optimum temperature was 35/$25^{\circ}C$(14/10hrs). The seeds had a capability to germinate under NaCl-treated condition even at a concentration of 1.0%, whereas the germination of Echinochloa crus-galli seeds was completely inhibited by 0.5% NaCl. This result indicates that D. fusca has an advantage over E. crus-galli to survive in reclaimed 1and from the sea.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.497-503
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• 2018

A strawberry variety 'Arihyang' was derived as an artificial cross between 'Tochiotome' and 'Seolhyang' in 2014. The seedling and line selections were conducted from 2014 to 2015. Preliminary and advanced yield trials of '14-5-5,' which was the final selected line, were conducted from 2015 to 2017. 'Arihyang' is suitable for forced cultivation and has strong plant vigor, uniformly large-sized fruit, and a high yield compared to those of the check variety, 'Seolhyang' and 'Maehyang.' Especially, vitamin C was at a significant level, which was approximately 15% higher than that of 'Seolhyang.' The average number of flowers per first flower cluster was 10.5, which could reduce the labor of thinning fruit. Its fruit has a conical shape, dark red color, and glossy skin. The fruit was of good quality but has recommendations for harvest at the fully ripened stage. 'Arihyang' has intermediate resistant to phytophthora crown rot, but is susceptible to powdery mildew, gray mold, anthracnose, and fusarium wilt. It is reguired to manage major diseases and pests using optimum cultivation techniques and chemical control.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.21-27
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• 1996

This experiment was conducted to find out an effective propagation method for reed(Phragmites communis Trin.), ensuring a continuous herbicide screening for reed control. Reed propagation methods were compared under a greenhouse condition using tour different materials; seeds, rhizomes, depressed stolons of P. japonica Steud., and stem cuttings. Although reed seeds were easy to harvest and store, their germination rate(${\leq}$5%) was very low and seedling growth from the seeds was slow. Rhizomes were difficult to harvest and their harvest time was limited from November to March. Furthermore, reed propagation using rhizomes had problems of a relatively low germination rate(46%), no uniformity in size and shape, individual differences at the early stage of growth, and difficulties in material storage. Rate of reed growth from rhizomes was higher in commercial soil mix(Boo Nong soil) than in sand or in sand+upland soil(1:1). Depressed stolons of P. japonica had a moderate germination rate(65%) and were relatively easy to harvest. However, their harvest time was limited only from August to September. Propagation method using stem cuttings had several advantages over the above methods using other materials. Reed plants could uniformly be propagated from the stem cuttings with a relatively high germination rate(75%). Stem cuttings of central nodes showed a higher germination rate compared to those of upper or lower nodes. Stem cuttings from the field should be used immediately after harvest, since their germination rate decreased rapidly when they were stored under a wet- or a dry-refrigerated condition. Furthermore, the germination of stem cuttings tended to decrease when they were collected from the field after August. This indicates that there is a limitation of harvest time for stem cuttings. However, a year-round propagation of reed using stem cuttings is possible if parent plants are grown in a greenhouse, and thus herbicide screening for reed control could continuously be performed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.9-16
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• 2016

To investigate the effect of soluble silicate zeolite dressing of the rice against bakanae disease, field trial in reclaimed land and in vitro were carried out. The coated rice seeds (SCS) which were dressed with the mixture of 25% silicic acids (binder), and the zeolite (coating powder). In wet direct seeding, uniform scattering of rice seeds on the soil surface and the better seedling establishment were shown in SCS treatment plots. The incidence of bakanae disease began from the mid tillering stage toward the heading stage. Around heading stage, the ratio of infected tillers reached its highest point by 9.9% in non-SCS treatment plots. While, in SCS treatment plots, the ratio of infected tillers was no more than 0.01%. The vitality of the pathogenic fungi of bakanae disease in the SCS and non-SCS samples were assessed. Samples were incubated for one week keeping proper humidity at $30^{\circ}C$ after inoculated with panicles of infected rice plants from experimental field plots. In non-SCS treatment, pinkish colonies were formed on the grain surface of panicle of infected plants, and mycelium, macro-conidia and micro-conidia were developed actively inside part of infected grain inoculated. While in SCS treatment, micro-conidia and mycelium were not survived and the growth of macro-conidia, mycelia were greatly inhibited and withered. Based on the results, it is concluded that the environmental friendly control of bakanae disease by use of SCS is possible and soluble silicate can be applied as agents for replacement of seed disinfection.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.10-17
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• 2014

This study was conducted to elucidate the relationship between light and coloring and to obtain basic results for promoting redness expression in 'Kalle' (Pyrus communis L.) pear skin. It was investigated in location of anthocyanin layer by microscopic observation and differences in skin color expression of 'Kalle' bagged with paper bag which has different light transmittance rate and inside temperature. However, there was no anthocyanin layer in the brown skin and golden yellow color, anthocyanin layer was distributed in epidermins or hyperdermis of red skin pear and apple. Dark red colored 'Kalle' had more anthocyanin content, $29.8mg{\cdot}100g^{-1}$ FW than light red colored apple 'Hongro'. Light transmittance rate of physical characteristics used paper bags was the highest in white paper bag, 42.2% and it also had more light quantity, $8.9{\mu}mol$ than any other tested paper bags in specific wave length 650-655 nm. The maximum temperature of inner bag was higher about $3^{\circ}C$ in yellow paper bag. The red coloration and anthocyanin contents in no bagged fruits were higher than in any other bagged fruit. However, red color expression among the bagged fruits was higher in white paper bag than in double layered black paper bag and yellow paper bag. Also, chromaticity value seemd to be a good index to explain variation of fruit skin color, because anthocyanin content and chromaticity value were higher. Based on these results, it is desirable to cultivate 'Kalle' without bag for stable redness expression but bagging is essential for decreasing damage by insect in Korea. Further examination to find suitable time of removing paperbag for redness expression and decreasing insect damage. In addition, it is required to develop paperbag whose transmittance rate is high in specific light wavelength or temperature of inner bags is low. Additional key words: anthocyanin, bagging, chromaticity value, light transmittance, Pyrus communis L.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.401-410
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• 2005

A series of studies involving formulation processes, bubbling activity test, diffusibility test and biological efficacy test was undertaken to develop Jumbo herbicide formulations in paddy rice field. Gas evolution speed from the tablets prepared by different organic acids was in the order of oxalic acid, malonic acid, citric acid, and tartaric acid. The total volume of evolved gas from the tablet and diffusibility of the active ingredient in the submerged water were increased with increase of water temperature; the volume from 1 g of tablet at 10, 15, 25 and $30^{\circ}C$ for 5 minutes after immersion into water was 20, 25, 28, 45, 57 mL, respectively. The concentration of halosulfuron-methyl and pyriminobac-methyl in submerged water at 5, 15, 20 and $30^{\circ}C$ at the 2.4 m distance from the applied spot of the tablet was 20, 48, 85, and 97% of the concentration of treated spot, respectively. The evolved gas volume from the tablets was not affected by pH of submerged water. The concentration of halosulfuron-methyl in different sizes of submerged water within 24 hours after treatment of the tablet was maintained 0.16 ppm, which is ideal concentration at standard dosage regardless of the submerged water area. The concentration of pyriminobac-methyl was also uniformly dispersed in the water within 24 hours after applying it into the submerged water. The wind velocity of 5 m $sec^{-1}$ on concentration distribution of halosulfuron-methyl and pyriminobac-methyl in the submerged water 24 hours after treatment was not influenced; an equal concentration in the up the wind and down the wind from the applied spot was maintained. Spot treatments of one tablet formulations(5 g) including 4 times higher dosage at 4 different spots resulted in even concentration distribution of active ingredient in the water 24 hours after applying it into the submerged water.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.352-362
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• 2023

Harvest time is one of the most important determining factors of seed quality, especially for species that produce seeds over irregular and long-term periods, such as Larix kaempferi. A cone collection plan must be established to increase seed production efficiency and stable mass production. We investigated seed qualities such as seed efficiency, germination rate, and T₅₀ (germination speed), with 7 or 8 cone collection times at a clonal seed orchard of L. kaempferi in Chungju between 2021 and 2022. A multivariate analysis was then performed for the collected data. In early August, decreases in the moisture contents and browning of cones were observed. These were followed by a decrease in germination rate, with a peak at the end of September, but no clear trend was observed. The later the cones were harvested, the better the seed vigor (T₅₀). However, the seed yield and efficiency decreased owing to increases in seed scattering and the number of insect-damaged seeds. As a result, the optimal time of seed harvest for the seed orchard was in early August. To produce uniform seedlings, insect damage must be reduced through timely control and harvest cones in early September. This shows that the degree of browning and moisture content of cones can be used as indicators of the timing of cone collection in L. kaempferi seed orchards.