• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.336-343
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• 2019

Wet direct-seeding (WDS) is an important method for improving the competitiveness of rice production in South Korea. We analyzed the optimum direct-seeding date to establish the rice standing rate in each area and selected suitable areas for WHS by considering the heading stage limit date for improving cultivation safety. As a result, the rice direct-seeding date to control weedy rice was around 5.15, 5.17-5.19, and after 5.20 in southern Youngnam, southern Honam, and the Middle Coast areas, respectively. However, the optimum seeding date for good standing rice was in late March in most areas. Analyzing by area, most of the southern plains and parts of the central inland plain are suitable for WHS. However, most parts of Gwangwon-do, and the northern parts of Chungbuk, Gyeongbuk, and Yeonghonam areas are not suitable for WHS, and should therefore avoid WHS.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.551-559
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• 1992

These studies were conducted to investigate the biological effects of buprofezin 25% WP on the adult of the brown planthopper (BPH) and its control effects on the BPH population, when buprofezin was treated on different days after the introduction of the BPH adult to the potted rice. Also age structures of the BPH population at the time of buprofezin treatment were observed. The results were as follows: Buprofezin (7.0 g a.i./l0 a) could reduce the longevity and fecundity of the newly emerged female but did not affect the biology of older female, and it did not affect the biology of the male. The larval densities at the time of buprofezin treatment was reduced to nearly zero after treatment. The higher the residual effect and the proportion of larvae at the time of buprofezin treatment were, the higher its con¬trol effect on the BPH population was. In case of buprofezin 7.0 g a.i./l0a treatment, the time interval of treatment that could show the highest control effect was about 10 days (from 18 days after the adult introduction to the adult emergence days of next generation).

• Korean Journal of Organic Agriculture
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• v.13 no.3
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• pp.301-314
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• 2005

Insect pests were surveyed in 5 Rice paddy field areas of Organic paddy field and conventional paddy field. At the each rice-growth period, the occurrence rate of 'Small brawn plant hopper was high at the case of duck raising and rice bran farming on middle stage of rice paddy field in Gang-Hwa region. The occurrence rate of Rice water weevil was high at the conventional paddy field on the early stage of rice paddy field in Yeo-Ju region. In the Hong-Seong region, the occurrence rate of 'Rice water weevil' and 'Green rice leafhopper' was high at the 'duck raising compare to the conventional farming on the early stage of rice paddy field. According to each period, the occurrence rate of insect was high at late stage of rice paddy field, and there was no difference between each region. It showed high-occurrence tendency at duck pasture farming rice paddy field. The major natural enemies were spiders and parasites. Theridiidae and Linyphiidae were highly occurred on the conventional farming rice paddy field in Hong-Seong. Web builders containing Theridiidae, Linyphiidae and Tetragnathidae was occurred more than wandering spiders containing Lycosidae, Clubionidae and Pisauridae at various regions, and then occurrence of spiders was different at the various regions but was not different at each farming system.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.106-112
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• 2015

This experiment was carried out to investigate the best spray timing for the control of the bacterial shot hole with Bordeaux mixture (6-6) after wintering in the peach orchard. We sprayed Bordeaux mixture (6-6) on 'Mibaekdo', 'Yumyeong' and 'Cheonhong' of peach verities from late-March to mid-April in 2001, 2002 and 2014, and examined how much bacterial shot hole and chemical injure occurred. The infection rate of bacterial shot hole according to spray time was 10.2 to 11.7% at leaves, and 1.7 to 2.2% at fruits in 2002. And Efficacy of the Bordeaux mixture treatment for control of bacterial shot hole at full blooming time 21.2 to 30.4% at leaves, 1.7 to 4.4% at fruits in 2014. The chemical injure occurred slightly for one week hence. The fruit bearing rate was 20.7 to 29.8% at 'Mibaekdo', and 35.4 to 61.9% at 'Yumyeong' peach trees. When the spray at the time of blooming period by bordeaux mixture was investigated the control effect of bacterial shot hole disease. The infected leaves was better than 21 to 25% twice the quantity of finished products and bordeaux self-preparation about 28 to 30% base quantity of finished products, also the control efficacy was higher in infected fruits trends in bordeaux self-preparation method and twice the quantity of finished products.

• Korean journal of applied entomology
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• v.51 no.2
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• pp.141-148
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• 2012

An outbreak of Ricania sp. occurred in the Kurye, Jeonnam area in 2011. This outbreak damaged many kinds of fruit trees such as Cornus, Persimmon and Chestnut. This experiment was conducted to survey the occurrence ecology of Ricania sp. such as host plants, oviposition characters, morphological characters and life cycle, as well as to select environmental friendly control agents. Ricaina sp. host plants included 51 species such as 32 xylophytes, and 19 herbaceous plants. Ricaina sp. preferred Cornus officinalis, Diospyros kaki, Castanea crenata, Eucommia ulmoides, Styrax japonicus for oviposition. Adults laid eggs on new inner twigs with 28.8 eggs per egg-mass. Egg size was 1.24 mm(length), 0.55 mm(width) in an oval shape. Nymphs molted four times. Every nymph stage had an x shape of yellow or white beeswax around the anus. Overwintered eggs of Ricania sp. hatched from the mid May to early June. Nymphal periods were from mid May to mid August and adults appeared from mid July but spawning began in mid August. Ricania sp. damaged new twigs by oviposition and retarded growth by sucking nutrients and producing a sooty mold. Sophora and natural plant extracts were effective environmentally friendly agricultural materials used to control the nymph and adult Ricania sp. Mortality was > 80%.

• Journal of Korean Society of Forest Science
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• v.94 no.1 s.158
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• pp.21-25
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• 2005

In order to prevent the pine mushrooms, Tricholoma matsutake, from being damaged by the pine needle gall midges, Thecodiplosis japonensis, and thereby, to increase their production and improve their quality, a sprinkler system was installed on the mushroom field. A low-concentration insecticide (deltamethrin 1% EC, x2,000) was sprayed once at insects' most active time every day during the period of insects' adult occurrence and thereafter, the irrigation by ground water spraying was periodically enforced. Such a test was conducted at Yangyang-Gun, Kwangwon-do, Korea for 2 years from 2000 through 2001. The pine needle gall midges generally emerged for about 40 days from late May to early July. 50% emergence of them was about June 6, and peak emergence (more than 80%) was early or mid-June. Gall formation rate was 3.5% on average with this ground insecticide spraying, while 51.3% when not treated. Control effectiveness of this insecticide spraying was 92.3%, which was higher than 82.5% by the conventional injection of insecticide into tree stems. Pine mushrooms emerged for about 35 days from mid-September through earlier October, and around 80% of them did for about 15 days from late September through early October. As a result of the periodic ground water-spraying (30 mm per week) for 2 months (from August to October), the production of mushrooms increased by 74.3% (110% in terms of weight), with their quality improvement. The mushrooms produced from the treated stand by the spraying system were priced 8,670,000 wons per hectare, and thus, the net income deducting the facility and management cost was 4,310,000 wons, about 5% higher than value from the control stand. It was analyzed that this treatment was significantly cost effective when the facilities are used more than 5 years.

• Research in Plant Disease
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• v.15 no.3
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• pp.230-235
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• 2009

Postharvest skin sooty dapple and decay disease of pear fruit often originates at small stain symptoms that occurred during harvest and handling. Experiments were conducted to characterize the effect of timing of application of disease control materials, and to evaluate sequential postharvest applications of fungicides or fungicides and bio-control agents. Fungicides and bio-control agents were increasingly less effective when the period between harvest and application was prolonged. Thiabendazole (TBZ) applied to fruit without artificial wounding or inoculation effectively reduced skin sooty and decay disease when applied within 3 weeks or 6 weeks in 2 years of study. TBZ, Fludioxonil and pyrimethanil were effective in controlling skin sooty and decay disease at artificial wounds inoculated with Cladosporium tenuissimum up to 14 days after inoculation. Application of TBZ at harvest followed 3 weeks later by application of Fludioxonil was superior to application of TBZ at harvest alone. Two bacterial biocontrol agents reduced skin sooty and decay disease at pear wounds inoculated with C. tenuissimum up to 14 days after inoculation with C. tenuissimum, but were ineffective when applied at 28 days after inoculation. Of possible sequential arrangements of fungicide and bio-control treatments, application of the most effective material promptly after harvest generally resulted in the highest level of disease control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.383-393
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• 1991

Lodging of rice plant is the most important damage by unfavourable weather conditions in rice cultivation. High levels of nitrogen application and growing of Japonica rice variety is one factor to increase the lodging damage. Lodging of rice plant decreasing grain yield; 34% at milky. 21% at dough. 20% at yellow stage. decreasing grain Quality. increasing green rice. and increasing labor cost to harvest. To decrease lodging damage. the lodging resistant varieties will be selected and cultural practices such as amount and time of nitrogen application. planting density. water management. and disease and pest control methods have to be study for the short and strong culm. and good rooting system. Also. application methods such amount and time of plant growth regulators and new types of chemicals will be develop for the reducing lodging of rice plant. To decrease the lodging damage in direct seeding cultivation. first identifying the differences of lodging mechanisms between hand transplanting and direct seeding, second establish the suitable direct seeding methods such as seedling establishement. fertilization. and water menagement.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.481-496
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• 2022

In order to establish an effective pest control strategy, we investigated the occurrence of lepidopteran insects in the major trees growing in urban forests from 2019 to 2021. In total, we recorded 76 species of 14 families in Prunus spp., 40 species of eight families in Acer spp., 43 species of 10 families in Zelkova serrata, 28 species of seven families in Rhododendron spp., and 10 species of four families in Hibiscus syriacus. Among these, Hyphantria cunea and Lymantria dispar were recorded from all five tree taxa monitored. The most frequently occurring species in the different tree groups were as follows: H. cunea and Phalera flavescens in Prunus yedoensis, Epinotia ulmicola in Z. serrata, and Rehimena surusalis in H. syriacus. H. cunea also occurred in Rhododendron spp. and Acer spp., although the numbers were lower than those recorded in Prunus spp. and Z. serrata. Our results highlight the importance of focusing on the frequency of occurrence of lepidopteran insects in Prunus spp. and Z. serrata, whereas the presence of these insects in both Acer spp. and Rhododendron spp. Appears to be less problematic. From the perspective of reducing the risks to human health, our findings indicate that the application of pheromones for monitoring lepidopteran species and the use of mating disruptors would be desirable approaches that would contribute to minimizing the spraying of pesticides in urban forests.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.353-355
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• 2000

The seasonal occurrence of aphids was investigated in the soybean Held to increase the control efficiency of aphid vectors of Soybean Mosaic Virus. The patterns of aphids occurrence were different according to planting time. There were two peaks in late June and mid-August in aphid population in optimum seeding (May 20), whereas the peak was around mid-June in early seeding(Apr, 20). Acyrthosiphon solani was dominant Species in early seeding, while Aphis glycines was dominant in optimum seeding. In early seeding, SMV incidence increased rapidly between 20 June and 30 June, suggesting that virus spread was strongly correlated with increased colonization of aphids. Imidacloprid WP, benfuracarb EC and acephate WP showed a good effect for the control of aphids without phytotoxicity. In the plot with infurrow treatment of imidachloprid G until 52 days after shooting, aphids were controled effectively. Acephate WP was applied as a foliar spray at V4, V6, or V4/V6 stage and all the treatments were effective on reducing: SMV incidence.