• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.174-178
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• 2013

Lime-bordeaux mixture has been used to prevent diseases in the field of ginseng. The purpose of this study is to investigate the efficacy of lime-bordeaux depending on the concentration and treatment time on major diseases of ginseng such as Alternaria blight and anthracnose, and to evaluate the root growth of ginseng. Lime-bordeaux caused damage on leaf when it was sprayed on ginseng between April and early May. No difference was found in root growth by spraying lime-bordeaux mixture between ratio 4-4 and 8-8 ratio in concentration. Plot of 6-6 raito and 8-8 ratio appeared to be similar efficacy compared to that of practical chemical control. However, the plot of 4-4 ratio showed lower than that of chemical control.

• Korean journal of applied entomology
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• v.2
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• pp.38-43
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• 1963

1) These experiments were couducted to compare the effectiveness of with several new insccticides for the control of the rsce stem borer at Kimhae and Suwon in Korea from 1962 to 1963. 2) Gam ma-dol dusf and gramular were applied on the water surbul by hand and the other insecticides were sprayed on the leves of the paddy rice plaut by knap sack spayer(Table 1). 3) Gamma-dol was for the control of rice stem borers. more effective than other insecticidesused. timing for the applioation of$\gamma-dol$ was 10 days before hatching from the eggs. 4) There were no any significant differences in the effect of$\gamma-dol$ to the rice stem borer in both areas of Kimhae and Suwon.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.97-105
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• 2017

An investigation was conducted to determine the characteristics of seasonal occurrences and effective insecticides for minimizing the occurrence of Pseudaulacaspis cockerelli in sweet persimmon orchards. Most of the nymphs or female scales that mated in mid-September overwintered on twigs, matured to lay eggs in the next spring in accordance with temperature increase, and survived till mid to late May to lay all of their eggs. Males mostly died after mating by the end of September, while the males on the fallen leaves died during the hibernating period. Egg laying in P. cockerelli showed differences in accordance with the weather conditions in each year. They laid eggs from mid-April to mid- or late May, with a peak in early or mid-May. A female was estimated to lay 160 eggs; eggs hatched a week later from the peak period of egg laying. In summer, egg laying started in early or mid-July and ended in mid- or late August, with a peak in late July or early August; a female laid approximately 130 eggs in summer. The estimated egg period was 4 days. The first generation nymph that hatched from the eggs laid by the overwintered female on twigs showed 10% occurrence on twigs and 90% on leaves. The first generation nymphs on twigs mostly developed into female scales. The occurrence of the second generation nymphs reached a peak on July 27, 2009; they lived on the twigs as their overwintering site from mid- or late August. The female and male scales on leaves developed at the similar rate as the first generation nymphs up to August. The occurrence of male scales indicated that the peak occurrence of nymphs was on August 12, 2009, male scales on August 27, and adults approximately on September 14, which showed steady relationship in the sequence of development from nymphs to adult males. Among the nymphs that occurred on the leaves on August 12, 75% of them emerged into male adults, mated, and died. Buprofezine+dinotefurn (20+15) WP treatment on June 9 and 16 resulted in 90.6% control of P. cockerelli, when mortality was checked 7 weeks after treatment.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.463-472
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• 2010

It was conducted to investigate the control efficacy of carboxylic acid amide (CAA) fungicides, such as benthiavalicarb, iprovalicarb, dimethomorph and mandipropamid, against pepper Phytophthora blight caused by P. capsid in the laboratory and the field. The fungicides inhibited mycelial growth and direct sporangium germination of P. capsid strongly, while there was no activity of all fungicides against zoospore release from sporangium. In greenhouse test, they showed the good protective and curative effect against pepper Phytophthora blight. Benthiavalicarb applied at $100{\mu}g\;mL^{-1}$ 7 days before inoculation prevented pepper Phytophthora blight by 100%, even though the zoosporangiurn suspension of P. capsid adjusted to not only $5{\times}10^3$ zoosporangia $mL^{-1}$ but also $1{\times}10^5$ zoosporangia $mL^{-1}$ was inoculated by soil-drenching. Except for dimethomorph, the other fungicides showed an excellent control activity over 2 years from 2009 to 2010 in the field test. The control value of dimethomorph applied at $250{\mu}g\;mL^{-1}$ was low, 27.2% in 2009, but that of dimethomorph applied even at $125{\mu}g\;mL^{-1}$ was high, 89.5% in 2010. All the fungicides showed good inhibitory effect on the mycelial growth and the direct germination of zoosporangiurn, and controlled pepper Phytophthora blight preventively and curatively, can be used to establish the spray system for control1ing the pepper disease.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.237-243
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• 2009

This study was conducted to develop economic injury level (ElL) and economic threshold (ET) of Cabbage armyworm, Mamestra brassicae L. on cabbage (Brassica oleracea L. var). The changes of cabbage biomass and M. brassicae density were investigated after introduction of larval M. brassicae (2nd instar) at different densities: 0, 1, 2, 4, 8, and 16 larvae per plant at 40 d after planting for an open field experiment, and 0, 2, 5, 8 and 12 larvae per plant at 25 d after planting for a glass house experiment. In the field experiment, the yield loss of cabbage was not significantly different among treated-plots at 30 d after the larval introduction, showing an over-compensatory response of cabbage plants to M. brassicae attack. In the glasshouse experiment, however, the biomass of cabbage at 15 d after the larval introduction significantly decreased with increasing the initial introduced number of M. brassicae, resulting in 38.3, 36.7, 21.7, 23.3 and 16.7g in above treated-plots, respectively. The relationship between cumulative insect days (CID) and yield loss (%) of cabbage was well described by a nonlinear logistic equation. Using the estimated equation, ElL of M. brassicae on cabbage was estimated at 44 CID per plant based on the yield loss 14%, which take into account of an empirical gain threshold 5% and marketable rate 91% of cabbage. Also, ET was calculated at 80% of the EIL: 35 CID per plant. Until a more elaborate EIL-model is developed, the present result may be useful for M. brassicae management at early growth stage of cabbage.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.65-72
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• 2005

Creeping bentgrass (Agrostis palustris Huds.) had been the problematic weed for Kentucky bluegrass (Poa pratensis L.) fairway since it shows light green color all year. Experiment was carried out to determine the best herbicides combination to control creeping bentgrass in Kentucky bluegrass. fairway without injury. To investigate the efficacy of herbicides, five post-emergence herbicides of asulam WG ($87.6\%$), imazaquin SL ($20\%$), fenoxaprop-P-ethyl EC ($7\%$), mecoprop SL ($50\%$), triclopyr-TEA SL ($30\%$) and one pre-emergence herbicide pendimethalin EC ($31.7\%$) treated on 21 Sept. and 10 Nov. 2003. Kentucky bluegrass visual quality evaluated 30 and 50 days after application for phytotoxic effects of the herbicides. As a result, asulam WG (0.2g/$m^{2}$) and imazaquin SL (0.3ml/$m^{2}$) showed approximately $90\%$ of control in creeping bentgrass, but visual quality of Kentucky bluegrass significantly decreased from 20 to 50DAT (day after treatment). However, creeping bentgrass was acceptably controlled(over $80\%$) by fenoxaprop-P-ethyl EC (0.4ml/$m^{2}$)+triclopyr-TEA SL(0.3 ml/$m^{2}$) applied twice on 21 Sept. and 1 Oct. 2003 without serious injury on Kentucky bluegrass. Therefore, it is suggested that an application of fenoxaprop-P-ethyl EC (0.4ml/ $m^{2}$)+triclopyr-TEA SL (0.3 ml/$m^{2}$) may be more effective to control creeping bentgrass in Kentucky bluegrass with the least phytotoxicity by herbicides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.273-281
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• 2018

Wet hill seeding (WHS) is one of the more famous labor and money saving methods technology used for rice cultivation. In WHS, rice standing percentage and weedy rice occurrence are the most important factors considered to secure a rice yield. We investigated the optimum seeding date of WHS in the Southern Plain area of South Korea. Weedy rice needed two weeks at $15^{\circ}C$ to show over 80% emergence. Germinated rice seed grown at $20^{\circ}C$ needed over for 10 days to achieve a shoot length over 3 cm. In field cultivation, the mean temperature for ten days after seeding showed a highly positive correlation with rice standing rate, spikelet number per square meter and yield index that favorably compared to machine transplanting. With these data, we suggest that the optimum seeding date of WHS that can secure over 98% of yield index of machine transplanting in Southern part of Korea is May. 21~Jun. 5 in Honam and May. 16~Jun. 5 in Yeongnam area.

• 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.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.191-197
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• 2015

Fruit drop due to Eurytoma maslovskii infestations of Japanese apricot (Prunus mume) is a serious economic issue in most parts of Jeonnam Province, with the exception of the coastal areas such as Wando, Shinan, Yeosu, and Muan. The average incidence of fruit drop was 67% in 2013 and 33.3% in 2014. E. maslovskii larvae overwinter inside the pits of Japanese apricots. Larval survival rates decrease to less than 30% after a rainy summer season. The eggs are long oval of 0.68 mm, 0.29 mm and ivory white. Mature larva is of 6.56 mm, 3.18 mm. Free pupa are black, adult females and males of 6.97 mm, 4.90 mm lengths, respectively, while the ovipositor is 0.64 mm in length. Adult emergence occurs from early April to early May, when Japanese apricot fruits are from 4 mm to 17 mm in diameter. Adults persist for 13.5 d after emergence, and the sex ratio of females to males was found th be 45.9:54.1. Although up to four eggs may be oviposited per fruit, only one larva will ultimately survive, ans the larvae are cannibalistic. The period during which E. maslovskii is able to oviposit on Japanese apricots only lasts from mid- to late April (fruit diameter: 12~16 mm). When the diameter of the fruit is >16 mm, the pit of the Japanese apricot hardens and larvae have difficultly penetrating the stone. Therefore, the most effective method of controlling this pest is to spray orchards with a control agent 2~3 times, at 5 d intervals, beginning in mid- April.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.134-145
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• 1986

The experiment was crried out to evaluated the herbicidal properties of bensulfuron methyl [methyl 2-[[[[[(4, 6-dimethoxy pyrimidine-2yl) amino] carbonyl] amino] sulfonyl] methyl] benzoate]. No phytotoxicity was observed when bensulfuron methyl was applied at 3 and 6 g a.i./ 10a while the application rate 12 g a.i./10a slightly retared the growth of rice. The phytotoxicity decreased as the application time was delayed. The effect of application rate, leaching grade, transplanting depth, soil type and temperature on crop injury was little. Japonica variety (Dong-Jin) was more sensitive to bensulfuron methyl than indica X japonica variety (Sam-Kang). Bensulfuron methyl controlled effectively perennial weeds such as Sagittaria pygmaea Miq., Potamogeton diatinctus A. Benn., Cyperus serotinus Rottb., Sagittaria trifolia L., Eleocharis kuroguwai Ohwi. including most annual weeds except Echinochloa crus galli P. Beauv. The effect slightly decreased with lowering the temperature increasing the leaching grade. Application time and soil type employed did not affect the weeding effect.