• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.439-452
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• 2018

This study was carried out to establish of environment-friendly control system and to survey the occurrence status of Ricania shanthungensis in Jeonnam province from 2016 to 2017. R. shanthungensis occurred at 1,344 ha in 61 towns of 15 cities in Gwangju and Jeonnam province. At four sites in the stationary area, the densities of eggmass and pupae were lower in 2017 than in 2016, the hatching rate decreased, and the first hatching time, emergence of adults, and the start of spawning tended to be slower. Telenomus sp., an egg parasitoid of R. shanthungensis, was found in most areas. Sunchon had the highest rate of 46.1%, followed by Muan 40.6, Goksung 29.2, Gurye 25.8, and Gwangju 17, respectively. The optimum spraying time for the control of R. shanthungensis was early March. The spraying material and the dilution multiples are 10 times of the machine oil at environmental friendly cultivation and 500 times of the chlorpriphosphate wp. at normal cultivation. When sprayed these materials, 95% of egg prohibited to hatch. There was more than 80% of the insecticidal effects on the organic materials of the machine oil emulsion, the Sophora root extrect + microbial extract agent, and the castor emulsion. For adults, Sophora root extrect + microbial extract, neem extract, and machine oil were better. Four kinds of chemical pesticides such as dinotefuran wp were effective for nymph and adult control. We have developed an adult catching device using the most preferred daylight color and behavioral habits of R. shanthungensis. The capture device consisted of two daylight compact lamps (30W and 20W), a yellow plate, and a catcher using water, and caught about 700 individuals a day. Based on the above results, we have established a system for controlling and life cycle of R. shanthungensis in Jeonnam province.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.151-156
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• 2011

Economic injury levels (EILs) and economic control threshold (ET) were estimated for the Tea red spider mite, Tetranychus kanzawai Kishida(Acari, Tetranychidae) in Rubus coreanus Miquel. T. kanzawai density increased until the early-July and thereafter decreased in all plots except the non-innoculation plot where initial density of the mite were different each 0, 5, 10, 20 and 40 adults per plant branch on May 7 in 2008. And the occurrence of the densities were increased higher innoculated density than different innoculation density. The yield was decreased with increasing initial mite density and thereby the rates of yield loss was increased with increasing initial mite density. And T. kanzawai occurrence density, yields and the rates of yield loss, where initial density of the mite were different each 0, 2, 5, 10 and 20 adults per plant branch on May 8 in 2009 were similar tendency to 2008 year results. The relationship between initial T. kanzawai densities and the yield losses was well described by a linear regression, Y = 0.6545X + 3.0425 ($R^2$ = 0.93) in 2008, Y = 0.9031X + 2.0899($R^2$ = 0.96) in 2009. Based on the relationship, the number of adults per plant branch(EILs) which can cause 5% loss of yield was estimated to be approximately 3.0 in 2008 and 3.2 in 2009. And the ET was estimated to be approximately 2.4 in 2008 and 2.6 in 2009. The relationship between initial T. kanzawai densities and occurrence density of mid-May considering the best spray timing against T. kanzawai was well described by a linear regression, Y = 0.471X + 2.495($R^2$ = 0.95) in 2008, Y = 0.9938X + 3.1858($R^2$ = 0.96) in 2009. Based on the relationship, the number of adults per leaf(ET) in mid-May which can cause 5% loss of yield was estimated to be approximately 3.6 in 2008 and 5.8 in 2009.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.137-140
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• 1975

Field experiments on red-pepper were conducted in Suweon area during 1972-1974 to determine the seasonal fluctuation of Heliothis assulta H. using black light traps and direct counts. Adult moths emerged in late May, and showed three peaks of fluctuation from late June to middle July, from middle August to late August, and in mid-September. Eggs were first discovered in the field in early July, with peak incidence Iron late August to early September. Larval peaks occurred in late July to early August, in late August and mid-September to mid-October Initial hatching in the field occurred in early July. The numbers of the first larval generation were the highest. The parasitization ratio of Trichogramma spp. on eggs averaged 51 percent during mid-July to mid-September. The numbers of Trichogramma spp. emerging from one tobacco bud-worm egg ranged from one to four, but in most cases one or two egg parasitizing wasps emerged.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.22-27
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• 2000

National plant quarantine inspector of exporting country should inspect agricultural products according to the quarantine requisites of counterpart country when the commodities are shipped. Export of pear fruits was held because quarantine pests including Conogethes punctiferalis were found at the point of entry in Canada. In order to examine the problems in detail, the inspected pear fruits were stored at a low temperature for 43 days, almost the same period necessary for fruit sorting, quarantine procedures, and transportation by ship. Dead larvae of fruit moths, C. punctiferalis and Grapholita molesta were found during cold storage. Quarantine pathogens were not found, but non-quarantine ones such as Penicillium sp. was infected through wounds by bruises and stabs resulted from sorting procedures. Because of the wounding problem during export procedures, pear fruits with thin exocarp, such as fruits of P. pyrifolia Nakai cv. Whangkeumbae, are required more careful handling during fruit sorting and conveyance.

• Research in Plant Disease
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• v.26 no.4
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• pp.222-228
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• 2020

Erwinia amylovora, a causal bacterium of fire blight disease, is registered as a prohibited quarantine pathogen in Korea. To control the disease, the government should diagnose the disease, dig and bury the host trees when fire blight occurs. Fire blight was the first reported in 43 orchards of Anseong, Cheonan, and Jecheon in 2015, and 42.9 ha of host trees were eradicated. However, the disease spread to eleven cities, so that 348 orchards and 260.4 ha of host trees were eradicated until 2019. Fire blight of Asian pear occurred mainly in the southern part of Gyeonggi, and Chungnam province, on average of 29±9.2 orchards per year. And the age of the infected trees were mostly 20-30 years old. In apple trees, the disease occurred mainly in the northern part of Gyeonggi, Gangwon, and Chungbuk province, on average of 41±57.6 orchards per year, increased highly in 2018 and 2019. The age of infected apple trees were under 20 years old. Therefore, because the disease spread rapidly in young apple trees, spraying control agents to the trees in a timely manner and removing infected trees quickly are important to prevent the spread of fire blight in the orchard of immature trees.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.6-11
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• 1999

This experiment was carried out to estimate the appropriate seedling stand and to find out the factors of good establishment and the reason of the reduction of yield by water foxtail. The seedling stands was improved by the ice straw mulching and treading by the tracks of combine. The effect of mulching was higher than the treading. The appropriate seedling stands for example yield were estimated about 507 plants per $m^2$ and its yield was 24kg/10a. The higher density of water foxtail, the less the grain yield; 21.8% by 17 to 22 water foxtail stands per $m^2$ and 11.0% by 6 to 11 plants.

• Research in Plant Disease
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• v.21 no.2
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• pp.67-73
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• 2015

Bacterial blossom blight of kiwifruit (Actinidia deliciosa) caused by Pseudomonas syringae pv. syringae is known to be largely affected by weather conditions during the blooming period. While there have been many studies that investigated scientific relations between weather conditions and the epidemics of bacterial blossom blight of kiwifruit, no forecasting models have been developed thus far. In this study, we collected all the relevant information on the epidemiology of the blossom blight in relation to weather variables, and developed the Pss-KBB Risk Model that is based on the Maryblyt model for the fire blight of apple and pear. Subsequent model validation was conducted using 10 years of ground truth data from kiwifruit orchards in Haenam, Korea. As a result, it was shown that the Pss-KBB Risk Model resulted in better performance in estimating the disease severity compared with other two simple models using either temperature or precipitation information only. Overall, we concluded that by utilizing the Pss-KBB Risk Model and weather forecast information, potential infection risk of the bacterial blossom blight of kiwifruit can be accurately predicted, which will eventually lead kiwifruit growers to utilize the best practices related to spraying chemicals at the most effective time.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.145-154
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• 2021

Integrated pest management system in Korean apple has significantly advanced for last few decades. However harmful effects of pesticides threats the ecosystem services of natural enemies and pollinators. Apple require cross-pollination and Insect pollination with diversity and abundance is one of the keys to profitable apple production in quantity and quality as well. Thus crop protection tools are to be administered in harmony to meet the pest suppression and protection of beneficial organisms such as natural enemies and pollinators. Adding onto the established IPM system, integrated pollinator-pest management (IPPM) concept is proposed as the future direction of apple IPM. For this, ecological enginnering of creating habitats for pollinators, landscape management and agroecosytem diversification as well as selective soft pesticide uses on time guided by pest monitoring and phenologyand targeted delivery are further proposed. Recent shift of agroecosystem from climate change and new pest outbreaks require new paradigm of pest management for sustainable agricultural production.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.18-43
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• 2011

The results of study on planting and cultivate of Hong Man-Seon(1643~1715)'s 'Salimkyungjae(The Economy of Forest)' the first summative textbook of agricultural skill of South Korea, are as follows. First, 'Salimkyungjae' suggests that one can enrich oneself, eat fruits in fall, enjoy the shade of trees in summer, and enjoy flowers in spring if one plants tree with 10 year plan with knowledge of ecology. Second, the number of plants had increased continuously from the early Chosun Dynasty to the mid Chosun Dynasty. The 52 plants in the book are classified into 31 trees, 8 shrubs, 3 others, and 10 herbs, and 28 of them are fruit trees. Hence, we can see that the book is for the promotion of welfare. Third, planting(transplantation) is the best on January of the lunar calendar, and the second on February, and fertile soil should be added much. Trees must be planted as deep as once it was planted, and buttressed. It will sprout well if it is planted at the depth of one inch, and planting a cutting should be carried out at the early March with 5 inch and finger-thick branches. Grafting is the best when it begins to sprout. Fruit trees will bear many fruits if they are grafted at the direction of South, and fruits will be greater if the trees' branches are cutting off on January. Especially, January was selected for the best season of planting traditionally. Fourth, flower trees are planted or sowed with manure around January and February of the lunar calendar, and it is recommended to replant them into flowerpots with manure when having flower buds around March and April of the lunar calendar. It would bloom earlier when using water mixed with stable manure, and sulfur smoke can be used in order to change the flower color from red to white. Flowerpots would be placed at half shaded lot with being supported by bricks. Pomegranate, gardenia, camellia and four-season flower should be planted after flowers fallen. When flower trees are beside walls, they need to be rotated frequently since their branches all point toward house. Seeds need to be preserved in a sunny hut, where its entrance and ventilating openings would be at south because it is convenient to manage pots. Fifth, insects hidden at fruit trees would be destroyed by torch smoke when roosters cry on New year's day of the lunar calendar. Insects would be decoyed into straw hanged at dawn of Cheongmyeongday(淸明日). Insects on fruit trees would be controlled using sulfur powder to close up holes or sulfur smoke to fumigate. Particularly, it suggests that utilization of fertile soil would be the best solution for growing health plants and preventing pest.

• Journal of Life Science
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• v.28 no.3
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• pp.357-360
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• 2018

This study developed a method to minimize rice damages and enhance timely control by accurately classifying Whitebacked Planthopper (WBPH). The body size of the 1st-3rd instar was 1.5-2 mm, and the body size of the 4-5 instar was 2.5-3.5 mm. In the third instar, the ratio of the front wing bud and the back wing-bud was 1:1. The fourth instar occupied 3/4 of the front wing-bud, and the 5th instar showed that the front wing-bud covers the back wing-bud. It was confirmed that the 1st instar does not have a sensory plate, the 2nd instar has 2-3, the 3rd instar has 4-5, the 4th instar has 6-9, the 5th instar has 10-15, and the adult instar has 15-20 sensory plates. The female spawning organs were reddish when the spawning horn was inserted. WBPH showed that the larvae of 2-3 larvae most actively feed on rice, and the damaged area was the stem of rice near the ground. In addition, a partial black wound was observed after the feeding. WBPH-susceptible 'Chucheong' was yellowish, and early growth was slower than that of 'Cheongcheong', which was resistant; moreover, a difference between susceptibility and resistance was observed. The identification of the number of such wounds in the bioassay will be a better basis for understanding the difference in susceptibility between WBPH strains and cultivars. These results will be used as basic data for cultivating the WBPH-resistant varieties of rice.