• Korean journal of applied entomology
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• v.31 no.3
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• pp.256-275
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• 1992

Insects are among the most important abiotic and biotic constraints to rice production. National rice research programs are in various stages in the development and implementation of integrated pest management (IPM) stratagies for rice insect control. Among the various control tactics, insect resistant cultivars are sought as the major tactic in rice IPM. Through the activities of interdisciplinary teams of scientists significant progress has been made in the development and release of insect resistant cultivars to farmers. Because of its compatibility with other control tactics insect resistance has proven to fit well into the IPM approach to rice insect control agents and minimize the need for insecticide applications. The development of biotypes which overcome the resistance in rice plants has been a significant constraint in the breeding of rice for resistance to insects. Most notable examples in Asia are the green leafhopper, Nephotettix virescens, brown planthopper, Nilaparvata lygens and the Asian rice gall midge, Orseolia oryzae. The current breeding stratege is to develop rice cultivars with durable resistance on which virulent biotypes cannot adapt. In spite of the significant progress made in the breeding of insect resistant cultivars there are still numerous important rice insect species for which host plant resistance as a control tactic has not been fully utilized. Advances in biotechnology provide promise of solving some of the problems that have limited the use of host plant resistance as a major tactic in the integrated management of rice insect pests.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.251-255
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• 1987

This study was conducted to investigate the effects of cultural methods on infection by Rhizoctonia disease(Rhizoctonia solani $K\"{u}hn$) of potato (Solanum tuberosum L.). Two potato cultivars, i.e., Irish Cobbler and Superior were planted in 1984 at the Alpine Experiment Station and 4 cultural methods were used in Combinations or separately. The deeper planting showed the later germination of sprout. The degree of infection on underground stems didn't show any differences between the treatments, but the yield was higher in deeper planting. When seed tubers were planted on April 28 the underground stems showed severely discolourated epidermis comparing to later planting, consequently the yield was low. The glazed chitting tubers produced healthy sprouts comparing to the untreated tubers, consequently the yield was also increased. The density of sclerotia on tuber skin was remarkably increased between 6 to 15days of delayed digging after haulm killing. Underground stems of Irish Cobbler were easily discolourated by the disease, where-as the density of sclerotia was higher on tuberskin of Superior than of Irish Cobbler.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.141-151
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• 2002

The success of sericulture industry in India is mainly attributed to the well-planned annual sericultural activity and the systematic implementation of pest preventive and control measures. The insect spectrum of silkworm and its food plants is complex and plays a major role in limiting the production of silk. Insects cause extensive damage to plant whereas predators and parasites either kill the silkworm larvae or force them to spin flimsy cocoons. Unilateral control measure against this pest is mainly based on the use of synthetic organic insecticides. Though these approaches initially paid rich dividends, the undesirable consequences soon surfaced. Insecticide induced resurgence of gall midges, leafhopper, leaf roller, secondary pest out breaks and development of pest biotypes has led to realization of Integrated Pest Management in sericulture. Various components of IPM, viz. Host plant resistance, cultural practices, biological control, chemical control and integrating them at various technological levels have been studied. Sources of host plant resistance have been identified for some of the major insect pests. High yielding mulberry variety has been propagated and their resistances towards major pests have been recorded. Cultural practices like pruning, pollarding, judicious use of nitrogen, optimum spacing and weed management have preyed to be the powerful tools in containing pests. Natural control over the pest population build- up exerted by the wide range of parasitoids, predators and pathogens has been well documented with identification of natural enemies and studies on their potential. Augmentation, through inoculation or inundative releases of parasitic arthropods, is the most direct way of increasing the numbers of these beneficials in sericulture.

• Journal of Conservation Science
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• v.37 no.3
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• pp.191-208
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• 2021

In this study, the status of damage by subterranean termites and their management according to the region and type of domestic wooden cultural properties were identified. This was based on the survey reports of agencies conducting regular nationwide and regional monitoring of subterranean termites. In addition, using geographical information system (GIS) based on the survey contents, a map was constructed of termite infestation and its progress on 2,805 wooden cultural properties that were surveyed nationwide. Based on the map produced, a total of 486 cases of termite infestation were confirmed in wooden cultural properties during 2018-2019, of which 143 cases (approximately 29.4%) were confirmed to be owing to the invasion of termites in the ground and infestation of wood materials. A web platform and an application using a mapping application program interface were created to increase accessibility to the investigated damage status data. The methods employed by each institution for investigating and monitoring the invasion of termites in the ground included the use of detection dogs, visual observation, installation of wood specimens made of pine, and microwave equipment. However, it was confirmed that monitoring and survey methods were not applied to determine the territorial range of the subterranean termite colonies. Accordingly, the use of dyeing and mark-release-recapture methods were deemed necessary to understand the current status, such as calculating the scope of the target wooden cultural property, when monitoring subterranean termite colonies.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.199-208
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• 1977

Activities of various hydrolytic enzymes produced by three plant pathogenic fungi, Sclerotium rolfsii Sacc., Sclerotinia sclerotiorum (Lieb.) deBary and Helminthosporium sigmoideum var. irregulare Crallery et Tullius, were measured. Activties and amounts of the enzymes in mycelia, cultural filtrates, and sclerotia(except of sclerotia of H. sigmoideum var. irregulare) were estimated at various pH levels in order to find out optimal pH for their enzymatic activities. Enzymes such as cellulase (ex), invertase, xylanase, $\beta-amylase$, polymethylgalacturonase, polygalacturonase, phosphatase and protease were estimated. Culture solution for production of enzymes was prepared by adding of 10g, D-glucose, 1.3g $NH_4NO_3,\; 0.5g\; MgSO_4,\;7H_2O,\; and\; 1.0g\; KH_2PO_4$ into 1 liter of potato decoction plus 2ml of micro element solution consisting of 0.2mg. Fe, 0.2mg Zn, and 0.1mg Mn as the sulphates into 1 liter of distilled water. All tested mycelia and cultural filtrates were obtained from the cultures incubarted in previous solution for ten days at $25^{\circ}C$, and sclerotia were harvested from PDA plates of 3. days old, The crude enzyme solutions were prepared according to the method of Miyazaki etal. Ten days after incubation, activities of Cx produced by Scl. sclerotiorum were higher than those of the other fung and each of Cx from three fungi showed different pH optima, such as S. rolfsii and Scl. schlerotiorum in acid side (around pH 3.0), H. sigmoideum var. irregulare in neutral side (around pH 6.3). Invertase activities of S. rolfsii were 20 times higher than those of the other fungi in all samples. All tested fungi, however, showed no significant difference between the enzymatic activities of their cultural filtrate and mycelia and the activities in sclerotia of S. rolfsii and Scl. sclerotiorum were hardly recognized. There were multiple peaks on the xylanase activity curves of three fungi in terms of pH values. High activities of the xylanase were revealed in sclerotia of S. rolfsii and Scl. sclerotiorum, and in mycelia of H. sigmoideum var. irregulare. The highest activities of $\beta-amylase$ were shown both in mycelia and cultural filtrate of H. sigmoideum var. irregulae among the tested fungi, and their optimal pH was 6.2 in both mycelia and cultural filtrate. In the S. rofsii and Sel. sclerotiorum, however, the activities of cultural filtrates were higher than those of the other fungi, and optimal pH was 3.0 and 6.2 for cultural filtrate and both mycelia and sclerotia, respectively. Activities of PMG were high in cultural filtrates of all tested fungi, especially in Scl. sclerotiorum and H. sigmoideum var. irregulare. Mycelia of themalso showed the considerable activities. Optimal pH for enzymatic activities were variable with thekind of fungi or with the samples measured. The highest activities of PG were presented by mycelia of S. rolfsii and Scl. sclerotiorum. $9.l\mu /min.\; and\; 9.5\mu g/min.$, respectively. Optimal pH for activity of PG in mycelia was around 4.5 in S. rolfsii and around 3.0 in Scl. sclerotiorum. Phosphatase of S. rolfsii and Scl. sclerotiorum was more active in acid side (optimal PH3. 5) and that of H. sigmoideum var. irregulare showed one peak each in acid, neutral and alkaline side. But the highest peak was at pH 9.5. Protease of all tested fungi was more active at pH 10.0, especially that of the cultural filtrate of H. sigmoideum var. irregualre.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.84-97
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• 1983

Under the limited arable land, the enhancement of agricultural productivity is indispensable to provide the food demand which is concomitant with the rapid increase in population. From this viewpoint, the upbringing and dissemination of high-yielding varieties has been promoted continuously and several modifications in cultural practices, including heavy fertilization, dense planting, and early transplanting, also have been gradually developed. However these changes in cultivation have led to the increased outbreak of insect pests and diseases. And this unexpected results have accelerated the number and complexity of pesticides employed as well as their consumption. Even though pesticides are essential materials contributing to the steady production of agricultural crops, large scale consumption of them has given rise to several adverse impacts, such as mammalian hazard and/or environmental contamination. In this respect, recent development of new pesticides has been concentrated on 'safe pesticide', as it were, that has the highly selective properties without unfavorable side influences on other ecosystem. According to literature cited up to now, feasibilities of safe pesticide development would be summarized as two categories. One of them is the development of chemical pesticides, which include the molecular structure modification of established pesticides for increased safety and synthesis of new safe chemicals which can attack the vulnerable point of physio-ecological characteristics in insect pests and diseases. The other is the biological pesticides which comprise natural enemies and microorganisms to act selectively on confined insect pests and diseases, In addition, improvement of physico-chemical properties of available pesticide formulations would be one of the desirable means for safe pesticide development in view of efficacy enhancement and minimization of hazardous properties or safe pesticide development, various approaches are feasible and needed to study, however, long period and much financial outlay are necessary to develop a new item. And under the present situation in Korea, there are many difficulties for performing research on all the possible routes. Therefore, combined pesticides by the reasonable combination of already registered resticides evaluated as the fairly safe pesticides and safe formulation based on their physico-chemical properties would be developed primarily. And many efforts would be given gradually for the development of new chemical and biological pesticides.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.207-215
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• 1994

The brown planthopper (BPH), Nilaparuata lugens, is the major pest 01 nce in Asla. Cument control tactics rely pnmalily on chemical ~nsecticides and resistant nce varieties In Korea, the most important biolog~cal conb-ol agent appears to be the naturally-occuning, mermlthid nematode, Agarnermrs unka. Although parasitism of BPH is highly variable from place to place and from year to year. the rnermithid is a promising biological control agent because it reduces the fecundity of the host and ultimately causes its death. The memithid has only one generation per year compared to the three to four generations of BPH, but the mermithid lemales stagger their egg production so that many individuals in all BPH generations are parastized. Augmentation of this rnermithld into BPH populations is only psslble on a limited scale because it is an obligate parasite and mass production technology has yet to be developed. Conservation of naturally-occumng populations through cultural techniques and the use of compatible resistant rice varieties and chemical insecticides may lead to an effective integrated pest management program for BPH.

• Korean journal of applied entomology
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• v.34 no.1
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• pp.75-81
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• 1995

To reduce crop damage from root-knot nematode, Meloidogyne spp. chemical, cultural, physical control methods were compared in commercial greenhouse for 3 years from 1992 to 1994. Timing of sol exchange for economic losses due to the nematodes is important: every 3 years for coarse sand (Masatto) and every 4 years for red-yellow soil. Control effects on Meloidogyne spp. in cucumber were 78.2% in Dazomet DP, 72.1% Carbo G+Soil reverse+submergence, and 66.3% in Carbo G+submergence. Pesticide effects were temporally different after treatment: 77.7~80.6% in 20 days and 33.7~49.5% in 60 days. Cropping system in oriental melon gave an excellent control effect of 81.1% at oriental melon/rice culture. All methods controled root-knot nematodes at the time of the treatment but the number of the nematodes increased at the end of the season. However, soil exchange was effective for 3 years. The most economic control practice is rotation with rice for every three years.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.489-494
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• 2016

Biological control of the fungus gnat Bradysia difformis by the predatory mite Hypoaspis aculeifer was examined in hydroponic systems of strawberries in Namwon and Hapcheon varieties of Jeollabuk-do and Gyeongsangbuk-do provinces, respectively, from 2012 to 2013. The damage to strawberries caused by B. difformis was examined in seedling stages and during cultivation periods. To achieve environment-friendly management of B. difformis, 60.6 individuals of H. aculeifer were released per square-meter three and four times during cultivations periods of the Namwon and Hapcheon strawberry varieties, respectively. H. aculeifer had better control efficiency against of B. difformis than that observed with conventional cultural practices. Wilt symptoms and damage of strawberries due to B. difformis were decreased by approximately 7.4-10.4%.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.71-76
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• 1986

Bacillus thuringiensis var. thuringiensis H1 (BTT) strain was cultured in the 4 different fermentation media and then measured their growths and the productions of endotoxin crystals from the culture media. Out of the 4 media, the productions of the endotoxin crystals and spores were maximal in the pH9-M-3 medium. The wet weight of BTT cells grown in the 150ml culture was approximately 3.218g and the number of the viable spores was $3.3{\times}10^{10}/ml$, and the ratio of the endotoxin weight over total cell weight was 20.05%. The generation time of the BTT bacteria in the M-1 was about 47.6 minutes in the M-2, 132.9 minutes in the M-3 and 110.2 minutes in the M-4. The proper pH for the production of the endotoxin by BTT appeared to be pH 6.5.