• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.101-106
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• 1979

Present studies were carried out to get a basic information for biological control of soybean rod borer, Grapholitha glycinivorella Matsumura, causing main injury in soybean cultivation in Korea. 1474 native strains were cultivated in field to evaluate the pod borer damage. Pubescence density and color, maturity group, seed coat color, aphid and general leaf damage and seed damage by pod borer were investigated, and determined among their relationships. As another basic study for ecological control of insect, 6 leading varieties were planted on different planting date with 3 levels of plant spacing, on which pod borer damage and some related agronomic characters were studied. The results obtained one summarized as follows: Average injury of soybean pod borer was $5.2\%$ ranging $0-38\%$ in 1474 strains planted on 20 May. Non-significant correlations were found between pod borer damage and pubescence density and color, while pod borer damage closely related with maturity groupand aphid damage at $5\%$ level ofttests. Most severe damage was found in green seed coast color and maturity group V. Late and sparse plantings tend to have more damages to the pod borer than those of early and dense plantings. Pod setting date and period of pod maturing seemed related with pod borer damage. Bongeui and Chungbuk-baik cultivars were resistance to soybean pod borer, while Clark and Kumkang-daerip were susceptible in field tests.

• Research in Plant Disease
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• v.21 no.4
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• pp.315-320
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• 2015

Soybean mosaic virus (SMV) is a prevalent pathogen that causes significant yield reduction in soybean production worldwide. SMV belongs to potyvirus and causes typical symptoms such as mild mosaic, mosaic and necrosis. SMV is seed-borne and also transmitted by aphid. Eleven SMV strains, G1 to G7, G5H, G6H, G7H, and G7a were reported in soybean varieties in Korea. A reverse transcription loop-mediated isothermal amplification (RT-LAMP) method allowed one-step detection of gene amplification by simple procedure and needed only a simple incubator for isothermal template. This RT-LAMP method allowed direct detection of RNA from virus-infected plants without thermal cycling and gel electrophoresis. In this study, we designed RT-LAMP primers named SML-F3/B3/FIP/BIP from coat protein gene sequence of SMV. After the reaction of RT-LAMP, products were identified by electrophoresis and with the detective fluorescent dye, SYBR Green I under daylight and UV light. Optimal reaction condition was at $58^{\circ}C$ for 60 min and the primers of RT-LAMP showed the specificity for nine SMV strains tested in this study.

• Korean journal of applied entomology
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• v.23 no.4 s.61
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• pp.197-202
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• 1984

Two soybean cultivars Hanan and Kwanggyo were used to monitor SMV spread in the field. The Haman producing mosaic symptoms by infection with SMV strain G7 was planted in $2.2m^2$ at the coater of $320.7m^2$ field and Kwanggyo producing necrosis by infection with SMV-G7 was planted around the Haman one day after inoculation of Heman with SMV-G7. The most severe incidence of the necrotic disease in soybean cultivar Kwanggyo occurred on 43 days after planting(July 13) whereas aphid population reached peak around 22 days after planting(June 22). Total incidence of the necrotic disease was $20.4\%$, in the whole field and $56\%$, in eight $mall plots around the spreader of SMV. The spread of S MV outward from the spreader source was greater downwind than it was upwind. Spread also showed a signigicant gradieut pattern leeward from the infection focus.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.41-45
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• 1977

The systemic insecticides carbofuran $(Curaterr\; 3\%\; G)$ mephosfolan $(Cytrolane\; 2\%\; G)$ and disulfoton$(Disyston\; 5\%\; G)$ were evaluated in the field for conrol of some insects on soybeans when the insecticides were applied in seeding-pits at the rates of 4.6, 9.2 and 13.8 mg(a.i)/pit at the planting time. Control of the soybean aphid (Aphis glycines Matsumura) and the two-spotted spider mite (Tetranychus telarius(L.)) on soybeans was obtained for about 2 to 3 months, but their treatments were ineffective against the soybean moth (Grapholitha glycinivorella Matsumura). For the control of aphids and mites, disulfoton was better than carbofuran and mephosfolan. The insecticides slightly reduced the soybean stands, while the low-dose treatments of carbofuran slightly increased the stands. Carbofuran and mephosfolan caused severe phytotoxicity at the early stages, but disulfoton showed slight or negligible phytotoxicity. The phytotoxic symptoms in carbofuran and mephosfolan treatments were shelving the large number of brown or black-brown spots on the cotyledon and the first-leaves, and in addition to that showing necrosis along the leaf-margin. The symptoms in disulfoton treatments were slight withering along the leaf-margin of the first-leaves. In spite of good control of aphids and mites, there were no differences in soybean yield.

• Research in Plant Disease
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• v.27 no.3
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• pp.99-106
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• 2021

The fungal isolate Isaria javanica pf185 has potential as a mycopesticide because it demonstrates insecticidal activity against the green peach aphid and antifungal activity against Colletotrichum gloeosporioides. For commercialization of this isolate, determination of the optimal and least expensive culture conditions is required; however, these data are not currently available. This study describes the conditions for optimal development of conidia and production of metabolites for the biocontrol of the fungal pathogen. The optimal culture conditions were examined using cultures on solid agar and liquid media. High growth temperature enhanced spore formation but reduced antifungal activity in both solid and liquid media. The highest spore yield was obtained in a medium containing glucose as a carbon source and yeast extract as a nitrogen source. Soybean powder and wheat bran were effective nitrogen sources that promoted spore production and antifungal activity of the isolate. These results revealed the basic, cost-effective growth media for commercial production of a biopesticide with insecticidal and antifungal properties for use in integrated pest management.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.113-120
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• 1986

Soybeans collected from different locations in Korea were planted for tests of seed transmission of soybean mosaic virus (SMV). The percentage of seed transmission ranged from 20.5 to 29.5% in 14 seedlots including soybean cultivar Namhe and 12 to 19% in other 44 seedlots. However, no seed transmission of SMV was observed in soybean cultivar Younkiyongho. SMV was detected from embryo and cotyledon of soybean seeds. The infection of SMV was highly detected from premature seeds than from fully mature seeds, and higher from seeds harvested from plants infected before June 20 than plants infected around July 20 and August 20. No significant relationship was observed between seed transmission of SMV and mottling of seeds. The incidence of soybean mosaic disease followed by one month after peak of aphid population. The number of aphids was less on leaves of soybeans with short and dense trichomes whereas it was higher on leaves of soybean with long and sparse trichomes. Generally, the number of aphids was decreased on leaves with long and dense trichomes as the growth progressed. Soybean cultivar Columbus and 14 cultivars were susceptible, Chief and 14 cultivars were moderate, but Jangbaek and 17 other cultivars were resistant to SMV when inoculated with one isolate of SMV.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.231-236
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• 2021

The Aphid, Myzus persicae, and the bean bug, Riptortus clavatus, are major insects in crops. This study examined the insecticide susceptibility and phytotoxicity of insecticides dispersed using an Unmanned Aerial Vehicle (UAV, multi-copter) against the insects. Sulfoxaflor suspension concentrate (SC, 16X) on potato fields and etofenprox, methoxyfenzide suspo-emulsion(SE, 8X) on soybean fields were dispersed after deploying water-sensitive paper within the field to measure the distribution pattern and coverage index of the falling insecticide. Both insecticides showed a controlled mortality of 76.4% against aphids and 97.5% and 94.4% against the 2nd nymphal, and 5th nymphal stage of the bugs, respectively. The droplet distribution was less than 0.5mm, and coverage analysis revealed an inside and outside coverage of 3.1 and 1.6, respectively. The surrounding area was affected by insecticide spraying using a multi-copter. This study is expected to help expand UAV control and use it safely in the future.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.1-5
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• 2009

Crude saponin, extracted from the starfish Asterias amurensis, was assessed for its capacity as a biological pesticide. As part of this analysis, its insecticidal and repellent activities, in addition to its acute and chronic toxicities were tested. In comparison with the control group, insecticidal activity of saponin against tobacco cutworm, Spodoptera litura, in kale, Brassica loeracea was low at 36.4%. Repellent activities of the extracted saponin against green peach aphid, Myzus persicae, and S. litura, on soybean leaf, Glycine max and kale were 65.6% and 35.0% at $1^{st}$ day, and 54.5% and 30.0% at $3^{rd}$ day, respectively. Acute and chronic toxicity analysis was carried out using acute immobilizatioin test and reproduction impairment test, respectively. The saponin had 48 h-$EC_{50}$ of $65.21{\mu}g/mL$. Twenty-one day accumulative reproduction after treatment was lower in Daphnia magna at $7{\mu}g/mL$ saponin (78 youngs), compared with the control group (129 youngs). These results indicate that the extracted saponin exhibited some toxicity and has potential as a repellent against insects.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.496-508
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• 1992

Phytophagous insects associated with Dicotyledoneae weeds and host specificities in the field populations were investigated for the survey of biological control agents of weeds in Korea. Fifty four weed species in 39 genera were collected during the survey. The most insects were collected from Polygonales by 24 species in 22 genera and followed by Urticales and Centrospermales by 17 species of 17 genera. The insects collected in the other weed orders were ranged from 1 to 12 species. Out of 17 insect species collected in Urticales, Baris sp. damaged the leaves of Hamulus japonicus in Cannabinaceae as scattered holeshape and showed host specificity. In Polygonaceae, Rumex japonicus and R. crispus were severely damaged by Aphis rumicis and Gastrophysa atrocyanea. G. atrocyanea leaf beetle had host specificity on R. japonicus and ate all the leaves except veins. The leaf beetle, Lypesthes japonicus was a potential biological control agent by feeding leaves of Persicaria spp .. And Lixus spp. were also often collected from Persicaria spp .. Liothrips vaneeckei was first collected from weed, P. modosa. P. senticosa was damaged by unidentified geometrid moth larvae and P. perfoiliata by Miarus atricolor snout beetle. Cassida piperata damaged leaves of Chenopodium album of Centrospermales and showed host specificity. In a soybean field, C. album and Amaranthus mangostanus were severely damaged by Spodoptera litura larvae which were eating soybean leaves. This phenomenon indicates that the presence of weed in cultivated land influences the outbreak of insect pests. Altica oleracea leaf beetle was frequently collected from Oenothera spp. of Onagraceae in Myrtales. Aphis gossyphi was outbroken on Solanum nigrum and Phylliodes brettinghami leaf beetle was first recorded on the same plant. Leaf beetles, Longitarsus scutellais and Hemipyxis plagioderoides were first collected from Plantago asiatica of Plantaginaceae in Plantaginales. They showed host specificities in the fields. The hemipterans were collected from many weeds during the survey and their roles on weeds should be investigated. A tractomorpha bedeli was also collected from many kinds of weeds in forest areas.