• The Korean Journal of Mycology
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• v.26 no.1 s.84
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• pp.78-85
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• 1998

During the screening of biological control agents for insect pests in the greenhouse, 70 dead insect-related fungi were isolated and tested insecticidal effect of their culture filtrates was tested. From this studies, CNAB-63 isolate showed strong control effects against the cotton aphids and the two-spotted spider mite as 65.19% and 77.55%, respectively. The insecticidal active compound of CNAB-63 isolate was purified from culture filtrate by silica gel chromotography, thin layer chromatography and HPLC. Purified active compound (CNAB) showed control effects against the two-spotted spider mite with 63.45% at $100\;{\mu}g/ml$ concentration. However, it did not exhibit antimicrobial activity against fungi and bacteria.

• The Korean Journal of Mycology
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• v.26 no.3 s.86
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• pp.403-406
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• 1998

An entomophthoraceous fungus, Entomophthora planchoniana, was found in populations of the green peach aphid, Myzus persicae, at Kunsan city on June 2, 1998. Occurrence of this species has never been recorded in Korea. Microscopic observations of this fungus are described, and illustrated. Unique characters are that it forms unitunicate muscae-like conidia with $4{\sim}6$ nuclei, and is the only Entomophthora species which can attack aphids.

• Research in Plant Disease
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• v.28 no.1
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• pp.32-38
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• 2022

A survey of Barley yellow dwarf virus (BYDV) was conducted in major oat-growing areas of Korea in 2020. BYDV is an economically important pathogen of cereal crops that can be transmitted by aphids. The present study evaluated the genetic composition of BYDV in oat from eight geographical areas in Korea. Multiplex reverse transcription-polymerase chain reaction was used to screen 322 oat leaf samples for six BYDV strains (PAV, MAV, SGV, PAS, RPV, and RMV). The 125 samples (~39%) tested positive for BYDV. BYDV-PAV, BYDV-SGV, BYDV-PAS, and BYDV-RPV were detected from oat in different areas. Most of the BYDV-infected samples were assigned to subgroup I (n=112). The results indicate that BYDV-PAV could be dominant throughout Korea. Also, the phylogenetic analysis of coat protein sequences indicated that 23 BYDV isolates from Korea could be separated into two clades, which exhibited high nucleotide sequence similarity. In conclusion, the present survey provides a BYDV infection assessment for domestic oat varieties in Korea and basic information for the development of BYDV control measures in Korea's oat industry.

• The Plant Pathology Journal
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• v.22 no.1
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• pp.51-62
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• 2006

Three strains of Cucumber mosaic virus (CMV) have been found to cause a lethal disease, referred to as fern leaf syndromes and mild mosaic symptoms in tomato (Lycopersicon esculentum Mill.) crops grown in Kuwait. CMV strains were detected and identified based on host range, symptomatology, serology, electron microscopy, and ribonucleic acid (RNA) electrophoresis in polyacrylamide gels. A high degree of viral genomic heterogeneity was detected among CMV strains isolated in Kuwait, with no apparent correlation to symptomatology in tomato host plants. Two different virus satellites of 'CMV associated RNA 5', designated CARNA 5, were detected in two virus strains that caused both lethal disease and mild symptoms, designated CMV-D1 and CMV-S1 respectively. CARNA5 was not detected in the third CMV strain that caused fern leaf syndromes designated CMV-F. All the three isolated strains were serologically indistinguishable from each other and may belong to one serotype according to Ouchterlony gel diffusion tests. These strains transmitted via aphids (Myzus persicae Sulz) in a non-persistent manner. Physical properties of the virus strains were very similar where thermal inactivation test showed that virus withstood heating for 10 min at $70^{/circ}$, dilution end point was $10^{-4}$, and the longevity in vitro at room temperature was less than 5 days for all virus strains. CMV-D1 and CMV-F were the most devastating diseases spreading in both greenhouse and field-grown tomato where aborted flower buds failed on fruit setting due to the viral infection. This is the first report to isolate three different strains of CMV in Kuwait.

• Korean journal of applied entomology
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• v.50 no.1
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• pp.79-82
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• 2011

Biological control of Aphis gossypii by natural enemies was carried out in watermelon from April to June. Aphidius colemani was released 3 times at rate of $2/m^2$ to control A. gossypii(April 24, May 8, and May 22 in 2007). In A. colemani-released plots, A. gossypii showed low population density of < 0.6 per leaf with the highest parasitism of 57.2%, and 2.0~10.6% in the percentage of leaves with aphids. In control, the population of A. gossypii kept on increasing from early May and reached 653.2/leaf on may 29.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.63-65
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• 1999

Conidiobolus obscurus and C. thromboides (Zygomycetes: Entomophthorales), aphid-attacking fungi, were found on the Dactynotus species (Homoptera: Aphididae) in June 1998 for the first time in Korea. They produce globose primary conidia typical to the genus Conidiobolus but their dimensions are clearly distinguished. Conidiobolus thromboides produces rhizoids and conidiophores with cylindrical constriction at their apices but C. obscurus does not form rhizoids or constricted conidiophores. Resting spores were not found in our specimens of both species, but their vegetative structures observed readily allowed identification.

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.2
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• pp.93-99
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• 2008

The turnip aphid is a worldwide pest, damaging mainly to crucifers. In order to understand the life parameters of Lipaphis erysimi for the eventual goal of control, the developmental periods, survival rates, lifespan, and fecundity of the species were investigated under five temperature regimes ($15^{\circ}C-35^{\circ}C$). Furthermore, the efficacy of several environment-friendly agricultural materials (EFAMs) that are on the market was subjected to test in order to obtain further accurate information. The developmental period of the turnip aphid nymph was longest at $15^{\circ}C$ as 16.9 days, shortened as temperature goes up to $25^{\circ}C$ (5.4 days), and then somewhat increased at $30^{\circ}C$ (5.9 days), suggesting that the most efficient temperature for nymphal development could be around $25^{\circ}C$. Mortality of the nymphal turnip aphid was obvious at $35^{\circ}C$, whereas it was minimal at other temperature schemes. The longevity of adults shortened as temperature goes up to $30^{\circ}C$. In particular, the maximum lifespan for adults continued for 55 days at $15^{\circ}C$, but shortened to 21 days at $30^{\circ}C$. The total fecundity was 35.7 at $15^{\circ}C$, 81 at $20^{\circ}C$, 64.2 at $25^{\circ}C$, and 6.6 individuals at $30^{\circ}C$, showing the highest fecundity at $20^{\circ}C$. After the turnip aphids were successfully stabilized in indoor environment the insecticidal activity was tested and mortality was determined 12, 24, 36, and 48 hrs after EFAMs are treated. Several on-the-market EFAMs showed more than 90% of insecticidal activity within 24 hrs or 48 hrs, but a few showed less than 90% activity, signifying importance of selection of proper EFAMs.

• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1833-1840
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• 2007

Viruses in garlic plants (Allium sativum L.) have accumulated and evolved over generations, resulting in serious consequences for the garlic trade around the world. These viral epidemics are also known to be caused by aphids and eriophyid mites (Aceria tulipae) carrying Potyviruses, Carlaviruses, and Allexiviruses. However, little is known about viral epidemics in garlic plants caused by eriophyid mites. Therefore, this study investigated the infection of garlic plants with Allexiviruses by eriophyid mites. When healthy garlic plants were cocultured with eriophyid mites, the leaves of the garlic plants developed yellow mosaic strips and became distorted. In extracts from the eriophyid mites, Allexiviruses were observed using immunosorbent electron microscopy (ISEM). From an immunoblot analysis, coat proteins against an Allexivirus garlic-virus antiserum were clearly identified in purified extracts from collected viral-infected garlic plants, eriophyid mites, and garlic plants infected by eriophyid mites. A new strain of GarV-B was isolated and named GarV-B Korea isolate 1 (GarV-B1). The ORF1 and ORF2 in GarV-B1 contained a typical viral helicase, RNA-directed RNA polymerase (RdRp), and triple gene block protein (TGBp) for viral movement between cells. The newly identified GarV-B1 was phylogenetically grouped with GarV-C and GarV-X in the Allexivirus genus. All the results in this study demonstrated that eriophyid mites are a transmitter insect species for Allexiviruses.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.20-26
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• 1999

Ultraviolet light is required for the sporulation of Didymella bryoniae, a gummy stem blight fungus in cucurbits such as watermelon, melon, oriental melon, cucumber and pumpkin. In this experiment, the upper limit of wave length for the production of pycnidia of D. bryoniae was 365 nm - 375 nm. Two plastic houses were covered with either common transparent film (wave length longer than 225 nm is transmitted) or UV-absorbing film ( wave lenght shorter than 388 nm is absorbed). In both houses, seedlings inoculated with D. bryoniae were placed in the center of the house at 30 days after transplantation of watermelon (cv. Whanhoseong), and the disease incidences between the houses were compared until 80 days after transplantation. The number of disease lesions and incidence of pycnidia-producing lesions under the UV-absorbing film were reduced by 90% and 80%, respectively, compared to the common transparent film. The internode lengths of plants grown in the two houses were not significantly different, but the plants grown under the UV-absorbing film had longer vines and more leaves than plants under the common transparent film. However, fruit characters such as weight, length, width, rind thick and brix, were not different between the two houses. Occurrence of aphids was reduced in the UV-absorbing film, but those of mites or diseases (powdery mildew and sooty mold) were not different between the houses. These results suggest that disease incidence of gummy stem blight of watermelon in the greenhouse can be controlled by the use of UV-absorbing film.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.3
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• pp.35-40
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• 1980

In order to evaluate the fluctuation of soybean aphid (Aphis glycines Matsumura) population, six leading soybean cultivars were planted on five different planting dates with three plant spacings. The survey of aphid population and climatical condition were made from June through September in 1978. According to the differences of planting dates and plant spacings the soybean aphid populations were varied, and varietal response to the aphid was significantly different. Counting of aphid infestation on top third trifoliolate leaf seemed to be efficient for the estimation of soybean aphid population.