• Microbiology and Biotechnology Letters
• /
• v.41 no.4
• /
• pp.398-406
• /
• 2013

For the maximal production of aphicidal metabolites produced by the Beauveria bassiana Bb08, statistical methods such as the Box-Behnken experimental design and response surface methodology were used. The fungal culture filtrate was sprayed towards 3-star aphids and the mortality was examined. After the statistical analysis of the aphid mortality, the optimal culture conditions were found to be a culture temperature of $26.2^{\circ}C$, medium pH 5.9, flask shaking speed of 209.0 rpm, and culture time of 5.9 days. The expected mortality on days 4, 5, and 6 after spraying the filtrate on to the aphids were 76.8%, 84.9%, and 89.4%, respectively. All 4 factors of the culture conditions significantly affected the production of the aphicidal metabolites, and the order of significance was temperature, pH, culture time and shaking speed.

• Korean journal of applied entomology
• /
• v.24 no.1 s.62
• /
• pp.11-14
• /
• 1985

Some experiments were conducted to evaluate the aphidivorous activity of coccinellid beetle, Harmania axyridis Pallas. Experiments were carried out using with laboratory reared beetles and two aphid species(Aphis gossypii and Myzus persicae). Factors referred in the study of aphidivorous activity were the age of beetle, aphid species, temperatreu and illumination time. The aphidivorous activity was greatly different in relation to aphid species, developmental stages of the beetle, and the temperature. The 3rd and 4th instar larvae consumed more aphids than the 1st and 2nd instar larvae. Though the beetles consumed more number of cotton aphid, total weight of aphids consumed the more or less the same. Aphidivorous activity of the 1st to 4th instar larvae increased with a rise in temperature and adult activity was relativel high at $20^{\circ}C$ and low at $15^{\circ}C\;and\;30^{\circ}C$. The aphidivorous activity of the beetles was not influenced by the illumination period under the conditions given in this experiments, however, seem to require further study.

• Korean journal of applied entomology
• /
• v.48 no.2
• /
• pp.171-178
• /
• 2009

The changes of feeding pattern and the amount of insecticide penetrated into the leaf were monitored for 420 min after treatment of three concentrations of dinotefuran. At about 30 min after treatment of insecticide, the overall feeding pattern in EPG (Electrical Penetration Graph) monitoring was started to change, and there was significant difference in proportions of NP (non-penetration), PA (pathway activity), and phloem-feeding patterns among the different concentrations of dinotefuran treatment. Especially, as the amount of insecticide penetrated into a leaf increased, the reactive behaviors against this insecticide such as withdrawal of proboscis and movements of stylet of aphid were more quickly exhibited. And also, total time at which the proboscis of the aphids did not penetrate the plant was getting longer. The amount of dinotefuran penetrated into a leaf was monitored with HPLC. When the recommended concentration (100 mg/L) of the insecticide was treated, 5.24${\sim}$7.24 mg/L of the insecticide was detected from the leaf, and the proboscis of the aphids was apparently withdrawn from the leaf at approximately 60 minutes after treatment of this insecticide.

• Korean journal of applied entomology
• /
• v.48 no.4
• /
• pp.503-508
• /
• 2009

Biological-control-based-integrated-pest-management of major pests occurring on sweet pepper in greenhouse during summer season was tried. As many as 2.1 Orius laevigatus per $m^2$ were released in two times on June 6 and 19, and the population of thrips was kept under control and accordingly the damage was negligible throughout the season. To control aphids, a total of 0.8 Aphidius colemani per $m^2$ were released in four times, 0.2 of them at a time, flonicamid on May 14 and July 18 and pymetrozine on June 14 and September 4 were sprayed on the spots of high aphid occurrence to reduce the release of the wasp, and the density of aphids was kept under control. Whitefly was controlled successfully by releasing a total of 343.4 Amblyseius swirski per $m^2$ in nine times, 38.1 of them at a time, from May 9 until November 12 and dinotefuran was sprayed on November 12 when the density of whitefly increased up to 200 per trap. Tetranichus kanzawai was controlled by both Phytoseiulus persimilis which was released a total of 44.4 per $m^2$ in five times 8.9 of them at a time from May 23 to September 10, and the A. swirski which was released for the control of whitefly.

• Korean journal of applied entomology
• /
• v.53 no.4
• /
• pp.409-413
• /
• 2014

This study was conducted to observe the effects of dried tobacco leaf smoke on controlling aphids in a laboratory and a greenhouse. Insecticidal activity of tobacco smoke against Aulacorthum solani in an acrylic cage was higher when a burley cultivar, rather a flue-cured cultivar, was used. Mortality of A. solani, Aphis gossypii, and Myzus persicae was 63.9%, 94.4%, and 97.2%, respectively, after 50mg of tobacco smoke on their host plants in an acrylic cage. Mortality of M. persicae after tobacco smoke was used was higher in eggplant than in Chinese cabbage. When 100 g and 200 g of flue-cured tobacco were smoked in a $100m^2$ greenhouse for 2 h, the control values against A. solani were 28.9% and 95.4%, respectively; the control value after 14 h of smoking was more than twice the value after 2 h of smoking. The control value against A. gossypii was more than 80% after tobacco smoke was used in a greenhouse in an organic cucumber farm. Tobacco smoke can be an effective control against aphid pests in greenhouses if an appropriate amount of tobacco and smoking time on the basis of the greenhouse conditions are used.

• Research in Plant Disease
• /
• v.26 no.2
• /
• pp.103-108
• /
• 2020

Evaluations were made for the effects of cheese whey treatment on infection of pepper plants by cucumber mosaic virus-Vch (CMV-Vch) and pepper mottle virus-Kr (PepMoV-Kr). In a greenhouse, pepper plants sprayed with whey, prior to inoculation by CMV-Vch using aphids, showed a viral infection rate significantly lower (6.6%) than for the control (23.3%). In an open field experiment, in which CMV infection relied on natural transmission by aphids, pepper plants were sprayed with undiluted whey once a week, starting on the transplanting date (May 2) to the end of June. On June 5, these whey-sprayed plants showed a CMV infection rate reduced by 18.9% and 16.7%, compared to untreated and pesticide-treated plants, respectively. In the greenhouse, pepper plants inoculated with PepMoV-Kr mixed with whey showed a viral infection rate decreased by 60% compared to the control. The accumulated amount of PepMoV-Kr coat protein was less than that for the virus-only control at 6 days post inoculation (dpi), but increased up to a similar level as the control at 9 dpi. This study showed that cheese whey is effective in reducing infection of both CMV and PepMoV in pepper plants.

• Korean Journal of Organic Agriculture
• /
• v.17 no.2
• /
• pp.227-236
• /
• 2009

This research was carried out to investigate the seasonal occurrence of major pests and the effects of releases of natural enemies for biological control of the major pests in eggplant greenhouse. A total of 8 pest species in 7 families were identified. Among these pests, Myzus persicae, Aphis gossypii, Frankliniella occidentalis, Tetranychus urticae and Trialeurodes vaporariorum were the dominant species in eggplant greenhouse. Two aphid species occurred mainly from May to June, but their populations decreased rapidly from July. The population density of F. occidentalis was high from June to July and T. urticae and T. vaporariorum were abundant from July to September during the growing season of eggplant. In the trials of biological control of pests, aphids could be suppressed within the range of $87{\sim}97%$ by two times releases of Chrysopa pallens eggs. F. occidentalis and T. urticae could be suppressed within the range of $76{\sim}90\;and\;87{\sim}91%$ by three times releases of Orius sauteri adults, respectively. The releases of C. pallens eggs and O. sauteri adults were as effective as three times applications of insecticides for the control of aphids, F occidentalis and T. urticae from May to September.

• Korean Journal of Organic Agriculture
• /
• v.18 no.4
• /
• pp.573-586
• /
• 2010

This study was carried out to evaluate characteristics of Chrysanthemum sp. and to bioassay Tetranychus urticae, Nilaparvata lugens, and Aphis gossypii by different extracts part and method. Flower type of Chrysanthemum sp. line was anemone except 0706 line which was pompon. The flowering date was from April to June but 0721 line kept up November. They could overwinter except 0706 line. The Ethanol extracts of 0718 line of flower was high mortality as 63.8% on Tetranychus urticae. Ethanol mixed emulsifier extracts were the highest mortality as 69.4% at 5 days after. Mortality in water extract was lower than in ethanol and ethanol mixed emulsifier extracts. Ethanol mixed emulsifier extracts were higher mortality as 69.4% at 5 days after in 0718 line on Nilaparvata lugens. Mortality in water extract was lower than in ethanol and ethanol mixed emulsifier extracts. On Aphis gossypii, Chrysanthemum flower extracts could decrease the density of aphids in early days but the density of that was increase as time goes by because aphids produce offspring.

• The Plant Pathology Journal
• /
• v.32 no.4
• /
• pp.321-328
• /
• 2016

We examined the effects of temperature on acquisition of Potato virus Y-O (PVY-O), Potato virus A (PVA), and Potato leafroll virus (PLRV) by Myzus persicae by performing transmission tests with aphids that acquired each virus at different temperatures. Infection by PVY-O/PVA and PLRV increased with increasing plant temperature in Nicotiana benthamiana and Physalis floridana, respectively, after being transmitted by aphids that acquired them within a temperature range of $10-20^{\circ}C$. However, infection rates subsequently decreased. Direct qRT-PCR of RNA extracted from a single aphid showed that PLRV infection increased in the $10-20^{\circ}C$ range, but this trend also declined shortly thereafter. We examined the effect of temperature on establishment of virus infection. The greatest number of plants became infected when N. benthamiana was held at $20^{\circ}C$ after inoculation with PVY-O or PVA. The largest number of P. floridana plants became infected with PLRV when the plants were maintained at $25^{\circ}C$. PLRV levels were highest in P. floridana kept at $20-25^{\circ}C$. These results indicate that the optimum temperatures for proliferation of PVY-O/PVA and PLRV differed. Western blot analysis showed that accumulations of PVY-O and PVA coat proteins (CPs) were lower at $10^{\circ}C$ or $15^{\circ}C$ than at $20^{\circ}C$ during early infection. However, accumulation increased over time. At $25^{\circ}C$ or $30^{\circ}C$, the CPs of both viruses accumulated during early infection but disappeared as time passed. Our results suggest that symptom attenuation and reduction of PVY-O and PVA CP accumulation at higher temperatures appear to be attributable to increased RNA silencing.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.2
• /
• pp.173-178
• /
• 2011

BACKGROUND: Starfish is one of major sea invertebrates that have become a serious economic threat to aquacultural farms in Korea. Much effort has sacrificed to reduce the economic losses of the farms by predatory starfish, including developing and searching biological resources for medicinal and agricultural purposes. In the present study, we investigated aphicidal activity of the extracts from the starfish Asterina pectinifera against green peach aphid. METHODS AND RESULTS: Fresh starfishes were cut into small pieces, homogenized and soaked in methanol. The methanol extracts were centrifuged and the resulting supernatant was subjected to aphicidal activity assays and a series of silica gel column chromatography. More than 70% mortality of aphids were observed by the extracts at a concentration of 1,000 mg/L, exhibiting dose-dependent mortality. TOF-MS analyses detected polyhydroxysteroid as a main aphicidal compound from the starfish extracts. Transmission electronic microscopy could demonstrate that the extracts with polyhydroxysteroid caused aphids death by affecting their epicuticular membrane. CONCLUSION(s): This is the first report of aphicidal activity of the starfish Asterina pectinifera extracts against green peach aphid. Starfish biological resources may be used as a potential candidate for developing a new type natural insecticide.