• Korean journal of applied entomology
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• v.54 no.4
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• pp.419-423
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• 2015

Small brown planthopper (SBPH), Laodelphax striatellus, gives a lot of damage to the rice by insect vector of rice stripe virus (RSV). This study compared the RSV acquisition and infection rates according to wing form, sex, and life stage of SBPH. The RSV acquisition rate in macropterous and brachypterous was 60.7% and 63.1%, respectively. The RSV acquisition rate by sex was 61.9% in female and 52.2% in male. However, there was no difference in significance. The RSV acquisition rate of nymphs and adults was 51.2% and 58.7%, respectively. The RSV infection rate by wing form was 53.3.% in macropterous and 48.2% in brachypterous. According to life stage, nymphs was 38.2% and adults was 42.6%. There was no difference in significance. On the other hand, female and male of RSV infection rate was 50.5% and 22.3%, respectively. There was a significant difference. Additionally, developmental periods of SBPH by RSV infection, the longest when inoculated with RSV-infected SBPH in healthy rice, while the shortest when inoculated healthy SBPH in healthy rice.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.247-253
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• 2002

Based on accumulated data during 1977-2001, seasonal fluctuations of migrated aphids at Daegwallyeong highlands were analyzed. In addition, rates of PLRV transmission by migrated aphids were investigated by inoculation on indicator plant, Physazis floridana, and ELISA in 2000-2001, and the change of PLRV transmission rates by aphids was compared with that of 1989-1991. The average migrated aphid population densities in 1976-1980, 1991-1995, and 1996-2000 were 575.2, 2959.4 and 2281.6, respectively, showing gradual increase in recent years. The average peak time of aphid migration was from early to mid June during 1977-2001, showing any significant differences over the years. The dominant species, however, changed slowly; before mid 1980s M. persicae flied dominantly, but after mid 1980s Aphis gossypii did. Hahm et al. (1991) reported that PLRV transmission rate of migrated aphids during 1989-1991 was 6.7-10.0%. In 2000-2001, however, migrated aphids at Daegwallyeong highland showed 10.1-11.0%. Although present PLRV transmission rate was slightly higher than that of 10 years ago, taking increased population densities and diversity of migrated aphids into account, there was no significant change of PLRV transmission rate over the years.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.05a
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• pp.72-72
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• 2002

• Research in Plant Disease
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• v.18 no.3
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• pp.245-249
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• 2012

The small brown planthopper (Laodelphax striatellus) is one of the most important rice pests in Republic of Korea because it damages rice plants not only by sap-sucking but also by transmitting Rice stripe virus (RSV). Outbreaks of RSV are closely related to outbreaks of the small brown planthopper (SBPH). Therefore, it is very important to control SBPH for the management of RSV. Mass-migrating SBPH collected by aerial net traps in June 2011 at Taeanup, Geunheungmyon and Gonammyon in Taeangun were examined for virus carrier status and effects of the pesticide, 'Myungtaja', on the control of RSV. Among 1,217 SBPH trapped, about 7.7% were detected as RSV positive and 4.4% were positive for Rice black streak dwarf virus (RBSDV) by RT-PCR. After the mass migration, pesticide 'Myungtaja' was sprayed once or twice on rice fields and compared to untreated fields. The incidence of RSV was not affected by the frequency of spraying 'Myungtaja' but was influenced by the time of pesticide treatment. Myungtaja' treatment within 5-7 days after mass migration resulted in the most efficient RSV control, resulting in RSV incidence decreased by 87.6% compared to the control. Therefore, we conclude that pesticide spraying for RSV control was most effective when it was done within 5-7 days after mass migration.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.415-423
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• 2018

Aphid is a typical vector that transfers various kinds of viruses to potatoes. Therefore, it is very important to control aphids moving into potato fields. We investigated the seasonal movement pattern of aphids and its virus transmission rates mainly in the three seed potato production regions at highland in Gangwon-do, Korea. In addition, we identified the aphid species with over-wintering eggs collected from barks or twigs of total 57 tree species around potato fields in winter season. The peak time of summer and winter migration of aphid was at the mid-June and the early October, respectively. A 2.8% of total aphid trapped in yellow water-pan trap was turned out PLRV-borne, and the virus transmission rate was 15.4% by Myzus persicae and 9.1% by Macrosiphum euphorbiae. PLRV-borne aphids started to flow in from the late May, and virus transmission rate of aphid trapped in mid-June was the highest with 10.4%. Totally 14 species of aphid eggs wintered in the 17 species of trees including Acer pictum subsp. mono and Acer pseudosieboldianum at the 11 sites. In particular, because it is not certain that Betula platyphylla var. japonica and Yamatocallis hirayamae do transmit potato virus, but they over-wintered in host plants distributed over a wide area, further research on transmission ability is necessary.

• Research in Plant Disease
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• v.28 no.1
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• pp.39-45
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• 2022

Patterns of occurrence of tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) with whitefly on summer-cultivated tomato in Gwangju-si, Gyeonggi Province were surveyed using multiplex reverse transcription-polymerase chain reaction in 2020. In addition, distribution of the whiteflies species and their viral transmission rates were investigated throughout the tomato growing season. The infection rates of TYLCV and ToCV increased sharply during harvest, and the single infection rates were 30.9% and 5.0%, respectively, with a mixed infection rate of the two viruses being the highest at 52.2%. Single infection with TYLCV and double infections with TYLCV and ToCV accounted for the majority with 83.1%. Bemisia tabaci were dominant over Trialeurodes vaporariorum in greenhouse grown plants, and all of the investigated B. tabaci biotypes were identified as Mediterranean (MED, formerly known as Q biotype). The transmission rate of TYLCV, detected in every sampled B. tabaci MED population, was 21.4%, and the mixed transmission rate with ToCV was 35.5%. Viruliferous MED whiteflies with ToCV showed a higher rate than that of T. vaporariorum. In the transplant stage, viruliferous rate of both TYLCV and ToCV of B. tabaci was 42.7%; this rate was highest in the harvest stage. In examination of tomato yield, the increase in the mixed infection rate of TYLCV and ToCV led to complete yield loss. When the mixed infection rate increased by 10%, the yield decreased by 405.4 kg/10a.

• Research in Plant Disease
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• v.19 no.2
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• pp.84-89
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• 2013

The incidence factors of Rice stripe virus (RSV) were analyzed by studying the population density and the viruliferous insect rate (VIR) of small brown planthopper (SBPH), the incidence of stripe disease, alternate host, and susceptible cultivar in Chungnam Province. The population of overwintering SBPH had been decreasing, but the VIR of overwintering SBPH had not been differing for three years, 2008 to 2010. No RSV was detected in the natural host plants, such as short awn, annual bluegrass, and barley. In 2009, relatively large population of SBPH with the VIR of 5.4% migrated from China. However, there was no evidence relating of migration large amount of SBPH from China in 2008 and 2010. Also the infection rate of RSV in rice was less than 1% in these periods. The cultivation area of the susceptible varieties had steadily decreased from 41% to 19% from 2007 to 2009. Therefore, the reduction factors of rice stripe disease in Chungnam Province with higher influx of inoculum could be with an appropriate forecasting and chemical control, cultivation of resistant varieties, changes in the cropping system, and the low winter-spring temperature.