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Hu G.,Nanjing Agricultural University | Lu F.,Nanjing Agricultural University | Zhai B.-P.,Nanjing Agricultural University | Lu M.-H.,China National Agro Tec Extension and Service Center | And 5 more authors.
PLoS ONE | Year: 2014

An effective control strategy for migratory pests is difficult to implement because the cause of infestation (i.e., immigration or local reproduction) is often not established. In particular, the outbreak mechanisms of the brown planthopper, Nilaparvata lugens (Stål), an insect causing massive losses in rice fields in the Yangtze River Delta in China, are frequently unclear. Field surveys of N. lugens were performed in Jiangsu and Zhejiang Provinces in 2008 to 2010 and related historical data from 2003 onwards were collected and analyzed to clarify the cause of these infestations. Results showed that outbreaks of N. lugens in the Yangtze River Delta were mostly associated with an extremely high increase in population. Thus, reproduction rather than immigration from distant sources were the cause of the infestations. Although mass migration occurred late in the season (late August and early September), the source areas of N. lugens catches in the Yangtze River Delta were mainly located in nearby areas, including the Yangtze River Delta itself, Anhui and northern Jiangxi Provinces. These regions collectively form the lower-middle reaches of the Yangtze River, and the late migration can thus be considered as an internal bioflow within one population. © 2014 Hu et al. Source

Sanada-Morimura S.,Kyushu Okinawa Agricultural Research Center | Otuka A.,Kyushu Okinawa Agricultural Research Center | Matsumura M.,Kyushu Okinawa Agricultural Research Center | Etoh T.,Saga Prefectural Agriculture Research Center | And 3 more authors.
PLoS ONE | Year: 2015

Overseas migration of the small brown planthopper, Laodelphax striatellus (Fallén), occurs during the winter wheat harvest season in East Asia. Knowing the take-off time of emigrating L. striatellus is crucial for predicting such migrations with a simulation technique because winds, carriers of migratory insects, change continuously. Several methods were used in China and Japan from late May to early June 2012 and again in 2013 to identify the precise timing of take-off. These methods included: a tow net trap mounted to a pole at 10 m above the ground, a helicopter-towed net trap, and a canopy trap (which also had video monitoring) set over wheat plants. Laodelphax striatellus emigrated from wheat fields mainly in the early evening, before dusk. The insects also emigrated during the daytime but rarely emigrated at dawn, showing a pattern that is unlike the bimodal emigration at dusk and dawn of two other rice planthoppers, the brown planthopper, Nilaparvata lugens (Stål), and the white-backed planthopper, Sogatella furcifera (Horváth). There was no significant difference in the temporal pattern of take-off behavior between females and males of Japanese L. striatellus populations. © 2015 Sanada-Morimura et al. Source

Otuka A.,Japan National Agriculture and Food Research Organization | Zhou Y.,Jiangsu Academy of Agricultural Sciences | Lee G.-S.,South Korean National Institute of Animal Science | Matsumura M.,Japan National Agriculture and Food Research Organization | And 4 more authors.
Applied Entomology and Zoology | Year: 2012

A method has been developed for predicting the overseas migration of Laodelphax striatellus (Fallén) from eastern China to Japan and Korea. The method consists of two techniques: estimation of the emigration period in the source region and simulation of migration. The emigration period was estimated by calculating the effective accumulated temperature for the insect by use of real-time daily surface temperatures at the source. During the emigration period, migration simulations were performed twice a day, at every dusk and dawn. The prediction method was evaluated, by cross-validation using migrations in the 4 years from 2008 to 2011. The results showed that the emigration periods included the mass migrations, and that the method successfully predicted those migrations. © 2012 The Japanese Society of Applied Entomology and Zoology. Source

Tang X.-T.,Yangzhou University | Ji Y.,Yangzhou University | Chang Y.-W.,Yangzhou University | Shen Y.,Agriculture and Forestry Bureau of Binhu District | And 3 more authors.
Bulletin of Entomological Research | Year: 2016

While Liriomyza sativae (Diptera: Agromyzidae), an important invasive pest of ornamentals and vegetables has been found in China for the past two decades, few studies have focused on its genetics or route of invasive. In this study, we collected 288 L. sativae individuals across 12 provinces to explore its population genetic structure and migration patterns in China using seven microsatellites. We found relatively low levels of genetic diversity but moderate population genetic structure (0.05 < F ST < 0.15) in L. sativae from China. All populations deviated significantly from the Hardy-Weinberg equilibrium due to heterozygote deficiency. Molecular variance analysis revealed that more than 89% of variation was among samples within populations. A UPGMA dendrogram revealed that SH and GXNN populations formed one cluster separate from the other populations, which is in accordance with STRUCTURE and GENELAND analyses. A Mantel test indicated that genetic distance was not correlated to geographic distance (r = -0.0814, P = 0.7610), coupled with high levels of gene flow (M = 40.1-817.7), suggesting a possible anthropogenic influence on the spread of L. sativae in China and on the effect of hosts. The trend of asymmetrical gene flow was from southern to northern populations in general and did not exhibit a Bridgehead effect during the course of invasion, as can be seen by the low genetic diversity of southern populations. Copyright © Cambridge University Press 2015. Source

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