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Itou M.,Kochi Agricultural Research Center | Watanabe M.,Hiroshima University | Watanabe E.,Hiroshima University | Miura K.,Hiroshima University | Miura K.,Japan National Agriculture and Food Research Organization
Entomological Science

Nesidiocoris tenuis is considered to make significant contributions to the control of greenhouse pests such as whiteflies, thrips, leafminers, lepidopterans, and spider mites, although there is little information based on direct observation of the predation of N. tenuis on these target pests. We developed a method to perform gut content analysis of N. tenuis based on DNA in which specific PCR primers were designed to detect the DNA of target pests. By means of gut-content analysis, we found that the percentage of N. tenuis preying on Bemisia tabaci and Thrips palmi was approximately 40% in the field. © 2012 The Entomological Society of Japan. Source

Okazaki S.,Forestry and Fisheries Research Center | Okuda M.,Japan National Agricultural Research Center | Komi K.,Kochi Agricultural Research Center | Yamasaki S.,Forestry and Fisheries Research Center | And 3 more authors.
Australasian Plant Pathology

The acquisition efficiency of Tomato spotted wilt virus (TSWV) by Frankliniella occidentalis was examined using TSWV-infected Datura stramonium with various virus titres. TSWV quantities in leaves were measured using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The percentages of viruliferous F. occidentalis significantly correlated with DAS-ELISA and qRT-PCR values in the fed leaf piece. The detectable period of TSWV in viruliferous F. occidentalis adults trapped on sticky traps was also examined at various temperatures. At 25°C or less, TSWV could still be detected by DAS-ELISA in the bodies for at least 20 days after the capture of viruliferous F. occidentalis, although ELISA values had decreased gradually over time more rapidly at higher temperatures. The quantities of TSWV RNA detected by qRT-PCR rapidly decreased. The mean value decreased to half in a day, and reduced to 7.3% of the initial mean value after 14 days. © 2010 Australasian Plant Pathology Society Inc. Source

Shimomoto Y.,Kochi Agricultural Research Center | Kobayashi K.,Ehime University | Okuda M.,Japan National Agriculture and Food Research Organization
Journal of General Plant Pathology

In 2007, lisianthus (Eustoma grandiflorum) plants with necrotic ringspots on the leaves were found in Kochi Prefecture, Japan. Tospovirus-like spherical enveloped particles with ca. 160 nm in diameter were observed with electron microscopy. The complete nucleotide sequence of the S RNA segment of the virus was determined, and phylogenetic analysis using deduced amino acid sequences of the nucleocapsid protein and the nonstructural S protein indicated that the virus is phylogenetically distinct from any known tospovirus species. The results suggest that the virus is a new member of the genus Tospovirus, in the family Bunyaviridae. The virus is the fifth distinct tospovirus occurring naturally in lisianthus in Japan. The necrotic symptoms were reproduced on lisianthus seedlings after mechanical inoculation. The host range of the virus isolate on several test plants was also examined. © 2014 The Phytopathological Society of Japan and Springer Japan. Source

Nagasaka K.,Japan National Agricultural Research Center | Takahasi N.,Kochi Agricultural Research Center | Okabayashi T.,Kochi Prefectural Government
Applied Entomology and Zoology

In order to elucidate the impact of secondary parasitism on a banker plant system, aphid parasitoids on banker plants were surveyed for four years in commercial greenhouses producing eggplant and sweet pepper in Kochi Prefecture, Japan. A banker plant system using Aphidius colemani was introduced into the greenhouses in November or December for the control of pest aphids from February through May. The mean rate of secondary parasitoids to total parasitoids on the alternative host aphid (Rhopalosiphum padi) on banker plants was less than 35% in the early season. In March or April, the mean rate exceeded 40%, and was more than 70% by May or June. Three main species of secondary parasitoids, Alloxysta sp. nr victrix, Dendrocerus laticeps and Syrphophagus sp., occurred throughout the season. In addition, Asaphes suspensus and Pachynouron aphidis occurred later in the season. In greenhouses where the banker plant system of aphid control failed, the increase of secondary parasitism on banker plants was sharper than in greenhouses with successful aphid control. In March and April, the higher rates of secondary parasitism on banker plants had a significant influence on the failure of aphid control. Source

Horita M.,Japan National Institute for Agro - Environmental Sciences | Tsuchiya K.,Kyushu University | Suga Y.,Nagasaki Pest Control Station | Yano K.,Kochi Agricultural Research Center | And 3 more authors.
Journal of General Plant Pathology

Ralstonia solanacearum is the causal organism of bacterial wilt of more than 200 species representing 50 families of plants in tropical, subtropical, and warm temperate regions in the world. Traditionally classified into five races based on differences in host range, R. solanacearum has also been grouped into six biovars on the basis of biochemical properties. With recent developments in molecular biology, various DNA-based analyses have been introduced and used to confirm that this binary system does not completely represent the diversity within R. solanacearum strains. Therefore, a new hierarchical classification scheme has been suggested, which defines R. solanacearum as a species complex and reorganized the concept of the species as a monophyletic cluster according to a phylogenetic analysis based on genomic sequence data. Here we discuss the current bacterial wilt situation and genetic relationships based on the recent classification system of Japanese R. solanacearum strains as well as worldwide strains. We also review the genetic, biochemical, and pathological characteristics of R. solanacearum strains, in particular, those affecting potato and Zingiberaceae plants as distinctly important pathogens in relation to continuously problematic and recent emergent diseases in Japan. © 2014, The Phytopathological Society of Japan and Springer Japan. Source

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