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Takahashi M.,Tokyo University of Agriculture and Technology | Takahashi M.,Chiba Prefectural Agriculture and Forestry Research Center | Nakai M.,Tokyo University of Agriculture and Technology | Saito Y.,Tokyo University of Agriculture and Technology | And 3 more authors.
Viruses | Year: 2015

The smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae), is an economically important pest of tea in Japan. Previous work showed that a fast-killing nucleopolyhedrovirus (NPV) isolated from A. orana (AdorNPV) and a slow-killing NPV isolated from A. honmai (AdhoNPV) are both infectious to A. honmai larvae. Field application of these different NPVs was conducted against an A. honmai larval population in tea plants, and the control efficacy and transmission rate of the two NPVs were compared. The slow-killing AdhoNPV showed lower field efficacy, in terms of preventing damage caused by A. honmai larvae against the tea plants, than the fast-killing AdorNPV. However, AdhoNPV had a significantly higher horizontal transmission rate than AdorNPV. These results show that AdorNPV is suitable as an inundative agent, while AdhoNPV is an appropriate inoculative agent. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source

Suetsugu K.,Kyoto University | Fukushima S.,Chiba Prefectural Agriculture and Forestry Research Center
Plant Species Biology | Year: 2014

Pollination biology studies of the endangered orchid Cypripedium japonicum were conducted in its natural habitat using pollinator observation and hand-pollination experiments. The observed fruit set was as follows: artificial outcross-pollinated, 100%; artificial self-pollinated, 100%; pollinator-excluded, 0%; and emasculated flowers, 0%. These results show that this species, although self-compatible, is neither autogamous nor agamospermous. The fruit set for open-pollinated flowers was 14.9%, which suggests that the study population was subject to pollinator limitation. The nectarless flowers of C.japonicum were exclusively visited and pollinated by the queens of two bumblebee species (Bombus ardens and B.diversus diversus). It is probable that the nectarless flowers of C.japonicum attract pollinators through a generalized food deceptive system. © 2013 The Society for the Study of Species Biology. Source

Sakai H.,Japan National Agriculture and Food Research Organization | Takeda A.,Chiba Prefectural Agriculture and Forestry Research Center | Mizukubo T.,Japan National Agriculture and Food Research Organization
ZooKeys | Year: 2011

Mixed populations of Xiphinema americanum-group species were detected from a root zone soil sample of Japanese holly, Ilex crenata, during a survey for plant-parasitic nematodes of commercial ornamental plant nurseries in Chiba Prefecture, Japan. From the result of the morphological study, the species were identifed as X. brevicolle and Xiphinema sp. Tis is the frst record of X. brevicolle in Japan. Morphometrics of X. brevicolle generally agree with those of the type specimens and the topotype specimens. Xiphinema sp. morphometrically resembles X. paramonovi except for tail length. Te mitochondrial COI region, the nuclear 18S rDNA and the nuclear large subunit rDNA D2/D3 region of the species were sequenced and compared in the molecular study. For the COI region, PCR primers were newly designed to obtain longer sequences, ca. 900 bp, than previously used. Sequence identities of COI, 18S and D2/D3 regions between these two populations were 84.0-84.1%, 99.9% and 98.1-98.2%, respectively. Phylogenetic analyses of maximum likelihood trees were carried out to compare genetic relationships among the group and some suggestions were made on the X. brevicolle-subgroup. © Hiromichi Sakai et al. Source

Hisaka H.,Chiba Prefectural Agriculture and Forestry Research Center
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2011

Retort pouch peanuts are a new product manufactured with the aim of increasing peanut production and consumption. Retort pouch peanuts are produced using raw pods and have a soft texture, similar to when boiled. This product is ready-to-eat and can be stored for long periods at room temperature. Cultivation controls and low temperature maintenance of raw pods, from harvest to retort treatment, are important for the manufacture of high quality products, both in appearance and taste. Retort pouch peanuts are a food produced by close co-operation of the grower and manufacturer, and since its introduction over 10 years ago, it has maintained a stable presence in the peanut-processing sector. Source

Ishii H.,Japan National Institute for Agro - Environmental Sciences | Ishii H.,University of Tsukuba | Miyamoto T.,Horticultural Research Institute | Ushio S.,Chiba Prefectural Agriculture and Forestry Research Center | Kakishima M.,University of Tsukuba
Pest Management Science | Year: 2011

Background: Recently in Japan, isolates resistant to boscalid, a succinate dehydrogenase inhibitor (SDHI), have been detected in Corynespora cassiicola (Burk & Curt.) Wei and Podosphaera xanthii (Castaggne) Braun & Shishkoff, the pathogens causing Corynespora leaf spot and powdery mildew disease on cucumber, respectively. Resistant isolates of C. cassiicola are widely distributed and represent a serious problem in disease control at present. Novel SDHI fungicides, including fluopyram, are now under development. Results: The growth of very highly boscalid-resistant, highly resistant and sensitive isolates of C. cassiicola was strongly suppressed on fluopyram-amended YBA agar medium. Although boscalid and another SDHI, penthiopyrad, hardly controlled Corynespora leaf spot and powdery mildew on cucumber plants when very highly or highly boscalid-resistant isolates were employed for inoculation, fluopyram still exhibited excellent control efficacy against these resistant isolates as well as sensitive isolates of C. cassiicola and P. xanthii. Conclusion: Differential sensitivity to boscalid, penthiopyrad and fluopyram, clearly found in these two important pathogens of cucumber, may indicate involvement of a slightly distinct site of action for fluopyram from the two other SDHIs. This finding may lead to the discovery of unique SDHIs in the future. Copyright © 2011 Society of Chemical Industry. Source

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