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Takikawa Y.,Laboratory of Plant Pathology | Takahashi F.,Laboratory of Plant Pathology | Takahashi F.,Shizuoka Prefectural Research Institute of Agriculture and Forestry
Journal of General Plant Pathology | Year: 2014

Bacterial leaf spot and blight diseases caused by Pseudomonas syringae pv. maculicola (Psm) and P. cannabina pv. alisalensis (Pcal) are becoming a significant concern for producers of crucifer crops worldwide. Since Psm was first described in 1911, many have reported on its diverse phenotypic, genetic and pathogenic characteristics. Japanese isolates of Psm are also heterogeneous and differ in their host preferences. Pcal was first described in 2002 and has quickly spread globally. Recent work demonstrated that some isolates that had been identified as Psm are actually Pcal. Pcal was also shown to be split into two groups, A and B, based on bacteriological properties, genetic traits and pathogenicity. Group A of Pcal consists mostly of isolates from Japanese radish and radish, isolated before 1990s, that are more aggressive on radish leaves but less aggressive on other Brassica plants compared with group B. Group B of Pcal consists of recent isolates from various crucifer plants including the pathotype of Pcal. In this review, we suggest that group A of Pcal may have existed since the 1950s and survived as a relatively minor pathogen on radish or Japanese radish, whereas group B emerged in the late 1990s, causing global epidemics because of its stronger virulence on various Brassica crops. We also suggest that emergence of a new group of a pathogenic bacterium may cause a re-emergence or new epidemics of a disease that previously was of minor importance. © 2014, The Phytopathological Society of Japan and Springer Japan.


Ichihara M.,Gifu University | Ichihara M.,University of Shizuoka | Maruyama K.,University of Shizuoka | Yamashita M.,University of Shizuoka | And 4 more authors.
Agriculture, Ecosystems and Environment | Year: 2011

The extent of post-dispersal weed seed predation in upland wheat fields converted from paddy fields was quantified in Shizuoka Prefecture, central Japan. We investigated the temporal variability in seed predation of Italian ryegrass (Lolium multiflorum Lam.), a non-native winter annual weed in Japan, during summer after the seed shed in both the field interior areas and boundary strips, and estimated the total seed loss due to predation during the summer. Furthermore, the contribution of invertebrates and vertebrates to seed predation was estimated by using exclosures. The total seed loss due to predation during four months (from late June to late October) in the field interior areas and boundary strips was estimated to be 35-43% (the maximum proportion of seed predation per two weeks = 27%) and 42% (25%), respectively. The seed predators in the field interior areas were vertebrates (rodents or birds) and invertebrates (crickets and ground beetles). In contrast, seed predators in the boundary strips were mainly invertebrates (crickets and ground beetles). The results of this study suggest that predators make a substantial contribution in the depletion of post-dispersal seeds of Italian ryegrass in converted paddy fields. © 2010 Elsevier B.V.


Zhang L.,University of Shizuoka | Ma G.,University of Shizuoka | Shirai Y.,University of Shizuoka | Shirai Y.,Shizuoka Prefectural Research Institute of Agriculture and Forestry | And 4 more authors.
Planta | Year: 2012

In the present study, two LCYb genes (CitLCYb1 and CitLCYb2) were isolated from Satsuma mandarin (Citrus unshiu Marc.), Valencia orange (Citrus sinensis Osbeck) and Lisbon lemon (Citrus limon Burm. f.) and their functions were analyzed by the color complementation assay in lycopene-accumulating E. coli cells. The results showed that CitLCYb1 and CitLCYb2 shared high identity at the amino acid level among the three citrus varieties. The N-terminal region of the two proteins encoded by CitLCYb1 and CitLCYb2 was predicted to contain a 51-residue chloroplastic transit peptide, which shared low similarity. In Satsuma mandarin, the secondary structures of the CitLCYb1 and CitLCYb2 encoding proteins without the transit peptide were quite similar. Moreover, functional analysis showed that both enzymes of CitLCYb1 and CitLCYb2 participated in the formation of β-carotene, and when they were co-expressed with CitLCYe, α-carotene could be produced from lycopene in E. coli cells. However, although CitLCYb2 could convert lycopene to α-carotene in E. coli cells, its extremely low level of expression indicated that CitLCYb2 did not participate in the formation of α-carotene during the green stage in the flavedo. In addition, the high expression levels of CitLCYb1 and CitLCYb2 during the orange stage played an important role in the accumulation of β,β-xanthophylls in citrus fruits. The results presented in this study might contribute to elucidate the mechanism of carotenoid accumulation in citrus fruits. © 2012 Springer-Verlag.


Sugiyama K.,Shizuoka Prefectural Research Institute of Agriculture and Forestry | Katayama H.,Shizuoka Prefectural Research Institute of Agriculture and Forestry | Saito T.,University of Shizuoka
Applied Entomology and Zoology | Year: 2011

The toxicities of 24 insecticides for the biological control of whiteflies were evaluated for Eretmocerus mundus (Mercet), Eretmocerus eremicus Rose and Zolnerowich and Encarsia formosa Gahan using the residual film method (for adults) and the dipping method (for pupae). Mortalities from insect growth regulators (IGRs) (flufenoxuron and lufenuron), Bacillus thuringiensis (Bt), pymetrozine and sulfur were <30% for both pupae and adults of all three species, indicating that the parasitoids were not seriously affected by these insecticides. Neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid and nitenpyram), synthetic pyrethroids (etofenprox and permethrin), organophosphates (acephate and fenitrothion), chlorphenapyr, emamectin benzoate, spinosad and tolfenpyrad were seriously harmful (100% mortality) and acaricides (chinomethionat, milbemectin and pyridaben) were moderately harmful or seriously harmful to adult parasitoids (leading to mortalities of >92%). For each insecticide, the mortality of pupae was generally lower than that of adults, even though the toxicity classification for the two groups was similar. The results indicate that IGRs, Bt, pymetrozine and sulfur are relatively harmless, and are compatible with the use of parasitoids to help control whiteflies for integrated pest management in greenhouses. © 2011 The Japanese Society of Applied Entomology and Zoology.


PubMed | Japan National Institute of Information and Communications Technology, University of Shizuoka and Shizuoka Prefectural Research Institute of Agriculture and Forestry
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2016

Agricultural systems using advanced information and communication (ICT) technology can produce high-quality crops in a stable environment while decreasing the need for manual labor. The system collects a wide variety of environmental data and provides the precise cultivation control needed to produce high value-added crops; however, there are the problems of packet transmission errors in wireless sensor networks or system failure due to having the equipment in a hot and humid environment. In this paper, we propose a reliable wireless control system for hydroponic tomato cultivation using the 400 MHz wireless band and the IEEE 802.15.6 standard. The 400 MHz band, which is lower than the 2.4 GHz band, has good obstacle diffraction, and zero-data-loss communication is realized using the guaranteed time-slot method supported by the IEEE 802.15.6 standard. In addition, this system has fault tolerance and a self-healing function to recover from faults such as packet transmission failures due to deterioration of the wireless communication quality. In our basic experiments, the 400 MHz band wireless communication was not affected by the plants growth, and the packet error rate was less than that of the 2.4 GHz band. In summary, we achieved a real-time hydroponic liquid supply control with no data loss by applying a 400 MHz band WSN to hydroponic tomato cultivation.


PubMed | Shizuoka Institute of Science and Technology, University of Shizuoka, Shizuoka Prefectural Research Institute of Agriculture and Forestry, Southwest University and CAS South China Botanical Garden
Type: Journal Article | Journal: Journal of agricultural and food chemistry | Year: 2016

A recently developed method enabled us to simultaneously characterize and quantitate glycosidically bound volatiles (GBVs) at picomole levels using liquid chromatography-mass spectrometry (LC-MS). On the basis of the analytical data it is possible to screen tea varieties most suitable for black tea processing, in which higher concentrations of primeverosides accumulate. The primeverosides decreased at the rolling step in black tea processing, whereas the glucopyranosides did not change much. The total contents of GBVs gradually increased at the withering steps and then remarkably increased after the fixing step at 230 C, during oolong tea processing. The presence of 6-O-malonyl ester type -D-glucopyranosides in the tea samples suggested a contribution to the increment in glucopyranosides during oolong tea processing. The method was also used to analyze GBVs and their derivatives to understand their possible role in the metabolic pathway of tea.


Platynaspidius maculosus (Weise, 1910) (Coleoptera: Coccinellidae) is a ladybird beetle that preys on aphids and is distributed in China, Taiwan, and Vietnam. Recently, P. maculosus has invaded the southern parts of Japan; it was recorded on Okinawa Island in 1998, in Kagoshima Prefecture in 2006, and in Fukuoka Prefecture in 2010. In citrus groves in Shizuoka City, Central Japan in 2009-2012, the exotic ladybird was monitored by use of yellow sticky traps set inside citrus tree canopies. Adults of P. maculosus were captured in three out of the eight groves in 2010. This capture might be the first record of the ladybird from Honshu Island. Adults were trapped in three consecutive years, 2010-2012, in two groves; this suggests the possibility that the ladybird has become established in Shizuoka City. Adults were almost continuously caught on the traps from late April through October, being more abundant in early autumn (early September to early October), late spring (late April to mid-June), and mid-summer (early July to early August). During these periods, citrus shoots are growing and aphids are abundant. This finding suggests that the exotic ladybird might prey on citrus-infesting aphids, thereby reproducing in citrus groves. Based on the results obtained, potential impacts of the exotic ladybird on native aphidophagous ladybirds are also discussed. © 2013 The Japanese Society of Applied Entomology and Zoology.


Van N.N.,Shizuoka Prefectural Research Institute of Agriculture and Forestry | Yamane S.,Shizuoka Prefectural Research Institute of Agriculture and Forestry
American Society of Agricultural and Biological Engineers Annual International Meeting 2013, ASABE 2013 | Year: 2013

The harvesting of lettuce in Japan totally involves the manual removal of produce from the field using a sharp cutting implement such as a knife. This harvesting method is labor-intensive and has bad working posture. In the circumstance of continuous decrease of agricultural population in Japan, a need has existed to reduce the labor-intensity of the lettuce harvesting and to make that working process safer as well as to increase cropping acreage of lettuce. Therefore, a harvester has been developed for winter-clipping crisphead lettuce production. In this paper, a reciprocating cutting component of the harvester was designed and its cutting performance was verified in laboratory test conditions. The component was designed with minimized space requirement and low mass in order to reduce acceleration and inertia during operation. In order to optimize the cutting performance of the component, a method for measuring lettuce cutting resistance was developed. Maximum lateral cutting resistance and cutting power requirement for two plants were measured with cutting frequency of 4 Hz, cutting stroke length of 18 mm, and forward cutting speeds of 5.0, 7.5 and 10.0 cm/s. Lettuce cutting tests with lifting component was also conducted to simulate harvest condition. The experimental results indicated that the cutting component could smoothly cut lettuce stems and the mean values of the maximum cutting resistance and the cutting power requirement were 61.9 N and 29.1 W, respectively.


Nang V.N.,Shizuoka Prefectural Research Institute of Agriculture and Forestry | Yamane S.,Shizuoka Prefectural Research Institute of Agriculture and Forestry
Engineering in Agriculture, Environment and Food | Year: 2015

Method of manual removal of produce from the field has been a bottle-neck for lettuce production in Japan. In order to reduce the production cost of this fresh commodity, a prototype harvester has been developed for head lettuce production. The harvester consists of a cutting component to slice the lettuce head at the desired location and a lifting component that transports the harvested produce from the cutting site onto elevating conveyor and trimming station. A cutting component with reciprocating blade was proposed. Laboratory tests were performed to verify ability of reciprocating blade to slice lettuce stump at forward cutting speed of 0.1 m/s, reciprocating stroke of 18 mm, and different reciprocating frequencies of 2, 4 and 6 Hz. In addition, power requirement for reciprocating the cutting knife as slicing two lettuce stumps was measure. Tests in lettuce fields were also conducted at different working speed to investigation the cutting and lifting performances of the harvester mounted with the reciprocating-blade cutting component. The results of laboratory tests indicated that the cutting component could smoothly cut lettuce stumps and the maximum cutting torque and cutting power requirement were 0.73 Nm and 27.7 W, respectively at 6 Hz reciprocating frequency. Field test results showed that the harvester could cut and lift the lettuce heads without damaging and blemishing the produce at working speed of 0.04 m/s and the commercial head percentage was 94.5%. At higher working speed of 0.08 m/s, the head damage rate was 12.8% reducing the percent of commercially accepted heads to 87.2%. © 2014 Asian Agricultural and Biological Engineering Association.


Masui S.,Shizuoka Prefectural Research Institute of Agriculture and Forestry
Japanese Journal of Applied Entomology and Zoology | Year: 2010

The effect of trimming and harvesting host tea plants and bigleaf podocarp trees on the dispersal of Scirtothrips dorsalis Hood adults to citrus orchards was investigated in tea fields and in the windbreaks of bigleaf podocarps adjacent to a citrus orchard. The days of the highest trap catch in the three types of fields coincided with each other and with the days on which there were the maximum number of adults in the citrus orchards, estimated as a function of generation temperature. In all three types of fields, when the tea plants and bigleaf podocarp trees were not trimmed after the peak days, the number of adults captured by the trap decreased within 10 d to the level observed 5 d before the peak. This decrease was not observed when the tea plants were trimmed 1-9 d after the peak days. These results suggest that the flight activity of adults is highest immediately after emergence and that trimming host plants encourages the flight behavior of adults by reducing the amount of food available.

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