Journal of Weed Science and Technology

Occurrence and background of wild oats and Italian ryegrass in winter cereals in the Kanto-Tokai region

Motoaki Asai, Yasuhiro Yogo

2005 Volume 50 Issue 2 Pages 73-81
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.73

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An investigation into the occurrence of wild oats and Italian ryegrass in winter cereal fields in the Kanto-Tokai region was conducted by questionnaires to agricultural extension service offices (AESO) and annual field surveys. Wild oats and Italian ryegrass were found in all prefectures; half of the AESO that replied observed infestation in winter cereal fields.
‘Severe infestation’ was reported from Saitama and Ibaraki prefectures for wild oat, and Saitama and Shizuoka prefectures for Italian ryegrass. Paddy rice was not part of crop rotation in such fields. Field monitoring confirmed that wild oats tend to dominate fields in which winter cereals had been cropped annually until fields were left fallow or were planted other crops because of weed loss. These weeds were assumed to have escaped from fodder crops, manures and revegetation materials. Field surveys detected no tame oat infestations. Continuous winter cereal cropping, as well as lack of effective control methods, were assumed to be involved in the spread of weeds into the fields. This result suggests that there is a growing threats of by winter grass weeds in locations where field conversion from paddy to upland is promoted.

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A note on phenology and seed-germination behavior in two natural populations of the endangered aquatic macrophytes, Sparganium erectum var. erectum and S. erectum var. macrocarpum (Sparganiaceae)

Tempei Ishii, Yuichiro Nakayama, Hirofumi Yamaguchi

2005 Volume 50 Issue 2 Pages 82-90
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.82

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Annual fluctuation of the phenological features and seed-germination behavior in two natural populations of Sparganium erectum L. var. erectum and var. macrocarpum Hara, in the Kinki district, Japan were monthly monitored from July, 1999 to November, 2000, and seeds from natural populations were examined by pericarp removal and a gradually increasing and decreasing temperature method (GT method). Two varieties showed a standard phenological pattern as summer green perennials. They emerged as above-ground juveniles in spring, bore flowering inflorescences in July, disseminated fruits in late summer to autumn, and withered aboveground shoots in winter. Plants of S. erectum var. erectum bore many flowering shoots in summer and disseminated seeds and/or ramets with disturbance of its natural habitats by flood caused by typhoon and/or with normal seed disseminations. Its seedlings naturally emerged in spring and autumn with wide annual fluctuations. Plants of S. erectum var. macrocarpum showed a low rate of flowering shoots compared with that of var. erectum, and no seedlings were found in the natural habitat after seed dissemination. The seeds of two varieties showed a similar primary dormancy immediately after dissemination. The seeds which excised their pericarps broke dormancy one year later. The GT method indicated that seeds of var. erectum required more temperature fluctuation than those of var. macrocarpum, suggesting adaptation of germinating behavior to a particular season. Our results suggested that var. erectum has a life history trait adaptable to the disturbed habitat near a river and var. macrocarpum to a relatively stable environment such as a pond with stable water.

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Selective phytotoxicities of acetolactate synthase inhibitors between creeping woodsorrel (Oxalis corniculata L.) and Zoysia japonica Steud

M. Ogasawara, T. Otsuka, Y. Suto

2005 Volume 50 Issue 2 Pages 91-95
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.91

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Physiological and Ecological Characteristics, and Control of The Perennial Weed Torpedograss (Panicum repens L.) in Crop Field and Turf in Ryukyu Islands, Japan

Md. Amzad Hossain

2005 Volume 50 Issue 2 Pages 96-105
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.96

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Transition of herbicides use in Japan

3. Herbicides of Turf, Levee·Noncropping paddy and Non-crop lands

Takafumi Takeshita

2005 Volume 50 Issue 2 Pages 106-118
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.106

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So many weeds, so many weedings (5) Herbaceous plants of paddy ecosystem in middle Laos

Yasuyuki Kosaka

2005 Volume 50 Issue 2 Pages 119-120
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.119

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Review of Herbicides

2005 Volume 50 Issue 2 Pages 121-124
Published: June 24, 2005
Released on J-STAGE: December 17, 2009

DOIhttps://doi.org/10.3719/weed.50.121

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