The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Phillip W Stahlman - One of the best experts on this subject based on the ideXlab platform.
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soil bacteria as selective biological control agents of winter annual Grass Weeds in winter wheat
Applied Soil Ecology, 1996Co-Authors: Pamela A Harris, Phillip W StahlmanAbstract:Abstract Many winter annual Grass Weeds, such as downy brome (Bromus tectorum L.) and jointed goatGrass Aegilops cylindrica Host.), are difficult to control selectively in winter wheat (Triticum aestivum L.) grown in the central and western US. The difficulty is due partially to a lack of selective chemical herbicides. Bacteria were isolated from soil and plant roots and evaluated for inhibition of germination and root and shoot growth of both Weeds and wheat. Laboratory bioassays identified 162, 202, and 129 isolates that inhibited root growth of downy brome, Japanese brome (B. japonicus Thunb. ex. Murr.), and jointed goatGrass, respectively. Nine isolates inhibited downy brome shoot and root growth in soil in pot studies. In a field study established in the fall of 1990 under adverse environmental conditions (high temperature/low moisture), application of two isolates increased winter wheat yields as compared to untreated wheat (P = 0.10).
Pamela A Harris - One of the best experts on this subject based on the ideXlab platform.
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soil bacteria as selective biological control agents of winter annual Grass Weeds in winter wheat
Applied Soil Ecology, 1996Co-Authors: Pamela A Harris, Phillip W StahlmanAbstract:Abstract Many winter annual Grass Weeds, such as downy brome (Bromus tectorum L.) and jointed goatGrass Aegilops cylindrica Host.), are difficult to control selectively in winter wheat (Triticum aestivum L.) grown in the central and western US. The difficulty is due partially to a lack of selective chemical herbicides. Bacteria were isolated from soil and plant roots and evaluated for inhibition of germination and root and shoot growth of both Weeds and wheat. Laboratory bioassays identified 162, 202, and 129 isolates that inhibited root growth of downy brome, Japanese brome (B. japonicus Thunb. ex. Murr.), and jointed goatGrass, respectively. Nine isolates inhibited downy brome shoot and root growth in soil in pot studies. In a field study established in the fall of 1990 under adverse environmental conditions (high temperature/low moisture), application of two isolates increased winter wheat yields as compared to untreated wheat (P = 0.10).
Giuseppe Zanin - One of the best experts on this subject based on the ideXlab platform.
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seed longevity and dormancy of four summer annual Grass Weeds in turf
Weed Research, 2006Co-Authors: Roberta Masin, Mc Zuin, Stefan Otto, Giuseppe ZaninAbstract:Summary Digitaria sanguinalis, Eleusine indica, Setaria glauca and S. viridis are troublesome summer annual Weeds in turf. For taking rational decisions on the necessity for the level and type of weed management, it is important to know when Weeds are ready to emerge (dormancy status) and also how long weed seeds can survive in the soil. Seeds of these four species were buried 4.0–4.5 cm deep in steel mesh net bags placed under permanent turf and periodically exhumed for 3 years to evaluate viability and determine the dormancy/non-dormancy cycle. D. sanguinalis, S. glauca and S. viridis showed the typical dormancy cycle of summer annual species, and their seed viability declined completely after 3 years of burial. In contrast, E. indica demonstrated unusual behaviour, with long persistence and no dormancy.
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weedturf a predictive model to aid control of annual summer Weeds in turf
Weed Science, 2005Co-Authors: Roberta Masin, Maria Clara Zuin, David W Archer, Frank Forcella, Giuseppe ZaninAbstract:Predicting weed emergence is useful for planning weed management programs. Unfortunately, our ability to anticipate initial emergence and subsequent levels of emergence from simple field observations or weather reports is often inadequate to achieve optimal control. Weed emergence models may provide predictive tools that help managers anticipate best management options and times and, thereby, improve weed control. In this study, the germination characteristics of four annual Grass Weeds (large crabGrass, gooseGrass, green foxtail, and yellow foxtail) were investigated under different temperatures and water stresses to calculate base temperatures and base water potentials. These parameters were used to develop a mathematical model describing seedling emergence processes in terms of hydrothermal time. Hydrothermal time describes seed germination in a single equation by considering the interaction of soil water potential and soil temperature. The model, called WeedTurf, predicted emergence with some accuracy, especially for large crabGrass (lowest efficiency index [EF] value 0.95) and green foxtail (lowest EF value 0.91). These results suggest the possibility of developing interactive computer software to determine the critical timing of weed removal and provide improved recommendations for herbicide application timing.
G H Cook - One of the best experts on this subject based on the ideXlab platform.
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crop sequences for managing cereal cyst nematode and fungal pathogens of winter wheat
Plant Disease, 1994Co-Authors: Richard W Smiley, R E Ingham, W Uddin, G H CookAbstract:In the Pacific Northwest, Heterodera avenae is spreading to soils infested with root-infecting fungal pathogens of wheat. A poorly drained, silty clay foam infested with multiple pathogens was used to examine productivity of winter wheat in 11 crop sequences. Breaks between wheat crops included summer fallow or crops of pea, barley, rape, alfalfa, or Kentucky blueGrass. In the fifth year, winther wheat was planted in all sequences, after one-half of each plot was treated with aldicarb. Yield of annual winter wheat was always 40-60% less than wheat alternated with fallow or any other crop, except alfalfa contaminated with Grass Weeds
Rex A Wichert - One of the best experts on this subject based on the ideXlab platform.
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mesotrione a new selective herbicide for use in maize
Pest Management Science, 2001Co-Authors: Glynn Mitchell, David W Bartlett, Torquil Eoghan Macleod Fraser, Tim R Hawkes, David C Holt, Jane Karen Townson, Rex A WichertAbstract:Mesotrione is a new herbicide being developed for the selective pre- and post-emergence control of a wide range of broad-leaved and Grass Weeds in maize (Zea mays). It is a member of the benzoylcyclohexane-1,3-dione family of herbicides, which are chemically derived from a natural phytotoxin obtained from the Californian bottlebrush plant, Callistemon citrinus. The compound acts by competitive inhibition of the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD), a component of the biochemical pathway that converts tyrosine to plastoquinone and alpha-tocopherol. Mesotrione is an extremely potent inhibitor of HPPD from Arabidopsis thaliana, with a Ki value of c 6-18 pM. It is rapidly taken up by weed species following foliar application, and is distributed within the plants by both acropetal and basipetal movement. Maize is tolerant to mesotrione as a consequence of selective metabolism by the crop plant. Slower uptake of mesotrione, relative to susceptible weed species, may also contribute to its utility as a selective herbicide for use in maize.
