Chemistry: molecular biology and microbiology – Plant cell or cell line – per se ; composition thereof;...
Reexamination Certificate
2001-01-03
2003-01-14
Lankford, Jr., Leon B. (Department: 1651)
Chemistry: molecular biology and microbiology
Plant cell or cell line, per se ; composition thereof;...
C504S116100, C047S05810R
Reexamination Certificate
active
06506601
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a composition and method for measuring the foliar uptake of an agrochemical. More specifically, it pertains to a composition for measuring the foliar uptake of an agrochemical comprising said agrochemical and Congo Red as a tracer; and a method for measuring the foliar uptake of an agrochemical using same.
BACKGROUND OF THE INVENTION
Hundreds of agrochemicals have been developed and used commercially to protect crops from weeds, pathogens and insects. However, the prolonged use of agrochemicals have induced the appearance of species which are resistant to once effective agrochemicals, and in order to control such resistant weeds, pathogens or insects, ever increasing amounts of agrochemicals have been applied, causing a serious environmental issue as well as a cost problem. Accordingly, besides the need to develop new classes of environmentally friendly agrochemicals, it is required to suppress the application rates of existing agrochemicals by way of improving, for instance, delivery systems through the addition of effective adjuvants thereto.
Examples of adjuvants used to enhance the activity of an agrochemical include a spreader or spreader-sticker which facilitates the adherence of an agrochemical to a subject crop, a rainfasting agent for preventing the loss of an agrochemical due to rainwash, and a penetrant which allows the absorption of a larger than normal amount of an agrochemical by a subject crop.
As a larger amount of an agrochemical is absorbed by plant tissues in a short time, the manifestation of the intended effect of the agrochemical becomes faster and stronger, as in case of a herbicide. In case of a fungicide, its protective and curative effects against a pathogenic disease increase when a suitable penetrant is employed. Further, in case a proper penetrant is added to a pesticide, it is possible to obtain a superior pesticidal effect of killing harmful insects at sites where the pesticide was not directly applied.
For example, B. Terence et al. have reported that dimethomorph, which is used for treating vine plants infected by downy mildew, potato late blight and pepper blight, showed significantly higher curative activity when used in combination with a nonionic surfactant, e.g., lauryl alcohol ethoxylates(
Pesticide Science,
46, 199-213 & 355-359(1996)).
Further, it has been reported that the absorption of glyphosate(N-(phosphonomethyl)glycine, a non-selective herbicide) by plants is significantly facilitated when used in combination with Silwet L-77(Hanjung Chemicals, Inc., Korea), an organosilicon surfactant(Megh Singh, et al.,
Proceedings of Fourth International Symposium on Adjuvants for Agrochemicals,
385-390(1995)).
As described above, environmental and economic issues demand that the application rate of an agrochemical be kept at a minimal level, while maximizing the intended effectiveness thereof in protecting crops. This effectiveness depends on the amount of the agrochemical absorbed by the crops.
A general method for measuring the amount of agrochemicals absorbed by plants is based on the steps of applying a radiolabelled pesticide to a subject plant, washing the plant with a suitable solvent after a fixed time period, and measuring the radioactivity thereof. However, this method has problems of high cost and complexity which requires a special equipment and the attention of a specialist.
Accordingly, there exist no cost-effective methods for quantifying the foliar uptake of an agrochemical.
As to the procedure for screening penetrants which promote the uptake of an agrochemical by a subject crop, there have been reported the following two methods.
The first method comprises treating a subject plant with a mixture of a radiolabelled agrochemical and a penetrant candidate, and tracing the radio label. However, this method has the aforementioned problems of high cost and complexity.
The second method is based on the steps of applying a mixture of an agrochemical and a penetrant candidate to a subject plant and measuring directly the control effect of the agrochemical against weeds, pathogens or harmful insects. However, this method which requires cumbersome long experimental procedures yield only semi-quantitative data.
The present inventors have endeavored to develop a simple and accurate method for measuring the uptake rate of an agrochemical by a plant and a method for selecting a penetrant suitable for a given agrochemical and plant, and have discovered that a novel tracer can be advantageously employed in accomplishing the above objective.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a composition for quantifying the uptake of an agrochemical by a plant.
Another object of the present invention is to provide a method for quantifying the uptake of an agrochemical by a plant by employing said composition.
A further object of the present invention is to provide a method for selecting a penetrant by employing said method.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, there is provided a composition for measuring the foliar uptake of an agrochemical comprising the agrochemical and Congo Red as a tracer which is totally unabsorbable by plants.
Further, the present invention also provides a method for measuring the foliar uptake of an agrochemical comprising the steps of: (a) applying a composition containing said agrochemical and Congo Red to a plant and a control plate, (b) washing the plant and the control plate with a solvent to extract the agrochemical and Congo Red, (c) measuring the concentrations of the agrochemical and Congo Red in the wash extracts, and (d) calculating the foliar uptake of the agrochemical.
The method of the present invention can be applied for the selection of a suitable penetrant which enhances the uptake of a given agrochemical.
The present invention is described in more detail as follows.
A. Preparation of a Composition for Measuring the Foliar Uptake of an Agrochemical
An agrochemical or a formulation thereof is dissolved, emulsified or suspended in water or a water-soluble solvent and Congo Red is added thereto as a tracer and mixed thoroughly to obtain the inventive composition for measuring the foliar uptake of the agrochemical. It is preferable to add Congo Red to the agrochemical solution at a lowest possible concentration, provided that it can be quantitatively analyzed by HPLC or spectrophotometry. For instance, Congo Red can be added to the agrochemical solution at a concentration ranging from 1 &mgr;g/ml to 1,000 &mgr;g/ml. If the concentration of Congo red in the agrochemical solution is higher than that of the agrochemical, penetration of the agrochemical into the plant may be inhibited, thereby biasing the uptake rate.
Exemplary agrochemicals that can be used in the present invention include all herbicides, insecticides, fungicides, plant growth regulators and the like known in the art.
In preparing the agrochemical solution, an available commercial formulation of agrochemical is merely diluted to a desired concentration by a conventional method. In case of a liquid or jelly-like agrochemical, it may be dissolved in a small amount of an organic solvent such as acetone, or dissolved or emulsified in water with the addition of a small amount of a surfactant, if necessary. In case of a solid agrochemical, it may be pulverized and mixed with a surfactant as a dispersing agent.
For the purpose of selecting a penetrant for a specific agrochemical, the inventive composition may further comprise a penetrant candidate material. The penetrant candidate material may be dissolved in water or an organic solvent and added to the inventive composition.
B. Application of the Inventive Composition to a Plant and to a Control Plate
The inventive composition prepared as in section A above is then applied to a plant and to a control plate which does not absorb the agrochemical or the tracer.
Plant species that can be used in the present invention is not limited, but it is preferable to use
Cho Kwang-Yun
Choi Gyung-Ja
Kim Jeong-Han
Lim He-Kyoung
Yu Ju-Hyun
Katten Muchin Zavis & Rosenman
Korea Research Institute of Chemical Technology
Lankford , Jr. Leon B.
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