Plant protecting and regulating compositions – Plant growth regulating compositions – Micro-organisms or from micro-organisms
Reexamination Certificate
1997-10-27
2001-01-09
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Micro-organisms or from micro-organisms
C435S254100
Reexamination Certificate
active
06172003
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to strains of
Drechslera monoceras
having herbicidal activity against barnyard grasses at temperatures ranging from 26° C. to 35° C. and weed control compositions containing the same as an active ingredient.
2. Description of the Related Art
Environmental pollution caused by synthetic agricultural chemicals has become a modern social problem. As a result, new herbicides utilizing natural microorganisms are being touted as a new type of agricultural chemical which will not pollute the environment. For example, DeVine (effective component:
Phytophthora palmivola
) is commercially available in the United States as a weed control composition for strangle vine, a weed of family Asclepiadaceae, and Collego (effective component:
Colletotrichum gloeosporioides
), BioMal (effective component:
Colletotrichum gloeosporioides
f.sp.
malvae
) and LuboaII (effective component:
Colletotrichum gloeosporioides
f. sp.
cuscutae
) are commercially available as a weed control agent for northern jointvetch, a leguminous weed, in the United States, Canada and China, respectively.
No herbicides, that utilize living cells, are currently registered as agricultural chemicals in Japan. However, research is being done on the effect of mycoherbicides on weeds in rice paddies or lawns (Integrated Management of Paddy and Aquatic Weeds in Asia. FFTC Book Series No. 45, 1994). In particular, intensive research on mycoherbicides for barnyard grasses, which is a troublesome weed in rice cultivation, is being performed and it is reported in Japanese Patent Laid-open No. 1991/219883 (kokai 3-219883), Japanese Patent Laid-open No. 1994/329513 (kokai 6-329513) and others that a strain of genus Drechslera, which is a plant pathogen, is effective for controlling weeds of genus Echinochloa. However, such research has not reached the stage of practical applications.
Wild species of barnyard grasses are known as weeds in rice cultivation regions of the world, particularly in Japan, where they have long been regarded as troublesome weeds. According to Yabuno (Zasso Kenkyu (Weeds Research), volume 2, 1975), six species of wild barnyard grasses are known in the world, i.e.,
Echinochloa oryzicola, E. colona, E. pyramidalis, E. stagnina, E. haploclada
and
E. crus
-
galli
. This latter species is further divided into three varieties, i.e.,
E. crus
-
galli
var.
formosensis, E. crus
-
galli
var.
crus
-
galli
and
E. crus
-
galli
var.
pratycola.
Barnyard grasses known as troublesome weeds in rice cultivation are considered to be those produced by the natural crossing of plants between different species or subspecies of genus Echinochloa. A mycoherbicide to control barnyard grasses must have herbicidal activity against plants of all species and subspecies of genus Echinochloa, but must have no pathogenicity in major crops including rice. Further, weeds of genus Echinochloa start to germinate at 10° C. and grow vigorously over a broad range of temperatures ranging from 15° C. to 35° C. Therefore, a mycoherbicide to control barnyard grasses should preferably have selective herbicidal activity against weeds of genus Echinochloa over a broad range of temperatures from a low of about 15° C. to a high of about 35° C.
Strains of mold fungi isolated from plants of genus Echinochloa,
Drechslera monoceras
IFO-9619 and IFO-9800, are stored at the Institute for Fermentation in Osaka. However, as explained below, these strains have no herbicidal activity against barnyard grasses known as troublesome weeds in rice cultivation.
Strains of
Drechslera monoceras
having herbicidal activity against barnyard grasses, such as MH-9011 (FERM BP-3416) are described in Japanese Patent Laid-open No. 1992/226905. However, as explained below, these strains have herbicidal activity against barnyard grasses at normal temperatures, i.e., about 25° C., but almost no activity at temperatures above 30° C.
The reality is that many species other than barnyard grasses grow in rice paddies and croplands, and these weeds also have to be controlled in rice cultivation. The general practice today is to apply several herbicides effective on different weeds in combination or as a composition of mixture of a multiple number of herbicides. As a result, the use of synthetic agricultural chemicals has increased considerably. Application of large amounts of synthetic agricultural chemicals is creating not only concerns about pollution of the water, soil or the like, but is creating a vicious circle of inducing chemically-resistant weeds and insect pests or pathogens having drug resistance. Thus, there is an urgent need to develop new agricultural chemicals that are safe to humans and animals but do not pollute the environment. At the same time, enforceable measurements to reduce the use of synthesized agriculture chemicals are required.
SUMMARY OF THE INVENTION
The problem that the present invention attempts to solve is the elimination of the disadvantages of the conventional weed controlling method in which only synthetic agricultural chemicals are used by providing a mycoherbicide that is harmless to humans and animals and does not cause environmental pollution. Accordingly, an objective of the present invention is to provide new strains of
Drechslera monoceras
having selective herbicidal activity against barnyard grasses troublesome in rice cultivation at a range of temperatures in which said grasses grow vigorously, and to provide a weed control composition containing living cells of said strains as an effective component.
A further objective of the present invention is to provide a weed controlling method which would reduce the use of synthetic agricultural chemicals so as to curtail their impact on the environment by using said cells and existing chemical herbicides in combination.
In order to solve the abovementioned problems, the present inventors searched among various plant pathogens existing in nature and isolated a new strain of
D. monoceras
having practical herbicidal activity against barnyard grasses at a range of temperatures in which said weeds grow vigorously, but having no pathogenicity in major crops, including rice, thereby the present invention has been accomplished.
Thus, the present invention comprises strains of
D. monoceras
having a selective herbicidal activity against barnyard grasses (Echinochloa spp.) at temperatures ranging from 26° C. to 35° C., and a weed control composition containing said
D. monoceras
cells as an effective ingredient.
Strains of
D. monoceras
according to the present invention have herbicidal activity against all species of barnyard grass weeds (Echinochloa spp.) at temperatures ranging from 26° C. to 35° C., as well as normal temperatures, and exhibit a practical weed controlling effect. On the other hand, they have no pathogenicity in major crops, including rice, and they exhibit a high selectivity which is considered to be difficult to attain in chemical herbicides.
Furthermore, the combined application of cells of strains of
D. monoceras
according to the present invention plus a chemical herbicide or a mixed composition of the two can reduce the amount of chemicals necessary to control barnyard grasses, thus helping to eliminate the recent phenomena of environmental pollution and an increased incidence of chemically-resistant weeds.
REFERENCES:
patent: 5424271 (1995-06-01), Yamaguchi et al.
patent: 5434121 (1995-07-01), Gohbara et al.
patent: 5498591 (1996-03-01), Gohbara et al.
patent: 5498592 (1996-03-01), Gohbara et al.
patent: 0374499 B1 (1994-02-01), None
patent: 0464416 B1 (1994-09-01), None
patent: 3-219883 (1991-09-01), None
patent: 4-226905 (1992-08-01), None
patent: 6-329513 (1994-11-01), None
patent: 7-79784 (1995-03-01), None
Yabuno, “The Classification and Geographical Distribution of the GenusEchinochloa”, WeedS Research, vol. 20, pp. 97-104 (1975).
Gohbara et al, “Biological Control Agents for Rice Paddy Weed Management in Japan”, Proceedings of International Symposium on Biological Contro
Fukai Shungo
Hirase Kangetsu
Ishihara Kazuto
Nakamura Takeshi
Nishida Makoto
Burns Doane Swecker & Mathis L.L.P.
Clardy S. Mark
Mitsui Chemicals Incorporated
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