CN1237877C - Synergistic herbicidal composition - Google Patents

Abstract

Control of weeds in a rice crop is obtained by applying to the crop, the weeds, or the locus of either, a herbicidal composition containing molinate and oxyfluorfen in a weight ratio of from about 500:1 to about 30:1.

Description

Synergistic herbicidal composition

Background of the Invention and Prior Art

The present invention relates to synergistic herbicidal compositions, especially compositions for controlling weeds in rice crops.

Molinate (S-ethylhexahydro-1H-azepine-1-thiocarboxylate) is a thiocarbamate herbicide that has been used for many years to control weeds in rice crops, The products are generally sold under the ORDRAM(R) trademark. Molinate can be applied in different formulations and concentrations before planting, before flooding or after flooding to control weeds in various rice crops, and the application rate is generally about 500 to about 11000 g/ha. However, as with many pesticides, it would be desirable if weed control could be achieved with lower application rates of molinate. This also results in less impact on the environment and/or workers who come into contact with the product.

It has now surprisingly been found that lower amounts of the herbicide oxyfluorfen can be combined with molinate to produce a synergistic effect, thus allowing the application of lower amounts and/or rates of molineat to obtain equivalent weed control effect.

Oxyflufen, 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethylbenzene), is a diphenyl ether herbicide, mainly Sold under the trademark GOAL(R). Oxflufen is primarily marketed as a herbicide on fruit trees, nuts and vegetables, and in cotton fields. Oxyflufen is not generally used for weed control in rice crops because the rates of application to control weeds in rice crops often cause unacceptable damage to the rice. However, oxyfluorfen is also used on a small scale for weed control in rice crops in China. However, according to the present invention, when oxyfluorfen is used in combination with molinate in an amount that does not substantially cause phytotoxicity to rice crops, especially when it is used in combination with less or lower amount of molinate than conventionally applied, it can A synergistic effect is produced, and as a result, good weed control effects in rice crops can be obtained before or after flood irrigation.

Summary of the invention

The present invention includes a herbicidal composition and a method of controlling weeds in rice crops.

In one aspect, the invention relates to a synergistic herbicidal composition comprising molinate and oxyfluorfen.

In a second aspect, it comprises a synergistic herbicidal composition comprising molinate and oxyfluorfen in a weight ratio of about 500:1 to about 30:1, respectively.

In another aspect, the present invention includes a method of controlling weeds in rice crops, the method comprising applying a synergistic composition comprising molinate and oxyfluorfen to said crops, said weeds, or their Individually or co-grown loci, the preferred weight ratio is from about 500:1 to about 30:1, respectively.

Detailed description of the invention

The present invention relates to the control of weeds in rice crops using a herbicidal combination of molinate and oxyfluorfen. It is within the scope of the present invention that the combination is demonstrated to be synergistic, ie to achieve the unexpected effect of controlling the same weeds under similar circumstances when the two herbicides are used alone.

According to the present invention, the synergistic composition of molinate and oxyfluorfen is used to treat crops, weeds or the place where they grow individually or together in the presence of rice to control weeds. Generally, we have found that the mixture proves synergistic when the two herbicides are present in a weight ratio of from about 500:1 to about 30:1, preferably from about 250:1 to about 40:1, respectively. However, applicants have found that the synergistic effect between molinate and oxyfluorfen is not limited to the two herbicide compositions within these weight ratios, as other weight ratios are also possible. There is a synergistic effect.

Applying the composition in paddy fields under different planting methods at different times will produce synergistic or unexpected weed control effects. In order to control weeds, the composition can be applied before planting, after planting but before flooding (pre-flooding, post-emergence) or after rice crops emerge and after flooding (post-flooding, post-emergence), and can be applied on direct-seeding rice or transplanting Application on rice.

For use of the composition, it is not required that the two herbicides, molinate and oxyfluorfen, must be applied in a physical mixture, or even at the same time. Regardless of when they were applied, as long as the two herbicides were present in the paddy field at the same time, a combined synergistic effect could be produced. Thus, physical combinations of the two herbicides can be used, or one can be applied before the other. For example, one of the two herbicides can be applied even before rice planting in a controlled-release formulation such as a microencapsulated formulation, while the other is subsequently applied in a conventional liquid or solid formulation, as long as when the second herbicide is applied, The herbicide applied earlier still exists in the soil, and the weight ratio of the herbicide exerting medicinal effect is within the scope disclosed and claimed in the present invention.

Thus, not only can one of these two herbicides be applied in liquid or solid form, but also a mixed product containing both herbicides in liquid or solid form can be produced. Typical liquid formulations include emulsions, suspensions (including those containing microcapsules), solutions, emulsifiable concentrates and flowable formulations. Solid products include forms such as granules, wettable powders, water-dispersible solid products (including water-dispersible granules containing microencapsulated pesticides) or dusts. Both types of compositions may generally include other ingredients besides the active herbicide, such as solvents, wetting agents, suspension aids, anti-caking agents, dispersants, emulsifiers, antifreeze agents, defoamers, and other additive.

Either or both of these herbicides can be formulated in various forms of known controlled release compositions. Such compositions allow for relatively slow or controlled release of the active ingredient into the environment and include, for example, capsules, microcapsules and various forms of controlled release granules.

According to the present invention, a combination product or composition may contain these two herbicides in a variety of different physical forms. In some cases, blended products can be produced by simple physical blending (“tank blending”) of commercially available products containing the two active herbicides, such as emulsifiable concentrates containing the two herbicides, as long as The active ingredients of these two products are relatively compatible. Alternatively, a pack can be manufactured and sold that contains the entire pack of the two herbicides in separate containers, but packaged together, commonly referred to as a "double pack". The double pack is particularly suitable for the herbicidal compositions mentioned here, since the amount of molinate is substantially greater than the amount of oxyfluorfen, so that a total product package can be produced which includes the herbicidal large containers of herbicide-containing products and small containers of oxyfluorfen-containing herbicide products.

Furthermore, it is also possible to produce pre-prepared ("premix") compositions containing the two herbicides. Molinate is a liquid, whereas solid oxyfluorfen is soluble in many organic solvents. For this reason, it appears that liquid compositions are often the preferred formulation for products containing these two herbicides. Typical liquid compositions include emulsifiable concentrates containing the two herbicides, or two-phase emulsions (or microemulsions) with one herbicide in each phase.

However, in practice these two herbicides are currently also sold as solid formulations, i.e. soaking granules, so solid products containing these two herbicides, such as soaking granules, can also be similarly produced. Similarly, other solid formulations such as wettable powders or powders can also be prepared.

In addition, using suitable ingredients and conditions, microencapsulated products can also be prepared, wherein one or two herbicides are encapsulated in microcapsules, and the microencapsulated products can be in liquid form (i.e. capsule suspension) or solid Form (ie, water-dispersible granules produced by drying microcapsule suspensions) is sold. One type of liquid form may be a microencapsulated suspension in which one herbicide is encapsulated and the other is present in a continuous liquid phase in non-encapsulated form. Another type is a suspension containing molinate and oxyfluorfen separately encapsulated. The types of formulations or compositions that may contain these two herbicides are not limited to those listed here, and other types of formulations will readily occur to those skilled in the art.

The control of weeds with molinate and oxyfluorfen mixture can be illustrated by the following examples.

Example 1 This example demonstrates the weed control effect of molinate and oxyfluorfen mixture applied on rice crops transplanted after flood irrigation/post-emergence. Rice was grown alone to the 2-4 leaf stage in soil outside the test barrels. The soil in the test bucket was watered and raked (mixed) until uniformly mixed. The seedlings are then transplanted onto the mixed soil. Weeds (2-leaf stage) were grown either in the soil outside the barrels and then transplanted into the barrels or directly in the mixed soil in the test barrels. Herbicide application is generally carried out by spraying or spreading the chemical after flooding. The molinate and oxyfluorfen mixture with the indicated content are applied in the greenhouse at the application rate listed in Table 1 (expressed in grams of one or two herbicides applied per hectare), and applied after flood irrigation to The test flats included rice (Koshikan variety) and barnyardgrass ( Echinochloa crusgalli ECHCG), as well as heterosedge ( Cyperus difformis CYPDI) and monochoria vaginalis MOOVA. When the pesticide was applied, the rice crop was in the 3-leaf stage, the barnyardgrass was in the 2-leaf stage, and the other two weeds were in the period between the 2-leaf stage and the 3-leaf stage. The test results are shown in Table 1 below (expressed as the percentage of weed control or phytotoxicity compared with the untreated control plain).

Table 1 compound Application rate of molinate (g/ha) Application rate of oxyfluorfen (g/ha) Phytotoxicity% Control% Paddy 7 days Rice 28 days ECHCG MOOVA CYPDI Motilate 726 0 0 1 4 0 969 0 0 69 4 29 1453 1 0 51 0 38 Oxyfluorfen 3 1 0 0 twenty four 8 6 1 0 0 35 14 13 0 0 35 38 twenty three 25 3 0 100 50 30 Molinate/ Oxyfluorfen 726 3 1 0 99 twenty three 10 969 3 4 0 100 26 44 1453 3 1 0 100 19 44 Molinate/ Oxyfluorfen 726 6 3 0 100 34 30 969 6 4 1 100 34 54 1453 6 1 0 100 49 64 Molinate/ Oxyfluorfen 726 13 1 0 100 45 29 969 13 0 3 100 43 55 1453 13 1 0 100 44 66 Molinate/ Oxyfluorfen 726 25 5 0 100 63 55 969 25 1 0 100 59 88 1453 25 1 0 100 61 96

From above-mentioned embodiment, can draw following points:

1. Spraying with 726g/ha of fennel has no effect on controlling barnyardgrass. However, when only 3 g/ha of oxyfluorfen (which itself has no control effect) was added, the control effect reached 99%. Under the condition of high application rate, dibadi alone has a certain effect on controlling barnyard grass. However, when only 3-6 g/ha of oxyfluorfen was added, complete barnyardgrass control was achieved.

2. There is no unexpected effect on the control of sedge, and the unexpected effect is only obtained when the high application rate of oxyfluorfen (25g/ha) is used to control the heteromorphous sedge. However, these high application rate compositions are still within the scope of the present invention.

3. In some tests, the combination of molinate and oxyfluorfen within the scope of the present invention did not show synergistic effect, which is not unexpected, because synergistic effect is usually impossible in A given range is shown for all possible herbicide compositions or for all weeds.

Claims (4)

1. Herbicidal combinations that comprises molinate and Oxyfluorfen, wherein the weight ratio of molinate and Oxyfluorfen is 500: 1 to 30: 1.

2. according to the Herbicidal combinations of claim 1, wherein said weight ratio is 250: 1 to 40: 1.

3. the method for a management of weeds in the presence of rice crops is included in the composition according to claim 1 of using herbicidally effective amount on described crop, described weeds or described crop and/or the described weed growth place.

4. the method for a management of weeds in the presence of rice crops, be included in use on described crop, described weeds or described crop and/or the described weed growth place herbicidally effective amount according to claim 2 composition.