MXPA00009393A - Synergistic herbicidal combination - Google Patents

Abstract

Control of weeds in a rice crop is obtained by applying to the crop, the weeds, or the locus of either or both, a herbicidal composition containing molinate and carfentrazone-ethyl in a weight ratio of from about 60:1 to about 6:1.

Description

COMBINATION OF HERBICIDES WITH EFFECTS OF SYNERGISM BACKGROUND OF THE INVENTION This invention relates to combinations of herbicides with synergistic effects, particularly to such combinations for use in the control of weeds in rice cultivation. Molinate (S-ethyl hexahydro-lH-azepine-1-carbothioate) is a thiocarba ate herbicide that has been used to control weeds in rice crops by a number of years, and it is usually sold under the 4fc products bearing the ORDRAM® brand. In different formulations and resistances, the molinate is applied previously to the plant, previously to the area to be flooded and later to the flooded area to control a wide range of weeds in rice crops, and is generally applied in proportions ranging from 500 to approximately 11,000 g / ha. However, with many herbicides, it would be desirable to have the capacity to achieve • control of weeds while using a application with a lower proportion of molinate This could result in an impact on the environment and / or the workers handling the product. Molinate is also sold mixed with propanil (N-3,4- (dichlorophenyl) propanamide) in a branded product ARROSOLO®.

The compound carfentrazone-ethyl or ethyl-2-chloro-3- [2-chloro-5- (4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-lH-1, 2,4-triazole -l-il) phenyl] propionate (also known as F8426) is known as a selective herbicide for the • 5 control of broad-leaved weeds in cereal crops and is described in Van Suan et al., Proc. Brit. Crop .. Protection Conf. Weeds, p-19 (1993). Their preparation is described in the document of Theodoridis et al., Synthesis and Chemistry of Agrochemicals IV (American Chemical Society, 10 1995, Don R. Baker et al., Editors), p. 90 BRIEF DESCRIPTION OF THE INVENTION This invention comprises a herbicidal composition as well as a method for controlling weeds in rice crops. In one aspect, this invention relates to a herbicidal composition with synergistic effects comprising molinate and carfentrazone-ethyl. In a second aspect, this comprises a • herbicidal composition comprising molinate and carfentrazone-ethyl in an approximate weight ratio of 60: 1 to 6: 1, respectively. In another aspect, this invention comprises a method for controlling weeds in rice crops which comprises applying to said crop, said weeds or the site where any of the same or both is found, a combination with synergistic effects. which comprises molinate and carfentrazone-ethyl, particularly in an approximate weight ratio of 60: 1 to 6: 1, respectively. It has now surprisingly been found that the combination of a minor amount of the carfentrazone-ethyl herbicide with molinate can produce a synergistic effect such that an equivalent control of the weeds can be obtained with a smaller amount and / or percentage. from the application of molinate.

DETAILED DESCRIPTION OF THE INVENTION The invention comprises the use of the combination of the herbicides of molinate and carfentrazone-ethyl to control the weeds in a rice crop. The The combination, within the scope of this invention, demonstrates the effects of synergism, ie, which have been unexpected based on the individual yield of the two herbicides against the same bad weeds under the circumstances • Similar. In accordance with the invention, the weeds are controlled in the presence of the rice crop, when treating the crop, the weeds or the place where any of them is found or both, with a herbicidally effective amount of the combination of molinate and carfentrazone-ethyl herbicides with effects of iklláiittflil.Httl ^ ii.i.i.MHlMMA synergism. In general, we have found that the synergism is demonstrated when the combination includes these two herbicides in a percentage by weight respectively of 60: 1 to 6: 1, more preferably 20: 1 to 6: 1, however, our discovery is that the synergism between molinate and carfentrazone-ethyl, and not necessarily limited to the combinations of these herbicides within these percentages by weight, but as there may be synergism in other herbicides. This combination produces an effect of synergism or unexpected control of the weeds in rice, when it is applied at various times, and to rice planted in different ways. To control weeds, the combination can be applied before planting, but before flooding (prior to flooding, and after emergence) or after rice emergence and flooding (after flooding, after emergence) and It can be applied either to the seeds or to the transplanted rice. To be used in combination, it is not necessary that the two molinate and carfentrazone-ethyl herbicides be applied in a physically combined form, or even at the same time. The effect of the combination results in such a case when the two herbicides are present at the same time in the rice culture, regardless of when they were applied. So, for example, a physical combination of the two herbicides can be applied, or one can be applied before the other. For example, one of the two herbicides can be applied even before planting the rice • 5 for in a controlled release formulation, such as a microencapsulated formulation, and the other subsequently applied in a conventional liquid or solid formulation, in the event that the previously applied herbicide is still present in the soil when the second is applied, and in the case that the proportion by weight of the available p herbicides falls within what is disclosed and is claimed herein. Any herbicide can be applied in this way in a liquid or solid form, or a combination product containing both herbicides including emulsions, suspensions (including suspensions containing microcapsules), solutions, emulsifying concentrates, and products that are fluid. Solid products include • forms such as granules containing pesticides microencapsulated) or powders. Both types of compositions generally contain, in addition to the active herbicide, other ingredients such as solvents, wetting agents, suspending agents, anti-lumping agents, dispersing agents, emulsifiers, agents antifreeze, antifoaming agents, and other additives.

Any herbicide, or both, can be used in a number of known ways of controlled release compositions. Such compositions provide a relatively low or controlled release of the active ingredient into the environment and include, for example, encapsulations, microencapsulations, and various forms of controlled release granules. The combination products or compositions according to this invention may contain the two herbicides in numerous different physical forms. In some cases, a combination product can be produced by simply mixing in a physical manner ("mixed in an tank") the commercially available products containing the active herbicides, for example, two emulsifying concentrates containing the herbicides, in such case all The ingredients of the two products are relatively compatible. Alternatively, a package can be manufactured and sold which generally contains the two herbicides in separate containers, but packaged together, commonly referred to as a "double package". A double package is particularly suitable for the herbicidal compositions herein, since the amount of molinate is substantially greater than that of carfentrazone-ethyl, so that the package with the total product can be produced containing a relatively larger container. of the herbicidal product containing the molinate together with a smaller container of the herbicidal product containing the carfentrazone-ethyl. Alternatively, the previously prepared ("previously mixed") compositions containing the two herbicides can be made. Since both the molinate and the carfentrazone-ethyl are liquid under normal conditions, the liquid premixes will tend to be preferred. The liquid compositions typical will include an emulsifying concentrate containing • both herbicides and a two-phase emulsion (or microemulsion) with a herbicide in each phase. However, a similar sold product containing both herbicides could be produced in a similar, for example, as impregnated granules. Similarly, other formulations sold such as wetting powders can be prepared. Again in a similar way, when using the • appropriate ingredients and conditions, it would be possible to prepare microencapsulated products in which one or both herbicides are contained within a microcapsule in said microencapsulated products that could be sold in any liquid form (i.e., suspensions of microcapsules). A type of liquid form will be a The microcapsule suspension in which one of the herbicides is contained within the capsules while the other is present in a non-encapsulated form, in the continuous liquid phase. Another type would be the suspension containing molinate and carfentrazone-ethyl encapsulated separately. The • 5 types of formulations or compositions that may contain these two herbicides is not limited to those listed herein, but according to other types of formulations that would be similarly considered to those of skill in the art. In addition, other biocidally active ingredients or compositions can be combined with the herbicidal compositions of the present invention and used in the methods of the present invention. In addition to the herbicidal compositions of molinate and carfentrazone ethyl of the present invention may also contain insecticides, fungicides, bactericides, acaracides, nematicides or other herbicides, especially herbicides known to be useful for controlling weeds in • rice cultivation. For example, additional to molinate and carfentrazone-ethyl, the herbicidal compositions of the present invention may also contain propanil. Propanil is commercially available, and can also be obtained by mixing with molinate in a product sold under the ARROSOLO® brand that can be used in the herbicidal compositions of the present invention. In the ARROSOLO® product, the molmate and propanil are present in a weight percentage of 1: 1. As discussed above in connection with molinate and carfentrazone-ethyl, it is not necessary to additionally apply a biocidally active ingredient or composition in a physically combined form with the molinate or carfentrazone-ethyl, or even applied at the same time. The control of weeds by the combination of carfentrazone-ethyl and molinate is illustrated in the following examples. EXAMPLE 1. This example simulates the direct application of the combination of molinate and carfentrazone-ethyl in a rice culture under conditions typical of North America. The combinations of molinate and carfentrazone-ethyl in the indicated amount were applied in the greenhouse to the application rates shown in Table 1 (in the terms of grams per hectare of the herbicide or herbicides) to the planes containing rice.

(Oryza sativa, Katy variety) and the weeds as poultry pasture (Echinochloa crusgalli, ECHCG), morning glory (Ipomoea wrightii) (IPOWR) and flat sedge (Cyperus iria, CYPIR) in the pre-flooded stage, after the emergence, and in the growth phase 2 of the corral grass leaf. The weeds have grown separately in stage 2 of the leaf, transplanted to the rice lines. The results of these tests are shown below in Table 1, in terms of control or percentage damage compared to the untested run 30 days after treatment. A • 5 percent of 100% indicates complete control; of 0% that indicates no effect. The activity of the herbicide with synergistic effects can be calculated according to the Colby method (S.R. Colby, "Calculation of the Effects of Synergism and Antagonistic Responses to Herbicide Combinations ", Weeds 15 (1); 20-23, 1967) Colby's method represents a direct approach to measure the activity of the synergistic effects of the two herbicides. of Colby, E = X + Y - (XY / 100), where E is the percentage Expected from control of weeds by a combination of a first herbicide Hl and a second herbicide H2 at an application rate of p + q g / ha; X is the percentage of control of the weeds observed for Hl in a percentage of application p g / ha; and Y is the percentage of control of the weeds observed for H2 at a percentage of application q g / ha. The herbicidal activity with synergistic effects calculated according to the Colby method showed that an activity with synergistic effects was found with the Echinolochia crusgalli (ECHCG).

TABLE 1 EXAMPLE 2. This example showed that the • direct application of molinate and carfentrazone-ethyl prior to flooding, after emergence of a crop of rice planted under conditions typical of the Southeast of the United States. A dry rice seed was planted (variety Kaybonnet) at a depth of 1 cm, then it was filled with water and grew to stage 3 of the leaf. The bad herbs used • were ECHCG, IPOWR and CYPIR, as previously. The weeds grew separately at stage 2 of the leaf and were added to the tubes. The application of herbicide was sprayed or the chemical was spread. The tubes were flooded for 1 week or more after the application. The results of this are shown in the following Table 2. The percentages were taken 28 days after the application. The herbicidal activity with synergistic effects was calculated using the Colby method established in Example 1. Herbicidal activity with synergistic effects was found with Echinolochia crusgalli (ECHCG) and Ipompea wright: .i (IPOWR). 25 TABLE 2 • • 15 twenty • EXAMPLE 3. This example includes tests carried out using a post-flooded application, after emergence, (in a stage 2 of the corral grass blade) in the transplanted rice Koshihikari variety. The rice grew to a 2-4 stage of the leaf away in the form separated from the test tubes. The soil in the tube was formed of clay and gravel until a mixture was achieved. The • Rice plants were transferred to this mixture. The weeds used were ECHCG, flat small flower sedge (Cyperus Difformis, CYPDI), dwarf sagittaria (Sagittaria pygmae, SAGPY) and monochoria (Monochoria vaginalis, MOOVA). The weeds (stage 2 of the leaf) grew separately and were transplanted into the mixed soil tube or grown in the same tube of mixed soil. The herbicide application was typically carried out by injection or • 20 the chemical was spread after the waterlogging. The percentages were taken 29 days after the application and represent the average of the four land areas. The results are shown in the following table 3. The herbicidal activity with synergistic effects is I calculate using the Colby method established in Example 1. We found herbicidal activity with synergistic effects with Echinolochia crusgalli (ECHCG), Monochoria vaginalis (MOOVA), Sagittaria pygmae (SAGPY) and Cyperus difformis (CYPDI). • • riMH.tf. ^ tt-áM TABLE 3 • twenty 40 •

Claims (6)

CLAIMS 1. A herbicidal composition comprising molina ": oy carfentrazona-etil in an approximate weight percentage of 60: 1 to 6: 1, respectively 2. A herbicidal composition according to claim 1, wherein the percentage by weight is about 20: 1 to 6: 1 3. A liquid herbicidal composition according to claim 1. 4. A solid herbicidal composition according to claim 1. 5. A contrd release herbicidal composition in accordance with claim 1. A herbicidal composition according to claim 5, wherein at least one of molinate and carfentrazone-ethyl is contained in the microcapsules 7. A method for contrng weeds in the presence of a rice crop which comprises applying to said crop, said weeds or at the site where said crop and / or weeds are found, a herbicidally effective amount of a composition according to claim 1. 8. A method for contrng weeds in the presence of a rice crop comprising applying to said crop, said weeds or at the site where said crop is grown and / or the weeds, a herbicidally effective amount of a composition according to claim 2. 9. A method for contrng weeds in the • the presence of a rice crop which comprises applying to said crop, said weeds or at the site where said crop and / or weeds are found, a herbicidally effective amount of a composition according to claim 3. 10. A method to control weeds in. In the presence of a rice crop comprising applying to said crop, said weeds or at the site where said crop and / or weeds are found, a herbicidally effective amount of a composition in accordance with 15 claim 4. 11. A method for contrng weeds in the presence of a rice crop comprising applying to said crop, said weeds or at the site where it is grown. • find such a crop and / or bad weeds, a quantity Herbicide-effective composition of a composition according to claim 5. 12. A method for contrng weeds in the presence of a rice crop comprising applying to said crop, said weeds or at the place where it is grown. 25 find such a crop and / or the weeds, an amount ^^ jyyy * aj ^^^^ herbicidally effective of a composition in accordance with claim 6. -tuu? jjfcu = i. Control of the weeds in a rice crop is obtained by applying to the crop, the weeds, or the site where either or both are found, a herbicidal composition containing molinate and carfentrazone-ethyl in an approximate weight ratio of 60 : 1 to 6:

1.