PT108561A - HERBICIDE MIXTURE - Google Patents

Abstract

The present invention provides a synergistic herbicidal composition comprising a mixture of methyl isodiphosphorus (Compound I) or its salts, fluorosulfame (Compound II) or its salts and diflulufenium. The present invention also relates to a process for controlling infestation of winter and spring cranberry crops by the application of said composition.

Description

DESCRIPTION "HERBICIDE MIXTURE"

AREA OF THE INVENTION

This invention is in the field of crop protection and specifically relates to a synergistic herbicidal combination comprising iodosulfuron-methyl or its salts, florasulam or its salts and diflufenican, and the preparation and use of said composition for the control of weeds from winter and spring cereal crops.

BACKGROUND OF THE INVENTION

In the field of crop protection, the use of an active substance for the control of weeds may become increasingly difficult over time as a result of the emergence of resistance to the herbicides used. This leads to loss of efficacy in controlling weeds and, consequently, loss of crop yield and crop yield.

A highly developed approach to this problem is the use of a combination of different active substances presenting different biochemical mechanisms of action.

However, the combination of a plurality of active substances often causes problems of physical or biological incompatibility, which may be manifested, for example, in the lack of physical stability of the formulation, degradation of one or more active substances over time, antagonism in terms of biological effectiveness or phytotoxicity effects on the crop. The compound (I), iodosulfuron-methyl (IUPAC: methyl 4-iodo-2- [3- (4-methoxy-6-methyl-1,3,5-triazin-2-yl) ureidosulfonyl] benzoate), formula is:

(I) is a herbicidal substance described in EP 0574418.

The iodosulfuron-methyl sodium salt (iodosulfuron-methyl-sodium), which has the structural formula (Ia), is preferably used:

(Ia) Iodosulfuron-methyl-sodium is a sulfonylurea that acts by inhibiting the biosynthesis of essential amino acids from susceptible plants by inhibiting the enzyme acetolactate synthase (ALS). Its initial post-emergence (both as far as crops and weeds) use in wheat is known. The controlled weeds are ryegrass (Lolium rigidium), balance (Avena spp), annual Phalaris (Phalaris paradoxa) and various broadleaf weeds. The compound (II), florasulam (IUPAC: 2 ', 6', 8-trifluoro-5-methoxy [1,2,4] triazolo [1,5-c] pyrimidin-2-sulfonanilide), described in EP 0343752, has the following structural formula:

(II) Florasulam is a triazolopyrimidine sulfonanilide used in post-emergence cereals for the control of broad leaf weeds, which acts by inhibiting acetolactate synthase (ALS). The compound (III), diflufenican (IUPAC: 2R, 4R-difluoro-2- (α, α, α-trifluoro-m-tolyloxy) nicotinanilide) described in European Patent EP 053011 has the following structural formula:

(III) Diflufenican is a pyridine carboxamide which may be used in pre or post emergence in cereals to control broad leaf weeds and which acts to inhibit phytoene dehydrogenase, a key enzyme of carotenoid biosynthesis, pigments which are responsible for absorption of light for photosynthesis.

There are patent documents which refer to the use of the above-mentioned active ingredients in the composition of herbicidal mixtures: European Patent EP 0831707 BI relates to combinations of 4-iodo-2 - [(4-methoxy-6-methyl triazin-2-yl) carbamoylsulfamoyl] benzoic acid, in particular iodosulfuron-methyl and its salts, with another active substance selected from the group consisting of diflufenican. The patent provides an example of synergy in combating Lolium multiflorum in which the addition of 13 g / ha of diflufenican (which up to a dose of 25 g / ha did not show any herbicidal activity) at 10 g / ha of iodosulfuron methyl an increase in effectiveness in controlling said weed of 60 000 patent application EP2095712 AI relates to combinations of diflufenican with florasulam. The patent application provides an example of synergy in combating Lolium multiflorum in which neither the use of 9 g / ha of diflufenican nor the use of 0.5 g / ha of florasulam showed any herbicidal activity, but the combination of 9 g / ha of diflufenican with 0.5 g / ha of florasulam allowed an efficacy of 30.6,

In one aspect of the invention, the process is characterized by applying 7.5 g / ha to 10 g / ha of iodosulfuron; 3 g / ha to 4 g / ha florasulam and 60 g / ha to 80 g / ha diflufenican.

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to provide a mixture of active herbicidal substances exhibiting high effectiveness in weed control of winter and spring cereal crops (durum and soft wheat, barley, triticale oats and rye) selected from the group comprising Anagallis Arvensis, Anthemis spp., Galium aparine, Lolium multiflorum, Lolium rigidum, Matricaria chamomilla, Papaver rhoeas, Picris echioides, Poa annua, Rumex crispus, Sinapis arvensis, Stellar media and Veronica spp.

It has surprisingly been found that combining iodosulfuron-methyl (compound I) or its sodium salt (compound Ia) with florasulam (compound II) and diflufenican (compound III), a synergistic effect on biological efficacy is observed results in an unexpected increase in efficacy when compared to the efficacy of each of the active ingredients.

This synergistic effect allows for lower application rates or a more potent herbicidal action with the same application rates, which translates into an economically more advantageous to the user and also more environmentally friendly process.

The formulations may be in the form of wettable powder (WP), water dispersible granules (WG), aqueous suspension (SC), or oily suspension (OD) .

The formulations are prepared in a known manner, for example, by blending the active compounds with other inert formulations selected from inert dispersants, wetting, disintegrating, stabilizing agents, pH and viscosity correctors and combinations thereof.

Examples of preferred dispersants are sodium or calcium lignosulfonates (Borresperse pH (for example citric acid) and inert (e.g., silica or kaolin).

The application rates of the blend according to the invention are in the range of 7.5 g / ha to 10 g / ha iodosulfuron; 3 g / ha to 4 g / ha florasulam and 60 g / ha to 80 g / ha diflufenican.

FORMULATION EXAMPLE By way of example, a formulation in the form of water dispersible granules (WG) is carried out using the following composition and procedure:

Component

The compounds Ia, II and III and the cloquintocete-mexil are mixed and subsequently milled in an air jet mill until a sufficiently fine particle size is reached (at least 95% by weight).

Synergistic effect

To quantify the synergistic effect resulting from the association of the active substances, the methodology described by Colby (Colby, SR, "Calculating synergistic and antagonistic response of herbicide compositions", Weeds 15, pp. 20-22, 1967) was used according to which compares the expected efficacy (EE) for the active ingredient mixture determined using the Colby formula: EE = x + y - (xy) / 100 where: -EE is the expected efficacy, in%, using the active compound mixture A and B at concentrations a and b. -x is the efficacy, in%, using the active compound A in concentration a; -y is the efficacy, in%, using the active compound B in concentration b; with the efficacy observed experimentally.

For a mixture of three active substances A, B and C, the abovementioned reference presents a modification of Colby's formula according to which the expected efficacy (EE) is determined by: EE = x + y + z- (xy + xz + yz ) / 100 + (xyz) / 10000 where: - x and y are as defined in the above formula; -z is the efficacy, in%, using the active compound C in concentration c. -EE is the expected efficacy, in

TABLE A

synergistic effect resulting in an unexpected increase in effectiveness in combating weeds from winter and spring cereal crops.

Claims (4)

A synergistic herbicidal composition comprising iodosulfuron-methyl or its salts, florasulam or its salts and diflufenican. The herbicidal composition according to claim 1, characterized in that: - the concentration range of iodosulfuron is between 4.0 multiflorum, Lolium rigidum, Matricaria chamomilla, Papaver rhoeas, Picris echioides, Poa annua, Rumex crispus, Sinapis arvensis, Stellaria media and Veronica spp. Process for combating weeds from winter and spring cereals (durum and soft wheat, barley, triticale oats and rye), characterized in that a mixture of iodosulfuron-methyl or its salts, florasulam or their salts and diflufenican. A process according to claim 7, characterized in that 7.5 g / ha is applied to 10 g / ha iodosulfuron; 3 g / ha to 4 g / ha florasulam and 60 g / ha to 80 g / ha diflufenican.