Solid herbicidal composition comprising mesotrione

Abstract

The present invention relates to a solid herbicidal composition comprising: i. mesotrione; ii. at least one arene sulfonate condensed with formaldehyde (e.g. sodium alkylnaphthalene sulfonate condensed with formaldehyde); and iii. an acidifying agent. The present invention further provides a method of controlling weeds at a locus comprising diluting the solid herbicidal composition of the present invention and applying to the locus a weed controlling amount of the diluted herbicidal composition.

Claims

1. A solid herbicidal composition comprising: i. from 1% to 50% w/w of mesotrione; ii. from 1% to 25% w/w of at least one alkylnaphthalene sulfonate condensed with formaldehyde; and iii. from 0.5% to 5% of an acidifying agent selected from the group consisting of citric acid, phosphoric acid and mixtures thereof.

2. The solid herbicidal composition according to claim 1, which is a wettable granule.

3. The solid herbicidal composition according to claim 1, which further comprises at least one additional herbicide selected from the group consisting of sulfonylurea herbicides, triazine herbicides and auxin herbicides.

4. The solid herbicidal composition according to claim 1, wherein the at least one alkylnaphthalene sulfonate condensed with formaldehyde is present in an amount from 2.5% to 10% w/w.

Description

EXAMPLES

(1) A comparative experiment is performed to show the advantage that the solid herbicidal composition of the present invention has compared to those reported in the art (e.g. WO2007/133522). Water dispersible granules (WDG) are prepared according to the information provided in the table below. The WDGs are then stored in a thermostatic oven at a given temperature for a given time period (information provided in table). The content of Mesotrione in the water dispersible granules before and after the storage is quantitatively determined by liquid chromatography, and the decomposition rate of each water dispersible granules is calculated from the following formula to evaluate the change with time. The results obtained are shown in the table below.
Decomposition rate (%)={(XY)/X}100

(2) X: content immediately after preparation

(3) Y: content after storage

Example 1

(4) TABLE-US-00001 Component Comp* A B C Mesotrione 5 5 5 5 Anhydrous sodium sulfate 30 30 30 30 Calcium lignosulfonate 5 / 5 / Sodium alkylnaphtalenesulfonate 1 1 1 1 (Morwet IP) Calcium bentonite 59 59 57 57 Sodium 0 5 0 5 alkylnaphthalene sulfonate condensate (Morwet D-425) Citric acid 0 0 2 2 100 100 100 100 pH (1% in water) 4.0 4.0 3.5 3.5 % w/w Mesotrione loss 15.7 7.8 4.6 2.8 (2 w@54 C.) *Comp granule relates to one similar to that disclosed in WO2007/133522.
These results show that mesotrione is significantly more chemically stable in granules containing the alkylnaphthalene sulfonate condensed with formaldehyde.

Example 2

(5) In this example other active ingredients belonging here to sulfonylurea class are introduced to the composition. The content of mesotrione in the water dispersible granules before and after the storage is determined by using the analytical method described above.

(6) A fluid bed granule is prepared according to the following recipe. An aqueous slurry containing the ingredients described below is ground in a bead mill and sprayed into a granulation tower where suspension is dried by injecting warm air.

(7) TABLE-US-00002 D E Component % (w/w) % (w/w) Mesotrione 45 45 Prosulfuron 4.5 4.5 Nicosulfuron 9 9 Sodium lignosulfonate 20 Sodium salt of alkylnaphthalene sulfonate 20 condensate (Morwet D-425) Citric acid 2 0 Aluminium silicate Remainder Remainder pH (1% solution in water) 3.8 3.5 % w/w Mesotrione loss after 3 months@45 C. 13% 2%

(8) These results demonstrate that an alkylnaphthalene sulfonate condensed with formaldehyde improves the chemical stability of mesotrione in granule produced with fluid-bed technology and containing more than one herbicidal compound.