METHOD OF CONTROLLING GROWTH OF ALS-TOLERANT PLANTS

Abstract

A method for the control of the growth of ALS-resistant plants is provided, the method comprising applying to the plants and/or their locus a herbicidally effective amount of a combination of (A) metribuzin and (B) one or more sulfonylureas. A composition comprising a combination of (A) metribuzin and (B) one or more sulfonylureas is also provided.

Claims

1. A method for the control of the growth of ALS-resistant plants comprising applying to the plants and/or their locus a herbicidally effective amount of a combination of (A) metribuzin and (B) one or more sulfonylureas.

2. The method according to claim 1, wherein the one or more sulfonylureas are selected from amidosulfuron, azimsulfuron, bensulfuron, chlorimuron, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron, ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron, foramsulfuron, halosulfuron, imazosulfuron, iodosulfuron, iofensulfuron, metazosulfuron, methiopyrisulfuron, metsulfuron, mesosulfuron, monosulfuron, nicosulfuron, orthosulfamuron, oxasulfuron, primisulfuron, propyrisulfuron, prosulfuron, pyrazosulfuron, rimsulfuron, sulfometuron, sulfosulfuron, thifensulfuron, triasulfuron, tribenuron, trifloxysulfuron, triflusulfuron and tritosulfuron; preferably wherein the one or more sulfonylureas are selected from thifensulfuron, tribenuron, metsulfuron, sulfosulfuron, amidosulfuron, mesosulfuron, iodosulfuron, rimsulfuron, nicosulfuron and halosulfuron.

3. The method according to claim 1, wherein the components (A) metribuzin and (B) one or more sulfonylureas are applied at an application rate of from 0.03 kilograms/hectare (kg/ha) to 2 kg/ha of the total amount of active ingredients being applied.

4. The method according to claim 1, wherein component (A) metribuzin is applied in an amount of at least 5 g/ha.

5. The method according to claim 1, wherein the one or more sulfonylureas are applied in a total amount of at least 1 g/ha.

6. The method according to claim 1, wherein the weight ratio of (A) metribuzin and (B) one or more sulfonylureas is up to 400:1.

7. The method according to claim 1, wherein the weight ratio of (A) metribuzin and (B) one or more sulfonylureas is greater than 1:20.

8. The method according to claim 1, wherein the components (A) metribuzin and (B) one or more sulfonylureas are applied to the plants and/or their locus post-emergence.

9. The method according to claim 1, wherein the ALS-resistant plants are present in a crop of wheat, including both soft wheat and durum wheat, barley, rye, oats, maize, rice, sorghum, triticale, beans, lentils, peas, soybeans, and peanuts, cotton, flax, hemp, jute, spinach, lettuce, asparagus, cabbages, carrots, onions, tomatoes, potatoes, or paprika; preferably wherein the ALS-resistant plants are present in a crop of wheat, including both soft wheat and durum wheat, barley, rye, oats, triticale, maize, rice, soybeans, cotton, tomatoes and potatoes; more preferably wherein the ALS-resistant plants are present in a crop of wheat, including both soft wheat and durum wheat, barley, rye, oats and triticale.

10. The method according to claim 1, wherein the ALS-tolerant plants comprise Stellaria spp., Papaver spp. or Matricaria spp.; preferably wherein the ALS-tolerant plants comprise Stellaria media, Papaver rhoeas, Matricaria chamomilla or Matricaria inodora.

11. The method according to claim 1, wherein components (A) and (B) are applied in the form of one or more formulations selected from water-dispersible granules (WDG), water-soluble granules (SG) and oil-based suspension concentrates (OD).

12. A composition for the control of ALS-tolerant plants comprising a herbicidally effective amount of a combination of (A) metribuzin and (B) one or more sulfonylureas.

13. The composition according to claim 12, wherein the one or more sulfonylureas are selected from thifensulfuron, tribenuron, metsulfuron, sulfosulfuron, amidosulfuron, mesosulfuron, iodosulfuron, rimsulfuron, nicosulfuron and halosulfuron.

14. The method according to claim 1, wherein the components (A) metribuzin and (B) one or more sulfonylureas are applied at an application rate of from 0.05 kg/ha to 1.5 kg/ha of the total amount of active ingredients.

15. The method according to claim 1, wherein component (A) metribuzin is applied in an amount of at least 20 g/ha.

16. The method according to claim 1, wherein the one or more sulfonylureas are applied in a total amount of at least 2 g/ha.

17. The method according to claim 1, wherein the weight ratio of (A) metribuzin and (B) one or more sulfonylureas is up to 70:1.

18. The method according to claim 1, wherein the weight ratio of (A) metribuzin and (B) one or more sulfonylureas is up to 10:1.

19. The method according to claim 1, wherein the weight ratio of (A) metribuzin and (B) one or more sulfonylureas is greater than 1:5.

Description

EXAMPLES

Formulation Examples

a) Water Dispersible Granule (WG) Formulation

[0060] A water dispersible granule (WG) formulation was prepared from the components summarized in Table 1 below.

TABLE-US-00001 TABLE 1 Components Weight % Function Metribuzin 35%  Active ingredient Thifensulfuron 20%  Active ingredient Sodium alkyl naphthalene sulfonate blend (MORWET ® EFW POWDER 2% Wetting agent from AkzoNobel N.V.) Sodium alkyl naphthalene sulfonate, 8% Dispersing agent formaldehyde condensate (MORWET ® D-425 POWDER from AkzoNobel N.V.) Fatty acids, tallow and sodium 1% Antifoaming agent salts(AGNIQUE ® SOAP L from BASF) Mannitol balance to Filler 100%

b) Oil-Based Suspension Concentrates (OD) Formulation

[0061] An oil-based suspension concentrate (OD) formulation was prepared from the components summarized in Table 2 below.

TABLE-US-00002 TABLE 2 Components Weight % Function Metribuzin 30% Active ingredient Tribenuron 10% Active ingredient Modified  1% Antifoaming agent polyether-polysiloxane(Breakthru ® AF9902 from Evonik) Ethoxylated castor oil(ALKAMULS 15% Emulsifier OR/36 from Rhodia) Sodium alkylnaphthalenesulfonate,  8% Dispersing agent formaldehyde condensate (MORWET ® D-425 POWDER from AkzoNobel N.V.) Silica  3% Thickening agent Vegetable oil balance to Diluent 100%

c) Water-Soluble Granule (SG) Formulation

[0062] A water-soluble granule (SG) formulation was prepared from the components summarized in Table 3 below.

TABLE-US-00003 TABLE 3 Components Weight % Function Metribuzin 70%  Active ingredient Metsulfuron 5% Active ingredient Sodium lauryl sulfate (Supralate ® from 0.5%   Wetting agent Witco Inc., Greenwich) Sodium lignosulfonate(Reax ® 88B from 5% Antifoaming Westvaco Corp) agent Sodium hydrogen carbonate (NaHCO.sub.3) 2% PH regulator Potassium sulfate balance to Filler 100%

[0063] A range of different formulations was prepared according to the methods described above. The formulation type and the active ingredients present in the formulations are summarized in Table 4 below. Examples C1 to C11 were prepared for comparison purposes. Examples 1 to 16 are examples of the present invention.

[0064] In the formulations prepared, component (A) is metribuzin and components (B1) to (B10) are sulfonylureas as follows:

[0065] B1: Thifensulfuron

[0066] B2: Tribenuron

[0067] B3: Metsulfuron

[0068] B4: Sulfosulfuron

[0069] B5: Amidosulfuron

[0070] B6: Mesosulfuron

[0071] B7: Iodosulfuron

[0072] B8: Rimsulfuron

[0073] B9: Nicosulfuron

[0074] B10: Halosulfuron

TABLE-US-00004 TABLE 4 Active ingredients (weight %) B Example Type A B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 C1 WG 70 — — — — — — — — — — C2 SG — 40 — — — — — — — — — C3 WG — — 40 — — — — — — — — C4 OD — — — 40 — — — — — — — C5 OD — — — — 40 — — — — — — C6 SG — — — — — 40 — — — — — C7 OD — — — — — — 40 — — — — C8 WG — — — — — — — 40 — — — C9 OD — — — — — — — — 40 — — C10 WG — — — — — — — — — 40 — C11 WG — — — — — — — — — — 40  1 SG 35 20 — — — — — — — — —  2 SG 35 25 — — — — — — — — —  3 OD 10 35 — — — — — — — — —  4 WG 30 — 10 — — — — — — — —  5 OD 70 — 14 — — — — — — — —  6 WG 80 —   0.4 — — — — — — — —  7 SG 70 — —  5 — — — — — — —  8 WG 50 — —  5 — — — — — — —  9 OD 15 — —   2.5 — — — — — — — 10 WG 40 — — —  7 — — — — — — 11 SG 35 — — — — 20 — — — — — 12 WG 30 — — — — — 15 — — — — 13 WG 35 — — — — — —  5 — — — 14 SG 35 — — — — — — — 20 — — 15 WG 35 — — — — — — — — 20 — 16 WG 35 — — — — — — — — — 20

Biological Examples

[0075] A synergistic effect exists with a combination of two active compounds when the activity of a combination of both active compounds is greater than the sum of the activities of the two active compounds applied alone.

[0076] The expected activity for a given combination of two active compounds can be calculated by the so called “Colby equation” (see S. R. Colby, “Calculating Synergistic and Antagonistic Responses of Herbicide Combinations”, Weeds 1967, 15, 20-22):

[0077] whereby:

E=A+B−(A×B/100)

wherein:

[0078] A=the activity percentage of compound A when active compound A is employed at an application rate of m g/ha;

[0079] B=the activity percentage of compound B when active compound B is employed at an application rate of n g/ha;

[0080] E=the percentage of estimated activity when compounds A and B are employed together at an application rate of m g/ha and n g/ha.

[0081] If the actual activity observed for the combination of compounds A and B is greater than that calculated using the above formula, then the activity of the combination is superadditive, that is synergism is present.

[0082] The formulations of Examples C1 to C11 and 1 to 16 were tested for their biological activity against plants exhibiting resistance to sulfonylureas as follows:

[0083] Seeds of normal wild variety and ALS-resistant variant of each of Stellaria media, Papaver rhoeas, Matricaria chamomilla and Matricaria inodora were sown in trays of peat-based compost placed in a glasshouse to allow germination. At the cotyledon stage, four evenly sized seedlings were transplanted into each of 9 cm diameter plastic pots containing loam soil mixed with 25% by volume horticultural silver sand and further blended with coarse grit in the ratio 3:1. The resulting potting medium was supplemented with Osmacote slow-release fertilizer (16:8:9+Mg) to provide 1.4 g per 0.35 L pot.

[0084] The formulations of each of Examples C1 to C11 and 1 to 16 were applied to the seedlings by spraying. Three replicate pots were used per treatment. Prior to spraying, the plants were watered overhead. To ensure the foliage was dry, water was not applied on the day of spraying, with the last overhead watering being the day before spraying. The herbicide formulations were made up with mains tap water. The laboratory track sprayer was set up with a Lurmark OIE80 Even spray nozzle to deliver 200±20 L/ha using gear 4 and a pressure of 210 Pa (30 psi). The application rates of the active ingredients are set out in Table 5 below.

[0085] Following spraying, the plants were returned to the glasshouse and the sprayed pots were arranged in three randomized blocks. The temperature of the glasshouse ranged from 12.2° C. to 16.1° C. by day and 10.9° C. to 13.3° C. at night. The relative humidity ranged from 75% to 101%.

[0086] Throughout the experiment, the plants were watered to maintain the soil close to the field capacity. Following herbicide treatment, the plants were watered by sub-irrigation using individual plastic dishes for each pot to avoid any risk of cross contamination.

[0087] The visual percentage of control based on a 0-100 linear scale was assessed 21 days after treatment (DAT). The linear scale ranged from 0 (no effect) to 100 (dead plants).

[0088] The results of the visual inspections are summarized in Table 6 below. In Table 6, ‘Obs’ indicates an observed result and ‘Exp’ indicates the result expected from applying the Colby equation, discussed above.

TABLE-US-00005 TABLE 5 Example Application rate (g/ha) No. A B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 Untreated 0 0 0 0 0 0 0 0 0 0 0 Cl 20 — — — — — — — — — — Cl 30 — — — — — — — — — — Cl 50 — — — — — — — — — — Cl 70 — — — — — — — — — — Cl 200  — — — — — — — — — — Cl 400  — — — — — — — — — — C2 — 40 — — — — — — — — — C2 — 50 — — — — — — — — — C2 — 70 — — — — — — — — — C3 — — 10 — — — — — — — — C3 — — 14 — — — — — — — — C3 — —  1 — — — — — — — — C4 — — — 5 — — — — — — — C5 — — — — 70 — — — — — — C6 — — — — — 40 — — — — — C7 — — — — — — 15 — — — — C8 — — — — — — — 10 — — — C9 — — — — — — — — 40 — — C10 — — — — — — — — — 40 — C11 — — — — — — — — — — 40  1 70 40 — — — — — — — — —  2 70 50 — — — — — — — — —  3 20 70 — — — — — — — — —  4 30 — 10 — — — — — — — —  5 70 — 14 — — — — — — — —  6 200  —  1 — — — — — — — —  7 70 — — 5 — — — — — — —  8 50 — — 5 — — — — — — —  9 30 — — 5 — — — — — — — 10 400  — — — 70 — — — — — — 11 70 — — — — 40 — — — — — 12 30 — — — — — 15 — — — — 13 70 — — — — — — 10 — — — 14 70 — — — — — — — 40 — — 15 70 — — — — — — — — 40 — 16 70 — — — — — — — — — 40

TABLE-US-00006 TABLE 6 Percentage control (21 DAT) Type of weeds Papaver Matricaria Stellaria Stellaria Papaver rhoeas Matricaria chamomilla Matricaria Matricaria media media (ALS rhoeas (ALS chamomilla (ALS inodora inodora (ALS Example (wild) resistant) (wild) resistant) (wild) resistant) (wild) resistant) No. Obs Obs Exp Obs Obs Exp Obs Obs Exp Obs Obs Exp Untreated  0  0 0  0  0 0  0  0 0  0  0 0 C1 15  8 — 12  2 —  5  1 —  8  2 — C1 28 14 — 25 10 — 12  5 — 15 10 — C1 48 25 — 36 24 — 20 12 — 30 18 — C1 52 36 — 44 30 — 35 28 — 42 25 — C1 68 55 — 60 46 — 56 45 — 70 58 — C1 85 70 — 72 55 — 70 60 — 85 65 — C2 30  0 — 32  0 — 22  0 — 28  0 — C2 55  0 — 45  0 — 34  0 — 40  0 — C2 71 10 — 63  5 — 58  5 — 60  0 — C3 28  0 — 20  0 — 12  0 — 21  0 — C3 34  0 — 28  0 — 22  0 — 30  0 — C3  5  0 —  0  0 —  2  0 —  4  0 — C4 40  0 — 30  0 — 32  0 — 30  0 — C5 64  5 — 50 10 — 50  0 — 60  5 — C6 55  0 — 42  0 — 45  0 — 48  0 — C7 50  0 — 30  0 — 40  0 — 42  0 — C8 48  0 — 32  0 — 40  0 — 30  0 — C9 35  0 — 25  0 — 36  0 — 40  0 — C10 40  0 — 36  0 — 28  0 — 35  0 — C11 50 10 — 40  0 — 36 10 — 42  5 —  1 98 90 36 90 88 30 87 85 28 85 80 25  2 98 92 36 95 90 30 90 88 28 95 92 25  3 80 70 17.2 82 70 6.9 80 78 5.95 82 75 2  4 86 72 14 78 69 10 75 70 5 78 70 10  5 80 70 36 75 70 30 78 72 28 75 70 25  6 88 78 55 75 70 46 75 70 45 84 78 58  7 95 85 36 92 84 30 88 82 28 92 88 25  8 85 80 25 80 75 24 80 75 12 85 80 18  9 75 70 14 72 70 10 68 62 5 78 72 10 10 99 94 71.5 95 90 59.5 98 92 60 96 90 66.75 11 90 88 36 88 85 30 90 85 28 95 92 25 12 80 70 14 75 70 10 70 65 5 80 75 10 13 85 80 36 78 72 30 81 75 28 82 78 25 14 96 85 36 95 90 30 90 85 28 95 90 25 15 98 88 36 94 89 30 92 88 28 92 90 25 16 95 90 42.4 92 88 30 95 90 35.2 95 88 28.75

[0089] From a review of the data presented in Tables 5 and 6 above, as expected, metribuzin caused damage to both the ALS-tolerant and wild plants (composition C1).

[0090] Further, as expected, the sulfonylureas, namely Thifensulfuron, Tribenuron, Metsulfuron, Sulfosulfuron, Amidosulfuron, Mesosulfuron, Iodosulfuron, Rimsulfuron, Nicosulfuron, Halosulfuron had little or no effect on all ALS-tolerant plants (composition C2-C11), while significantly damaging the wild (non-tolerant) plants.

[0091] Surprisingly, the combination of metribuzin with each of the sulfonylureas, caused damage to the ALS-tolerant plants that was significantly in excess of that caused by the metribuzin alone. The data demonstrate that a combination of metribuzin and a sulfonyl urea exhibits synergy in the control of ALS-tolerant plants.