INSECTICIDAL COMPOSITION AND METHOD

1 . A solid particulate insecticidal formulation which is formulated to be mechanically incorporated into or onto soil, the formulation comprising:

i. a microencapsulated volatile insecticide selected from insecticidal active ingredients having:

(a) a vapour pressure at 25° C. in the range from about 1 mPa to about 1,000 mPa; and

(b) a water solubility at 25° C. less than about 100 mg/Litre;

ii a bulking agent; and

iii. a disintegrating agent.

2 . The formulation according to claim 1 , further comprising:

iv. a binding agent, and/or

v. a dispersing agent.

3 . The formulation according to claim 2 , further comprising:

vi. a rheology modifier.

4 . The formulation according to claim 1 , wherein the formulation is formulated as a granule, a bait, or a tablet.

5 . The formulation according to claim 4 , wherein the formulation is formulated as a granule.

6 . The formulation according to claim 2 , wherein the volatile insecticidal active ingredient is selected from chlorethoxyfos, chlorpyrifos, chlorpyrifos-methyl, diazinon, dichlorvos, disulfoton, fenitrothion, fenthion, phorate, pirimiphos-methyl, tebupirimfos, tefluthrin, terbufos, thiodicarb, and a mixture thereof.

7 . The formulation according to claim 1 , wherein the microencapsulated volatile insecticide has a mean microcapsule diameter from about 100 nm to about 1,000 μm.

8 . The formulation according to claim 7 , wherein the mean microcapsule diameter is from about 200 nm to about 50 μm.

9 . The formulation according to claim 8 , wherein the mean microcapsule diameter is from about 500 nm to about 20 μm.

10 . The formulation according to claim 1 , wherein the microencapsulated volatile insecticide is a blend of two microcapsules, each containing a different active ingredient.

11 . The formulation according to claim 1 , wherein the formulation contains from 0.1% to 50% by weight of the insecticidal active ingredient based on the total weight of the formulation.

12 . The formulation according to claim 2 , wherein the:

ii. bulking agent is selected from clays, starches, lactose, calcium carbonate, calcium sulphate, calcium phosphate, and a mixture thereof; and

iii. disintegrating agent is selected from microcrystalline cellulose, sodium starch glycolate, crosslinked PVP, sodium sulphate, sodium citrate, polycarboxylates, sodium phenylsulphonates, and a mixture thereof.

13 . The formulation according to claim 3 , wherein the

ii. bulking agent is selected from clays, starches, lactose, calcium carbonate, calcium sulphate, calcium phosphate, and a mixture thereof;

iii. disintegrating agent is selected from microcrystalline cellulose, sodium starch glycolate, crosslinked PVP, sodium sulphate, sodium citrate, polycarboxylates, sodium phenylsulphonates, and a mixture thereof;

iv. binding agent is selected from polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate copolymers, polyacrylate, gelatine, polyacrylamide, oligosaccharides, sugar alcohols, lecithin, and a mixture thereof; and

v. dispersing agent is selected from calcium, aluminium or sodium lignosulfonate, sodium naphthalene sulfonate, polymeric dispersants, and a mixture thereof.

14 . The formulation according to claim 13 , further comprising

vi. a rheology modifier selected from magnesium aluminium silicates, xanthan gum, methyl cellulose, ethyl cellulose, and a mixture thereof.

15 . The formulation according to claim 14 , wherein the solid formulation comprises 10-80% by weight of the bulking agent, 2-20% by weight of the disintegrating agent, 2-20% by weight of the binding agent, 2-20% by weight of the dispersing agent, and 0.1-15% by weight of the rheology modifier.

16 . The formulation according to claim 1 , wherein the microencapsulated volatile insecticidal active ingredient is supplemented with a different insecticidal active ingredient having a mode of action other than vapour phase activity.

17 . The formulation according to claim 16 , wherein the supplementary active ingredient is root absorbed and systemically active, and is soluble in a water-immiscible solvent appropriate for microencapsulation.

18 . A method for producing a solid particulate insecticidal formulation according to claim 1 , said method comprising:

(A) preparing a suspension by combining components comprising a microencapsulated volatile insecticide selected from insecticidal active ingredients having:

(a) a vapour pressure at 25° C. in the range from about 1 mPa to about 1,000 mPa, and

(b) a water solubility at 25° C. less than about 100 mg/Litre; and

iv. a binding agent;

v. a dispersing agent; and

vi. optionally a rheology modifier;

(B) preparing a dry mixture by combining and thoroughly mixing dry ingredients comprising:

ii. a bulking agent; and

iii. a disintegrating agent;

(C) combining the microcapsule suspension (A) and the dry mixture (B) and mixing to produce a homogeneous moist mass;

(D) extruding the homogeneous moist mass (C) to a diameter ranging from about 0.2 mm about 5 mm to form an extruded mass; and

(E) reducing the moisture content of the extruded mass by drying.

19 . The method according to claim 18 , wherein the dry mixture (B) optionally further comprises a dry binding agent and/or a dry dispersing agent.

20 . The method according to claim 18 , further comprising spheronizing the extruded mass prior to drying.

21 . A method of treating soil to minimise insect attack from soil dwelling insects on planted seeds, growing plants and/or mature plants by incorporating into the soil or applying onto the soil a solid particulate insecticidal formulation according to claim 1 in the form of a granule, a bait, or a tablet.

22 . The method according to claim 21 wherein the formulation is applied at a rate of from about 200 grams gai/ha to about 3,000 gai/ha.

23 . The method according to claim 21 , wherein the formulation is applied at the time of drilling or planting, or at any subsequent stage of the crop or pasture growth cycle.