Microencapsulated insecticide formulations
View Patent ↗Various microencapsulated insecticide formulations for the control of pests such as aphids and beet army worm. These formulations exhibit excellent knockdown activity towards both chewing and non-chewing pests as LD 50 values for toxicity in female rats in the range of about 2,500 mgKg −1 . Some of these formulations include a wall comprised of a polymer formed, for example, by an interfacial polycondensation of a water soluble monomer and a water insoluble monomer, which at least partially surround an organophosphate insecticide. In some aspects the organophosphate in the microcapsule is chlorpyrifos. The microcapsule have a diameter in the range of about 2 to about 25 micron and the wall has a thickness in the range of about 5 to about 25 nanometers.
1. A pesticide formulation, comprising:
an organophosphate pesticide; and
a polymer forming a capsule wall which at least partially encapsulates the organophosphate pesticide to form a microcapsule, the wall having an average thickness of between about 5 nm to about 10 nm, said microcapsule having an average diameter in the range of about 2 microns to about 3 microns; wherein the wall is formed by an interfacial polycondensation between at least one oil soluble monomer selected from the group consisting of: diisocyanates, polyisocyanates, diacid chlorides, poly acid chlorides, sulfonyl chlorides and chloroformates; and at least one water soluble monomer selected from the group consisting of: diamines, polyamines, water soluble diols and water soluble polyols.
2. The pesticide formulation according to claim 1 , the capsule wall having an average thickness of about 10 nm.
3. The pesticide formulation according to claim 1 , wherein the organophosphate pesticide is selected from the group consisting of: acephate, azinphos-mehyl, chlorfenvinphos, chlorethoxyfos, chlorpyriphos-methyl, diazinon, dimethoate, disulfoton, ethoprophos, fenitrothion, fenthion, fenamiphos, fosthiazate, malathion, methamidophos, methidathion, omethoate, oxydemeton-methyl, parathion, parathion-methyl, phorate, phosmet, profenofos, and trichlorfon.
4. The pesticide formulation according to claim 1 , wherein the organophosphate pesticide is chlorpyrifos.
5. The pesticide formulation according to claim 4 , wherein the microcapsule includes between about 15 wt. percent to about 35 wt. percent chlorpyrifos.
6. The pesticide formulation according to claim 1 , wherein said microcapsule exhibits toxicity in female rats of greater than about 5,000 mgKg −1 and an LC 50 for initial control of cotton aphids of less than about 30 ppm chlorpyrifos.
7. The pesticide formulation according to claim 1 , wherein said microcapsule exhibits toxicity in female rats of greater than about 2,500 mgKg −1 and an LC 50 for initial control of beet army worm of less than about 400 ppm chlorpyrifos.
8. A method of synthesizing microcapsule, comprising the steps of:
providing an organophosphate insecticide, and at least one monomer;
mixing the organophosphate insecticide, and the at least one monomer; and
forming a microcapsule, the monomers forming a polymer, the polymer forming a wall, wherein the wall at least partially encompasses a portion of the insecticide, forming said microcapsule, the wall having an average thickness of between about 5 nm to about 10 nm, said microcapsule having an average diameter in the range of about 2 microns to about 3 microns; wherein the polymer is formed by an interfacial polycondensation between at least one oil soluble monomer selected from the group consisting of: diisocyanates, polyisocyanates, diacid chlorides, poly acid chlorides, sulfonyl chlorides and chloroformates; and at least one water soluble monomer selected from the group consisting of: diamines, polyamines, water soluble diols and water soluble polyols.
9. The method of synthesizing an insecticidal particle formulation according to claim 8 , wherein the organophosphate pesticide is selected from the group consisting of acephate, azinphos-mehyl, chlorfenvinphos, chlorethoxyfos, chlorpyriphos-methyl, diazinon, dimethoate, disulfoton, ethoprophos, fenitrothion, fenthion, fenamiphos, fosthiazate, malathion, methamidophos, methidathion, omethoate, oxydemeton-methyl, parathion, parathion-methyl, phorate, phosmet, profenofos, and trichlorfon.
10. The method of synthesizing an insecticidal particle formulation according to claim 8 , wherein said organophosphate pesticide is chlorpyrifos.
11. The method according to claim 10 , wherein said microcapsule includes between about 15 wt. percent to about 35 wt. percent chlorpyrifos.
12. A method of controlling an insect population, comprising the steps of:
providing a insecticidal microcapsule formulation, the microcapsule including:
an organophosphate insecticide; and
a polymer; the polymer forming a wall which at least partially encapsulates the organophosphate pesticide to form a microcapsule, the wall having an average thickness of between about 5 nm to about 10 nm, said microcapsule having an average diameter in the range of about 2 microns to about 3 microns; and
applying said encapsulated insecticide to an insect population or to an area adjacent to an insect population; wherein the polymer forming said wall is formed by an interfacial polycondensation between at least one oil soluble monomer selected from the group consisting of: diisocyanates, polyisocyanates, diacid chlorides, poly acid chlorides, sulfonyl chlorides and chloroformates; and at least one water soluble monomer selected from the group consisting of: diamines, polyamines, water soluble diols and water soluble polyols.
13. The method of controlling an insect population according to claim 12 , where
the organophosphate insecticide is selected from the group consisting of: acephate, azinphos-mehyl, chlorfenvinphos, chlorethoxyfos, chlorpyriphos-methyl, diazinon, dimethoate, disulfoton, ethoprophos, fenitrothion, fenthion, fenamiphos, fosthiazate, malathion, methamidophos, methidathion, omethoate, oxydemeton-methyl, parathion, parathion-methyl, phorate, phosmet, profenofos, and trichlorfon.
14. The method of controlling an insect population according to claim 12 , wherein said organophosphate pesticide is chlorpyrifos.
15. The pesticidal formulation, according to claim 1 , wherein the capsule wall comprises a polymer of polymethylene polyphenylisocyanate.
16. The pesticidal formulation according to claim 1 , wherein the capsule wall has an average thickness of about 5 nm.
17. The pesticidal formulation according to claim 1 , wherein the microcapsule has an average diameter in the range of about 3 microns.
18. The pesticidal formulation according to claim 1 , wherein the microcapsule has an LC 50 for initial control of a non-chewing pest equal to or better than that of a similar rate of pesticide applied as an emulsion.
19. The pesticidal formulation according to claim 1 , wherein the microcapsule has an LD 50 for initial control of a non-chewing pest of 2000 mg/kg or greater.