WO2000018235A1

WO2000018235A1 - Method of sugarcane flower inhibition and new composition

Info

Publication number: WO2000018235A1
Application number: PCT/EP1999/007787
Authority: WO
Inventors: Robert Carlisle Ligon; Juan Carlos Toledo Rivera
Original assignee: Aventis Cropscience S.A.
Priority date: 1998-09-29
Filing date: 1999-09-27
Publication date: 2000-04-06
Also published as: AU1039000A; AR020669A1; PE20000996A1; PA8483201A1

Abstract

A method of substantially prohibiting flowering in sugarcane comprising applying a composition comprising 2-chloroethylphosphonic acid. A new composition comprising chloroethylphosphonic acid.

Description

METHOD OF SUGARCANE FLOWER INHIBITION AND NEW COMPOSITION

The present invention relates to a new method of the treatment of sugarcane and a method of substantially inhibiting flowering in sugar cane. It also relates to a new composition for use in sugarcane.

It is known in the production of sugarcane that it has been a long-established need to maximize the amount of sugar produced by sugarcane plants. It has also been known that the process of flowering of the sugar cane substantially reduces the amount and quality of the sugar produced by the said cane. Sugarcane which has gone through a flowering process also has a consistency and texture which makes it difficult to extract the sugar therefrom.

It is a long-standing problem in aerial spraying of phytoprotection products for the improved health of plants and crops to provide lower volumes of spray so as to make those application^'processes more efficient. One means to accomplish this task is to apply phytoprotection products as ultra-low-volume compositions (referred to in the present description and claims as a "ULV" composition) in an oil, particularly a vegetable oil. An advantage of this approach is to provide a composition which will not evaporate rapidly upon atomization from a spray nozzle, as is generally the case with water. Generally vegetable oils used in such an application have higher vapor pressures than water.

It is known that 2-Chloroethylphosphonic acid, commonly known as ethephon may be applied to plants as a plant growth regulator. This compound and its use are described inter alia in The Pesticide Manual 11^th edition, 1997, British Crop Protection Council, page 477 and in US Patent No. 3 879 188.

An object of the present invention to provide a new composition comprising 2- chloroethylphosphonic acid.

Another object of the present invention is to provide a new ULV composition comprising 2-chloroethylphosphonic acid. Another object of the present invention is to provide a method of increasing the amount of sugar produced per unit area of land.

An object of the present invention is to provide a new method of preventing flowering in sugarcane. Another object of the present invention is to provide sugarcane that is of a substantially better consistency to extract in a sugar processing mill.

These and other objects are met in whole or in part by the present invention.

The present invention provides a method of substantially prohibiting flowering in sugarcane, which method comprises applying a composition comprising 2- chloroethylphosphonic acid or an agriculturally acceptable salt thereof or an agriculturally acceptable ester thereof during a period of flowering induction of the said sugarcane. By the term "substantially prohibiting flowering" is meant that a majority of the sugar cane plants treated in a field of sugarcane plants do not flower. Generally according to the invention about from 5 to 30% of the sugarcane flowers, more preferably from 10 to 25%.

The period of induction is generally when there is sunlight on the said cane during a period of from 10 to 14 hours per day, preferably from 11 to 13 hours per day. The period of induction is about 45 days. More preferably, the period of induction will generally begin after the summer solstice, that is when the number of hours of sunlight per day is generally decreasing in the northern hemisphere.

Although the calendrical time will vary by latitude, in general the regions of the world that this will take place for sugarcane are between 20° north and 20° south of the equator, for example, in Central America north of Ecuador, For example, in Guatemala the period of induction is from about July 20 to September 1, preferably from about July 30 to about August 25. Other applicable countries include Mexico, Honduras, El Salvador, Nicaragua, Costa Rica and Panama.

The said cane generally has from 4 to 8 nodes, preferably from 5 to 7 nodes, preferably 6 nodes. An node is generally known as a segment of the sugarcane main stem which is defined by two rings around the stem. Most preferably the cane is the variety CP-722086 or CP-731547. In general, 2-chlorophosphonic acid is generally applied at a rate from 400 to 1000 grams of active ingredient per hectare, preferably from 500 to 800 grams per hectare, most preferably from 500 to 720 grams per hectare. The active ingredient is most preferably used as the commercial product Ethrel® and is applied by aerial application. The active ingredient may be applied as an aqueous or oil-based composition. It also may be applied as an ultra-low volume application.

The present invention also provides a method of increasing the weight of harvested sugarcane per hectare, which method comprises the application of 2- chlorophosphonic acid during the period of flower induction and according to the preferred features hereabove recited. Generally, there is an increase in the amount of harvested sugarcane from 5 to 25 tons per hectare, preferably from 10 to 20 tons per hectare.

The present invention also provides an agriculturally acceptable liquid composition comprising 2-chloroethylphosphonic acid or an agriculturally acceptable salt thereof, water, and a hydrophilic organic solvent. Preferably, the composition has a viscosity acceptable for application from an airplane or ground-based spray unit. Preferably the composition contains substantially no hydrophobic solvents. By the term "substantially no hydrophobic solvents" is meant that the composition contains less than 2% by weight of hydrophobic solvents, preferably less than 1% by weight. This composition is a preferred embodiment of an ultra-low volume formulation w

Generally, the solvent is a polyhydroxylated solvent. It may also be a humectant. By the term "humectant" is meant a material that is generally hygroscopic and is substantially non-volatile at atmospheric pressure. By the term non-volatile is meant that the boiling point of the humectant at 760 mm Hg is greater than 200°C. By the term hygroscopic is meant a material that generally absorbs water from the atmosphere at from 50% to 90% relative humidity. Generally a humectant is a approved additive according to the United States Code of Federal Regulations, 40 CFR Chapter 1 (Edition of July 1, 1995) subpart D, Section 180.1001. It is assumed that the skilled addressee has access to the Chemical Abstracts and the Federal Register.

Preferably the solvent contains from two to ten hydroxy groups, preferably from three to five hydroxy groups. A hydroxy group is generally known as an "OH" radical on an a organic compound. Preferably the solvent contains from 3 to 6 carbons. Most preferably the solvent is glycerol.

Generally the viscosity of the composition is from 5 to 1500 centipoise (cps), preferably from 10 to 1000 cps, more preferably from 10 to 100 cps. The viscosities are Brookfield viscosities measured with a viscosimeter in the form of a flat palate rotating at 20 rounds per minute. In another embodiment, the composition of the present invention when having a viscosity greater than 500cps may be psuedo-plastic or thixotropic.

Most preferably, the solvent is substantially non-toxic to mammals. The weight percentage of the 2-chloroethylphosphonic acid in the composition is certainly variable, but in general, it is preferable to have the concentration of the active ingredient as high as possible. It is generally from 5 to 50% by weight, preferably from 10 to 30% by weight. It generally contains from 100 to 500 g/L, preferably from 200 to 400 g/L of 2-chloroethylphosphonic acid when measured on a weight/volume basis. The present invention provides a method of substantially prohibiting flowering in sugarcane, which method comprises applying an ultra-low-volume composition comprising 2-chloroethylphosphonic acid or an agriculturally acceptable salt thereof or an agriculturally acceptable ester thereof during a period of flowering induction of the said sugarcane. By the term "substantially prohibiting flowering" is meant that a majority of the sugar cane plants treated in a field of sugarcane plants do not flower. Generally according to the invention about from 5 to 30% of the sugarcane flowers, more preferably from 10 to 25%).

The period of induction is generally when there is sunlight on the said cane during a period of from 10 to 14 hours per day, preferably from 11 to 13 hours per day. The period of induction is about 45 days. The said cane generally has from 4 to 8 nodes, preferably from 5 to 7 nodes, preferably 5 nodes. An node is generally known as a segment of the sugarcane main stem which is defined by two rings around the stem.

In general, 2-chlorophosphonic acid is generally applied at a rate from 400 to 1000 grams of active ingredient per hectare, preferably from 500 to 800 grams per hectare, most preferably from 500 to 720 grams per hectare and is applied by aerial application. It has been unexpectedly found that the composition of the invention may be applied to sugarcane in order to improve the plant growth promotion of the treated sugarcane as compared to the conventional route of application of 2- chloroethylphosphonic acid. The volume of application is from 1 to 10 L of composition per hectare.

The present invention also provides a method of increasing the weight of harvested sugarcane per hectare, which method comprises the application of 2- chloroethylphosphonic acid during the period of induction and according to the preferred features described above. Generally, there is an increase in the amount of sugarcane from 5 to 25 tons per hectare, preferably from 10 to 20 tons per hectare.

The following examples illustrate the invention:

EXAMPLE 1

A homogenous composition is prepared containing:

24.7kg of a composition containing 75% 2-chloroethylphosphonic acid, 17% water and 8% inactive hydrophilic phosphorous byproducts is mixed with 75.3 kg glycerol. The composition has a viscosity of about 800 cp. at ambient temperature.

EXAMPLE 2 Sugarcane in a field is grown up to a height of about 5 to 7 nodes. During a period of time wherein there is about 12 hours of sunlight per day, the composition of Example 1 is applied at a rate of 720 grams per hectare. It is observed that the droplets of the composition generally stick to the leaves of the sugarcane and do not drain off immediately. There is an economic advantage to the grower as a result of the application

EXAMPLE 3 A sugarcane plantation containing plants of the variety CP-722086 was grown up to a height of from 5 to 7 nodes during a period when there was about 12 hours a day of sunlight which was the optimum period for sugarcane flowering. An aqueous composition comprising 2-chlorophosphonic acid as the commercial product Ethrel® was applied to the field by airplane at rates of 600 and 720 grams per hectare. For both rates about 10% of the sugarcane flowered vs. 85% for the untreated check.

EXAMPLE 4

Example 3 was repeated in replicated trials. Flowering was reduced an average of 70% versus untreated fields and the amount of sugarcane harvested was about 14 tons more per hectare than the untreated fields.

EXAMPLE 5

Example 3 is repeated using the composition of Example 1. Flowering is reduced about 70% versus untreated fields and the amount of sugarcane harvested is as good or better than the yield of sugarcane using Ethrel and better than the untreated fields. There is economic benefit to the grower.

Claims

1. A method of substantially prohibiting flowering in sugarcane, which method comprises applying a composition comprising 2-chloroethylphosphonic acid or an agriculturally acceptable salt thereof or an agriculturally acceptable ester thereof during a period of flowering induction of the said sugarcane.

2. The method according to Claim 1 wherein the period has sunlight from 10 to 14 hours per day, preferably from 11 to 13 hours per day.

3. The method according to Claim 1 or Claim 2 wherein the sugarcane has from 4 to 8 nodes, preferably 5 to 7 nodes, most preferably 6 nodes.

4. The method according to any one of the foregoing claims wherein the sugarcane is the variety CP-722086 or CP-731547.

5. The method according to any one of the foregoing claims wherein the 2-chloroethylphosphonic acid is applied at a rate of 400 to 1000 grams per hectare, preferably 500 to 800 grams per hectare, most preferably from 500 to 720 grams per hectare.

6. The method according to any one of the foregoing claims wherein from 5 to 30%) of the cane so treated flowers, preferably from 10 to 25%).

7. The method according to any one of the forgoing claims wherein the composition is applied by aerial application.

8. The method according to any one of the foregoing claims is an ultra- low volume formulation.

9. An agriculturally acceptable liquid composition comprising 2- chloroethylphosphonic acid or an agriculturally acceptable salt thereof, water, and a hydrophilic organic solvent.

10. The composition of claim 9 wherein the viscosity is acceptable for application from an airplane or ground-based spray unit.

11. The composition according to any one of claims 9- 10 which contains substantially no hydrophobic solvents.

12. The composition according to any one of claims 9-11 wherein the solvent is a polyhydroxylated solvent.

13. The composition according to any one of claims 9-12 wherein the viscosity is from 10 to 1000 cpoise, preferably from 300 to 900 cpoise.

14. The composition according to any one of claims 9-13 wherein the solvent is essentially non-toxic to mammals.

15. The composition according to any one of claims 9-14 wherein the solvent is glycerol.

16. The composition according to any one of claims 9-15 wherein the composition by weight contains from 10 to 50 percent of 2-chloroethylphosphonic acid.

17. The composition according to any one of claims 9-16 wherein the amount of 2-chloroethylphosphonic acid is from 100 to 500 g/L.

18. A method of increasing the sugar content of sugarcane plants comprising applying the composition as defined in any one of claims 9-17.

19. The method according to claim 18 wherein the composition is applied at a rate from 1 to 10 liters per hectare.

20. The method according to claim 18 or claim 19 wherein the composition is applied at a rate from 200 to 1000 g/Ha.

21. The method according to claim 8 wherein the ultra-low volume formulation is as defined in any one of claims 9-17.