Controlled-diffusion semiochemical composition

Abstract

The present invention describes a new technology for the formulation of semiochemicals in wick diffusers particularly effective in controlling the diffusion of semiochemicals over periods of several months regardless of the outside temperature.

Claims

1. An insect pheromone liquid formulation comprising: a) 20% to 90%, by volume, of ethanol, based on total volume of the formulation, b) 0.1% to 10%, by weight based on total weight of the formulation, of at least one insect pheromone whose boiling temperature is greater than 180° C. at atmospheric pressure, c) 0.1% to 10% by weight based on total weight of the formulation of a polymer whose solubility in ethanol is greater than 10% (w/v) at 70° C. and less than 1% (w/v) at 20° C., d) 0 to 40% by weight based on total weight of the formulation of ethyl acetate or isoamyl acetate, e) 0 to 5% by weight based on total weight of the formulation of antioxidant, wherein the polymer is a PMMA-PABu-PMMA triblock acrylic block copolymer.

2. The formulation according to claim 1, wherein the antioxidant is selected from vitamin E, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and mixtures thereof.

3. The formulation according to claim 1, wherein the insect pheromone is selected from red palm weevil pheromone, banana weevil pheromone, click beetle pheromone, olive fly pheromone, codling moth pheromone, husk fly pheromone, Eudemis pheromones, vine moth pheromones, sordidin, ferrugineol, ferrugineone, sordinin, codlemone and mixtures thereof.

4. The formulation according to claim 1, wherein the insect pheromone is selected from lepidopteran sex pheromones, coleopteran pheromones, dipteran pheromones and mixtures thereof.

5. The formulation according to claim 1, wherein the insect pheromone b) is sordidin and the compound d) is isoamyl acetate.

6. The formulation according to claim 1, wherein the insect pheromone b) is ferrugineol or codlemone and the compound d) is ethyl acetate.

7. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 1, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

8. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 2, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

9. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 3, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

10. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 4, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

11. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 5, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

12. A diffuser comprising: a tank with an opening, a formulation as claimed in claim 6, a cap closing the tank and having an opening, a diffusion means passing through the cap and having a portion in contact with the formulation and the other portion extending above the cap; said diffusion means allowing migration of the formulation from the portion in contact with the formulation to the portion extending above the cap and allowing evaporation of the formulation.

13. A method for protecting a crop against insect pests, comprising applying a formulation according to claim 1 in the proximity of the crop.

14. A method for protecting a crop against insect pests, comprising placing a diffuser according to claim 7 in the proximity of the crop.

Description

EXAMPLES

Example 1

(1) Material and Method of Manufacture

(2) The diffusers consist of commercial PET bottles with a capacity of 50 ml, capped by a polyamide or polypropylene wick holder.

(3) The wicks used are commercial so-called “wood composite” wicks purchased for example from the company Shanghai Prima.

(4) Additive polymers are Nanostrength block copolymers manufactured by Arkema. The item numbers of these products are: Nanostrength M22 and M53 (both corresponding to an acrylic block copolymer consisting of a central block of poly(butyl acrylate) surrounded by two blocks of poly(methyl methacrylate)).

(5) The cold and hot solubilities of these polymers in ethanol are given in the following table:

(6) TABLE-US-00001 M22 ® M53 ® Solubility at 19° C. (% by weight)  0.022%  0.045% Solubility at boiling point (70° C.)  >15%  >10% (% by weight)

(7) The polymers M22® and M53® therefore meet the definition of the invention. They have the feature of not being cold soluble (therefore not viscosifying the solution when cold, but viscosifying the solution when hot).

Example 2

(8) The formulations in the following examples are manufactured using the following process: A mixture containing the mixture of pheromone and pheromone synergizing compound in alcohol is prepared in a round-bottom flask. This mixture is heated to 40° C. and then the desired amount of polymer additive is added and kept stirred at 40° C. until the polymer is completely dissolved. The temperature of the mixture is then returned to room temperature. The bottles are then filled with 24 g or 48 g per bottle and capped with the wick holder, the wick and the screw cap.

(9) The following table summarizes the mixtures that were manufactured according to the invention under these conditions:

(10) TABLE-US-00002 Example 2A 2B 2C 2D 2E 2F 2G* Pheromone Ferrugineol Ferrugineol Ferrugineol Ferrugineol Sordidin Codlemone Ferrugineol Pheromone Ethyl Ethyl Ethyl Ethyl Isoamyl Ethyl Ethyl synergizing acetate acetate acetate acetate acetate acetate acetate compound alcohol (g) 17.61 17.52 17.36 16.89 19.76 19.51 17.61 Pheromone 5.87 5.84 5.79 5.63 6.59 19.51 5.87 synergizing compound (g) pheromone(g) 0.94 0.93 0.93 0.90 0.13 7.80 0.94 Polymer M53 0.12 0.23 0.46 1.13 0.26 0.39 0 (g) Tocopherol 0.47 0.47 0.46 0.45 0.26 0.78 0.47 total (g) 25 25 25 25 27 48 25 *not of the invention

(11) It can be seen in Examples 2C and 2D that the formulations are clear at 40° C. but show a slight haze at 20° C. which is characteristic of the limited solubility of polymers at temperatures of the order of 20° C.

Example 3

(12) Comparison of Evaporation Kinetics as a Function of Composition in Ventilated Ovens

(13) In order to compare the evaporation kinetics, we have placed bottles corresponding to the solutions in Examples 2A-2D and 2G in 2 ventilated ovens. The first oven is set at 30° C. and the second at 40° C.

(14) We regularly measure the weight of each bottle by weighing and deduce the amount evaporated since the beginning of the experiment. The half-lives and corresponding to 90% diffusion are reported in the following table.

(15) TABLE-US-00003 Example 2A 2B 2C 2D 2G 40° C. T50 (d) 48 68 94 149 3 T90 (d) 96 154 232 296 7 30° C. T50 (d) 61.00 82.00 109 168.00 15.00 T90 (d) 133.00 189.00 272 365.00 30.00

(16) This table shows that the durations of formulations with the polymer M53 all have half-lives of more than 2 months regardless of oven temperature, whereas the formulation without polymer (2G) evaporates in fewer than 10 days.

(17) We also observe that the difference in evaporation at 30° C. and 40° C. for these formulations is no more than 50%, whereas the formulation 2G evaporates 5 times faster at 40° C. than at 30° C. It is another interest of the invention to limit the differences in diffusion time as a function of temperature.

Example 4

(18) Example of Red Weevil Trapping with Diffusers Filled with Formulation 2B

(19) Wick diffusers containing the solution are placed in 5 water-filled pitfall traps on 21 Mar. 2017. They are placed 10 meters from palm trees infested with red weevils. The diffuser is replaced on 12 Sep. 2017.

(20) TABLE-US-00004 Month (2017) April May June July August September monthly 4.7 8.4 8.2 7.9 13.2 14.4 average per trap

(21) We note that trapping has increased from the beginning of the experiment until 12 Sep. 2017 when the diffusion bottles were changed. This shows that the diffusion time in real conditions is more than 4.5 months.