WO1990014896A1

WO1990014896A1 - Active material dispersal system

Info

Publication number: WO1990014896A1
Application number: PCT/AU1990/000231
Authority: WO
Inventors: Henry Jonathan Banks; Brian Sydney Fletcher; Richard James Milner; Thomas Edward Bellas; Christopher Playford Whittle; Richard Alan Vickers; Michael James Lacey
Original assignee: Commonwealth Scientific And Industrial Research Organisation
Priority date: 1989-05-31
Filing date: 1990-05-31
Publication date: 1990-12-13

Abstract

An active material dispersal system for an agricultural site comprising a source of gaseous or vapourisable active material such as pheromone, a source of pressurised carrier gas and a plurality of outlets in fluid communication with the source of active material and the pressurised carrier gas for dispersing the active material in gaseous or vapour form at or near the agricultural site.

Description

ACTIVE MATERIAL DISPERSAL SYSTEM

Technical Field

This invention relates to an active material dispersal system for use at an agricultural site.

Background Art

Various techniques are available for the dispersal of agricultural chemicals at sites such as orchards, citrus groves, plantations, vineyards, crops and the^' like.

One conventional method for the dispersal of active material such as pesticides or insecticides involves dissolving or dispersing the active material in water and spraying the resulting suspension or solution onto the target site. Although this method clearly has its uses, it is not suitable for all treatments nor all active materials. For example the activity of the material may depend on it existing in the form of a vapour or gas in the atmosphere for a finite or sustained period. An obvious disadvantage of the spray technique is that at least some of the active material will find its way to the soil, plants or produce. Accordingly it is desirable to have a system which is capable of dispersing the active material into the atmosphere as a gas, vapour, fine mist or aerosol so that the material can come into contact with pests and the like, with minimum contamination of soil, plants or produce. It would also be advantageous to have a system which provides for more efficient use of high cost materials.

Sex attractant pheromones are examples of vapourisable active material which are normally dispersed in the atmosphere as a vapour in very low concentrations. One device for the sustained release of a vapour of these pheromones comprises a tube made of a plastic such as polyethylene which is sealed at both ends and which contains the pheromone compound or compounds and sometimes other components, in liquid form. The pheromone is capable of permeating through the walls of the tube to provide a release of the pheromone in vapour form over a period. These pheromone containing tubes, may be placed at strategic points at the site, for example by attachment to trees or plants. A disadvantage of this dispensing system is that the active material is exposed to the elements. Thus the active material may lose its activity over time as a consequence of degradation of the material caused by exposure to UV light, oxygen or moisture. Furthermore, evolution is continuous and is not controllable at will.

Disclosure of the Invention

It is an object of the present invention to provide an alternative active material dispensing system which is suitable for use at' n agricultural site.

Accordingly, in one form the present invention provides an active material dispersal system for use at an agricultural site comprising:-

a source of active material which is capable of being fluidised;

a source of a pressurised carrier gas; and

a plurality of outlet means for dispersing said active material in fluid form in said carrier gas said plurality of outlet means being in fluid communication with said source of carrier gas and said source of active material.

Preferably the carrier gas is substantially inert with respect to the active material. Examples- of suitable carrier gases are nitrogen, carbon dioxide. Air may be used for materials not subject to oxidation.

By "agricultural site" we mean any site where plants or trees are grown whether for profit or recreation.

The active material may be a biologically active chemical. It may be a material capable of altering the behaviour or growth of insects or other organisms, for example, fungi.

The supply of carrier, gas may be separate from the supply of active material. Preferably there is a source of active material located adjacent to each outlet. Alternatively, the active material may be contained in the same container as the carrier gas.

Preferably the outlet means is designed to prevent backflow of oxygen into the system. Examples of suitable outlet means are a pressure actuated valve or a restriction opening such as a capillary tube.

The system of the invention is particularly adapted for controllable output in response to environmental stimuli such as atmospheric temperature, day length, light intensity, moisture level or wind velocity. The output may be controlled by, for example, rate of flow and/or rate of vapour generation. Control of rate of flow may, for instance, be achieved by varying gas pressure or regulation by a combination of pressure and outlet characteristics (e.g. diameter of orifice or capillary) .

Accordingly in a further form a present invention provides the system as described above and also including one or more sensing means for control of the output of active material.

The one or more stimuli sensed by the sensing means may be inputted to a microprocessor adapted to control the dispersal system in terms of duration of dispersal, time of dispersal and/or amount of material dispersed per unit time.

The system may also include a timer which ;Ls adapted to control the time and/or duration of dispersal of active material by the system.

In yet a further form the present invention provides an active material dispersal system for an agricultural site comprising:

a' source o.f a pressurised carrier gas;

a source of active material;

one or more distribution conduits located at preselected position(ε) on or near said site and in fluid communication with said source of carrier gas and said source of active material; and

one or more outlet means disposed at predetermined poεition(ε) on said site for dispersing said active material in said carrier gas, said outlet means being in fluid communication with said one or more distribution conduits.

The distribution conduits may be any suitable form of piping. Flexible plastic piping is preferred. Particularly preferred is piping made from a material which is substantially impervious to oxygen, for example, nylon.

The present invention is particularly suitable for the dispersal of gaseous or vapourisable active materials. For example the active material may be a volatile compound such as an insect growth regulator or fungicide. Accordingly, in a still further embodiment the present invention provides an active material dispersal apparatus for use at an agricultural site comprising:

a source of gaseous or vapourisable active material;

a source of a pressurised carrier gas; and

one or more outlet means for dispersing said active material in said carrier gas, said outlet means being in fluid communication with said source of active material and source of carrier gas.

In another embodiment, the present invention provides a method of dispersing an active material at a site wherein said active material is dispersed at one or more preselected locations on or near said site, characterised in that the active material is dispersed at a controlled rate at the or each location in admixture with a carrier gas. The site may be an agricultural site.

The present invention also provides apparatus for use in the method of the invention said apparatus comprising:

a source of pressurised carrier gas;

dispenser means for containing a source of active material;

One or more distribution conduits located at pre-εelected position(ε) on or near said site and in fluid communication with said dispenser means and said source of active material; and One or more outlet means adapted to prevent substantial backflow of air into said system disposed at pre-determined position(s) on εaid εite for diεpensing said active material and said carrier gas, said outlet means being in fluid communication with said one or more diεtribution conduits.

In the case of dispersal at a number of locations, the active material/carrier gas mixture may be provided by a network of outlets connected to .a single source of active material and carrier gaε or there may be individual dispersal units at each location.

The system of the present invention is particularly suitable for the dispersal of photolabile or rapidly oxidisable active materials such as the synthetic sex pheromone composition of co-pending application number PCT/AU87/00396 (hereinafter referred to as "Codlemone") -the disclosure of which is incorporated herein by reference. The pheromone may be a composition trans, trans-8,10, dodecadien-1-ol and at leaεt one additional component selected from dodecanol and/or tetradecanol, and optionally a carrier material. We have found that when using the conventional permeation tube dispenser system referred to above, the activity of the pheromone composition decreases over time. We believe that this may be caused by the isomerisation and oxidation of double bonds in the active component as a result of exposure to UV light and oxygen in the air.

The apparatus, system and method of the present invention provides a controlled, constant supply of pheromone to a locus in circumstanceε where the source of pheromone is protected from the adverse effects of the elements such as UV light and oxygen. The invention will now be more particularly described with reference to the disperεal of pheromone, however it is emphaεiεed that the invention is not reεtricted to thiε particular active material nor is the following description to be read as limiting the generality of the invention in any way.

The invention will now be described in reference to the accompanying Figures in which:

Brief Description of Drawings

Figure 1 is a schematic representation of an active material disperεal εyεtem in accordance with, the preεent invention;

Figure 2 is a εchematic representation of one form of active material source which may be used with the present invention;

Figure 3 is another form of active material source which may be used with the invention;

Figure 4 is a further form of active material source which may be used in accordance with the invention; and

Figure 5 is yet a further example of an active material source for use with the present invention.

Figure 6 is a schematic representation of a further dispersal system in accordance with the invention;

Figure 7 is a plot of log counts at 24°C, 200mL/min flow rate of pheromone composition against days of operation.

Figure 8 is a plot of pheromone composition release from a controlled release device in accordance with the invention versus carrier gas flow. Figure 9 is a plot of release rates for a number of controlled release devices in a field versus air temperature.

Figure 10 is a table showing release rates , for a single controlled release device at various temperatures.

Modes for Carrying out the Invention

Figure 1 shows a schematic diagram of a crop or plantation wherein trees or plants 20 are set out in rows. Carbon dioxide in pressurised container 1 is supplied to a network of outlets located at preselected sites within the crop or plantation. The carrier gas is supplied to the system via a pressure or flow regulator 2. .. The regulator 2 may be manually controlled or it may be controlled via a control loop 4 in response to signals produced by a timer and/or sensor 3. The system may be microprocessor controlled. The carrier gas is supplied to the network of outlets through a main gas line 5 and reticulated through the crop or plantation via nylon piping network 6.

The outlets of the system may be located in any desirable configuration. For example outlets may be located at selected plants along a line of plants (7). Alternatively there may be an outlet at each plant (8) or there may be a line with multiple outlets at selected positions in selected trees or^' plants (9).

The outlets may be a combination of (7), (8) and (9) and/or there may be one or more outlet(s) outside the periphery of the crop or plantation at (10).

The pheromone source may be located in or near the gas source 1 or it may be positioned adjacent to the, or each, outlet so that the carrier gas passes over or through a source of the active material. One or more active material sources may be used to supply each outlet. Various forms of active material dispenεers are shown in Figures 2 to 5.

Figure 2 shows a dispenser wherein the pheromone is contained in dispenser 30 such as permeable capillary dispenser referred to previously and located in a cartridge 29 fabricated from a lightproof material or coated with a UV screening material and provided with gas inlet 39 and outlet 40.

Alternatively the active material may be used as a free liquid or solution 31 at the base of the chamber 29 as shown in Figure 3 such that the active material and vapour formed above the liquid is entrained with the carrier gas.

Figure 4 shows a further means of active material supply wherein the carrier gas is bubbled through the liquid active material or solution thereof 32, or a mixture of the active material with a solvent (to lower the melting point of the active material) so that the vapouriεed material iε entrained in the carrier gas.

Figure 5 shows yet a further form of active material source where a concentrate of the active material 38 iε applied to an evaporative surface 36.

Heating meanε may be provided to heat the carrier gaε or εource of active material so as to control the rate of evaporation of active material.

The outlet of the system 35 may be a pressure opening valve or a restricted outlet such as a glass capillary. A capillary having an internal diameter of 0.05 to 1 mm may be used.

As mentioned above the dispersal syεtem of the invention is particularly uεeful for the release of pheromones. In the case of control of codling moth .(Cydia pomonella ) using the pheromone composition of co-pending application PCT/AU87/00396 ) a disperεal rate greater than c_a 2 mg per hectare per hour is preferred. Dispersal rates in the range of ca 2mg-20mg per hectare per hour may be suitable, ispersal rates in the range 5mg-20mg are particularly preferred.

In a particular embodiment a pressurised gas supply 70 (for example Nitrogen) is connected by 6.4mm (nominal 1/4") nylon pressure tubing to a manifold 75 having forty outlets 80 (see figure 6). The length of the lines between regulator 90 and tree 100 .is kept constant to give constant output. Alternatively flow may be regulated by needle valves. Each outlet consists of a capillary leak of 0.2mm diameter and 32mm length and is connected in turn to an opaqued glass tube (150mm x 15mm) by 15m lengths of 3.2mm (nominal 1/8" nylon) pressure tubing (i.e. sleeved with black plastic to prevent photodegradation of the pheromone source) . Each glass tube opens to the atmosphere through a 32 mm length of 0.2 mm diameter capillary. The glass tubes contain a source of "Codlemone" (for example a wick soaked in Codlemone). The pressurised gas εupply is regulated (approx. 140kPa) such that the flow of gas through each outlet is about 200mL/min. The amount ( ) of Codlemone emitted from each dispenser obeys the following relationshipε:-

log(Q)« /T at constant flow « F at constant temperature

where T is the absolute temperature and F is the flow rate of the carrier gas. The amount of pheromone emitted by this system, measured at three-day intervals over a period of three months and corrected to 24°C and 200mL/min flow, is constant. In field trials dispensers emitted Codlemone at a total rate of 16mg/ha/hr (at 24°C with a carrier gas flow of 200 mL/min when placed 4/tree at 270 trees/ha) . Figure 6 iε a graph showing that the rate of release of pheromone is constant whereas figure 7 is a graph showing the amount of pheromone released from a controlled release device at various flow rates of carrier gas.

Figure 8 is a graph showing the dependency of release rate on air temperature for controlled release devices at a release rate.

Figure 9 is a table showing the release rate/temperature relationships for a single controlled release device.

To test the syεtem obεervationε were made of male codling moth approaches to synthetic baits.

Materials and methods

Treatments

1. Four rubber tubing baits loaded with 1 mg of (E E)-8,10-dodecadien-l-ol were suspended from apple trees with wire so that the baits protruded from the foliage boundary in line with and 45 cm in front of the outlets of 4 controlled release devices (CRD's).

2. Four blank pieces of tubing were placed in front of 4 CRD's in similar faεhion to that deεcribed in treatment 1.

3. Four baits (aε deεcribed in treatment 1) were placed at least lm from and to one side of the nearest CRD, protruding from the foliage.

All baits/blanks were εuεpended from εeparate treeε.

Observations During the male flight period the number of males orienting towards and landing on or near (within 5 cm) the baits and/or the CRD's was recorded. Observations were made on one night.

Results

Treatment Mean no. Mean no Approaches landings

Bait 8.3 3.0

Bait + CRD 0.3 0.0

Blank + CRD 0.5 0.0

It will be clear to the reader that various modifications and improvements may be made for the invention without departing from the spirit and scope of the invention.

Claims

C A I M S

1. An active material diεperεal system for use at an agricultural site, εaid εyεtem comprising: -

a source of active material which is capable of being fluidised;

a source of pressurised carrier gas; and

a plurality of outlet means for dispensing said active material in fluid form in said carrier gas, εaid plurality of outlet means being in fluid communication with said source of carrier gas and said source of active material.

2. An active material dispersal syεtem for an agricultural site comprising: -

a source of pressurised carrier gas;

a source of active material;

one or more distribution conduits located at pre-selected position(ε) on or near said site and in fluid communication with said source of carrier gas and said source of active material; and

one or more outlet means disposed at pre-determined position(ε) on εaid εite for diεpenεing said active material and said carrier gaε, said outlet means being in fluid communication with said one or more distribution conduits.

3. The syεtem of claim 1 or claim 2 wherein εaid active material iε a gaseous or vaporisable material.

4. The εystem of any one of claimε the preceding claimε wherein said source of carrier gas is separate from said source of active material.

5. The εystem of any one of the claims 1 to 3 wherein εaid source of active material is located adjacent each said outlet means.

6. The method of any one of any one of the preceding claims wherein said outlet means prevent εubstantial backflow of air into said system.

7. The system of claim 6 wherein said outlet means has a restricted opening such as a capillary tube.

8. The system of claim 7 wherein said outlet means is a capillary tube having an internal diameter of from 0.05 to lmm.

9. The syεtem of claim 8 wherein said capillary has an internal diameter of about 0.2mm.

10. The syεtem of claim 6 wherein said outlet means is a presεure actuated valve.

11. The system of any one of claims of the preceding claims further including means to control active material output from said system.

12. The system of any one of the preceding claims wherein εaid εystem includes timer means adapted to control the time and/or duration of output of active material.

13. The syεtem of claims 11 or 12 wherein said means to control is responsive to environmental stimuli such as temperature, day length, light intensity, moisture level and/or wind velocity.

14. The system of claims 12 or 13 wherein said means to control is a microprocessor.

15. The system of any one of claims 11 to 14 wherein said means to control controls rate of flow and/or rate of vapour generation of said active material.

16. The system of claim 15 wherein said control of rate of flow iε achieved by varying the carrier gas pressure.

17. The system of any one of the preceding claims wherein said εource of active material is contained within one or more diεpenεerε, said dispenεerε being εubεtantially opaque to UV-light.

18. The system of claim 17 wherein εaid dispenεer(ε) includes an evaporative surface.

19. The system of any one of the preceding claims wherein the active material is oxidizable or photolabile.

20. The system of any one of the preceding claims wherein said active material is a vapourisable solid or liquid.

21. The system of any one of the preceding claims wherein said active material is mixed with solvent.

22 . The system of any one of the preceding claims wherein the active material is a biologically active material.

23. The εystem of any claim 22 wherein the active material is a pesticide.

24. The system of any one of claims 22 wherein the active material is a material capable of altering the behaviour or growth of inεects or other organisms.

25. The syεtem of claim 24 wherein said active material is a pheromone.

26. The εystem of claim 22 wherein εaid active material iε an inεect growth regulator or fungicide.

27. A method of diεperεing an active material at a εite wherein εaid active material is dispersed at one or more preεelected locationε on or near εaid site, characteriεed in that the active material is dispersed at a controlled rate at the or each location in a mixture with a carrier gass.

28. The method of claim 27 wherein the active material is dispersed at a number of locations by means of a network of outletε connected to a single source of said active material and said carrier gas.

29. The method of claim 27 wherein the active material iε dispersed at a number of locations by meanε of a network of outlets wherein the εource of εaid active material is located adjacent each said outlet.

30. The method of any one of claims 27 to 29 wherein said active material is a photolabile or oxidizable material.

31. The method of any one of claim 27 to 30 wherein εaid active material is a biological active substance.

32. The method of claim 31 wherein the active material iε a pheromone.

33. The method of claim 32 wherein said pheromone is a composition comprising tranε, , trans-8, 10, dodecadien-1-ol RELEASE FROM CRD

DODECADIENOL WIT H N I TROGEN

10 20 30 0 50 60 70 80 90 100

DAYS

Release of Codlemone (measured over two minutes) from a CRD at intervals during 3 months (corrected to 24°C and carrier gas flow of 200ml/min)

CRD = Controlled Release Device Quantities expressed in gas chromatography integrator counts .

LW. 7.

SUBSTITUTE SHEET and at least one additional component selected from dodecanol and/or tetradecanol, and optionally a carrier material.

34. The method of claim 32 or 33 wherein said pheromone composition is dispersed at the rate of approximately 2-20mg per hectare per hour.

35. The method of claim 34 wherein the rate dispersal is within the range 5-20 mg per hectare per hour.

36. The method of claim 35 wherein said rate of disperεal iε approximately 16 mg per hectare per hour.

37. The method of any one of claimε 27 to^' 36 wherein εaid carrier gas flow rate is approximately 200 mL/min

38. The method of any one of claims 27 to 31 wherein said active material is a pesticide.

39. The method of claim claims 27 to 31 wherein said active material iε an inεect growth regulator or a fungicide.

40. Apparatus for uεe in the method of claimε 27 to 39 εaid apparatuε comprising:

a source of preεsuriεed carrier gas;

dispenεer means for containing a source of active material;

One or more distribution conduitε located at pre-εelected position(ε) on or near εaid εite and in fluid communication with εaid diεpenεer means and said source of active material; and

One or more outlet means adapted to prevent substantial backflow of air into said syεtem diεposed at pre-determined position(s) on said site for dispensing said active material and said carrier gas, said outlet means being in fluid communication with said one or more distribution conduits.

41. The apparatus of claim 40 wherein said outlet means has a restricted opening such as a capillary tube.

42. The apparatus of claim 40 wherein said outlet means is a capillary tube having an internal diameter of from 0.05 to lmm.

43. The apparatus of claim 42 wherein said capillary haε an internal diameter of about 0.2mm.

44. The apparatuε of claim 42 wherein εaid outlet meanε iε a presεure actuated valve.

45 The apparatuε according to any one of claims 40 to 44 wherein said dispenser means iε εubstantially opaque to UV-light

46. The apparatuε of any one of claimε 40 to 45 εubεtantially as hereinbefore deεcribed.