WO1999046986A1

WO1999046986A1 - An ant repellent

Info

Publication number: WO1999046986A1
Application number: PCT/US1999/006183
Authority: WO
Inventors: David H. Oi; David F. Williams
Original assignee: The United States Of America, Represented By The Secretary Of Agriculture
Priority date: 1998-03-20
Filing date: 1999-03-19
Publication date: 1999-09-23
Also published as: AU3107499A

Abstract

A repellent composition has been discovered for the control of social pest insects, particularly pest ants. The composition includes an alkadienal such as citral, neral or geranial and a carrier material.

Description

AN ANT REPELLENT

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to repellent compositions for the control of pest ant species. It also relates to the use of these compositions to control pest ant species.

2. Description of the Related Art

Various species of ants pose significant problems for man from both an economic and a health care point of view. In agriculture, pest ants attack cultivations and foodstuffs and can render fields and pastures unusable . Pest ants attack wooden buildings and structures in urban and rural areas. Furthermore, ants sting livestock and humans, sometimes causing death. For example, leaf-cutting ant species are a problem in Central and South America where they can defoliate a citrus tree overnight. Argentine ants endanger crops by domesticating and protecting other pest insects such as aphids and scale. Imported fire ants, Solenopsis invicta and Solenopsis richteri , are a substantial pest. Imported fire ants have plagued the United States farmers, homeowners, park directors, livestock, pets and wildlife ever since its introduction at Mobile, Alabama in 1918. When ornamental nurseries ship plants from the infested states to other uninfested areas of the country, they are required by law to take special precautions to prevent imported fire ants from moving with plants or soil . These precautions are mandated by the Federal imported fire ant quarantine regulating such nursery stock shipments and to comply with these regulations, soil is treated with insecticide. Fire ants sting humans and livestock, feed on germinating seeds and crop seedlings thereby reducing yields and

- 1 - damage farm machinery which strike ants ' mounds . This has an economic impact on agriculture in infested areas. Telephone companies spend substantial amounts of money each year on treating their electrical equipment to prevent fire ant invasion because fire ants are attracted to electrical fields and can cause short- circuits in electrical equipment. Fire ants also present a problem to wildlife, such as with ground nesting birds and animals. Furthermore, fire ants are known to excavate the soil from under roadways causing cracking and other structural damage. Pharaoh ants, Monomorium pharaonis, which are world wide household pests, thrive in wall spaces and detritus. In hospitals, they forage in soiled bandages and contaminate clean dressings, sterile I.V. tubing, and food with pathogenic microorganisms . They are very small ants and enter areas of hospitals in search of food and water. Many areas of hospitals that these ants are found in are ones that sterile conditions must be maintained such as operating rooms, critical care areas and neonatal wings. Pharaoh ants have the ability to carry at least twenty known pathogens on their bodies and therefore can be a major threat to the health of patients. Other Monomorium species are pests because of their mere presence in structures . Camponotus species or carpenter ants, form their nests in wood and other moist areas and although they do not consume the wood as termites do, they can cause structural damage. Ghost ants, Tapinoma melanocephalum, nest in potted plants, soil, gravel, aluminum doors and in organic material that collects at the base of palm fronds. Because the ants can be shipped with potted plants, they are also considered nuisance pests. Crazy ants, Paratrechina longicornis, named so because of their rapid and erratic movements, are nuisances as they collect crumbs and debris around gas stations, cafes and convenience stores. While not related to the imported fire ant, the little fire ant, Waεmannia

- 2 - auropunctata , can produce an irritating sting. They are found outdoors under bark, in rotting soil and in pine cones and have been found in clothing, food and beds indoors. Pheidole megacephala, the big-headed ant, is a pest in agricultural crops (pineapple) where it tends honeydew producing insects and protects them from natural enemies. The big-headed ants are also a pest in urban environments where large infestations often leave obvious piles of dead workers throughout the structure. Crematogaster species, a species that typically nests outdoors in hollow plant cavities, can also invade homes using branches and wires as a guideline. They have been known to short-circuit telephone wires and damage rafters, posts, shingles, insulation and fiberboard.

There is much interest in controlling pest ants . This interest has resulted in much research and resources being expended through the years to develop reagents and methods of controlling ants . While many useful insecticide formulations have resulted from this research, the problems associated with ants still exist. This is primarily because the relief gained by insecticide use is only temporary owing to the high reproductive capabilities, the efficient foraging behavior and the ecological adaptability of ants. While effective for controlling ants in relatively small defined areas, the use of insecticides, because of their toxicity, can create other problems. For example, some insecticides, which are effective for controlling ants, are banned from use because they pose a significant problem to the environment, including birds and animals. Furthermore, there is pressure from environmental groups to stop or at least substantially reduce the application of insecticides in general and to develop nontoxic reagents for controlling insects .

Ants can be excluded from areas by using chemical compounds called repellents which cause ants to either leave areas in which they are in highest concentrations or not pass across areas on which the repellents have been deposited (Shorey et al, Physiological and Chemical Ecology, Volume 22 (5) , 920-924, 1993) . Shorey et al tested a number of compounds that had been reported as alarm pheromones of ants or ant-defensive allomones elaborated by a variety of plants and animals . Some of the chemicals tested included methyl eugenol, citral, farnesol and β-citronellol as repellents for Argentine ants (Shorey et al, Journal of Chemical Ecology, Volume 18 (11) , 2131-2142, 1992) . The reference reports that farnesol is seen to be more active as a disruptant than methyl eugenol, citral or β-citronellol. In repellency tests against Formica aerata, Shorey et al (1992, supra) tested eleven chemicals that included farnesol, methyl eugenol, citral and β- citronellol (Shorey et al, 1993, supra) . For Formica aerata, the reference reports that citral, eugenol and methyl anthranilate were highly active in a 2 day experiment, reducing the number of crossing ants by 90% or greater compared with the untreated controls. They further report that in a 10 day test, the most active ingredients on days 1 to 3 after display in the field included farnesol, methyl eugenol, methyl salicylate, safrole, linalool and phytol . The reference reports that materials that were significantly inferior to these compounds were methyl anthranilate, eugenol, β-citronellol, citronellal, methyl palmitate, citral, benzaldehyde, methyl myristate, 3-carene, bornyl acetate, α-pinene, β-pinene, (s) - (-) -limonene, myrcene, and cedar wood. A third experiment shows farnesol to be more effective when used with stickem than methyl eugenol, citral and β-citronellol .

United States Patent No. 5,648,390 (Vander Meer et al) disclose a number of compounds that have repellent activity for the imported fire ant, Solenopsis invicta . These compounds include carboxylic acids such as octanoic acid, alcohols such as octanol , ketones such as 3-octene-2-one, and carboxylic acid esters such as l-nonen-3-yl acetate.

While various repellent compositions are known in the art, there remains a need in the art for highly effective repellents to improve the control of social pest insects, especially ants. The present invention provides a repellent composition and method of use which is different from related art repellents.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a repellent-containing composition for the control of pest social insects .

Another object of the present invention is to provide a repellent composition for the control of ants.

A further object of the present invention is to provide a repellent composition containing an alkadienal .

A further object of the present invention is to provide a repellent composition containing citral, (cis, trans) 3 , 7-dimethyl- 2, 6-octadienal, in amounts to be repellent to social pest insects.

A further object of the present invention is to provide a repellent composition containing repelling amounts of geranial .

A still further object of the present invention is to provide a repellent composition containing repelling amounts of neral .

A further object of the present invention is to provide a method for repelling social insects using a composition containing repelling amounts of an alkadienal .

Another object of the present invention is to provide a method for repelling social insects using a composition containing a repelling amount of citral (cis, trans) 3 , 7-dimethyl-2, 6- octadienal .

5 - A further object of the present invention is to provide a method for repelling social insects using a composition containing a repelling amount of geraniol .

A still further object of the present invention is to provide a method for repelling social insects using a composition containing a repelling amount of neral .

Further objects and advantages of the present invention will be apparent from the following detailed description.

DETAILED DESCRIPTION OF THE INVENTION

Social insects such as ants, wasps and termites have well developed foraging mechanisms. Social insect pests are treated in accordance with the invention by dispensing a repellent composition containing alkadienals in any suitable way in an area where it is necessary to prevent the presence of social pest insects .

The red imported fire ant, Solenopsis invicta; the Argentine Ant, , Linepi thema humile (formerly Iridomyrmex humilis) and the Pharaoh ant, Monomorium pharaonis, are used as a model system.

The term repellent for the purposes of this disclosure includes alkadienals in amounts effective to repel social pest insects from any desired area where social insects are a problem. Examples of alkadienals are the octadienals . The preferred octadienals are 3 , 7-Dimethyl-2 , 6-octadienal which includes the racemic mixture citral, the cis isomer-geranial and the trans isomer-neral . Citral is a constituent of oil of lemon grass and is also present to a limited extent in oils of verbena, lemon and orange. Citral is approximately 66.6% geraniol and approximately 33.4% neral. The alkadienals are used in a concentration range of from about 1% to about 50%. A preferred range is from about 20% to about 40%, with most preferred concentrations of about 25% or 33%. One of ordinary skill in the art could readily determine

- 6 - optimal concentration ranges for the repellency of any pest social insect . Amounts effective to repel social insects is defined as that amount which decreases the presence of an insect compared to a control that does not contain the repellent of the present invention. The solvent used for applying the repellent to a carrier can be, for example a vegetable oil; an organic solvent such as acetone or hexane; water, emulsifiers with water, etc.

Non-limiting examples of carriers suitable for the present invention include, for example, diatomaceous earth, alumina, silica, clays, inorganic oxides, powdered carbohydrates such as corn starch, dextrans and cellulose. The carrier may also be a solid substance, preferably one which will slowly release the repellent composition over a period of time. Non-limiting examples of slow release materials which are suitable for use herein include latex particles, capillary tubes, absorbent polymers, and microencapsulation. Of course the type of area or object to be treated and the degree of infestation in the vicinity of the area or object to be treated will dictate the type of carrier to be used. For example, when the object to be treated is a pot containing soil for nursery stock, it is preferred to use a formulation that can be easily incorporated into the soil, such as an aqueous suspension or a granular formulation.

The repellent compositions of the present invention can be combined with a solid carrier material by any appropriate means . For example, they may be combined by first dissolving or suspending the repellent in a suitable solvent or other liquid, soaking the solid carrier material with the resulting solution or suspension, thereby either impregnating the repellent into or depositing it onto, said solid carrier material, and drying said treated carrier material to drive off the solvent or other liquid. The resulting repellent material can then be applied in powder form, for example by spraying the object or area to be treated.

- 7 - The following examples are presented to illustrate the use of repellent compositions for the control of pest social insects using ants as the test model system. These examples are intended to further illustrate the invention and are not intended to limit the scope as defined by the claims .

EXAMPLE 1 Laboratory colonies of ants are maintained in nests which are plastic trays (approximately 39 cm L X 52 cm W X 12.7 cm H) coated with TEFLON 30B or FLUON on the inside walls to prevent ants from escaping. Rearing cells consist of petri dishes with a base of castone which sometimes has a water receptacle depending on the species reared. Rearing cells contain at least one queen, brood (eggs, larvae and pupae) and workers. Colonies receive a standard diet of adult house crickets and honeywater two to three times a week. Hard-boiled chicken egg is provided once a week. Colonies are maintained at 30 ± 2°C and 75 ± 10% relative humidity, with approximately 12 hour daylight cycle. A test tube filled with water and capped with a cotton ball provides moisture.

EXAMPLE 2 For testing repellent compositions, filter paper is treated with approximately 25% of the repellent in acetone. Red imported fire ants consisting of approximately 25,000 to about 30,000 workers plus brood and queens were placed into separate containers (approximately 6.5"W X 12.25"L X 3.25"H) with a nesting cell and water. Filter paper (Whatman #2, 2 X 8 cm) was treated with approximately 0.2 ml of about a 25% (volume/volume) solution of either citral, neral, geranial, or DEET in acetone. The control treatment consisted of acetone only. Citral is comprised of approximately 66.6% geranial and 33.4% neral. The DEET was used as a standard. Treated filter paper was allowed to air dry and

- 8 - then fastened around a 10 ml glass beaker with a narrow rubber band that did not conceal the treated paper. The beaker contained cotton saturated with soybean oil which is a food attractant for the ants. A single beaker was placed in each container approximately 15 cm from a nest cell. The number of ants that crossed the filter paper and were in the beaker was recorded at approximately 1, 24, 48, 72, and 96 hours. The average number of ants at each sampling time was analyzed by an analysis of variance and Tukey's HSD test. Each treatment was replicated 3 times.

For Pharaoh ants, the same procedure described above was used with the following exceptions. Each colony contained approximately 10,000 Pharaoh ant workers, plus brood and queens. Sampling times were approximately 1, 3, 48, 72 and 96 hours.

Results are presented below in Table 1. For red imported fire ants in this study, citral and its component parts did not consistently repel the ants. For Pharaoh ants, citral was repellent for 3 hours, while neral and geranial maintained repellency for 48 and 72 hours, respectively.

TABLE 1

RED IMPORTED F.A. HOURS OF CONTINUOUS EXPOSURE ACTIVE INGREDIENT 1 24 48 72 96

CONTROL (ACETONE) 102. 3A 42 .0A 31.7A 20.0AB 22.7A

CITRAL** 2. OA 22 .0A 45.7A 54.7A 63. OA

NERAL 21. 3A 7 .0A 14.7A 47. OA 41.7A

GERANIAL 13. 7A 10 .3AB 11.7A 6.3BC 33.7A

DEET 1. 3A 0 .7B 2.0A O.OC O.OB

PHARAOH . ANTS 1 3 48 72 96

CONTROL (ACETONE) 62.0A 53. .33A 62. OA 57.7A 57.7A

CITRAL 0.0B 0, .00B 44.7A 47.7A 48.0A

NERAL 0.0B 0. .33B 3.7B 70. OA 53.3A

GERANIAL 0.0B 0. .00B O.OB 1.3B 51.3A

DEET 0.0B 0. .00B O.OB 1.0B 2. OB

♦Means followed by the same letter within a column for each ant species are not significantly different (P>0.05) by Tukey's HSD Analyses were performed on transformed counts (loglO (X + 1) ) , untransformed means are presented

**Citral is comprised of approximately 66.6% geranial and 33.4% neral .

EXAMPLE 3 Natural product compounds were examined for repellency to colonies of red imported fire ants and Argentine ants . Compounds evaluated were dry dust formulation of a fragrance oil, neem cake, which is a dry by-product of neem seed oil extraction; citral; and farnesol . The latter two compounds were formulated onto an absorbent polymer, Culigel^®, at about 33% and 40% active ingredient by weight, respectively. All compounds were applied in a single layer of approximately Y-≥ tsp to the bottoms and tops of pots, 2 inch pots of approximately 5 cm L X 5 cm W X 5 cm H, filled with standard potting media used by the USDA/APHIS Imported

- 10 - Fire Ant Station and then saturated with water. Ten pots of each compound and an untreated control were exposed individually to small groups of fire ant workers and brood (approximately 500 workers and 1/4 teaspoon brood; 1 pot per groups of ants) for four days and then examined for infestation. Uninfested pots were replaced with untreated pots to ensure ants were still able to infest pots after the exposure period. Treatments with less than about 30% infestion were replicated four additional times (10 pots per replicate) with mean percent infestation analyzed by analysis of variance and Tukey's HSD test. Treatments with less than about 30% mean infestation were then exposed to groups of Argentine ants following the same procedures used with fire ants .

Results are reported in Tables 2-5 below. None of the citral treated pots were infested by either red imported fire ants or Argentine ants . All groups of ants that did not infest treated pots were able to infest untreated pots after the 4 day exposure period. The Culigel^® carrier by itself was not repellent to either ant species .

TABLE 2 Percentages of Pots Infested with Red Imported Fire Ants

TREATMENT No. of Pots Exposed Percent Infested

33% Citral on Culigel^® 48 0

40% Farnesol on Culigel^® 39 30.7

Fragrance Oil Dust 48 14.6

Neem Cake 10 100

Culigel^® (polymer carrier) 10 100

Untreated Control 10 100

11 TABLE 3 Percentages of Pots Infested with Argentine Ants TREATMENT No. of Pots Exposed Percent Infested 33% Citral on Culigel^® 48 0

Fragrance Oil Dust 47 38.3

Untreated Control 50 100

TABLE 4 Statistical Analysis of Average* Percent Infestation by Red Imported Fire Ants

TREATMENT AVERAGE PERCENT INFESTED 33% citral on Culigel^® 0.0a** Fragrance Oil Dust 13.6ab 40% Farnesol on Culigel^® 26.6b Untreated Control 100.0c

♦Average percentages based on 5 replicates of 10 pots each. ♦♦Averages followed by the same letter are not significantly different at the 5% probability level using Tukey's HSD test.

TABLE 5 Statistical Analysis of Average* Percent by Argentine Ants

TREATMENTS Average Percent Infested 33% Citral on Culigel^® 0.0a Fragrance Oil Dust 38.3b Untreated Control 100.0c

^♦Average percentages based on 5 replicates of 10 pots each. ^♦♦Averages followed by the same letter are not significantly different at the 5% probability level using Tukey's HSD test.

12 - The foregoing detailed description is for the purposes of illustration. Others skilled in the art can apply the knowledge described to other social insects . Such detail is solely for that purpose and those skilled in the art can make variations therein without departing from the spirit and scope of the invention.

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Claims

CLAIMS We claim:

1. A repellent composition for the control of pest social insects comprising

(a) a repelling amount of an alkadienal, and

(b) a carrier material.

2. The repellent composition of claim 1 wherein said alkadienal is selected from the group consisting of citral, geranial and neral .

3. A method for repelling pest social insects comprising

(a) treating an area with a pest arthropod repelling composition comprising

(a) a repelling amount of an alkadienal, and

(b) a carrier material.

4. The method of claim 3 wherein said alkadienal is selected from the group consisting of citral, geranial and neral.

5. The method of claim 3 wherein said method is for controlling ants.

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