GB2356141A - An attractant for fruit flies - Google Patents

Abstract

A method for selectively attracting fruit fly pests of the family Tephritidae to a particular location which method comprises placing at the location a lure comprising an effective amount of a pyrazine, preferably 2,5 dimethylpyrazine, in combination with an ammonium salt and putrescine (1,4-diaminobutane) and/or its breakdown products. Compositions for selectively attracting fruit fly pests of the family Tephritidae are also included.

Description

2356141 AN ATTRACTANT FOR FRUIT FLIES The present invention relates to a

method and composition for attracting fruit fly pests of the family Tephritidae which can be used in systems for detection, monitoring and/or controlling said pests.

Methods developed for monitoring, controlling and eradicating tephritid fruit flies have relied extensively upon the use of chemical attractants. In Bactrocera (Dacus) species the parapheromones methyl eugenol and Cue-lure (4-(p-hydroxyphenyl)-2-butanone acetate) have been successfully used as a lure to attract males. In Ceratitis capitata the parapheromone trimedlure (cyclohexanecarboxylic acid, 4/5-chloromethyl 1,1-dimethyl ethylester) has been successfully used as a male lure. These parapheromones are generally very ineffective at attracting female flies (Nakagawa et al, J. Eron.

Entomol. 63:227-229, 1970). They are also generally species specific. Female fruit flies require protein for the development and maturation of their eggs and so they actively seek out sources of protein in their environment. Water based protein food attractants such as fermenting yeast (Greany et al., Ent. Exp.et.

Appl. 21: 63-70, 1977) or protein hyrdolysate (McPhail, J. Econ. Entomo., 35:758-761, 1989) exploit this behaviour and have been used to attract fruit flies. While these are less species specific they are much more effective in attractin g.female flies as well as male flies. It is important to attract female flies as female flies may migrate into fruit crops or fruit growing areas before male flies and because it is the female flies which produce the progeny and cause the damage, by laying their eggs in the fruit. Any attempt to control the fruit fly pest population must target female fruit flies if it is to be successful.

2 One problem with water based protein baits is the difficulty of preparing and servicing traps. An additional problem is that protein based lures can often attract a range of non-target insects. There is thus a desire and need for a more selective lure which could be used in a dry or wet trap. New attractants have in the past been sought from various sources including sex pheromones, host fruit volatile components and food sources, including bacteria and fungi.

Chemical compositions based on decomposing protein food attractants, such as ammonium salts and putrescine (1,4-diaminobutane) have been shown to be selective for fruit flies Ceratitis capitata and is Anastrepha ludens capturing both males and females US Patents Nos. 5,766,617 and 5,907,923). Commercial formulations of these compositions are now available (BiolureTm, Consep Inc.). These compounds are the only commercial attractants available, other than protein baits, for any Anastrepha species. The use of amines, such as trimethyl amine, to synergise the actions of ammonium acetate and putrescine (1,4-diaminobutane) have been shown to improve catches of Ceratitis capitata (Epsky et al. J. Econ. Emntomol. 92: 156 164, 1999) However trimethyl amine does not improve the catches of Anastrepha, if anything it depresses catches of both males and females. Ammonium acetate and putrescine alone will attract both male and female Anastrepha, but the catches are low and not very competitive with commercially available formulations of protein hydrolysates (NulureTm, Miller Inc.). There is a desire and need for a much more effective lure for all Anastrepha species and in some countries a lure which will be effective for both Anastrepha species and Ceratitis capitata.

Pyrazines, including 2,5 dimethyl pyrazine, have 3 been shown to be components of the sex pheromone of certain Anastrepha species (De Lima et al Fruit Fly Pests; A. World Assessment of the Biology and Management, Chapter 80, pp 107-113, 1996, McPheron and Steck (Eds), St. Lucie Press, Florida, USA) as well as being produced by fermenting protein, bacteria and bacterial metabolites and these have been shown to attract tephritid fruit flies in the lab (Robacker et al., J. Chem. Ecol. 23:1263-1280, 1997 and Florida Entomologist 81: 417-508, 1998). However, pyrazines alone or in combination with each other are not usually successful in attracting significant numbers of male or female tephritid fruit flies in the field.

We have now developed an attractant composition and method for detecting, monitoring and/or controlling Tephritid fruit fly pests using a pyrazine, preferably 2,5 dimethyl pyrazine, in combination with other compounds which provide chemical stimuli.

Accordingly, in one aspect the present invention provides a method for selectively attracting fruit fly pests of the family Tephritidae to a particular location which method comprises placing at the location a lure comprising an effective amount of a pyrazine, preferably 2,5 dimethylpyrazine, in combination with an ammonium salt and putrescine (1,4 diaminobutane) and/or its breakdown products.

In a further aspect the present invention provides a composition for selectively attracting fruit fly pests of the family Tephritidae which comprises a pyrazine, preferably 2,5 dimethypyrazine, an ammonium salt and putrescine and/or breakdown products thereof.

Fruit fly pests of the family Tephritidae include Anastrepha ludens, Anastrepha suspensa, Anastrepha fraterculus, Anastrepha obliqua, Anastrepha mexicana, 4 Anastrepha serpentina, Anastrepha striata, Ceratitis capitata, Ceratitis rosa, Dacus spp., Bactrocera spp., or Rhagoletis spp.

It will be understood that the components of the lure which is used in the present invention may be formulated together and/or separately and/or in various combinations so that when used together they constitute the lure, i.e. the lure need not necessarily be a single device.

The ammonium salt which is used in the attractant compositions is preferably ammonium bicarbonate for an Anast.repha spp. or ammonium acetate for Ceratitis spp. Furthermore, an additional food based attractant compound such as an amine may also be incorporated into the compositions used in the method of the invention. Preferably methyl amine is included for an Anastrepha spp. or trimethyl amine for Ceratitis ssp. The breakdown product of putrescine is 1-pyrroline and this may be used in combination with putrescine, or as a substitute therefor.

The insect attractant composition for use in the present invention is preferably formulated as a slow release composition, for example by being incorporated into hollow glass or fibre capillaries, or impregnated onto rubber or porous polymeric substrates, cellulosic materials or wax.

The attractant composition for use in the present invention may also be used in combination with an insecticide and/or biopesticide and/or chemosterilant.

For example, the biopesticide may be of fungal, bacterial, viral or nemotode origin. The chemosterilant may be an insect growth regulator or a chitin synthesis inhibitor.

The compositions for use in the method of the invention may be placed inside an insect trap, or in the vicinity of the entrance to an insect trap.

An advantage of the compositions used in the method of the invention is that both male and female fruit flies are attracted by the composition, whereas certain of the prior art attractant compositions will attract one or other sex only.

It is to be understood that whilst the compositions of the present invention have been generally denoted as "attractant" compositions, this is the overall effect of the compositions where the combination of compounds acts to attract the insects to a particular place or location. Whilst the blends of compounds are attractant, the specific components may not be "attractants" per se and some may act as take-off or flight stimulants or act as attestants near the source, or generally increase activity or motivational state. It is the combined effect of the components of the composition which provides the composition with the resulting attraction.

The present invention will be further described with reference to the following Examples.

E:XAMPLE 1 This Example compares the effectiveness of the standard food-based attractants, ammonium acetate and putrescine (AA+PUT) (Biolure, Consep Membranes Inc.) and the standard protein hydrolysate liquid bait(from Agrisense-BCS Ltd) with (a) ammonium acetate, putrescine and 2,5 dimethyl pyrazine (AA+PUT+DMP); and (b) ammonium bicarbonate and putrescine (AB+PUT). All ammonium acetate and putrescine lures were Biolure (Consep Membranes Inc.) and the 2,5 dimethyl pyrazine lures were prepared by absorbing 50pl of 2,5 dimethyl pyrazine onto a rubber septa 12 hours prior to placement in the field. All the lures were tested in Tephritraps (Agrisense BCS Ltd). With the exception of the liquid protein bait traps DDVP (2,2-

6 dichlorovinyl dimethyl phosphate (20% w/w)) killing strips were used in each trap to kill the flies. Experiments were carried out in a Mango orchard in Tapachula, Chiapas, Mexico. Traps were placed in a random block/latin square design in mango trees 25m apart. There were four treatments and five replicates of each treatment. Each day the traps were inspected and the number of male and female Anastrepha obliqua captured were recorded. Following each inspection the traps in each row were rotated sequentially. Results are presented in Table 1 and Figure 1.

Table 1:Results of Example 1 Means (+/- s.e.) is DMP+AA+PUT AB + PUT AA+PUT Protein Males 6.05(l.006) 2.47(0.509) 0.85(0.326) 5.56(l.013) Females 5.85 (1.115) 1.79(0.394) 0.75(0.279) 6.94(l.073) AA = Ammonium Acetate PUT = Putrescine DMP = 2,5 Dimethyl Pyrazine AB = Ammonium Bicarbonate Protein = Protein Hydrolysate The test results clearly show that the mixture of DMP+AA+PUT is comparative to the liquid protein hydrolysate bait as an attractant and far superior to AA+PUT alone. The results also suggest that ammonium bicarbonate (AB) is a better ammonium salt for attracting Anastrepha spp. then ammonium acetate (AA).

EXAMPLE 2

This example compares the effectiveness of the standard food-based attractant the three component lure; ammonium acetate, putrescine and trimethyl amine (AA+PUT+TMA) with various combinations of these three 7 compounds and 2,5 dimethyl pyrazine (DMP) These combinations were (a) ammonium acetate, putrescine, trimethyl amine and 2,5 dimethyl pyrazine (AA+PUT+TMA+DMP); (b) ammonium acetate, 2,5 dimethyl pyrazine and trimethyl amine (AA+DMP+TMA); and (c) ammonium acetate, putrescine and 2,5 dimethyl pyrazine (AA+PUT+DMP). The ammonium acetate (AA), putrescine (PUT) and trimethyl amine (TMA) lures were all provided by Agrisense-BCS Ltd. The 2,5 dimethyl pyrazine lures were prepared by absorbing 50pl of dimethyl pyrazine onto a rubber septa 12 hours prior to placement in the field. The experiment was carried out in citrus orchard in Soller, Mallorca, Spain. There were five replicates of each of the four treatments. Traps were placed in citrus trees 15 m apart and arranged in a random block design. All the lures were tested in Tephritraps (Agrisense BCS Ltd) and DDVP killing strips were used in each trap to kill the flies. Each week the traps were inspected and the number of male and female Ceratitis capitata captured were recorded. Following each inspection the traps in each block were rotated sequentially. The results are presented in Table 2.

Table 2: Results of Example 2 Means (+/- s.e.) AA+Put AA+Put+ AA+DMP AA+Put +TMA TMA+DMP +TMA +DMP Females 81.06(12.01) 68.12(6.09) 64.81(7.72) 83.81(11.08) Males 21.18 (3.97) 16.25(2.55) 15.43(2.89) 21.87 (3.99) AA Ammonium Acetate TMA Trimethyl Amine Put Putrescine DMP 2,5 Dimethyl Pyrazine The results clearly show that 2,5 dimethyl pyrazine (DMP) can substitute for the trimethyl amine (TMA). The combination of ammonium acetate, putrescine and 2,5 dimethyl pyrazine (AA+Put+DMP) is as effective as the standard ammonium acetate, putrescine and trimethyl amine (AA+Put+ TMA) three component lure in attracting Ceratitis capitata females and males. The 2,5 dimethyl pyrazine (DMP) is also a reasonable substitute for putrescine (Put) in this lure.

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Claims (15)

CLAIMS:

1. A method for selectively attracting fruit fly pests of the family Tephritidae to a particular location which method comprises placing at the location a lure comprising an effective amount of a pyrazine, preferably 2,5 dimethylpyrazine, in combination with an ammonium salt and putrescine (1,4diaminobutane) and/or its breakdown products.

2. A method as claimed in claim 1 wherein the ammonium salt is ammonium bicarbonate for Anast-repha spp. or ammonium acetate for Ceratitis spp.

3. A method as claimed in claim 1 wherein an additional food based attractant compound, an amine is also used, preferably methyl amine for Anastrepha spp. or trimethyl amine for Ceratitis spp.

4. A method as claimed in any one of the preceding claims-wherein the breakdown product of putrescine is 1-pyrroline.

5. A method as claimed in any one of the preceding claims wherein the fruit flies are attracted to a surface, a target device, a trap or bait station or other device for the purposes of monitoring and/or control.

6. A method as claimed in any one of the preceding claims wherein the pyrazine, ammonium salt and putrescine are formulated individually or together into a controlled release composition in such a way that the attractants are released over a period of days at a concentration which is effective to attract said fruit flies.

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7. A method as claimed in claim 6 wherein the controlled release composition is incorporated into hollow glass or fibre capillaries, or impregnated into porous polymeric substrates, cellulosic materials, rubber or wax, or a reservoir with a release rate controlling system.

8. A method as claimed in any one of the preceding claims which further comprises the step of contacting said fruit flies with an insecticide and/or biopesticide and/or chemosterilant.

9. A method as claimed in claim 8 wherein the biopesticide is of fungal, bacterial, viral or nemotode origin.

10. A method as claimed in claim 8 wherein the chemosterilant is an insect growth regulator or a chitin synthesis inhibitor.

11. A method as claimed in any one of the preceding claims in which the flies are Anastrepha ludens, Anastrepha suspensa, Anastrepha fraterculus, Anastrepha obliqua, Anastrepha mexicana, Anastrepha serpentina, Anastrepha striata, Ceratitis capitata, Ceratitis rosa, Dacus spp., Bactrocera spp-, or Rhagoletis spp.

12. A method as claimed in_any one of the preceding claims whereby both male and female fruit flies are attracted.

13. A composition for selectively attracting fruit fly pests of the family Tephritidae which comprises a pyrazine, preferably 2,5 dimethypyrazine, an ammonium salt and putrescine and/or breakdown products thereof.

14. A composition as claimed in claim 12 wherein the ammonium salt is ammonium bicarbonate for Anastrepha spp. or ammonium acetate for Ceratitis spp.

15. A composition as claimed in claim 12 or claim 13 which additionally comprises an amine, preferably methyl amine for Anastrepha spp. or trimethylamine for Ceratitis spp.