METHOD OF DETECTING AN INSECT INFESTATION

Abstract

A method of detecting the presence of insects, including larvae, in an indoor environment, which includes the steps of (a) obtaining a sample of volatile organic compounds (VOCs); (b) separating the sampled VOCs; (c) detecting the presence or absence of target VOCs from at least one category: category 1 VOCsVOCs emitted independently of the support on which the insects develop and emitted only in an insect infestation VOCs, category 2 VOCsVOCs emitted independently of the support but may have biological origins other than insects, and category 3 VOCsVOCs emitted depending on the support and emitted only in an insect infestation; (d) calculating both an insect infestation index (3I) and a limit value (VL) based on the presence or absence of the target VOCs; and (e) comparing the 3I and VL values. The environment is infested for a 3I value strictly greater than the VL value.

Claims

1-6. (canceled)

7. A method of detecting the presence of insects in an indoor environment comprising: (a) taking a sample of volatile organic compounds (VOCs) in the indoor environment; (b) separating the VOCs sampled; (c) detecting the presence or absence of predetermined target VOCs, these predetermined target VOCs belonging to at least one of the following three categories of VOCs:VOCs that are emitted independently of the substrate on which the insects grow, and that are only emitted during an insect infestation, called category 1 VOCs; VOCs that are emitted independently of the substrate on which the insects grow but that may also have biological origins other than insects, called category 2 VOCs; VOCs that are emitted as a function of the substrate on which the insects grow, and that are only emitted during an insect infestation, called category 3 VOCs; (d) calculating respectively a value Insect Infestation Index called 3I (or 3I index) and a value Limit Value called VL, each of which depends on the presence or absence of the predetermined target VOCs; (e) comparing the values 3I and VL; if the value 3I is strictly greater than the value VL then the environment is infested, and if the value 3I is less than or equal to the value VL, the environment is not infested.

8. The method of detecting the presence of insects as claimed in claim 7, characterized in that step (d) is carried out in three substeps: (d-1) determining an incrementing value i, the incrementing value being obtained by assigning, to each of the predetermined target VOCs, a number 1, 0 or 1 depending on its presence or its absence, the numbers being assigned as follows: presence of a VOC of category (1) is characterized by the number 1 and its absence by 1; presence of a VOC of category (2) is characterized by the number 0 and its absence by 1; presence of a VOC of category (3) is characterized by the number 1 and its absence by 0; (d-2) determining a weighting value P (also called weighting factor) corresponding to the following formula: $P=\frac{\mathrm{Coefficient}.Math..Math.1}{\mathrm{Number}.Math..Math.\mathrm{of}.Math..Math.\text{"}.Math.\mathrm{weighted}.Math..Math.\mathrm{VOCs}.Math.\text{"}}$ in which: the weighted VOCs correspond to the VOCs found on substrates without active infestation but emitted in a larger relative amount in the presence of the insects, namely in an amount at least two times higher, coefficient 1 is an empirical real number established by iteration with a panel of environments whose infestation is known; (d-3) determining the value 3I and VL, the value (3I) corresponding to the following formula:
(3I)=.sub.j=n.sup.1i.sub.jP.sub.j in which: n represents the number of target VOCs, j represents an integer, i represents the incrementing value as defined in step (d-1), P represents the weighting value as defined in step (d-2), i.sub.j represents the incrementation of the j-th target VOC, P.sub.j represents the weighting of the j-th target VOC, the value (VL) corresponding to the following formula: $\begin{array}{cc}\mathrm{VL}=\frac{\begin{array}{c}\mathrm{Number}.Math..Math.\mathrm{of}.Math..Math.\text{"}.Math.\mathrm{unweighted}.Math..Math.\mathrm{VOCs}.Math.\text{"}+\\ P\mathrm{Number}.Math..Math.\mathrm{of}.Math..Math.\text{"}.Math.\mathrm{weighted}.Math..Math.\mathrm{VOCs}.Math.\text{"}\end{array}}{\mathrm{Coefficient}.Math..Math.2}& \end{array}$ in which the unweighted VOCs correspond to the VOCs only emitted in the presence of insects, coefficient 2 is an empirical real number established by iteration with the same environment panel as that used for determining coefficient 1.

9. The method of detecting the presence of insects as claimed in claim 7, wherein the predetermined target VOCs are selected from the group consisting of 2,2-bi-1,3-dioxolane; n-butyl acetate; 1,3,5,7-cyclooctatetraene; alpha-pinene; 1-propanol; methanecarbothiolic acid; 3,3-dimethyl-1-hexene; 2-butanone; ethyl acetate; 4-hydroxy-2-butanone; 1-butanol; 2,5-dimethyl-furan; 2-ethenyl-2-butenal; butyl formate; pyrazine; pyrrole; 1-pentanol; 1-(3,4-dimethylthieno[2,3-b]thiophen-2-yl)-ethanone-oxime; 1,4-octadiene; 1,3-octadiene; 2-methyl-pyrimidine; 1-hexanol; 2-heptanone; 2,5-dimethyl-pyrazine; camphene; 2-octanone; 1-methyl-4-(1-methylethenyl)-cyclohexene; 2-methyldecane; acetophenone; 2-nonen-1-ol; 1,10-dichlorodecane; dodecanal; 2-pentyl-thiophene; 2-decen-1-ol; naphthalene; diethyl phthalate, and mixtures thereof.

10. The method of detecting the presence of insects as claimed in claim 7, wherein: the predetermined target category 1 VOCs are selected from the group consisting of 2,2-bi-1,3-dioxolane and n-butyl acetate; the predetermined target category 2 VOCs are selected from the group consisting of 1,3,5,7-cyclooctatetraene and alpha-pinene; the predetermined target category 3 VOCs are selected from the group consisting of 1-propanol; methanecarbothiolic acid; 3,3-dimethyl-1-hexene; 2-butanone; ethyl acetate; 4-hydroxy-2-butanone; 1-butanol; 2,5-dimethyl-furan; 2-ethenyl-2-butenal; butyl formate; pyrazine; pyrrole; 1-pentanol; 1-(3,4-dimethylthieno[2,3-b]thiophen-2-yl)-ethanone-oxime; 1,4-octadiene; 1,3-octadiene; 2-methyl-pyrimidine; 1-hexanol; 2-heptanone; 2,5-dimethyl-pyrazine; camphene; 2-octanone; 1-methyl-4-(1-methylethenyl)-cyclohexene; 2-methyldecane; acetophenone; 2-nonen-1-ol; 1,10-dichlorodecane; dodecanal; 2-pentyl-thiophene; 2-decen-1-ol; naphthalene and diethyl phthalate.

11. The method of detecting the presence of insects as claimed in claim 7, wherein the insects are in the larval state.

12. The method of detecting the presence of insects as claimed in claim 7, wherein: the insect is Tineola bisselliella, coefficient 1 has a value from 1 to 3, and is preferably equal to 2, coefficient 2 has a value from 3 to 5, and is preferably equal to 4.

Description

EXAMPLE

[0094] The aim of the work presented below is to determine, in a first laboratory phase, a list of target VOCs emitted during infestation of substrates by an insect at the larval stage. In practice, infested and uninfested substrates will be placed in emission chambers before taking samples of the VOCs.

[0095] In the second phase, the targets VOCs will be sought in samples taken from indoor environments that do or do not have an infestation by these insects.

[0096] Material and Methods

[0097] Biological Material

[0098] The insect species used is a keratophagous microlepidopteron, the clothes moth, Tineola bisselliella. In the laboratory phase, two or three larvae of this species obtained from a breeding station were deposited in the chambers, which were called infested chambers.

[0099] According to one embodiment of the detection method of the invention, when the insect is Tineola bisselliella, then: [0100] coefficient 1 has a value from 1 to 3, and is preferably equal to 2, [0101] coefficient 2 has a value from 3 to 5, and is preferably equal to 4.

[0102] Growth Substrate

[0103] Two types of substrates, vulnerable to moths, are used in the laboratory phase: [0104] a piece of woven wool, [0105] rabbit skin.

[0106] Emission Chamber

[0107] Emission chambers of 300 cm.sup.3, developed by CSTB, are used in the laboratory phase. They are made of glass and are equipped with PTFE valves for taking the VOC samples.

[0108] For each series of analyses, a reference chamber, free from moths and containing only the nutrient substrate, namely wool or rabbit skin, was used. The emission chambers are then incubated in an incubator at a temperature of 25 C., away from the light. The incubation time varies depending on the experiments conducted, and is between 3 and 6 months.

[0109] Environments In Situ

[0110] Three types of environment were investigated. Visual diagnosis and diagnosis coupled with the use of pheromone traps were carried out for determining the presence or absence of clothes moths in the different places examined. These are a palace located in the Ile-de-France region (2 rooms), two dwellings and a museum (in an infested horse-drawn carriage and in the shed).

[0111] Table 2 describes the environments investigated and their state of infestation.

TABLE-US-00002 TABLE 2 Environments investigated and state of infestation Type Place State of infestation Palace Palace 1 Infested Palace 2 Infested Museum Carriage int Infested Carriage ext Not infested Dwelling Dwelling 1 Not infested Dwelling 2 Not infested

[0112] Sampling

[0113] The VOCs are collected in tubes containing an adsorbent, TENAX TA (Sigma Aldrich). This is an apolar phase, consisting of an adsorbent polymer of 2,6-diphenyl-p-phenylene oxide. The latter makes it possible to retain the molecules whose number of carbons is between C.sub.4 and C.sub.20. Sampling is active, and is carried out using a pump. The sampling flow rate is fixed at 100 cm.sup.3/min and the sampling time is sufficient for renewing the chamber volume at least ten times.

[0114] In the case of environmental sampling carried out in enclosed spaces, the flow rate is 150 cm.sup.3/min and the sampling time is one hour.

[0115] Analysis

[0116] Desorption of the tubes of TENAX TA is carried out on an ATD 400, Perkin Elmer. The VOCs are injected simultaneously on a column of the VF-5 ms type (Agilent); they are then separated and analyzed with a GC-MS system (GC 3800-MS Saturn 2000, Varian). The analytes are identified from their retention and by comparing their mass spectrum with the NIST 2008 library. Identification of the compounds is confirmed by passage of a standard, depending on availability.

[0117] Results

[0118] Laboratory Phase

[0119] This phase makes it possible to identify a list of target VOCs emitted during insect infestation of substrates. Each target VOC was then assigned to one of the three categories category 1, 2 or 3 as described in the present application (classification of the VOCs produced according to their specificity).

[0120] The presence or absence of the target VOC (category 1, 2 or 3) in the reference context made it possible to determine an incrementation i and then the weighting P, and finally the 3I index.

[0121] In the present case, the following are obtained, respectively: [0122] a weighting P equal to 1 for the unweighted VOCs, [0123] a weighting P equal to 0.08 for the weighted VOCs.

[0124] The weighting P less than 1 (P=0.08) makes it possible to limit the effect of a weighted VOC. Thus, several weighted VOCs are necessary to have the same effect as an unweighted VOC.

[0125] The results obtained are presented in Table 3.

[0126] Regarding the column Presence/Absence, the number 0 indicates absence of the VOCs and the number 1 indicates presence of the VOCs.

[0127] Regarding the column Incrementation, the numbers 1, 0 and 1 are as described in Table 1.

TABLE-US-00003 TABLE 3 Emission of the VOCs on uninfested, previously infested and infested substrates Presence/Absence Uninfested Uninfested Uninfested wool wool rabbit Previously Previously (reference (reference skin infested infested Infested Infested Infested Infested 1) 2) (reference) wool 1 wool 2 wool 1 wool 2 wool 3 wool 4 1-propanol 0 0 1 0 0 0 1 1 0 Methanecarbothiolic acid 0 1 0 0 1 1 0 1 1 3,3-dimethyl-1-Hexene 0 0 0 0 0 1 0 0 0 2-Butanone 0 0 1 0 0 0 0 0 1 Ethyl Acetate 0 0 0 0 1 0 1 0 1 4-hydroxy-2-Butanone 0 0 1 0 0 0 0 0 0 2,2-Bi-1,3-dioxolane 1 0 0 0 0 1 1 1 1 1-Butanol 0 1 1 0 1 0 1 1 1 2,5-dimethyl-Furan 0 1 0 0 1 0 1 1 1 2-ethenyl-2-Butenal 0 0 1 0 1 0 0 1 1 Butyl formate 0 1 0 0 0 0 1 0 1 Pyrazine 0 0 0 0 0 0 0 1 0 Pyrrole 0 0 0 0 0 0 1 0 0 1-Pentanol 0 0 1 1 1 0 0 0 1 1-(3,4-dimethylthieno[2,3- 0 0 0 0 0 1 0 0 0 b]thiophen-2-yl)- Ethanoneoxime n-Butyl acetate 0 0 1 0 1 0 1 0 1 1,4-Octadiene 0 0 0 0 0 0 1 0 1 1,3-Octadiene 0 0 1 0 0 0 0 0 0 2-methyl-Pyrimidine 0 0 0 0 0 0 0 1 0 1-Hexanol 0 0 1 0 0 0 0 1 1 2-Heptanone 1 0 1 0 1 0 0 0 1 1,3,5,7-Cyclooctatetraene 1 1 1 1 1 1 1 0 1 2,5-dimethyl-Pyrazine 0 0 0 0 0 1 0 0 0 a-pinene 0 1 1 1 1 1 1 1 1 Camphene 0 0 0 0 1 0 1 0 1 2-Octanone 1 0 1 0 0 0 1 1 1 1-methyl-4-(1-methylethenyl)- 1 1 1 0 0 0 1 1 1 Cyclohexene 2-methyl-Decane 0 0 0 0 0 0 0 0 0 Acetophenone 1 1 1 1 1 1 0 0 0 2-Nonen-1-ol 1 1 1 1 1 1 1 1 1 1,10-Dichlorodecane 1 0 0 0 1 0 1 1 1 Dodecanal 0 0 0 0 0 0 1 0 1 2-pentyl-Thiophene 0 0 0 0 0 0 0 0 0 2-Decen-1-ol 0 1 1 1 1 0 1 1 0 Naphthalene 1 1 1 1 1 1 1 1 1 Diethyl Phthalate 0 1 1 0 1 0 1 1 1 Index 3I Presence/ Absence Incrementation (i) Infested Incrementa- Incrementa- Wool rabbit VOC tion if tion if Weighting i P if i P if (reference skin category presence absence (P) presence absence 1) 1-propanol 1 3 1 0 0.08 0.08 0 0 Methanecarbothiolic acid 0 3 1 0 0.08 0.08 0 0 3,3-dimethyl-1-Hexene 0 3 1 0 0.08 0.08 0 0 2-Butanone 1 3 1 0 0.08 0.08 0 0 Ethyl Acetate 0 3 1 0 1 1 0 0 4-hydroxy-2-Butanone 1 3 1 0 0.08 0.08 0 0 2,2-Bi-1,3-dioxolane 1 1 1 1 1 1 1 1 1-Butanol 1 3 1 0 0.08 0.08 0 0 2,5-dimethyl-Furan 1 3 1 0 0.08 0.08 0 0 2-ethenyl-2-Butenal 1 3 1 0 0.08 0.08 0 0 Butyl formate 0 3 1 0 0.08 0.08 0 0 Pyrazine 1 3 1 0 1 1 0 0 Pyrrole 1 3 1 0 1 1 0 0 1-Pentanol 1 3 1 0 0.08 0.08 0 0 1-(3,4-dimethylthieno[2,3- 0 3 1 0 1 1 0 0 b]thiophen-2-yl)- Ethanoneoxime n-Butyl acetate 1 1 1 1 0.08 0.08 0.08 0.08 1,4-Octadiene 0 3 1 0 1 1 0 0 1,3-Octadiene 1 3 1 0 0.08 0.08 0 0 2-methyl-Pyrimidine 1 3 1 0 1 1 0 0 1-Hexanol 1 3 1 0 0.08 0.08 0 0 2-Heptanone 1 3 1 0 0.08 0.08 0 0.08 1,3,5,7-Cyclooctatetraene 1 2 0 1 0.08 0 0.08 0 2,5-dimethyl-Pyrazine 1 3 1 0 1 1 0 0 a-pinene 1 2 0 1 0.08 0 0.08 0.08 Camphene 0 3 1 0 1 1 0 0 2-Octanone 1 3 1 0 0.08 0.08 0 0.08 1-methyl-4-(1-methylethenyl)- 1 3 1 0 0.08 0.08 0 0.08 Cyclohexene 2-methyl-Decane 1 3 1 0 1 1 0 0 Acetophenone 1 3 1 0 0.08 0.08 0 0.08 2-Nonen-1-ol 1 3 1 0 1 1 0 1 1,10-Dichlorodecane 0 3 1 0 0.08 0.08 0 0.08 Dodecanal 0 3 1 0 1 1 0 0 2-pentyl-Thiophene 1 3 1 0 1 1 0 0 2-Decen-1-ol 0 3 1 0 0.08 0.08 0 0 Naphthalene 1 3 1 0 0.08 0.08 0 0.08 Diethyl Phthalate 1 3 1 0 0.08 0.08 0 0 Index 3I 2.32 Incrementation (i) Wool Rabbit Previously Previously Infested (reference skin infested infested Infested Infested Infested Infested rabbit 2) (reference) wool 1 wool 2 wool 1 wool 2 wool 3 wool 4 skin 1-propanol 0 0.08 0 0 0 0.08 0.08 0 0.08 Methanecarbothiolic acid 0.08 0 0 0.08 0.08 0 0.08 0.08 0 3,3-dimethyl-1-Hexene 0 0 0 0 0.08 0 0 0 0 2-Butanone 0 0.08 0 0 0 0 0 0.08 0.08 Ethyl Acetate 0 0 0 1 0 1 0 1 0 4-hydroxy-2-Butanone 0 0.08 0 0 0 0 0 0 0.08 2,2-Bi-1,3-dioxolane 1 1 1 1 1 1 1 1 1 1-Butanol 0.08 0.08 0 0.08 0 0.08 0.08 0.08 0.08 2,5-dimethyl-Furan 0.08 0 0 0.08 0 0.08 0.08 0.08 0.08 2-ethenyl-2-Butenal 0 0.08 0 0.08 0 0 0.08 0.08 0.08 Butyl formate 0.08 0 0 0 0 0.08 0 0.08 0 Pyrazine 0 0 0 0 0 0 1 0 1 Pyrrole 0 0 0 0 0 1 0 0 1 1-Pentanol 0 0.08 0.08 0.08 0 0 0 0.08 0.08 1-(3,4-dimethylthieno[2,3- 0 0 0 0 1 0 0 0 0 b]thiophen-2-yl)- Ethanoneoxime n-Butyl acetate 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 1,4-Octadiene 0 0 0 0 0 1 0 1 0 1,3-Octadiene 0 0.08 0 0 0 0 0 0 0.08 2-methyl-Pyrimidine 0 0 0 0 0 0 1 0 1 1-Hexanol 0 0.08 0 0 0 0 0.08 0.08 0.08 2-Heptanone 0 0.08 0 0.08 0 0 0 0.08 0.08 1,3,5,7-Cyclooctatetraene 0 0 0 0 0 0 0.08 0 0 2,5-dimethyl-Pyrazine 0 0 0 0 1 0 0 0 1 a-pinene 0 0 0 0 0 0 0 0 0 Camphene 0 0 0 1 0 1 0 1 0 2-Octanone 0 0.08 0 0 0 0.08 0.08 0.08 0.08 1-methyl-4-(1-methylethenyl)- 0.08 0.08 0 0 0 0.08 0.08 0.08 0.08 Cyclohexene 2-methyl-Decane 0 0 0 0 0 0 0 0 1 Acetophenone 0.08 0.08 0.08 0.08 0.08 0 0 0 0.08 2-Nonen-1-ol 1 1 1 1 1 1 1 1 1 1,10-Dichlorodecane 0 0 0 0.08 0 0.08 0.08 0.08 0 Dodecanal 0 0 0 0 0 1 0 1 0 2-pentyl-Thiophene 0 0 0 0 0 0 0 0 1 2-Decen-1-ol 0.08 0.08 0.08 0.08 0 0.08 0.08 0 0 Naphthalene 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 Diethyl Phthalate 0.08 0.08 0 0.08 0 0.08 0.08 0.08 0.08 Index 3I 0.64 1.28 0.24 2.96 4.24 7.88 4.8 7.2 9.28

[0128] As already stated, for the value (3I) dedicated to Tineola bisselliella, the coefficients 1 and 2 are fixed at 2 and 4, respectively.

[0129] In Situ Phase

[0130] This phase makes it possible on the one hand to compare the list of target VOCs identified in the laboratory phase with several background noises encountered in real environments. On the other hand, it makes it possible to compare the emissions in infested and uninfested environments.

[0131] The results are presented in Table 4.

TABLE-US-00004 TABLE 4 Emission of VOCs from infested and uninfested environments Incrementation (i) Presence/Absence Incrementa- Incrementa- Carriage Dwelling Dwelling Carriage Palace Palace VOC tion if tion if ext 1 2 int 1 2 category presence absence 1-propanol 1 0 0 0 1 1 3 1 0 Methanecarbothiolic acid 0 1 1 1 1 1 3 1 0 3,3-dimethyl-1-Hexene 0 0 0 0 0 0 3 1 0 2-Butanone 1 1 0 1 1 1 3 1 0 Ethyl Acetate 1 0 0 0 1 1 3 1 0 4-hydroxy-2-Butanone 1 0 0 1 0 0 3 1 0 2,2-Bi-1,3-dioxolane 1 0 0 1 1 1 1 1 1 1-Butanol 1 0 1 0 0 1 3 1 0 2,5-dimethyl-Furan 0 0 0 0 0 0 3 1 0 2-ethenyl-2-Butenal 0 0 0 0 0 0 3 1 0 Butyl formate 0 0 0 0 0 0 3 1 0 Pyrazine 0 1 1 0 0 0 3 1 0 Pyrrole 0 0 1 0 1 0 3 1 0 1-Pentanol 1 0 0 1 1 1 3 1 0 1-(3,4-dimethylthieno[2,3- 0 0 0 1 0 1 3 1 0 b]thiophen-2-yl)- Ethanoneoxime n-Butyl acetate 1 0 1 1 1 0 1 1 1 1,4-Octadiene 0 0 0 0 0 0 3 1 0 1,3-Octadiene 0 0 1 0 0 0 3 1 0 2-methyl-Pyrimidine 0 0 0 0 0 0 3 1 0 1-Hexanol 0 0 0 0 0 0 3 1 0 2-Heptanone 0 1 0 1 0 0 3 1 0 1,3,5,7-Cyclooctatetraene 1 0 0 1 1 1 2 0 1 2,5-dimethyl-Pyrazine 0 0 0 0 0 0 3 1 0 a-pinene 1 1 1 1 1 1 2 0 1 Camphene 0 0 0 0 0 0 3 1 0 2-Octanone 0 1 0 0 0 0 3 1 0 1-methyl-4-(1-methylethenyl)- 0 1 0 0 1 0 3 1 0 Cyclohexene 2-methyl-Decane 0 0 1 0 0 1 3 1 0 Acetophenone 1 1 1 1 0 1 3 1 0 2-Nonen-1-ol 0 0 0 1 0 1 3 1 0 1,10-Dichlorodecane 0 0 0 0 0 0 3 1 0 Dodecanal 0 0 0 0 1 0 3 1 0 2-pentyl-Thiophene 0 0 0 0 0 0 3 1 0 2-Decen-1-ol 0 1 0 1 1 0 3 1 0 Naphthalene 1 1 1 1 0 0 3 1 0 Diethyl Phthalate 1 0 1 1 1 0 3 1 0 Index 3I Incrementation (i) Weighting i P if i P if Carriage Dwelling Dwelling Carriage Palace Palace (P) presence absence ext 1 2 int 1 2 1-propanol 0.08 0.08 0 0.08 0 0 0 0.08 0.08 Methanecarbothiolic acid 0.08 0.08 0 0 0.08 0.08 0.08 0.08 0.08 3,3-dimethyl-1-Hexene 0.08 0.08 0 0 0 0 0 0 0 2-Butanone 0.08 0.08 0 0.08 0.08 0 0.08 0.08 0.08 Ethyl Acetate 1 1 0 1 0 0 0 1 1 4-hydroxy-2-Butanone 0.08 0.08 0 0.08 0 0 0.08 0 0 2,2-Bi-1,3-dioxolane 1 1 1 1 1 1 1 1 1 1-Butanol 0.08 0.08 0 0.08 0 0.08 0 0 0.08 2,5-dimethyl-Furan 0.08 0.08 0 0 0 0 0 0 0 2-ethenyl-2-Butenal 0.08 0.08 0 0 0 0 0 0 0 Butyl formate 0.08 0.08 0 0 0 0 0 0 0 Pyrazine 1 1 0 0 1 1 0 0 0 Pyrrole 1 1 0 0 0 1 0 1 0 1-Pentanol 0.08 0.08 0 0.08 0 0 0.08 0.08 0.08 1-(3,4-dimethylthieno[2,3- 1 1 0 0 0 0 1 0 1 b]thiophen-2-yl)- Ethanoneoxime n-Butyl acetate 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 1,4-Octadiene 1 1 0 0 0 0 0 0 0 1,3-Octadiene 0.08 0.08 0 0 0 0.08 0 0 0 2-methyl-Pyrimidine 1 1 0 0 0 0 0 0 0 1-Hexanol 0.08 0.08 0 0 0 0 0 0 0 2-Heptanone 0.08 0.08 0 0 0.08 0 0.08 0 0 1,3,5,7-Cyclooctatetraene 0.08 0 0.08 0 0.08 0.08 0 0 0 2,5-dimethyl-Pyrazine 1 1 0 0 0 0 0 0 0 a-pinene 0.08 0 0.08 0 0 0 0 0 0 Camphene 1 1 0 0 0 0 0 0 0 2-Octanone 0.08 0.08 0 0 0.08 0 0 0 0 1-methyl-4-(1-methylethenyl)- 0.08 0.08 0 0 0.08 0 0 0.08 0 Cyclohexene 2-methyl-Decane 1 1 0 0 0 1 0 0 1 Acetophenone 0.08 0.08 0 0.08 0.08 0.08 0.08 0 0.08 2-Nonen-1-ol 1 1 0 0 0 0 1 0 1 1,10-Dichlorodecane 0.08 0.08 0 0 0 0 0 0 0 Dodecanal 1 1 0 0 0 0 0 1 0 2-pentyl-Thiophene 1 1 0 0 0 0 0 0 0 2-Decen-1-ol 0.08 0.08 0 0 0.08 0 0.08 0.08 0 Naphthalene 0.08 0.08 0 0.08 0.08 0.08 0.08 0 0 Diethyl Phthalate 0.08 0.08 0 0.08 0 0.08 0.08 0.08 0 Index 3I 2.72 0.48 2.48 3.8 4.64 5.4

[0132] Calculation of the Value (VL)

[0133] The limit value VL was calculated using the formula given in step d-3/ above, namely:

[00005]$\begin{array}{cc}\mathrm{VL}=\frac{\begin{array}{c}\mathrm{Number}.Math..Math.\mathrm{of}.Math..Math.\text{"}.Math.\mathrm{unweighted}.Math..Math.\mathrm{VOCs}.Math.\text{"}+\\ P\mathrm{Number}.Math..Math.\mathrm{of}.Math..Math.\text{"}.Math.\mathrm{weighted}.Math..Math.\mathrm{VOCs}.Math.\text{"}\end{array}}{\mathrm{Coefficient}.Math..Math.2}& \end{array}$

[0134] It can be seen from Tables 3 and 4 that there are 13 unweighted VOCs (since they are only present in the case of infestation) and 23 weighted VOCs.

[0135] In this case, the value VL is equal to 3.71=[13+(0.0823)]/4.

[0136] The values of the index (3I), shown above in Tables 3 and 4, are summarized in Table 5 below.

[0137] The uninfested conditions and environments correspond respectively to the first 5 lines of the section Laboratory conditions and to the first 3 lines of the section Environments in situ.

TABLE-US-00005 TABLE 5 Values of the indices 3I Value of Conditions and environments index 3I Laboratory Without Wool (reference 1) 2.32 conditions infestation Wool (reference 2) 0.64 Previously infested wool 1 0.24 Previously infested wool 2 2.96 Rabbit skin (reference) 1.28 With Infested wool 1 4.24 infestation Infested wool 2 7.88 Infested wool 3 4.80 Infested wool 4 7.20 Infested rabbit skin 9.28 Environments Without Carriage (exterior) 2.72 in situ infestation Dwelling 1 0.48 Dwelling 2 2.48 With Carriage (interior) 3.80 infestation Palace 1 4.64 Palace 2 5.40

CONCLUSIONS

[0138] All of the infested conditions and environments have, as expected, an index (3I) strictly greater than the Limit Value VL (in this case 3.71). In contrast, all of the uninfested conditions and environments have an index less than or equal to this same limit value.

[0139] Moreover, the two previously infested conditions have an index below 3.71, reflecting absence of residual VOCs once the infestation is finished and controlled.

[0140] The index (3I) therefore correlates well with the activity of the clothes moth, i.e. Tineola bisselliella.

[0141] The method of the invention for constructing the index (3I) and the value VL therefore advantageously allows detection of insects at the larval stage.