Indian Journal of Fibre & Textile Research Vol. 26, September 200 1 , pp. 308-3 1 2

Lambda-cyhalothrin spray as an insectproofing agent for woollen fabrics

Vijay Veera, N GopaJan & K M Rao

Defence Research & Development Establishment, Jhansi Road, Gwalior 474 002, India Received 15 December 1999; revised received and accepted 23 March 2000

The effectiveness of synthetic pyrethroid lambda-cyhalothrin at 0.0 1 , 0.025 and 0.05% concentrations as solvent-based sprays was evaluated against the larvae of the tropical case making clothes moth, Tinea translucens Meyrick and the furniture carpet beetle, Anthrenus Jalvipes leConte. Lambda-cyhalothrin spray at 0.025 % concentration provided high degree of protection to the wool fabric even after 30 months of the ageing of treated fabric from these two serious wool pests. Lambda-cyhalothrin showed ovicidal action as all eggs, laid on the treated fabric by the moths, were killed. The minimum effective concentration of lambda-cyhalothrin for complete protection of woollen fabric was determined to be 0.005% on wool weight against the larvae of A. jlavipes. T. translucens was found more susceptible than A. jlavipes to lambdacyhalothrin. Residue of lambda-cyhalothrin was estimated 25-35% lower than its initial deposits on the fabrics after 30 months of its application.

Keywords: Anthrenus jlavipes, Insectproofing, Lambda-cyhalothrin, Synthetic pyrethroid, Tinea translucens, Woollen fabric

1 Introduction Woollen fabrics and clothings, carpets and other

keratinous materials are frequently damaged or destroyed by the larvae of certain insect species of moth and beetle families in stores throughout the world. Nine species of beetles 1 ,2 and four species of moths have been recorded as wool pests in India. Of these, a dermestid beetle Anthrenus jlavipes Le Conte (the furniture carpet beetle) and a tineid moth Tinea translucens Meyrick (the tropical case making clothes moth) are the serious pests of woollen textiles in India and elsewhere 3.

Currently, the synthetic pyrethroid l ike permethrin are commonly used for protection of woollen fabrics and garments in various parts of the world after the ban on dieldrin insecticide which was an environmentally persistant organochlorine compound. The synthetic pyrethroid insecticides are characterized by very high insecticidal activity, low mammalian toxicity, and easy biodegradabil ity in the environment. One of the synthetic pyrethroids, the lambda-cyhalothrin [(±)-oc-cyno-3-phenoxybenzyl (+ )cis-trans-3-(2-dichlorovinyl)-2,2 dimethylcyc lopropane carboxylate] (Fig. 1 ) which is a 1 : 1 mixt ure of the (Z)-(- IR,3R) Sester and the (Z)-( l S,3S) R-ester, has been shown to be more toxic than so far known most active deltamethrin insecticide against mosquitoes4.5 and

"To whom all the correspondence should be addressed. Phone: 341980 Extn 1 42 ; Fax 009 1 -75 1 -34 1 148; E-mail : ento@drde.8m.com

CF ( S ) ( Z ) - (1 R ) - cis -3 , CH c(C=C�I�CO�;::c"vCN -...:::: 0'0 H' T ·H I I

CH3 fi .o

Fig. 1 - Structure of l ambda-cyhalothrin

cockroaches6. Deltamethrin has been reported about 8- 1 2 times more effective than permethrin against several insect species 7• Cyhalothrin has been recommended to use for protection of woollen textiles in Australia8. However, there is no informal ion avai lable on the effect iveness of lhe lambda-cyhalotl irin against wool pests and as a wool protectant from insect pests when used as solvent-based sprays for horne u se during storage.

This paper repOtts the results of studies made with lambda-cyha lothri n to determine ( i ) the minimum effective concentration agai nst the l arvae of A . Jlavipes and T. tralls/lICens by i mpregnation of fabrics, ( i i ) effectiveness of i t s sol vent-based sprays against the

VilA Y VEER et al. : LAMBDA-CYHALOTHRIN SPRAY AS AN INSECTPROOFING AGENT 309

larvae of both pest species immediately after treatment and after 30 months of ageing and storage of the treated fabrics, (iii) the toxicity of the fabrics after 30 months of treatment to the adults of pest species, and (iv) residue of lambda-cyhalothrin on the fabrics immediately after treatment and after 30 months ageing.

2 Materials and Methods A plain weave, undyed, soap scoured, 1 00% wool

fabric weighing 250 g/m2 was used as test fabric and also as control to determine the larval voracity.

The minimum effective concentration of lambdacyhalothrin was determined against both the pest species by padding 7 ml solution having desired concentration of the chemical in acetone onto weighed strip of 4 x 35 cm of test fabric. The strip was laid down on horizontal screen to deposit 0.00075-0.0 1 % (on wool weight) of insecticide. This volume of solution was just sufficient to saturate the test fabric without any run-off. The treated test fabric strips were air-dried for 4 days at room temperature (28-30°C). Controls were treated with acetone only.

The effectiveness of lambda-cyhalothrin as sprays for protection of woollen fabrics was determined by spraying of 0.0 1 , 0.025 and 0.05% lambda-cyhalothrin in white spirit solvent, commonly used for drycleaning of wool fabrics, on swatches of test fabric (32 x 32 cm) with a conventional sprayer (dispensing rate of 1 1 - 1 2 mlllOs) for lOs each on both surfaces from a distance of 0.35-0.45 m. Two swatches from each treatment were sampled for bioassay and chemoassay while other treated swatches were kept in a dark cabinet in a room at 28-35°C for 30 months.

The biological tests for the determination of textile resistance were done with l O-week old larvae of A. jlavipes and 25-27 days old larvae of T. translucens taken from standard laboratory culture according to the assessment of the visible damage and fabric weight loss procedure established by the International Organization for Standardization9. In this method, four discs of about 4 cm diam. of known weight from test fabric were exposed to 15 healthy larvae of test insect in glass petri dishes (50 x 1 8 mm) with perforated alumunium lid for 14 days in the controlled atmosphere of 27 ±_ 1 DC and 60 ±_5% RH in a darkened cabinet. A test fabric was considered satisfactorily insectproofed if the test specimens had no holes and/or surface damage (cropping) visible to the naked eyes and the mean weight loss of four test specimens and the weight loss of single specimen were less than 15 mg and 20 mg respectively.

The toxicity of the treated fabric to the adults of A. jlavipes and T. translucens was determined as given by Vijay Veer et al. lO• Briefly, 1 0 adults (2-3 days old) were released in a 0.25 litre glass jar on a 5 cm diam. sample of the treated fabric, which substantially covered the bottom of the jar, and the mouth of the jar was covered with a piece of muslin cloth held by a rubber band in four replicates. Controls consisted of solvent-treated fabric and untreated fabric samples. These jars were held in dark cabinet maintained at 27 ± 1 DC and 60 ± 5% RH, and the adult mortality was determined after 24 and 72 hours. The jars were then returned to the holding cabinet for an additional 6 weeks to determine whether any adult was able to oviposit and hatched larvae were able to damage the exposed test samples.

The residue of lambda-cyhalothrin on treated fabrics was determined with gas chromatography (Nucon 5700) equipped with an electron capture detector (ECD) fitted with a glass column (length, 1 m; I.D., 3 mm) with 2% OV- 1 7 on Chromosorb WAW DMCS. The treated fabric sample was conditioned at 27 ± 1 DC and 65 ± 5% RH for 24 h and then weighed and transferred to a Soxhlet apparatus. It was extracted with 2-methoxyethanol for 6 h at 6 cycleslh. Temperatures were 260DC for the oven and 280°C for the injector and detector, and the nitrogen gas flow was 2.5 kg/ cm2 mllmin. The retention time of lambdacyhalothrin under these conditions was 160s.

3 Results and Discussion The results of biological feeding tests with T.

translucens and A. jlavipes larvae are given in Tables 1 -3 . It is observed that the minimum effective concentration (MEC) of lambda-cyhalothrin for protection of woollen fabrics from A. jlavipes is 0.005% on wool weight (oww) while it is between 0.001 % and 0.005% (oww) against T. translucens (Table 1 ) . This shows that the minimum effective concentration of lambda-cyhalothrin for portection of the fabrics from A. jlavipes is at par with another potent pyrethroid, deltamethrin. The MEC of deltamethrin was found 0.005% (oww) against A. jlavipes and 0.0025% (oww) against T. translucens.

Solvent-based sprays of lambda-cyhalothrin provided high degree of protection to the fabrics at 0.025% and 0.05% concentrations against both the species of pests, both immediately after treatment and after 30 months of ageing of treatment (Tables 2 and 3) . While lambda-cyhalothrin at 0.01 % provides protection to the wool fabrics initially after treatment

3 1 0 INDIAN 1 . FIBRE TEXT. RES., SEPTEMBER 2001

Table 1 - Minimum effective concentration (MEC) of lambda-cyhalothrin for protection of woollen fabrics from larvae of Tinea translucens and Anthrenus jlavipes

Cone., % (on wool weight)

Tinea translucens .Anhrenus jlavipes

0.001 0.005 Control

Treated with solvent Untreated

Visible damage Mean wt. Cropping" Holesb loss, mg

3

3

4

C-D A

DD

1 5.25 2.08

85.0

9 1 .9 1

Status

Not proofed Proofed

Not proofed

Not proofed

Visible damage Cropping" Holes6

3 1 -2

4

4

C-D A

D

D

'Cropping (Surface damage): I = Not detectable, 2 = Very slight, 3 = Moderate, and 4 = Very heavy.

Mean wt. loss, mg

1 4.20 6.20

84.06

93.92

�oles: A = No detectable damage, B = Yams partially servered, C = Few small holes, and D = Several large holes

Status

Not proofed Proofed

Not proofed

Not proofed

Table 2 -Effectiveness of lambda-cyhalothrin spray against larvae of Tinea translucens and Anthrenus jlavipes

Cone., % Tinea translucens Anthrenus !J.avipes Visible damage Mean wt. Status Visible damage Mean wt. Status

Cropping Holes loss, mg Cropping Holes loss, mg

0. 01 A 2.65 Proofed 1 -2 A-B 1 2.44 Proofed 0.025 A 1 .70 Proofed A 2.72 Proofed 0.05 A 0.98 Proofed A 2.50 Proofed Control

Treated with 3-4 D 85.06 Not proofed 3-4 D 83.74 Not proofed solvent Untreated 3-4 D 9 1 .9 Not proofed 4 D 93.92 Not proofed

Table 3 - Effectiveness of lambda-cyhalothrin spray against larvae of Tinea translucens and Anthrenus jlavipes after the treatment had aged 30 months

Tinea translucens Anthrenus !J.avipes Cone., % Visible damage Mean wt. Status Visible damage Mean wt Status

Cropping Holes loss, mg Cropping Holes loss, mg

0. 0 1 2 A-C 7.05 Not proofed 4 D 26. 1 7 Not proofed 0.025 A 1 .64 Proofed 2 A 5.43 Proofed 0.05 A 0.57 Proofed A 4.95 Proofed Control

Treated with 44 D 74.35 Not proofed 4 D 1 00.42 Not proofed solvent Untreated D 1 1 1 .44 Not proofed 4 D 1 0 1 .65 Not proofed

from both the pest species, this concentration of lambda-cyhalothrin provides no protection to the fabrics after 30 months of treatment even from T. translucens (Table 3).

Mortality among the adults of T. translucens and A. jlavipes after exposing them to the 30 months aged lambda-cyhalothrin treated fabrics is reported in Table 4. It is observed that all adults of T. translucens and A. jlavipes knockdown after one hour of exposure to the treated fabrics. Adult mortality of T. translucens is between 1 6% and 34% after 24 h exposure while the mortality is 1 00% after 72 h exposure.

Mortality among the adults of A. jlavipes is 1 3-92% after 24 h of exposure and 56 - 1 00% after 72 h of exposure to the treated fabrics and none of them is able to oviposit except a few moths. However, none of those laid eggs hatch out due to the ovicidal action of the lambda-cyhalothrin.

Table 5 shows that the initial deposits of lambdacyhalothrin on fabrics sprayed for 20s with 0.0 1 , 0.025 and 0.05% concentrations are 0.007, 0.02 and 0.045%(oww) respectively, and the lambdacyhalothrin residues after 30 months ageing of fabrics are 25 - 35 % lower than initial deposit.

VUA Y VEER et al.: LAMBDA-CYHALOTHRIN SPRAY AS AN INSECTPROOFING AGENT 3 1 1

Table 4-Effect of exposing adults of Tinea translucens and Anthrenus jlavipes to the fabric samples treated 30 months previously with a pressurized formulation of lambda-cyhalothrin

Cone., % Time sprayed Knockdown (KD)" and dead + moribund (D+M)b s after indicated hours of exposure, %

24 h 72 h KD D + M KD D + M

Tinea translucens

0.0 1 20 100 16.6 100 1 00 0.025 20 1 00 33.3 100 1 00 0.05 20 100 34 1 00 100 Control

Treated with solvent 20 0 0 0 0 Untreated 0 0 0 0 0

Anthrenus jlavipes

om 20 40 13.3 70 56 0.Q25 20 83.3 26.6 100 73.3 0.05 20 1 00 92.5 1 00 1 00 Control

Treated with solvent 20 0 0 0 0 Untreated 0 0 0 0 0

"Knockdown (KD) when adults become immobilized after exposure. �oribund (M) when adults after knockdown become stationary and respond to probing by movements of legs, mouthparts or antennae.

Table 5 - Residue of lambda-cyhalothrin on fabic sprayed with thre pressurized concentrations

Time sprayed Intial deposit on Lambda-cyhalothrin residue fabric, % oww on fabric after 30 months

ageing, % oww

20 0.007 0.0045 20 0.02 oms 20 0.045 0.035

No objectionable odour or stain on dried and undyed test fabrics was observed. Larval feeding tests (Tables 1-3) show that the larvae of T. translucens are more susceptible to lambda-cyhalothrin than that of A. jlavipes. A similar observation was made with other synthetic pyrethroid, deltamethrinlO•

4 Conclusion

A solvent-based spray of 0.025% lambdacyhalothrin provides effective protection to woo.llen fabrics from two serious wool pests, Tinea translucens and Anthrenus jlavipes up to 30 months after application. When the adults of these two pest species come in contact with 30 months aged treated fabrics,

most of them die within 72 h and none is able to oviposit except a few moths. However, none of the laid eggs hatch out due to the ovicidal action of the compound. Moreover, lambda-cyhalothrin solvent-based spray causes no objectionable odour or stain on the fabrics. A solvent-based spray of lambda-cyhalothrin merits consideration for protection of wool fabrics in home storage and is at par with deltamethrin in effectiveness against wool pests.

Acknowledgement The authors are thankful to Dr R V Swamy,

Director, Defence R & D Establishment, Gwalior, for providing facilities and encouragement and to MIs Zeneca ICI Agrochemicals Ltd, Chennai, for providing technical lambda-cyhalothrin.

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