الفهرس 
Toxicological studiesOnly 14 pages are availabe for public view
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Abstract
The present study aimed to evaluate the sensitivity of Anthrenus verbasci and Tinea pellionella to modified atmospheres of argon and nitrogen at different temperatures and exposure time. Also, to determine the minimum time to provide 100% kill of all developmental stages and to investigate the damage caused by insects attack on wool textile. Moreover, studying the feasibility of using low oxygen atmosphere to rescue wool textile after infestation.1. Insect control studies.
1.1. The sensitivity of insects to gases.
Different concentrations of argon and 99.9% nitrogen in modified atmosphere (MA) were used in this study. The sensitivity of the fourth instars larvae and adults of Anthrenus verbasci and the late larvae and adults of Tinea pellionella to modified atmospheres containing nitrogen and argon gases was tested at 20 and 30˚C and 50% RH.
1.2. Sensitivity of Anthrenus verbasci to modified atmosphere containing various concentrations of argon gas.
The efficacy of different concentrations of argon (25%, 50%, 75% and 99.9%) against 4th larval instars and adults of A. verbasci was tested after 48, 96, 144, 192 and 240 hr at 20 and 30 ºC and 50% RH. Data indicate that, adults of A. verbasciwere more sensitive to all tested concentrations than larvae. At 20ºC, the LT50 values after 48, 96,144,192 and 240 hr of exposure, were 147.2, 121.8, 107.5 and 8.088hr for 4th larval instars, respectively. The LT50 values of Ar for Adults after 48, 96,144,192 and 240 hr of exposure were 136.7, 110.6, 96.26 and 7.75hr respectively. At 30ºC the results illustrated that, the LT50 values of Ar for 4th larval instars after 48, 96, 144, 192 and 240 hr of exposure, were140.8, 113.9, 99.45 and 7.72hr respectively. Also LT50 values for adults were 126.9, 105.4, 92.49 and 7.21hr respectively.
The results illustrated that, the mortality of A. verbasci increased as the gas concentration and the exposure time increased. According to LT50 values for A. verbasci, the concentrations of Ar were more effective at higher temperatures than lower temperatures and the larva were more tolerant than adults.
1.3. Sensitivity of Tinea pellionella to modified atmosphere containing various concentrations of argon gas.
The efficacy of different concentrations of Ar against the late larvae and adults of T. pellionella was tested after 48, 96, 144, 192 and 240 hr of exposure, at 20 and 30ºC and 50% RH.
Data revealed that, at 20ºC, larvae of T. pellionella were more tolerant than adults to all tested concentrations. The LT50 values of Ar for late larval instars after 48, 96, 144, 192 and 240 of exposure, were 139.4, 119.8, 100.7 and 7.27hr respectively. Also, the LT50 values were 122.5, 105.2, 90.57 and 6.55hr for adults, respectively. At 30ºC the results illustrated that, the LT50 values of Ar for late larval instars after 48, 96, 144, 192 & 240 hr of exposure, were 129.1, 114.6, 96.14 and 6.81hr respectively. The LT50 values were 116.7, 101.1, 86.97 and 6.36 hr for adults, respectively. According to LT50 values for T. pellionella, the concentrations of Ar were more effective at higher temperatures than lower temperatures and the adults were more sensitive to Ar than larval stages. Also the mortality of T. pellionella increased as the exposure time increased..4. Sensitivity of Anthrenus verbasci to modified atmosphere of high nitrogen content.
The efficacy of MA of 99.9% N2 against A. verbasci at 20ºC was tested. The results indicated that, LT50 of A. verbasci was 9.31 and 8.59 hr for 4th larval instars and adults respectively. Also, the results illustrated that, at 30ºC LT50 for 4th larval instars and adults were 9.24 and 7.84hr, respectively. The results revealed that, the mortality of A. verbasci increased as the exposure time and temperature increased. According to LT50 values for A. verbasci the concentration of 99.9% N2 was more effective at higher temperatures than lower temperatures and the larvae were more tolerant to MA than adult stage.
1.5. Sensitivity of Tinea pellionella to modified atmosphere of high nitrogen content.
The efficacy of MA of 99.9% N2 against T. pellionella at 20ºC was tested. The results indicated that, LT50 of T. pellionella was 8.32hr, for late larval instars, also LT50 values for adults were 7.53 hr. At 30ºC the results illustrated that, LT50 values of late larval instars was 7.15 hr. LT50 values of adults were 7.03 hr. Results illustrated that, the mortality of T. pellionella increased as the exposure time and temperature increased. According to LT50 values for T. pellionella the concentration of 99.9% N2 was more effective at higher temperatures than lower temperatures and the larva were more tolerant to MA than adults. Larvae and adults of T. pellionella were more sensitive to N 2 gas than larvae and adults of A. verbasci. Also, results show that Ar gas was generally more effective against larvae and adults of T. pellionella and A. verbasci than N2 gas.
2. Effect of insect infestation and argon or nitrogen gas on thermally aged textiles.
It’s important to detect the effect of insect infestation and the treatment with argon or nitrogen gas on the properties of the aged woolen samples. The change on tensile strength and chemical properties of woolen samples after infestation with the larvae of A. verbasci and T. pellionella and treatment with 99.9% of the tested gas was tested.
2.1. Effect of argon gas on the tensile strength of the thermally aged textile infested with A. verbasci and T. pellionella.
Data showed that larvae of A. verbasci had a deteriorating effect on wool as the tensile strength decreased from 34kg/5cm for untreated uninfested wool sample to 9 kg/5cm for untreated infested wool sample with percent reduction of 73.5%. The reduction after treatment of the infested wool with argon gas was 12 kg/5cm with percent reduction of 64.7%. On the other hand, the value of the tensile strength of infested wool sample with T. pellionella before treatment with argon gas was13kg/5cm, with percent reduction of 61.7% which reduced to 25 kg/5cm after treatment with argon. According to the results, A. verbasci was the most deteriorating insect on wool as the tensile strength decreased than T. pellionella.
2.2. Effect of nitrogen gas on the tensile strength of the thermally aged textile infested with A. verbasci and T. pellionella.
Results revealed that , A. verbasci made deterioration for aged wool samples as the tensile strength decreased from 34kg/5cm for untreated uninfested wool sample to 12 kg/5cm for treated infested wool sample with nitrogen with percent reduction of 64.7%. The reduction after treatment of the infested wool with T. pellionella was 20 kg/5cm with percent reduction of 41.1%. According to the results argon was the most effective gas on insects and save on wool as the tensile strength decreased with nitrogen than argon gas.
2.3. Effect of argon and nitrogen gases on the chemical properties of the thermally aged textile infested with A. verbasci and T. pellionella.
The results showed that all the amide I and amide II appeared at ≈1690 and ≈1480 cm-1 respectively, indicating that all the wool samples present are mainly in crystalline (α-helix) structure. Data showed a sharp decrease in the bands intensity of all functional groups of the infested wool samples with A. verbasci and T. pellionella larvae. The results also showed elevation in the intensities of all the functional groups (O-H, C-H, C=O, N-H and C-N) in all cases of treatments. Results of ATR-FTIR indicated that, treatment with argon or nitrogen had a positive effect on the wool chemical structure.
3. Effect of modified atmosphere containing argon or nitrogen gas on A. verbasci and T. pellionella and morphology of thermally aged textiles.
3.1. Effect of argon or nitrogen gas on antennae and their sensilla and larval case opening.
Treatment of 4th larval instars and adult A. verbasci with argon or nitrogen gas resulted in malformation and fall down or absence of the antennal structures. Argon and nitrogen gas caused abnormalities in the shape of antennal sensilla especially trichoid sensilla in males of A. verbasci and larval case opening in T. pellionella. The undesirable effects of argon and nitrogen gases on the structure of antenna and their associated sensilla may cause failure of treated males to mate with female and ultimately lower the population of insect pest. Also, treatment of late larval instars of T. pellionella with argon or nitrogen gas resulted in malformation of the case opening of larva. These studies suggest that argon and nitrogen gases may be potential fumigant against museum pests.