Kajian faktor fisiologi nyamuk berkaitan dengan kesan selepas pendedahan kepada lingkaran nyamuk

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Date
1995-03
Authors
Hong Peng, Lim
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Abstract
A study on physiological factors of mosquitoes in relation to the effects of exposure to mosquito coils. Three mosquito coil formulations with active ingredients d-a11ethrin (0.2% w/w) and d-trans allethrin (0.1% w/w) and blank coil have been tested in the laboratory against Culex quinquefasciatus Say and Aedes aegypti (Linnaeus) using a standard test method of the Standard & Industrial Research Institute Of Malaysia (SIRIM). Laboratory cultured mosquitoes established from Penang Island were used in this study. Mosquito coil ( 0.50 ±. 0 .003g) with both ends ignited were tested in glass chamber measuring 70 X 70 X 70 em. Results indicated that Ae. ae9ypti was more susceptible to mosquito coils than ex. quinquefasciatus . .so For example, the knockdown values (KTSO) for female Ae. ae9ypti and ex. quinquefasciattts aged day 4-5 tested against mosquito coil containing d-allethrin (0.2% w/w) were 2.24 ±. 0.02 minutes and 8.82 ±. 0.39 minutes, respectively. The blank coil caused neither significant - knockdown nor mortality of mosquitoes, while coils containing d-allethrin (0.2% w/w) and d-trans allethrin (0.1% w/w) could provide adequate knockdown of mosquitoes but with low mortalities. For example, the percentage mortalities of female Ae. aegypti and ex. quinquefasciatus aged day 4-5 tested against mosquito coil containing d-allethrin (0.2% w/w) were 13.67 ± 2.59% and 6.00 + 0.76%, respectively. Furthermore, the efficacies in term of knockdown and mortality for d- r allethrin (0.2% w/w) and d-trans allethrin (0.1% w/w) ~ were not siginificantly different. The susceptibility of mosquitoes to mosquito coils increased with age. Percentage mortalities of both mosquitoes species tested showed a positive relationship with aging. For example, the percentage mortalities of female Ae. aegypt.i tested against d-trans· allethrin (0.1% w/w) were 13.67 + 2.62%, 17.50 + 4.19%, 18.17 ± 2.17%, 51.17 ± 10.08% and 72.00 ± 15.74% when mosquitoes were assessed at age day 1-2, 4-5, 9-10, 14-15 and 19-20, respectively. Besides, female mosquitoes were more tolerant than the males. This study also indicated that blood-fed mosquitoes were more difficult to knockdown but· easier to kill than non blood-fed mosquitoes. However, the susceptibility -of mosquitoes to mosquito coils was not affected by oviposition. The longevity of both mosquito species decreased more than 40% after being exposed to mosquito coils· containing d-allethrin (0.2% w/w) and d-trans allethrin (0.1% w/w). The percentages of mosquitoes blood-feeding for· ex. quinquefascistus and Ae. segypti were reduced to less than 20% and 55%, respectively after a 20 minute exposure to d-allethrin (0.2% w/w) and d-trans allethrin ( o .1% w. w). Furthermore, ex. qui nquefssci atus also ·showed a decrease in blood-feeding ability ( <40%) after being exposed to blank coils. Nevertheless, the number of eggs oviposited by the treated females were not affected if the mosquitoes were able to blood-feed. This study also indicated that physiological effects on the mosquitoes after mosquito coil exposure were not carried over to the next generation.
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Fisiologi nyamuk , Pendedahan kepada lingkaran nyamuk
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