| 摘要: | 台灣地處亞熱帶，是登革熱的好發區，目前主要採用噴灑化學殺蟲劑進行登革熱病媒蚊防治。但因為長期使用化學殺蟲劑，已造成病媒蚊產生抗藥性，對人體健康與生態環境都造成重大衝擊。印楝素具有殺蟲作用，且對人與環境都有較高的安全性。本研究針對台灣登革熱的主要病媒：埃及斑蚊和白線斑蚊，以含印楝素之三種未經乳化的冷壓榨苦楝油 (編號NM1、NM2、NM3) 及三種苦楝油商品 (編號NM4、NM5、NM6) 共六種苦楝油，分別在500、1000、2000ppm及4000ppm四種濃度，測試兩蚊種的二、三、四齡幼蟲，於苦楝油溶液中靜置24、48、72小時後之致死濃度。顯示冷壓苦楝油NM2的殺蟲效果最佳，在四種濃度下對各齡期及不同靜置時間的埃及斑蚊與白線斑蚊，都具有相當高的致死力，其靜置時間24小時的半致死濃度為1821ppm。本研究預備試驗無意中發現，本土的無患子萃取油在500ppm下對二、三齡埃及斑蚊幼蟲的24小時致死率即高達80%以上，於2000ppm下對各齡期更可達90%。無患子為本土植物，取材方便，值得推薦，以取代進口苦楝油。 本研究建議使用苦楝油商品防治病媒蚊埃及斑蚊與白線斑蚊的幼蟲，以冷壓苦楝油 (編號NM2) 或39.5%w/w無患子油施用在孳生幼蟲的水體中，施用濃度達500ppm即可達100%致死率的殺蟲效果。
In Taiwan, a dengue fever epidemic area in subtropical region, the main strategy to control the dengue fever vector, mosquito, is still using traditional chemical pesticides. However, the long-term overuse of chemical insecticides, which caused the resistance of mosquitoes to pesticides, results in more and more side-effects to human health and the environments. The azadirachtin extracted from Melia azedaracha has significant insecticidal effects to dengue vectors, and more friendly to human and environments than chemical pesticides. This study focuses on Aedes aegypti and Aedes albopictus, the two main dengue fever vectors in Taiwan. The lethality of second, third and fourth instar mosquito larvae have been tested with three unformulated neem oil products (named: NM1, NM2, NM3) and three plant products (named: NM4, NM5, NM6) under 500, 1000, 2000, and 4000 ppm within 24, 48, and 72 hours. The study found that the toxicity of NM2 is the highest. It showed high toxicity on A. aegypti with nearly all three instars under each concentration, and also on A. albopictus (LC50: 1821.242 ppm, 24hr). We accidentally found that soap berry (Sapindus saponaria) extracted oil revealed over 80% lethality to second and third instar A. aegypti larvae under 500 ppm within 24 hours, and reached 90% lethality to all instars under 2000 ppm. S. Saponaria is recommended to replace the import neem oil since it is local species in Taiwan and easy to obtain. The neem oil related products are suggested to be the effective means to control the larvae of two dengue fever vectors, A. aegypti and A. albopictus. The extracted neem oil (NM2) or 39.5%w/w soap berry extracted oil (NM7) is recommended to be used in the larva-bred water body, and it represents 100% lethality to larvae under 500 ppm. |
