Musca domestica and Chrysomya megacephala, considered synanthropic insects, are medically important flies, as they transmit vector-borne diseases to humans and animals. In Thailand, Stemona (Stemonaceae) plants have been traditionally used as insecticides. This study was designed to determine the larvicidal activity of S. collinsiae root extract against M. domestica and C. megacephala larvae. A 70% ethanol crude extract from S. collinsiae roots was tested against the third-instar larvae of both species using direct and indirect contact methods. The development and mortality rates of the insects were observed, and the LC values were calculated. The extract caused irregular development in both species, shown as segmental puparia that could not emerge as adult flies. The LC₅₀ values of the extract against M. domestica tested by direct and indirect contact methods were 0.0064 ± 0.0005 mg/larva and 0.0165 ± 0.0002 mg/cm²/larva, respectively. In the case of C. megacephala, the LC₅₀ value determined by the indirect contact method was 1.0500 ± 0.0001 mg/cm²/larva. The ethanolic root extract of S. collinsiae was able to kill the larvae of both species after dermal administration. It is of interest to develop S. collinsiae root extract as a natural fly control biopesticide.

家蝇和大头金蝇被认为是同生昆虫，是医学上重要的苍蝇，因为它们将媒介传播的疾病传播给人类和动物。在泰国，百部（百部科）植物传统上被用作杀虫剂。本研究旨在确定S. collinsiae根提取物对M. Domestica和C. megacephala幼虫的杀幼虫活性。使用直接和间接接触方法，对来自S. collinsiae根部的 70% 乙醇粗提物进行了针对这两个物种的三龄幼虫的测试。观察昆虫的发育和死亡率，并计算LC值。该提取物导致这两个物种的发育不规则，表现为节段性蛹，无法发育成成年果蝇。通过直接和间接接触法测试的提取物对家蝇的LC ₅₀值分别为0.0064±0.0005mg/幼虫和0.0165±0.0002mg/cm ² /幼虫。对于大头蠹，通过间接接触法测定的LC ₅₀值为1.0500±0.0001mg/cm ² /幼虫。经皮给药后，柯林氏链霉菌的乙醇根提取物能够杀死这两个物种的幼虫。开发柯氏沙门氏菌根提取物作为天然蝇控制生物农药是很有意义的。