Seif Amal I, Shaarawi Fatma A
Department of Zoology and Entomology, Faculty of Science, Tanta University, Tanta, Egypt.
J Egypt Soc Parasitol. 2003 Apr;33(1):291-304.
Culicinomyces clavosporus was isolated from diseased larvae of Culex pipiens collected from brackish water habitat. Pure cultures of the fungus were grown on nutrient agar media. In the laboratory, the Egyptian isolate of the fungus was bioassayed against first instar larvae of Aedes caspius, Cx. antennatus and Cx. pipiens. The estimated LC50's for Ae. caspius, Cx. antennatus and Cx. pipiens were 4.4 x 10(2), 7.6 x 10(2) and 11.8 x 10(2) conidia/ml, respectively. Field studies were undertaken in a variety of habitats supporting populations of mosquitoes in Mahalet Marhoom, El-Gharbia Governorate, in the summer of 1999. Evaluations included artificial pool studies and field trials. The fungus was applied once to 3 different natural breeding habitats of mosquitoes at a dose rate of 10(10) conidia/m2. Cx. clavosporus introduction into unpolluted rice field that had high densities of Cx. antennatus and low densities of Anopheles tenebrosus Doenitz and Cx. perexiguus resulted in 100% control of the larvae 5 days post treatment. Introduction of the fungus into brackish water habitat supporting large brood of Ae. caspius, and few numbers of Culiseta longiareolata (Macquart), Cx. Pusillus, Cx. perexiguus and Cx. pipiens was equally effective. Dissection and examinations of larvae from both sites confirmed infection by the fungus. However, introduction of the fungus into a drain supporting high population density of Cx. pipiens was not effective. Microscopic examination of larvae removed from this site revealed that the conidia failed to germinate and penetrate the host cuticle. The presence of organic pollution in the breeding site drastically reduced the infectivity of the fungus. Thus, the fungus appears promising as a possible limiting factor for mosquito populations, and eventually its use in control of mosquitoes merits further investigations.
从采自咸水栖息地的致倦库蚊患病幼虫中分离出了棒孢库利蚊菌。该真菌的纯培养物在营养琼脂培养基上生长。在实验室中，对该真菌的埃及分离株针对尖音库蚊、触角库蚊和致倦库蚊的一龄幼虫进行了生物测定。尖音库蚊、触角库蚊和致倦库蚊的估计半数致死浓度分别为4.4×10²、7.6×10²和11.8×10²个分生孢子/毫升。1999年夏季，在盖勒尤比省马哈利特·马尔胡姆的各种支持蚊虫种群的栖息地进行了实地研究。评估包括人工池塘研究和田间试验。以10¹⁰个分生孢子/平方米的剂量率将该真菌施用于3个不同的蚊虫自然繁殖栖息地一次。将棒孢库利蚊菌引入触角库蚊密度高、深色按蚊和微小库蚊密度低的未受污染稻田，处理5天后幼虫得到了100%的控制。将该真菌引入支持大量尖音库蚊幼虫且长跗库蚊、微小库蚊、微小库蚊和致倦库蚊数量较少的咸水栖息地同样有效。对这两个地点的幼虫进行解剖和检查证实了真菌的感染。然而，将该真菌引入支持致倦库蚊高种群密度的排水沟中却无效。对从该地点采集的幼虫进行显微镜检查发现，分生孢子未能发芽并穿透宿主表皮。繁殖地中有机污染的存在大大降低了真菌的感染力。因此，该真菌似乎有望成为蚊虫种群的一个可能限制因素，最终其在蚊虫控制中的应用值得进一步研究。
