The New Zealand Institute for Plant & Food Research Limited, 412 No. 1 Road, RD2, Te Puke, New Zealand.
J Invertebr Pathol. 2011 Sep;108(1):46-51. doi: 10.1016/j.jip.2011.07.002. Epub 2011 Jul 12.
Several species in the fungal genus Cosmospora (synonym Nectria) (anamorph Fusarium) are specialist entomopathogens of armored scale insects (Diaspididae), known to cause periodic epizootics in host populations. Inconsistent mortality rates recorded under laboratory conditions prompted a study into the process of infection of armored scale insects by this fungus. Scale insect mortality following exposure to a Cosmospora sp. (Culture Collection Number: CC89) from New Zealand was related to insect age, with reproductively mature insects having a significantly higher infection rate than immature insects. Examination using scanning electron microscopy found no evidence that the fungus penetrated directly through the wax test (cap) of the scale insect or through the un-lifted interface between the test and the substrate on which the insect resided. However, fungal hyphae were observed growing beneath the test when the test of the reproductively mature insect lifted away from the substrate for the purpose of releasing crawlers, the mobile pre-settled juveniles. Once the hyphae of CC89 advanced under the test, germ-tubes readily penetrated the insect body through a number of natural openings (e.g. spiracles, vulva, stylet), with mycosis observed within seven days after inoculation. Direct penetration through the cuticle of the scale insect was not observed.
几种真菌属 Cosmospora（同义词 Nectria）（无性型 Fusarium）的物种是装甲介壳虫（Diaspididae）的专业昆虫病原物，已知会导致宿主种群周期性爆发疾病。在实验室条件下记录到的不一致死亡率促使人们对这种真菌感染装甲介壳虫的过程进行了研究。暴露于来自新西兰的一种 Cosmospora sp.（培养物收集编号：CC89）后，介壳虫的死亡率与昆虫年龄有关，生殖成熟的昆虫的感染率明显高于未成熟的昆虫。扫描电子显微镜检查未发现该真菌直接穿透介壳虫的蜡质外壳（帽）或未抬起的外壳与昆虫栖息的基质之间的界面的证据。然而，当生殖成熟的昆虫为释放爬行者（可移动的预先定居的幼虫）而将外壳从基质上抬起时，观察到真菌菌丝在外壳下生长。一旦 CC89 的菌丝在外壳下前进，芽管就会通过许多自然开口（例如气门、外阴、口针）轻易地穿透昆虫体，接种后七天内观察到真菌病。未观察到通过介壳虫的角质层的直接穿透。
