Animal Research Institute, Department of Employment, Economic Development and Innovation, 665 Fairfield Road, Yeerongpilly, Queensland 4105, Australia.
Vet Parasitol. 2010 Nov 24;174(1-2):85-91. doi: 10.1016/j.vetpar.2010.08.003. Epub 2010 Aug 11.
Control of sheep lice with conventional pesticides can be compromised by difficulty in contacting lice in the dense water repellent fleeces of sheep, particularly when sheep have not been recently shorn. Entomopathogenic nematodes (ENs) are motile and are able to actively seek out insect hosts. They have particular advantages for the control of pests in cryptic habitats, such as the fleeces of sheep and avoid many of the problems frequently associated with chemical controls. This study investigated whether ENs were able infect and kill Bovicola ovis and compared the effectiveness of different species at different temperatures and when applied to wool. Four species of nematodes, Steinernema carpocapsae, Steinernema riobrave, Steinernema feltiae and Heterorhabditis bacteriophora were tested. All were shown to infect and kill lice in Petri dish assays at 30°C. At 35°C, the percent infection for S. carpocapsae and S. riobrave was significantly higher than for the other two species and percent infection by S. feltiae was significantly greater than for H. bacteriophora (P<0.05). At 37°C the percent mortality induced by S. riobrave was significantly greater than for S. carpocapsae (P<0.05). All species were able to locate and infect lice in wool when formulated in water with 8% Tween 80. In wool assays the percent lice infected with nematodes was significantly greater for S. riobrave than H. bacteriophora at 25°C, but there were no other differences between species (P=0.05). S. carpocapsae, S. riobrave and S. feltiae caused significantly higher lice mortality than H. bacteriophora at both 25 and 35°C in wool assays, but mortality induced by the three steinernematid species did not differ significantly (P>0.05). It is concluded that of the ENs studied S. riobrave is likely to be most effective against B. ovis when applied to live sheep because of its greater tolerance to high temperatures and 'cruiser' foraging strategy.
用传统杀虫剂控制绵羊虱可能会因难以接触到绵羊密被防水羊毛中的虱而受到影响，尤其是当绵羊最近未剪毛时。昆虫病原线虫（ENs）是能动的，能够主动寻找昆虫宿主。它们在控制隐藏栖息地中的害虫方面具有特殊优势，例如绵羊的羊毛，并且避免了许多与化学控制相关的问题。本研究调查了 ENs 是否能够感染并杀死 Bovicola ovis，并比较了不同物种在不同温度下以及应用于羊毛时的效果。测试了四种线虫，即 Steinernema carpocapsae、Steinernema riobrave、Steinernema feltiae 和 Heterorhabditis bacteriophora。所有这些在 30°C 的培养皿试验中均显示出能够感染并杀死虱子。在 35°C 下，S. carpocapsae 和 S. riobrave 的感染率明显高于其他两种，而 S. feltiae 的感染率明显高于 H. bacteriophora（P<0.05）。在 37°C 下，S. riobrave 诱导的死亡率明显大于 S. carpocapsae（P<0.05）。所有物种在含有 8%吐温 80 的水中配制成制剂时，均能够在羊毛中定位和感染虱子。在羊毛试验中，25°C 时，S. riobrave 感染线虫的虱子比例明显大于 H. bacteriophora，但在物种之间没有其他差异（P=0.05）。在羊毛试验中，S. carpocapsae、S. riobrave 和 S. feltiae 引起的虱子死亡率明显高于 H. bacteriophora，在 25 和 35°C 下，但三种 Steinernema 线虫引起的死亡率没有明显差异（P>0.05）。因此，在所研究的 ENs 中，S. riobrave 由于其对高温的更强耐受性和“巡航”觅食策略，当应用于活体绵羊时，可能对 B. ovis 最有效。
