ABSTRACT

Slugs and snails are agricultural pests usually controlled by chemical bait pellets however an alternative method is the commercially produced malacopathogenic nematode Phasmarhabditis hermaphrodita, which is sold across northern Europe. P. hermaphrodita can kill several slug species but is unable to affect larger pestiferous snails. Therefore, we examined whether the closely related species Phasmarhabditis californica, isolated from the U.K. could kill neonate or adult common garden snails (Cornu aspersum). In our first experiment, neonate C. aspersum were exposed to 1000 nematodes per tube containing three strains of P. californica (designated DMG0017, DMG0018 or DMG0019) (as well as the commercial formulation of P. hermaphrodita DMG0001) and feeding inhibition and survival were monitored over 14 days. All nematodes apart from P. californica (DMG0017) killed the snails and caused feeding inhibition. In a follow up experiment we exposed adult C. aspersum to two doses (30 and 90 nematodes per cm²) of P. californica (DMG0019) and P. hermaphrodita (DMG0001) and monitored survival, feeding inhibition and changes in weight over 21 days. Neither nematode species affected survival, feeding inhibition or weight of the adult snails. In summary, P. californica (DMG0018 and DMG0019) are as pathogenic as P. hermaphrodita (DMG0001) and could be used to target neonate snails, however, the use of malacopathogenic nematodes to control large adult snails continues to be problematic.

摘要

蛞蝓和蜗牛是通常由化学诱饵颗粒控制的农业害虫，但另一种方法是商业生产的致病性线虫Phasmarhabditis hermaphrodita，它在整个北欧销售。P. hermaphrodita可以杀死几种蛞蝓物种，但不能影响较大的有虫害的蜗牛。因此，我们研究了从英国分离出的密切相关的物种Phasmarhabditis californica是否可以杀死新生或成年的普通花园蜗牛 ( Cornu aspersum ) 。在我们的第一个实验中，新生C. aspersum每管暴露于 1000 条线虫，其中含有三种P. californica菌株（指定为 DMG0017、DMG0018 或 DMG0019）（以及P. hermaphrodita DMG0001的商业制剂）和摄食抑制和存活监测超过 14 天。除P. californica (DMG0017)外的所有线虫都杀死了蜗牛并导致进食抑制。在后续实验中，我们将成年C. aspersum暴露于两剂（每厘米² 30 和 90 条线虫）的P. californica (DMG0019) 和P. hermaphrodita (DMG0001) 中，并在 21 天内监测存活率、摄食抑制和体重变化. 两种线虫都不影响成年蜗牛的存活、摄食抑制或体重。总之，P. californica(DMG0018 和 DMG0019) 与P. hermaphrodita (DMG0001)一样具有致病性，可用于针对新生蜗牛，但是，使用致病线虫控制大型成年蜗牛仍然存在问题。