Survival of larvae of the ragwort flea beetle, Longitarsus flavicornis (Coleoptera: Chrysomelidae), in water-logged soil

Water-logged soil could be a major factor affecting populations of the ragwort biological control agent, Longitarsus flavicornis, in Australia. Survival of L. flavicornis larvae in potted ragwort plants after inundation with water for up to 264 h ( 11 days) was compared to larval survival in control plants not exposed to inundation. Probit analysis indicated that 35.6% mortality of the larval population occurred after 24 h inundation and 50.4% after 72 h. As high mortality was recorded at periods of inundation known to occur in the field, it is concluded that winter flooding is likely to be detrimental to populations of L. flavicornis.