Extraction of small larvae of Wiseana spp. (Lepidoptera: Hepialidae) from pasture samples by high temperature gradient funnel

Abstract

A high‐gradient heat extraction apparatus for extracting porina (Wiseana spp.) larvae of less than 10 mm long from cores of pasture soil is described. Extraction by heat was more effective and faster than by soil‐washing, the only other practicable method. Of the larvae which were extracted from cores 15 mm deep, 77% emerged within 2 h and 96% within 5 h. The speed of extraction was not affected by moisture content of the cores but it was slightly reduced if deeper cores were used.

Keywords:

• Tullgren funnel
• heat extractor
• Wiseana
• Hepialidae
• Lepidoptera
• porina
• pasture pest
• sampling