EXTRACTION OF SMALL LARVAE OF WISEANA SPP (LEPIDOPTERA, HEPIALIDAE) FROM PASTURE SAMPLES BY HIGH-TEMPERATURE GRADIENT FUNNEL

A high-gradient heat extraction apparatus for extracting porina (Wisea na 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 so il-washing, the only other practicable method. Of the larvae which wer e extracted from cores 15 mm deep, 77% emerged within 2 h and 96% with in 5 h. The speed of extraction was not affected by moisture content o f the cores but it was slightly reduced if deeper cores were used.