Efficiency of Berlese-Tullgren Funnels for Removal of the Rusty Grain Beetle, Cryptolestes Ferrugineus, From Wheat Samples

The efficiency of Berlese-Tullgren funnels in removing the rusty grain beetle, Cryptolestes ferrugineus (Stephens), from wheat samples was tested by adding adults and larvae to wheat samples. The recovery of adults from 300 g samples was 79% at 12.3% moisture content (m.c.) and 49% at 16% m.c.; from 150 g samples the recovery was 84% at 16% m.c. The number of adults recovered represented at least 98% of those that did not escape from the top of the samples. The number that escaped varied with sample size and moisture content. The recovery of fourth instar larvae was 78% from samples of 300 g at 16% m.c. The percentage of first and second instar larvae recovered was 5.8 when larvae alone were mixed with the wheat sample and left for 65 h, 10.6 when larvae in flour were added to the surface of the wheat sample, and 27.9 when larvae in flour were added to the centre of the wheat sample.