The effect of a diatomaceous earth formulation on the larvae of Ephestia kuehniella Zeller

A diatomaceous earth formulation was tested against the larvae of the Mediterranean flour moth (Ephestia kuehniella Zeller) at relative humidities of 58%, 75% and 84% r.h. The LC50 of the formulation when mixed with broken wheat kernels was estimated to be 2.4, 4.4 and 5.2 g/kg in the three series respectively, The efficacy was influenced by the age of the medium with diatomaceous earth when investigated under the driest condition of 58% r.h. Used as a top-dressing in the order of a few millimetres depth, very little effect,vas obtained. The results indicate that it is possible to use diatomaceous earth against E. kuehniella in the milling industry, but the actual conditions must be considered carefully. Diatomaceous earth is a natural product and may be useful in structural treatment of cracks and crevices in mills producing flour "organically", and also in conventional mills when prohibition of methyl bromide takes effect. (C) 1998 Elsevier Science Ltd, All rights reserved.