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 humi dities 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 i n the three series respectively, The efficacy was influenced by the ag e of the medium with diatomaceous earth when investigated under the dr iest condition of 58% r.h. Used as a top-dressing in the order of a fe w millimetres depth, very little effect,vas obtained. The results indi cate that it is possible to use diatomaceous earth against E. kuehniel la in the milling industry, but the actual conditions must be consider ed carefully. Diatomaceous earth is a natural product and may be usefu l in structural treatment of cracks and crevices in mills producing fl our ''organically'', and also in conventional mills when prohibition o f methyl bromide takes effect. (C) 1998 Elsevier Science Ltd, All righ ts reserved.