ACARICIDAL ACTIVITY OF INERT POWDERS AGAINST THE POULTRY RED MITE DERMANYSSUS GALLINAE (DE GEER, 1778) (MESOSTIGMATA: DERMANYSSIDAE)

Abstract

Dermanyssus gallinae is one of the most important ectoparasite of laying hens. The intensive use of chemicals has led to the selection of resistant mite populations. The difficulty in controlling the mites has promoted the search for alternative products. Thereby, the aim of this study was to assess in laboratory the acaricidal activity of inert mineral powders against D. gallinae, in dust and water suspensions (5 and 10%) treatments. The products were tested against eggs, nymphs and adults of the mite. There were differences in the activity of tested products. Some products based on diatomaceous earth, kaolin and talc, applied in powder form on adults of the mite were more efficient and selected for subsequent tests. In liquid suspension bioassay it was observed no ovicidal activity of any of the tested products. However, the products were efficient on the nymphs with no difference between both products and concentrations. The activity of diatomaceous earth and kaolin 2120 in 5 and 10% water suspension on adults was significatively higher than other treatments against adults. There was no difference between the treatments in residual activity. The morphological characterization and identification of diatom frustules present in the product PosturaSec^® indicated prevalence of the genus Brachysira Kützing, density of 5.7 x 10⁷ valves/g, 200 μm size particles and 86.2% of silicon.