In vitro assay and morphological characterization of a new product based on diatomaceous earth for lesser mealworm control in poultry houses

ABSTRACT: Diatomaceous earth (DE) is an inert powder obtained from milling the fossilized deposits of diatoms. Mainly composed of silica dioxide, DE is highly hygroscopic and is recommended for use in poultry houses as an evironmental conditioner, with a secondary action being the reduction of lesser mealworm populations Alphitobius diaperinus (Panzer). This study aimed to characterize and assess the insecticidal activity of a new environmental conditioner for poultry houses (Poultry Sec®, Vet Science Bio Solution, Maringá, Paraná, Brazil) in the laboratory. The study was conducted by adding DE to poultry feed (1, 2 and 3 g DE/kg feed), as well as by applying the DE to the poultry litter (86 and 172 g DE/m2), with A. diaperinus adults (26°C in the dark for 10 days). DE samples were analyzed by optical microscopy to measure and count the frustules and to identify the genera of the components. The insecticidal action of the product was observed. When applied to the litter, the DE caused between 83 and 85% mortality. With respect to the qualitative analysis of the diatoms, we estimated the concentration of 1.2 × 106 individuals/g of the product, distributed in nine distinct genera, with Brachysira Kützing being the predominant genus (40%)