(Dermanyssus gallinae) are a recurrent issue in laying hens: a 2004 study by Guy et al. estimates its prevalence around 87.5% in the UK livestock buildings, for example. The red mite life cycle is completed in just 1-2 weeks thanks to blood meals taken from his hosts. Red mites are a light-avoiding specie that live in the cracks and crevices and which is especially resistant (it can survive for months without feeding) and complex to eradicate.
Red mites causes irritation, nervousness and stress in animals, which can lead to feather pecking and cannibalism, causing a general deterioration of the animals’ well-being. It is also a vector for pathogens such as salmonella or viruses (St. Louis encephalitis, Newcastle disease). In terms of production, the economic impact can be devastating: stunting, egg drops, stained eggs. Within the EU, the losses due to red mite are estimated at 130 million € per year (George et al., 2009).
There is no solution to permanently eradicate red mites. Nevertheless, some principles of prevention and hygiene are recommended, especially during the cleaning of the buildings. As for synthetic insecticides and miticides, they are not an ideal solution, particularly be-cause of the emergence of resistance, the possible presence of residues in the animal feed and its environmental impact.
Treatments based on natural substances or plants can also be sprayed directly on the areas of concentration of the red mites. These substances are: silica, natural pyrethrum, sulfur or essential oils from plants. Several studies point out the repellent and regulation effect of products derived from certain plants, while being harmless to animal and environmental safety. Let’s underline for instance the work of Kim et al. (2002) that proves the toxic effect on red mites of 56 essential oils (cade oil, cinnamon oil, clove …). Other means can be deployed, such as the use of flash light during the night (however, incompatible with the respect of animal welfare) or the implementation of red mites predators, now under investigation.