The poultry red mite (Dermanyssus gallinae) is the main pest of poultry, causing severe problems by being a vector of several animal and human pathogens. The number of miticides is few, and their efficacy in practice implies problems of residues and resistance; therefore, the demand for a new and safe agent is constant. The present publication investigated the effectiveness of lithium chloride under in vitro conditions on poultry red mites. This chemical currently appears to be one of the most promising alternatives to study amongst potential applicants to treat varroosis, a fatal disease of honey bees. In Experiment I, the previously used experimental doses (5.52 M, 2.76 M, 1.38 M) on Varroa mites confirmed their in vitro activity on the poultry red mite. Three event times (uncontrolled movement, immobilisation and death) were recorded to base the response to treatment for each concentration. In Experiment II, the LD 50 value was calculated, i.e., the value at which 50% of the mites were killed by the treatment. This Experiment showed that the LD50 of lithium chloride = 0.265 M in the poultry red mite. It is to note that the study remained restricted to in vitro confirmation of lithium chloride’s effectiveness on the parasite. Thus, further extensive studies are needed to decide whether it has any relevance in practice against D. gallinae, and also to assess potential residue problems that could affect poultry products.

Tetranychus urticae is a severe threat and a major source of yield loss in some agricultural and horticultural crops and it is also as a vector for several viruses. The number of active substances used against the pest is limited. Therefore, there is a continuous need for new active substances. Recently, lithium salts have been shown to be one of the most promising potential alternatives to control Varroa destructor; an apicultural mite pest. Based on this, we aimed to test whether the efficacy of lithium chloride extends to other agricultural mite pests, such as the two-spotted spider mite. In the present pilot study, we report for the first time that the efficacy of lithium chloride is extended to the two-spotted spider mite. Additionally, this is the first report on the acaricidal effectiveness of lithium on a plant mite pest. In the present study, we report three different concentrations that bear 100% mortality at concentrations of 5.52 M, 2.76 M, and 1.38 M. The symptoms caused were similar and followed the same sequence compared to those observed on animal parasites such as V. destructor and Dermanyssus gallinae.