Evaluation of acaricidal activity of lithium-chloride against Tetranychus urticae (Acari: Tetranychidae)

Tetranychus urticae is a severe threat and a major source of yield loss in some agricultural and horticultural crops. Control is greatly complicated due to the hidden lifestyle of the species. In addition to its direct damage, it is considered a vector for several viruses. The number of active substances used against it is limited, and the development of resistance means that sustainable control is not achieved. Therefore, there is a continuous need for new active substances. Lithium salts have been shown to be a promising alternative to control Varroa destructor, an apicultural mite pest. Therefore, in the present study, we investigated whether the contact 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 extends to the two-spotted spider mite, showing 100% mortality at concentrations of 5.52 M, 2.76 M, and 1.38 M. It is to note, however, that the experiments did not cover residue and practical application aspects, and further extensive studies are needed in this area to clarify the relevance of the practical sub-classification.