3.5.2. Dipping

Dipping mites in a solution containing dsRNA resulted in gene knockdown (Campbell et al., 2010), demonstrating the potential of this procedure as a way to infect or contaminate mites with micro-organisms or genetic material. This study showed that when proper osmolality of the dipping solution is established, a high number of varroa mites (80 %) can survive long immersion periods (14 h at 4 °C) that might be necessary for infection/contamination. To achieve the right osmolality, 0.9 % NaCl was used. Dipping methods have rarely been used for varroa, and optimisation work should be done to improve the survival of the mite after immersion.