1.9.2. Inhibition in colonies

  1. Assess the degree of infection in colonies before treatment, as described in paragraph 1.3.1. (Quantify infection degree in colonies)
  2. Increase colony infection with A. apis as described in paragraph 1.5.2. (Infection bioassay of colonies)
  3. Apply the test item to the colony
  4. Assess the level of infection in the colony, as described in paragraph 1.3.1. (Quantify infection level in colonies) the next day after treatment and repeat the assessment depending of the aim of the experiment.

We propose an indirect assessment of in vivo treatments because quantifying the disease by counting mummies is very difficult and inaccurate. If the disease is increasing in the colony, the spore numbers will also increase; likewise, if the disease is decreasing, the spore number will be lower due to the natural behaviours of the bees such as hygienic removal of larvae. The degree of infection would most probably be related to the dynamics of A. apis spore load in the colony. Evaluation of the level of infection in the colony before and after treatment is therefore recommended.