Not going to comment on the specifics of the article, but just wanted to throw something out there:
Many plant / animal pathogens are already adapted to one insect or another. Take Malaria, for example, which has mechanisms to escape the mosquito gut, survive and grow in its bloodstream, and travel to the salivary glands.
In this case, TRSV was already known to spread via honeybees, so it's just a few steps more for the virus to develop a lethal effect on them. In that context,
seems just a bit of a stretch...