Sadly, even in the best case scenario with intensive management the rusty-patched bumblebee is doomed to go extinct in just 30 years. Disease issues from commercial bumblebee hives and, even more problematic, the production of sterile diploid males at low population sizes, thereby rendering small patches extinct, are the main issues. The extensive use of neonicotinoid pesticides have also been implicated, as well as the loss of habitat. Without captive breeding I doubt this species will survive. To make matters worse, another two species of bumblebee are also in the petition for endangerment process.
To read the recovery plan outline for this species (which lacks the 30 year outlook data), go here:
https://ecos.fws.gov/docs/recovery_p...gned%20(1).pdf