The suspicious device found at Babson College late last month that was destroyed in a controlled detonation turned out to be pesticide equipment unintentionally left behind by a crew the night before, according to the State Fire Marshal’s office. The pesticide device, which distributes chemicals into cracks and crevices, was used by exterminators to ward off dust mites and bed bugs, said Jennifer Mieth, spokeswoman for the State Fire Marshal’s office. Babson spokesman Michael Chmura said that the extermination crew was performing routine pesticide maintenance at the college’s Executive Conference Center on the night before the incident. Mieth said the crew accidentally left the device behind, adding that it was “not a hoax device.” The device was found Jan. 24 around 7 a.m. near the conference center, and was destroyed by State Police bomb technicians about four hours later out of “an abundance of caution,” college officials previously told the Globe. A portion of the center was evacuated after the device was found.