Lewis & Short

industrĭōsē, adv., v. industriosus.

industrĭōsus, a, um, adj. [industria], very active, diligent, or industrious (postAug.), Cassiod. Var. 8, 33; Sen. Prov. 2 dub.; Val. Max. 3, 4, 2 dub.
Hence, adv.: industrĭōsē, very industriously, Cassiod. Var. 5, 1; Suet. Vit. Juv.
Comp., Fronto ad M. Caes. 4, 3 med.
Sup., Cato ap. Charis. p. 181 P.