Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
vervăgo, ĕre, v. a. [etym. unknown; acc. to Plin. 18, 19, 49, § 176, from ver-ago], to break up land, i. e. to plough land for the first time after its lying fallow: agros, Col. 11, 2, 8.