Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sarrītĭo (sarītĭo, sartĭo), ōnis, f. [sarrio], a hoeing, weeding, Col. 2, 12, 1; 11, 2, 9; Serv. Verg. G. 1, 21.