Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ascălo, ōnis, f., = Ἀσκάλων, an important trading town in the southern part of Palestine, between Gaza and Azotus upon the sea, now Ascalon, Mel. 1, 11, 3; Plin. 5, 13, 14, § 68; cf. Mann. Palaest. 202.
Hence, adj.: Ascălōnĭus, a, um, of Ascalon: caepa, a shallot, Col. 11, 3, 57; 12, 10, 1; Plin. 19, 6, 32, § 101 sqq.