The plaintiff shall cause to be published once in a newspaper of general circulation in the county where the lands are situated a notice of the proceeding at least 14 days in advance of the date fixed by the court for consideration of the petition and appointment of appraisers, and shall at least 14 days before such date mail to each interested party as named in Kan. Stat. Ann. § 26-502, and amendments thereto, and whose address is known or can with reasonable diligence be ascertained a copy of such publication notice and petition insofar as it relates to his interest. No defect in any notice or in the service thereof shall invalidate any proceedings.