Look at man vsftpd.conf and search for the cmds_allowed option:
This options specifies a comma separated list of allowed FTP commands (post login.
USER, PASS and QUIT and others are always allowed pre-login). Other commands are
rejected. This is a powerful method of really locking down an FTP server. Example:
List all the command do you want except DELE, RMD, RNFR, RNTO (that are delete, rmdir, rename from and rename to respectively).