Create functions.php

functions.php

@@ -0,0 +1,18 @@
+<?php
+
+function prohibit_author_comment( $approved, $commentdata ) {
+
+  $post_id = $commentdata['comment_post_ID']; // get the post ID.
+  $author_id = get_post_field( 'post_author', $post_id ); // Get the author ID. 
+
+	if( $commentdata['user_ID'] == $author_id ) {
+		return 'trash'; // skip everything, comment goes straight to trash.
+
+	}
+
+	return $approved; // This is the approval status set on WP Dashboard.
+}
+
+add_filter( 'pre_comment_approved' , 'prohibit_author_comment' , '99', 2 );
+
+?>