diff --git a/phpBB/viewforum.php b/phpBB/viewforum.php
index a3fd9fa6fb..c60721e3f1 100644
--- a/phpBB/viewforum.php
+++ b/phpBB/viewforum.php
@@ -195,7 +195,7 @@ if ($forum_data['forum_topics_per_page'])
 // Do the forum Prune thang - cron type job ...
 if (!$config['use_system_cron'])
 {
-	$task = $cron->instantiate_task('core_prune_forum', $forum_data);
+	$task = $cron->instantiate_task('cron_task_core_prune_forum', $forum_data);
 	if ($task && $task->is_ready()) {
 		$url = $task->get_url();
 		$template->assign_var('RUN_CRON_TASK', '<img src="' . $url . '" width="1" height="1" alt="cron" />');