diff --git a/NEWS b/NEWS
index 800813f3d..1aa81e56a 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,6 @@
+1.5.8.dev0
+ * #336: Fix for traceback when running Cronitor, Cronhub, and PagerDuty monitor hooks.
+
 1.5.7
  * #327: Fix broken pass-through of BORG_* environment variables to Borg.
  * #328: Fix duplicate logging to Healthchecks and send "after_*" hooks output to Healthchecks.
diff --git a/borgmatic/hooks/cronhub.py b/borgmatic/hooks/cronhub.py
index e0c496897..79450b56a 100644
--- a/borgmatic/hooks/cronhub.py
+++ b/borgmatic/hooks/cronhub.py
@@ -39,3 +39,10 @@ def ping_monitor(ping_url, config_filename, state, monitoring_log_level, dry_run
     if not dry_run:
         logging.getLogger('urllib3').setLevel(logging.ERROR)
         requests.get(ping_url)
+
+
+def destroy_monitor(ping_url_or_uuid, config_filename, monitoring_log_level, dry_run):  # pragma: no cover
+    '''
+    No destruction is necessary for this monitor.
+    '''
+    pass
diff --git a/borgmatic/hooks/cronitor.py b/borgmatic/hooks/cronitor.py
index aa3e4fffc..f15256eaf 100644
--- a/borgmatic/hooks/cronitor.py
+++ b/borgmatic/hooks/cronitor.py
@@ -38,3 +38,10 @@ def ping_monitor(ping_url, config_filename, state, monitoring_log_level, dry_run
     if not dry_run:
         logging.getLogger('urllib3').setLevel(logging.ERROR)
         requests.get(ping_url)
+
+
+def destroy_monitor(ping_url_or_uuid, config_filename, monitoring_log_level, dry_run):  # pragma: no cover
+    '''
+    No destruction is necessary for this monitor.
+    '''
+    pass
diff --git a/borgmatic/hooks/pagerduty.py b/borgmatic/hooks/pagerduty.py
index 770934713..ffecc0cc9 100644
--- a/borgmatic/hooks/pagerduty.py
+++ b/borgmatic/hooks/pagerduty.py
@@ -69,3 +69,10 @@ def ping_monitor(integration_key, config_filename, state, monitoring_log_level,
 
     logging.getLogger('urllib3').setLevel(logging.ERROR)
     requests.post(EVENTS_API_URL, data=payload.encode('utf-8'))
+
+
+def destroy_monitor(ping_url_or_uuid, config_filename, monitoring_log_level, dry_run):  # pragma: no cover
+    '''
+    No destruction is necessary for this monitor.
+    '''
+    pass
diff --git a/setup.py b/setup.py
index c04ac81ee..5b6d5da12 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 from setuptools import find_packages, setup
 
-VERSION = '1.5.7'
+VERSION = '1.5.8.dev0'
 
 
 setup(