diff --git a/mbtrack2/tracking/beam_ion_effects.py b/mbtrack2/tracking/beam_ion_effects.py
index 167b15da8fe864732a8534a04489cc5726bbd7d6..da354ba011dec6978d5b7d4d45a131a4abcba1d8 100644
--- a/mbtrack2/tracking/beam_ion_effects.py
+++ b/mbtrack2/tracking/beam_ion_effects.py
@@ -431,7 +431,7 @@ class BeamIonElement(Element):
 
         if self.ion_beam_monitor_name:
             warnings.warn(
-                'BeamIonMonitor.ion_beam_monitor_name.close() should be called at the end of tracking',
+                'BeamIonMonitor.beam_monitor.close() should be called at the end of tracking',
                 UserWarning,
                 stacklevel=2)
             self.beam_monitor = IonMonitor(