diff --git a/pytest_hot_reloading/plugin.py b/pytest_hot_reloading/plugin.py
index ff85cbe..3d66d0d 100644
--- a/pytest_hot_reloading/plugin.py
+++ b/pytest_hot_reloading/plugin.py
@@ -324,7 +324,7 @@ def lagged_listdir(*args, **kwargs):
                 time.sleep(0.02 * poll_throttle)  # give CPU a break!
                 return listdir(*args, **kwargs)
 
-            super().__init__(stat, lagged_listdir, polling_interval * poll_throttle)
+            super().__init__(stat, lagged_listdir, polling_interval=polling_interval * poll_throttle)
 
     jurigged.live.PollingObserverVFS = NewPollingObserverVFS