diff --git a/pyqtgraph/SignalProxy.py b/pyqtgraph/SignalProxy.py
index 7463dfc3..46b44887 100644
--- a/pyqtgraph/SignalProxy.py
+++ b/pyqtgraph/SignalProxy.py
@@ -81,7 +81,7 @@ class SignalProxy(QtCore.QObject):
         except:
             pass
         try:
-            self.sigDelayed.disconnect(self.slot())
+            self.sigDelayed.disconnect(self.slot)
         except:
             pass