diff --git a/_pytest/main.py b/_pytest/main.py
index 5771a1699..3383400e1 100644
--- a/_pytest/main.py
+++ b/_pytest/main.py
@@ -455,10 +455,6 @@ class Collector(Node):
             return str(exc.args[0])
         return self._repr_failure_py(excinfo, style="short")
 
-    def _memocollect(self):
-        """ internal helper method to cache results of calling collect(). """
-        return self._memoizedcall('_collected', lambda: list(self.collect()))
-
     def _prunetraceback(self, excinfo):
         if hasattr(self, 'fspath'):
             traceback = excinfo.traceback
diff --git a/_pytest/pytester.py b/_pytest/pytester.py
index 651160cc7..da8996a04 100644
--- a/_pytest/pytester.py
+++ b/_pytest/pytester.py
@@ -10,6 +10,8 @@ import time
 import traceback
 from fnmatch import fnmatch
 
+from weakref import WeakKeyDictionary
+
 from py.builtin import print_
 
 from _pytest._code import Source
@@ -401,6 +403,7 @@ class Testdir:
 
     def __init__(self, request, tmpdir_factory):
         self.request = request
+        self._mod_collections  = WeakKeyDictionary()
         # XXX remove duplication with tmpdir plugin
         basetmp = tmpdir_factory.ensuretemp("testdir")
         name = request.function.__name__
@@ -856,6 +859,7 @@ class Testdir:
             self.makepyfile(__init__ = "#")
         self.config = config = self.parseconfigure(path, *configargs)
         node = self.getnode(config, path)
+
         return node
 
     def collect_by_name(self, modcol, name):
@@ -870,7 +874,9 @@ class Testdir:
         :param name: The name of the node to return.
 
         """
-        for colitem in modcol._memocollect():
+        if modcol not in self._mod_collections:
+            self._mod_collections[modcol] = list(modcol.collect())
+        for colitem in self._mod_collections[modcol]:
             if colitem.name == name:
                 return colitem
 
diff --git a/_pytest/runner.py b/_pytest/runner.py
index d1a155415..6f1759f14 100644
--- a/_pytest/runner.py
+++ b/_pytest/runner.py
@@ -330,7 +330,9 @@ class TeardownErrorReport(BaseReport):
         self.__dict__.update(extra)
 
 def pytest_make_collect_report(collector):
-    call = CallInfo(collector._memocollect, "memocollect")
+    call = CallInfo(
+        lambda: list(collector.collect()),
+        'collect')
     longrepr = None
     if not call.excinfo:
         outcome = "passed"
@@ -568,4 +570,3 @@ def importorskip(modname, minversion=None):
             raise Skipped("module %r has __version__ %r, required is: %r" %(
                           modname, verattr, minversion), allow_module_level=True)
     return mod
-