diff --git a/src/content_abm.cpp b/src/content_abm.cpp
index 0d0f0dedb713e89f5de43812a2c3ce068a2ed8f9..5812c7b502b0f9d063a63b9f4039e9415f3f4d7c 100644
--- a/src/content_abm.cpp
+++ b/src/content_abm.cpp
@@ -37,7 +37,7 @@ class GrowGrassABM : public ActiveBlockModifier
 	virtual std::set<std::string> getTriggerContents()
 	{
 		std::set<std::string> s;
-		s.insert("dirt");
+		s.insert("mapgen_dirt");
 		return s;
 	}
 	virtual float getTriggerInterval()
@@ -67,7 +67,7 @@ class RemoveGrassABM : public ActiveBlockModifier
 	virtual std::set<std::string> getTriggerContents()
 	{
 		std::set<std::string> s;
-		s.insert("dirt_with_grass");
+		s.insert("mapgen_dirt_with_grass");
 		return s;
 	}
 	virtual float getTriggerInterval()