diff --git a/bin/ontobio-parse-assocs.py b/bin/ontobio-parse-assocs.py
index 14c49a4c..a5313046 100755
--- a/bin/ontobio-parse-assocs.py
+++ b/bin/ontobio-parse-assocs.py
@@ -143,9 +143,11 @@ def main():
         rule_set = assocparser.RuleSet.ALL
     
     goref_metadata = None
+    goref_species = None
     if args.metadata_dir:
         absolute_metadata = os.path.abspath(args.metadata_dir)
-        goref_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "gorefs"))    
+        goref_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "gorefs"))
+        goref_species = metadata.yaml_set(absolute_metadata, "go-reference-species.yaml", "taxon_id")
 
     # set configuration
     filtered_evidence_file = open(args.filtered_file, "w") if args.filtered_file else None
@@ -161,6 +163,7 @@ def main():
         allow_unmapped_eco=args.allow_unmapped_eco,
         gpi_authority_path=args.gpi,
         goref_metadata=goref_metadata,
+        goref_species=goref_species,
         rule_set=rule_set
     )
     p = None
diff --git a/bin/validate.py b/bin/validate.py
index 9dd3f35d..ac3e658c 100755
--- a/bin/validate.py
+++ b/bin/validate.py
@@ -210,7 +210,7 @@ def create_parser(config, group, dataset, format="gaf"):
 """
 
 @tools.gzips
-def produce_gaf(dataset, source_gaf, ontology_graph, gpipaths=None, paint=False, group="unknown", rule_metadata=None, goref_metadata=None, db_entities=None, group_idspace=None, format="gaf", suppress_rule_reporting_tags=[], annotation_inferences=None, group_metadata=None, extensions_constraints=None, rule_contexts=[], gaf_output_version="2.2", rule_set=assocparser.RuleSet.ALL):
+def produce_gaf(dataset, source_gaf, ontology_graph, gpipaths=None, paint=False, group="unknown", rule_metadata=None, goref_metadata=None, goref_species=None, db_entities=None, group_idspace=None, format="gaf", suppress_rule_reporting_tags=[], annotation_inferences=None, group_metadata=None, extensions_constraints=None, rule_contexts=[], gaf_output_version="2.2", rule_set=assocparser.RuleSet.ALL):
     filtered_associations = open(os.path.join(os.path.split(source_gaf)[0], "{}_noiea.gaf".format(dataset)), "w")
     config = assocparser.AssocParserConfig(
         ontology=ontology_graph,
@@ -220,6 +220,7 @@ def produce_gaf(dataset, source_gaf, ontology_graph, gpipaths=None, paint=False,
         paint=paint,
         rule_metadata=rule_metadata,
         goref_metadata=goref_metadata,
+        goref_species=goref_species,
         entity_idspaces=db_entities,
         group_idspace=group_idspace,
         suppress_rule_reporting_tags=suppress_rule_reporting_tags,
@@ -516,9 +517,11 @@ def produce(ctx, group, metadata_dir, gpad, ttl, target, ontology, exclude, base
     # extract the titles for the go rules, this is a dictionary comprehension
     rule_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "rules"))
     goref_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "gorefs"))
+    goref_species = metadata.yaml_set(absolute_metadata, "go-reference-species", "taxon_id")
 
     click.echo("Found {} GO Rules".format(len(rule_metadata.keys())))
     click.echo("Found {} GO_REFs".format(len(goref_metadata.keys())))
+    click.echo("Found {} GO_REF Species".format(len(goref_species)))
 
     paint_metadata = metadata.dataset_metadata_file(absolute_metadata, "paint")
     noctua_metadata = metadata.dataset_metadata_file(absolute_metadata, "noctua")
@@ -546,6 +549,7 @@ def produce(ctx, group, metadata_dir, gpad, ttl, target, ontology, exclude, base
             group=group,
             rule_metadata=rule_metadata,
             goref_metadata=goref_metadata,
+            goref_species=goref_species,
             db_entities=db_entities,
             group_idspace=group_ids,
             suppress_rule_reporting_tags=suppress_rule_reporting_tag,
@@ -654,6 +658,7 @@ def rule(metadata_dir, out, ontology, gaferencer_file):
 
     goref_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "gorefs"))
     gorule_metadata = metadata.yamldown_lookup(os.path.join(absolute_metadata, "rules"))
+    goref_species = metadata.yaml_set(absolute_metadata, "go-reference-species", "taxon_id")
 
     click.echo("Found {} GO Rules".format(len(gorule_metadata.keys())))
 
@@ -667,6 +672,7 @@ def rule(metadata_dir, out, ontology, gaferencer_file):
     config = assocparser.AssocParserConfig(
         ontology=ontology_graph,
         goref_metadata=goref_metadata,
+        goref_species=goref_species,
         entity_idspaces=db_entities,
         group_idspace=group_ids,
         annotation_inferences=gaferences,
diff --git a/ontobio/io/assocparser.py b/ontobio/io/assocparser.py
index 28728900..622f0109 100644
--- a/ontobio/io/assocparser.py
+++ b/ontobio/io/assocparser.py
@@ -231,6 +231,7 @@ def __init__(self,
                  paint=False,
                  rule_metadata=dict(),
                  goref_metadata=None,
+                 goref_species=None,
                  group_metadata=None,
                  dbxrefs=None,
                  suppress_rule_reporting_tags=[],
@@ -255,6 +256,7 @@ def __init__(self,
         self.paint = paint
         self.rule_metadata = rule_metadata
         self.goref_metadata = goref_metadata
+        self.goref_species = goref_species
         self.group_metadata = group_metadata
         self.suppress_rule_reporting_tags = suppress_rule_reporting_tags
         self.annotation_inferences = annotation_inferences
diff --git a/ontobio/io/qc.py b/ontobio/io/qc.py
index dd89f745..fc950a4b 100644
--- a/ontobio/io/qc.py
+++ b/ontobio/io/qc.py
@@ -925,6 +925,22 @@ def test(self, annotation: association.GoAssociation, config: assocparser.AssocP
 
         return self._result(True)
 
+class GoRule64(GoRule):
+
+    def __init__(self):
+        super().__init__("GORULE:0000064", "TreeGrafter ('GO_REF:0000118') IEAs should be filtered for GO reference species", FailMode.HARD)
+
+    def test(self, annotation: association.GoAssociation, config: assocparser.AssocParserConfig, group=None) -> TestResult:
+        references = [str(ref) for ref in annotation.evidence.has_supporting_reference]
+        evidence = str(annotation.evidence.type)
+
+
+        #TreeGrafter reference is GO_REF:0000118
+        if evidence in [iea_eco] and 'GO_REF:0000118' in references and (config.goref_species is not None and str(annotation.subject.taxon) in config.goref_species):
+            return self._result(False)
+
+        return self._result(True)
+
 GoRules = enum.Enum("GoRules", {
     "GoRule02": GoRule02(),
     "GoRule05": GoRule05(),    
@@ -951,6 +967,7 @@ def test(self, annotation: association.GoAssociation, config: assocparser.AssocP
     "GoRule58": GoRule58(),
     "GoRule61": GoRule61(),
     "GoRule63": GoRule63(),
+    "GoRule64": GoRule64(),    
     # GoRule13 at the bottom in order to make all other rules clean up an annotation before reaching 13
     "GoRule13": GoRule13()
 })
diff --git a/ontobio/validation/metadata.py b/ontobio/validation/metadata.py
index 322ab489..8b370635 100644
--- a/ontobio/validation/metadata.py
+++ b/ontobio/validation/metadata.py
@@ -171,3 +171,18 @@ def groups(metadata) -> Set[str]:
         raise click.ClickException("Could not find or read {}: {}".format(groups_path, str(e)))
 
     return set([group["shorthand"] for group in groups_list])
+
+
+def yaml_set(metadata, yaml_file_name, field) -> Set[str]:
+    yaml_path = os.path.join(os.path.abspath(metadata), yaml_file_name)
+    try:
+        with open(yaml_path, "r") as yaml_file:
+            click.echo("Found yaml file at {path}".format(path=yaml_path))
+            yaml_list = yaml.load(yaml_file, Loader=yaml.FullLoader)
+    except Exception as e:
+        raise click.ClickException("Could not find or read {}: {}".format(yaml_path, str(e)))
+
+    return set([yaml[field] for yaml in yaml_list])   
+    
+    
+
diff --git a/tests/test_qc.py b/tests/test_qc.py
index 64514d4a..75479d4a 100644
--- a/tests/test_qc.py
+++ b/tests/test_qc.py
@@ -775,6 +775,34 @@ def test_go_rule_63():
     assoc = make_annotation(evidence="ISO", withfrom="").associations[0]
     test_result = qc.GoRule63().test(assoc, all_rules_config())
     assert test_result.result_type == qc.ResultType.WARNING
+    
+def test_go_rule_64():
+    config = assocparser.AssocParserConfig(
+        goref_species={
+            "NCBITaxon:7227", "NCBITaxon:123"
+        },
+        rule_set=assocparser.RuleSet.ALL
+    )
+            
+    assoc = make_annotation(evidence="IEA", references="GO_REF:0000118").associations[0]
+    assoc.subject.taxon = Curie.from_str("NCBITaxon:678")
+    test_result = qc.GoRule64().test(assoc, config)
+    assert test_result.result_type == qc.ResultType.PASS
+
+    assoc = make_annotation(evidence="IBA", references="GO_REF:0000118").associations[0]
+    assoc.subject.taxon = Curie.from_str("NCBITaxon:123")
+    test_result = qc.GoRule64().test(assoc, config)
+    assert test_result.result_type == qc.ResultType.PASS
+    
+    assoc = make_annotation(evidence="IEA", references="GO_REF:0000123").associations[0]
+    assoc.subject.taxon = Curie.from_str("NCBITaxon:123")
+    test_result = qc.GoRule64().test(assoc, config)
+    assert test_result.result_type == qc.ResultType.PASS         
+
+    assoc = make_annotation(evidence="IEA", references="GO_REF:0000118").associations[0]
+    assoc.subject.taxon = Curie.from_str("NCBITaxon:7227")
+    test_result = qc.GoRule64().test(assoc, config)
+    assert test_result.result_type == qc.ResultType.ERROR 
 
 def test_all_rules():
     # pass
@@ -791,7 +819,7 @@ def test_all_rules():
     assoc = gafparser.to_association(a).associations[0]
 
     test_results = qc.test_go_rules(assoc, config).all_results
-    assert len(test_results.keys()) == 25
+    assert len(test_results.keys()) == 26
     assert test_results[qc.GoRules.GoRule26.value].result_type == qc.ResultType.PASS
     assert test_results[qc.GoRules.GoRule29.value].result_type == qc.ResultType.PASS