18 MONTANA EXPERIMENT STATION BULLETIN 484 



plied treatments of paradichlorobenzene-linseed oil solutions have 

 apparently successfully controlled this insect. 



GREEN ASH APHID (Prociphilus venafuscus) 

 Few infestations of green ash aphids were reported dur- 

 ing the biennium. Infestations occurred in Yellowstone County in 

 1951, and in Ravalli County in 1952. 



ASH FLOWER GALL (Eriophijes fraxiniflora) 

 Only one infestation of ash flower gall was reported during 

 the biennium. This occurred in Musselshell County in 1952. 



WILLOW LEAF GALL (Pontania sp.) 

 The willow leaf gall which is caused by a hymenopterous 

 sawfly appears to have been prevalent during the biennium. Num- 

 erous reports and inquiries were received regarding this pest. 

 There are no known control measures at the present time. 



POPLAR BORER (Saperda calcarata) 

 A single infestation of poplar borers reported during the bi- 

 ennium occurred in Lake County in September of 1951. 



COTTONWOOD LEAF-STEM GALL (Pemphigus populi-transversus) 

 Two infestations of cottonwood leaf-stem gall aphids were 

 reported during the biennium. These were in Cascade and Yel- 

 lowstone counties in 1951. 



VAGABOND GALL (Mordwilkoja vagabunda) 

 Infestations of vagabond gall aphids were reported in Pondera 

 and McCone counties in 1951 and Pondera and Glacier counties 

 in 1952. 



COTTONWOOD LEAF BEETLE (Chrysomela scripta) 

 A single infestation of cottonwood leaf beetle was reported 

 in Sanders County in 1952. This is the only known occurrence 

 during the biennium. 



ELM LEAF CURL APHID (Eriosoma americanum) 

 Elm leaf curl aphids were reported in 1951 from Phillips, 

 Wibaux, Valley, and Dawson counties. The only infestation re- 

 ported in 1952 occurred in Chouteau County. 



SPIDER MITES (Acarina group) 

 Many moderate to severe infestations of spider mites occurred 

 on raspberries, mountain ash, coniferous trees, and other orna- 

 mentals over most parts of the state during the biennium. Such 

 infestations were generally more severe during the late summer 

 months. Tetraethyl pyrophosphate sprays were used in control 

 programs. 



