26 MONTANA EXPERIMENT STATION BULLETIN 474 



POPLAR BORER (Saperda calcarata) 



The poplar borer, which is probably quite common throughout 

 most of Montana, was reported only from Powder River County 

 during the last two years. 



COTTONWOOD LEAF-STEM GALL (Peviphigus populi-transversus) 



Numerous inquiries and specimens for identification have been 

 received concerning this aphid gall during the last two years. 

 These galls usually develop near the middle of the petioles of the 

 leaves, and are often as large as one-half inch long and an inch 

 in diameter. The gall is somewhat spherical in shape with a rel- 

 atively smooth covering which opens by a transverse slit extend- 

 ing more than half way around the gall. During the early summer 

 the interior of the gall is crowded with aphids. 



VAGABOND GALL (Mordwilkoja vagahunda) 



This is another aphid gall which is common to cottonwoods 

 throughout the state. The vagabond gall is easily distinguished 

 from the cottonwood leaf-stem gall because of its peculiar con- 

 voluted form and its occurrence at the tips of the twigs. 



COTTONWOOD LEAF BEETLE (Chrysomela scripta) 



The cottonwood leaf beetle, the larvae of which are voracious 

 feeders of cottonwood leaves, was reported in Fergus County in 

 1949. This is the only report received on this insect during the 

 past two years although it probably occurs throughout most of 

 the state. 



ELM LEAF CURL APHID (Eriosoma americanujn ) 



Elm leaf curl aphids occur over all of the state where Amer- 

 ican elm are grown. They have been particularly prevalent during 

 the past tvs-o years in most of these areas. This species is known 

 to attack only American elm and the principal injury from the 

 sucking activities of this insect is a rolling or curling effect of 

 the leaves 



WOOLEY APPLE APHID (Eriosoma lanigerum) 



The v.'ooley apple aphid which is also known as the wooley 

 elm aphid occurs generally throughout the state on apple and elm 

 trees. A serious infestation occurred in the Gallatin Valley in 1950. 

 This destructive insect has not been an economic factor during 

 the past two years in commercial apple plantings. 



LILAC BEETLE (Brachyrinus meridionalis ) 



The lilac beetle infestation reported at Hamilton in the Thirty- 

 Second Report of the State Entomologist is still present. There 

 has been little or no noticeable change in the population density 

 nor has any spread been detected. 



