Proteoteras willingana

Contarinia negundinis

Proteoteras willingana (Kearf.) (Boxelder twig borer) 

This borer was present in nearly 24 percent of the boxelder locations examined. It was widespread, and most of the infestations were classified as trace to light. In one area the infestation level was considered moderate. In recent years this species has become somewhat troublesome in the Northern Great Plains, particularly in southern Saskatchewan and Manitoba. By 1955 it had caused considerable injury to boxelder in shelterbelts and ornamentals ( Prentice and Hildahl 1956). Since then this infestation has declined (Prentice and Hildahl 1958, 1959). In North Dakota it was first noticed as a nursery problem but has since become a problem on shelterbelts. Each larva may kill a new shoot ( fig. 3 ) and potentially could cause considerable injury. 

Contarinia negundifolia Felt (Boxelder gall midge) 

Eight ( 4 percent ) of the boxelder areas examined had the boxelder gall midge in 1960; all were in North Dakota. The infestation level, rated by the quantity of galls on each tree, ranged from trace to light. Most areas were shelterbelts, but two natural stands had the insects. An insect, probably this species, was reared from galls on boxelder leaves at Ames, la., prior to 1900. According to Felt ( 1908 ) the infestation was considered "quite serious to boxelder." It was not explained whether this referred to actual injury to the tree or whether the galls were just numerous. The latter is suspected. Damage by this insect probably results from premature leaf fall. 

Forest Insects and Diseases in the Northern Great Plains: A Survey