MONTANA INSECT PESTS, 1953-1954 17 



CONIFERS 



BLUE SPRUCE GALL APHID (Adelges cooleyi) 



This periodic pest was present throughout most of the state during 

 the biennium. Inquiries were received from Gallatin, Yellowstone, Silver 

 Bow, and Musselshell counties. A new organic phosphate of low human 

 toxicity' known as malathion has been used very successfully against this 

 insect, which causes cone-like swellings on the new terminal growth. 



SPRUCE LEAF-TIER (Epinotia nanana) 



No cases of spruce leaf-tier infestations were reported during the 

 biennum. 



PINE LEAF SCALE (Chionaspis pimfoliae) 



Pine leaf scale was present throughout most of the state during the 

 biennium. Probably the worst infestations occurred in Yellowstone, Fergus, 

 Big Horn, Musselshell, and Toole counties. Although this insect is known 

 as the pine leaf scale, its preferred host under Montana conditions appears 

 to be Colorado blue spruce. This insect is controlled with timely applications 

 of dormant sprays or with organic phosphates. 



RED SPIDER (Order: Acarina) 



These pests were present in greater than usual numbers throughout 

 large areas of the state and did considerable damage to evergreens in the 

 south-central part of the state. 



SPRUCE NEEDLE MINER (Taniva albolineana) 



One infestation of spruce needle miner was reported during the bien- 

 nium from Lake County. 



SPRUCE BUDWORM (Choristoneura fumiferana) 



Although this insect is primarily a pest of timber trees, reports of infes- 

 tations on ornamentals in towns of the southwestern part of the state have 

 been received. Huge flights of the night-flying adults were lured into tovm 

 by the electric lights. 



DESTRUCTIVE HOUSEHOLD INSECTS 



CLOVER MITES (Bryobia praetiosa) 



Clover mites continued to represent a major household pest throughout 

 most of the state during the biennium. Reports and inquiries concerning this 

 pest were received from almost every county in the state. Since control of 

 this pest is very difficult, a program is being planned to work out the most 

 efficient methods of control. 



