MONTANA INSECT PESTS, 1947 AND 1948 iS 



CURRANTS 



CURRANT APHIS (Capitophorus rihis) 



In general, damage from this species of aphis has been Hght 

 during the past two j^ears. 



CURRANT FRUIT FLY {Epochra canadensis) 



This insect pest is widely distributed throughout Montana. In 

 general, infestations were light for both years of the biennium. 



INSECTS INJURIOUS TO SHADE TREES AND SHRUBS 



EVERGREENS 



SPRUCE GALL APHID (Adelges cooleyi) 



The spruce gall aphid has continued to be quite prevalent over 

 the entire state during the last two years. It has caused consider- 

 able damage to ornamental spruce trees. It is a difficult pest to 

 control due to the variations in the dates of appearance of the 

 cottony stage. It is only in this stage that control methods are 

 effective. 



PINE LEAF SCALE (Chionaspis pinifoliae) 



Infestations of the pine leaf scale in varying degrees of 

 severity have been observed on ornamental pine trees throughout 

 the southern and western parts of the state. This insect is 

 apparently found all over Montana and has been especially notice- 

 able during the last biennium. 



PINE BARK APHID (Chermes pinicorticis) 



This pest was recorded from Corvallis in 1947. As yet, its 

 distribution in Montana is not known. The presence of this aphid 

 is indicated by spots and patches of white cottony material on the 

 smooth bark of the trunk and on the under sides of the limbs of 

 white pine. The white waxy threads are also seen at the base of 

 the needles, especially at the ends of branches. Attacks by this 

 insect weaken the tree, making it less resistant to the attacks of 

 other insects and of fungus diseases. 



RED CEDAR APHID (Cinara sp.) 



In the Bitterroot Valley, Juniper has been found seriously 

 infested with the red cedar aphid. Where these insects are present 

 usually the damage has been severe, characterized by the killing 

 of the needles to such an extent that the plant dies. The injury 

 produced is similar to that resulting from winter injury or red 

 spider damage. 



