12 TENTH BIENNIAL REPORT 



dwarfed and stunted appearance. There is no remedy. Affected 

 trees should not be planted. 



Silver Leaf: Some orchards show several trees affected with 

 this disease, but with very few exceptions it cannot be said to be doing 

 any damage. 



Root Rot or Crov^tn Rot: It is not known what causes" this 

 condition. Some investigators have found the blight bacteria in af- 

 fected trees and they are inclined to attribute the condition to that 

 disease. 



The tree is usually affected at or near the surface of the ground 

 where the bark gradually dies. The roots finally become affected and 

 in seme cases the condition extends up the trunk of the tree. Event- 

 ually the tree becomes girdled and dies. There is no remedy. Many 

 courses of procedure have been suggested, but they are of very doubt- 

 ful value. Many orchards are beginning to show this condition, but 

 generally only on a few^ trees. There is no special cause for alarm. 



Insect Pests 



Blistek ]\riTE: (EriopJiyes pi/W Pgst.) Apple and pear trees 

 are attacked by this insect and badly affected trees lose their leaves 

 before the summer is over. The insect is a microscopic mite which 

 feeds within the leaf causing the characteristic browning of the leaves. 

 The injury caused is worse during dry seasons than during rainy 

 seasons. It was exceptionally bad during 1918 and was present in 

 practically all orchards not properly sprayed for it. This was espe- 

 cially true in the Bitter Root valley. The blister mite can easily be 

 controlled by spraying. 



Brn MoTH: (Spilonota (Tmetocera ) ocellana Schiff.) The bud 

 moth larva was apparent in most orchards' last year. The damage 

 done was, however, slight, but unless controlled it will become quite 

 serious in the future. It is easily controlled by spraying with arscn- 

 icals at the proper time. 



Codling Motii: (CarjxKapsa pomanella Linn.) Very little 

 spread of this pest has been noted in the past two years. It is present 

 in most of the cities, but the orchards of the Flathead Lake region, 

 Sanders county and the Bitter Root valley are as yet quite free. 

 There is, however, a slight infestation on the east side of the latter 



