376 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



beetle Scolytus multistriatus (Marsham) (pi. 11), introduced from 

 Europe, and a native bark beetle, Eylurgopinus ruflpes (Eich.). 

 Without these associates the disease could do no damage. In this 

 case, control emphasis has been placed on the disease, although actu- 

 ally the case is a close parallel to our bark beetle problems, where 

 several species of Ceratostomella^ or blue stains, are introduced by 

 Dendroctonus into the stems of pine and spruce to bring about their 

 destruction. More and more the control of this disease is becoming 

 a problem in the control of the vectors. 



Scolytus was introduced from Europe many years ago and is 

 widely distributed. When the disease first appeared in 1930 a survey 

 showed that it was well established in New Jersey and that a few 

 outlying infections existed. An eradication program was undertaken 

 in 1935. At the present time over $25,000,000 has been spent. 



As in the case of the gypsy moth control campaign, this large 

 intensive campaign has perfected methods, particularly in scouting 

 and chemical control, suitable for application to future similar 

 emergencies that may arise. 



RfiSUM^ ON DIRECT CONTROL 



Thus during a period of some 40 years, beginning at a time when 

 many of the most destructive of our forest pests were still new to 

 science, the threat of insects to our reserve timber stands, their 

 capacity in marring scenic and recreational values, their destruction 

 of second-growth forests, and their importance as a fire menace have 

 become widely appreciated, and highly specialized organizations for 

 the prevention or control of these losses have been developed. 



During this period more than $100,000,000 has been spent and in 

 recent years $5,000,000 to $10,000,000 annually has been utilized in 

 protective measures. The annual expenditures by the United States 

 Forest Service for fire protection is approximately $15,000,000. 



PROTECTION THROUGH MANAGEMENT 



The foregoing discussion presents a broad picture of insect activi- 

 ties in our forests and of man's efforts to counteract their destructive 

 tendencies where the timber stands are of sufficient value to warrant 

 direct expenditures for control. Such effort has been based, on the 

 theory that the necessary expenditures are justified because of the 

 greater value of the green timber saved by this action or because 

 of the recreational values involved. 



Gradually, while this was going on, entomologists and foresters 

 were thinking of the future, toward a time when methods for growing 

 timber crops so as to avoid insect losses could be substituted for 



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