4 io 



ures that can be attained through for- 

 est management. In the case of forest 

 products, changes in methods of man- 

 ufacture and storage often completely 

 avoid the attack of wood-boring in- 

 sects. Those preventive measures have 

 been termed indirect control. 



Two OF THE SO-CALLED insect dead- 

 enings occurred in widely separated 

 forests about 1895. One was in the 

 spruce forests of West Virginia, the 

 other in the ponderosa pine stands of 

 the Black Hills of South Dakota. A. D. 

 Hopkins, State entomologist of West 

 Virginia, conducted studies in both 

 cases and determined that two closely 

 related species of tree-killing bark bee- 

 tles were involved. He recommended 

 the destruction of the bark beetle broods 

 under the bark before they could de- 

 velop into winged beetles and fly off to 

 attack more green trees. The trees that 

 contained living broods of the beetle 

 were located, felled, and barked or 

 burned. For every tree so treated two or 

 three green trees were saved from attack. 



Many projects have been undertaken 

 since that time, in all costing some- 

 thing more than 12 million dollars up 

 to 1949. Insect control in all cases has 

 been the responsibility of the land- 

 managing agencies on the land under 

 their jurisdiction, but the many tech- 

 nical matters forming the basis for this 

 control work made it necessary, partic- 

 ularly in the larger projects, to assign 

 entomologists to supervise the activi- 

 ties. Entomologists have also assumed 

 responsibility for detection surveys and 

 the recommendation as to when and 

 where and how control work should 

 be done. 



As bark beetle control increased, it 

 became more and more evident that 

 successful operations depended not so 

 much on the control method used as 

 upon a complete knowledge of the bark 

 beetle situation on the immediate and 

 surrounding area. A complete picture 

 of the extent of the infestation 

 whether it was increasing or decreas- 

 ing, the points of greatest concentra- 

 tion, the direction of spread proved 



Yearbook of Agriculture 1949 



to be absolutely necessary. It was also 

 necessary to have a broad general 

 knowledge of the insect population 

 throughout all susceptible timber types 

 so as to be able to recognize outbreaks 

 in their early stages and make recom- 

 mendations for control before the in- 

 festation was completely out of hand. 

 Such information could only be ob- 

 tained by the careful surveys made by 

 skilled technicians. This unquestion- 

 ably became the function of the en- 

 tomologists. It is too bad that neither 

 funds nor trained men have been avail- 

 able to make these surveys sufficiently 

 extensive or of the needed accuracy. 

 The inadequacy of the present survey 

 system is illustrated by the outbreaks 

 that existed during the seasons of 1947 

 and 1948. 



THE ADOPTION BY CONGRESS of the 

 Forest Pest Control Act on June 25, 

 1947, should mark the beginning of a 

 new era in the prevention of the exten- 

 sive losses caused each year by forest 

 insects. This law provides authoriza- 

 tion for adequate surveys of all forest 

 regions of the United States on both 

 public and private lands. This act rep- 

 resents the culmination of a long effort 

 on the part of industry, foresters, and 

 entomologists. It was foreseen by those 

 instrumental in planning and shaping 

 this legislation that adequate surveys 

 and prompt control would gradually 

 improve our knowledge of the insect 

 situation so that the recurrence of such 

 widespread outbreaks as occurred in 

 1947 and 1948 should be largely pre- 

 vented. 



WITH DEFOLIATORS, direct control of 

 infestations in the forest has been much 

 slower in its development. Such insects 

 as caterpillars and sawflies that injure 

 or kill trees have always been difficult 

 for the entomologist or forester to deal 

 with. Defoliator outbreaks develop rap- 

 idly and the damage may often be com- 

 plete before the outbreak is noticed. 

 Insecticidal sprays have been expensive 

 to apply and the equipment designed 

 for street or orchard trees was imprac- 



