2 BULLtfT^ 407^.11..$^ DEPARTMENT OF AGRICULTURE. 



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Frequently, however, storms blow over many millions of feet of 

 saw timber. Cases are on record where a single firm has lost in such 

 a manner 100,000,000 board feet. It is a physical impossibility to log 

 these trees promptly and get them to the saw or into a place of safety, 

 although from 40 to 60 days' delay may mean total destruction of the 

 sapwood by borers. It might be feasible, however, to saw these trees 

 into log lengths and spray with some solution that would prevent 

 insect attack for two or three months, or until it was possible to haul 

 them to the mill. 



The increasing use of the national forests and parks for recrea- 

 tional purposes has resulted in the construction of many rustic cabins. 

 Insects attacking the timbers in these buildings cause annoying exu- 

 dations of boring dust and loosen the bark so that later it peels off, 

 thus marring the artistic effect. Much of this injury to rustic work 

 could be prevented by cutting the trees at certain periods and by 

 proper seasoning. Frequenters of summer camping grounds can not 

 always plan to cut the trees at the proper time; in fact, it is more 

 frequently the case that the building is constructed during the sum- 

 mer months and the timber felled at that time a period when the 

 wood is most susceptible to insect attack. 



Thus in both situations it is often the case that the more practical 

 and economical means can not be used. 



There is. also a considerable demand for a suitable repellent spray 

 against certain shade-tree insects. Wood borers attack various spe- 

 cies of living trees, causing considerable injury or death. Under 

 certain circumstances a spray could be used advantageously to repel 

 such insects and prevent oviposition. It would necessarily have to 

 be of materials that would not burn the younger bark, although, 

 except for mechanical difficulties, it would only be necessary to apply 

 the spray to the main trunk and larger limbs, $ince these are the only 

 parts attacked. Spray materials, the cost ofVwhich would be pro- 

 hibitive for the protection of forest products, nlight be employed on 

 shade trees. 



Under circumstances such as the foregoing it is evident that a 

 "practical spray for the prevention of insect injury would be of much 

 benefit and its use should result in a considerable saving of forest 

 products and shade trees. 



Owing to the many different insects, their different methods of 

 attacking the logs, the many kinds of wood to be protected, and the 

 exposure to weather conditions, the practical solution of this prob- 

 lem presents many difficulties. Several solutions have been found 

 to meet the requirements, except that they are too expensive or too 

 difficult to apply. In the hope that the results so far obtained may 

 be a stimulus for further suggestions or work along this line the 



