TEMPERATURES FATAL TO LARV^ OF THE RED-HEADED 

 ASH BORER AS APPLICABLE TO COMMERCIAL 

 KILN DRYING 



By F. C. Craighead, Bureau of Bntomology, and W. K. Lough- 

 borough, Forest Products Laboratory 



The demand for seasoned ash stock during the past few years 

 necessitated the extensive use of kiln-dried material. The attention 

 of the Bureau of Entomology was called to several cases where manu- 

 facturers, using such material in aircraft construction, reported con- 

 tinued injury by the red-headed ash borer (Neoclyfus erythrocephalus 

 Fab.) after the wood was kiln dried. As practically no information 

 was available as to what temperatures are fatal to these wood-boring 

 insects, a co-operative project with the Forest Products Laboratory of 

 the Forest Service was suggested by the Branch of Forest Insects of 

 the Bureau of Entomology to ascertain the fatal temperatures and de- 

 termine if the temperatures in the commercial kiln processes recom- 

 mended by the Forest Products Laboratory are sufificient to destroy 

 the borers. 



The purpose of these experiments and the entomological features 

 were outlined by the Branch of Forest Insects which also furnished the 

 material. The methods of conducting the experiments were outlined 

 by the Forest Products Laboratory in accordance with the laboratory 

 facilities and commercial practices in kiln drying. 



Subjecting wood to dry kiln temperatures for the sole purpose of 

 destroying wood-boring insects is, of course, only necessary in cases 

 where more practical methods of preventing the injury have been over- 

 looked or can not be applied under existing circumstances. In these 

 cases considerable injury is already under way which should have been 

 avoided and kiln processes will, therefore, only arrest the damage and 

 prevent further injury by the borers. However, practically no damage 

 from insect attack need be expected if the lumber is kiln dried shortly 

 after it has been felled. 



The seasonal history and methods of preventing losses by this insect, 

 as well as another insect, "the banded ash borer" (Neoclytus caprcra 

 Say), causing similar injury, have been discussed in publications of the 

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