Vol. XXVIII, No. 10 
1038 Journal of Agricultural Research 
An examination of the larvae chopped out on December 17 showed that tem¬ 
peratures of 120° and 130° F., when held for only one-half hour, were not fatal 
to the insects. Living larvae of the powder-post beetle were obtained from these 
samples. In addition, immature and mature stages of a beneficial insect known 
to be predacious on the powder-post beetle were also found alive and in consider¬ 
able numbers. There*'were not enough present, unfortunately, to exterminate 
the injurious forms. 
A further examination on December 21 verified these results and showed a 
revival of the larvae in samples subjected to temperatures varying from 120° to 
140° F. when held there for only one-half hour (PL 1, A). Other samples in 
these lots showed that the larvae were affected and did not recover until January 3. 
A final examination was made on January 10, and the above-recorded results 
verified. Larvae probably revived in the samples subjected to temperatures up 
to 140° F. because all parts of the wood had not reached kiln temperature when 
removed, or, if so, were not held at that temperature long enough to cause the 
death of the insects. The samples held at 140° F. had an accumulation of 
temperatures for one and one-half hours. 
It will be noted that samples of Lot I were exposed to temperatures gradually 
raised to 130° F., and were kept at that temperature for 1^2 hours. This treat¬ 
ment was fatal to the powder-post beetles because the wood had remained in 
the kiln over night at temperatures ranging from 100° to 110° F., and all 
parts of the samples had reached kiln temperature. Under such conditions 
the subsequent treatment proved fatal to the beetles. 
Results obtained from treating Lot II show that placing samples in the kiln, 
raising the temperature at once to the initial temperature of 130° F., and holding 
it there for 2 Yi hours, is effective in killing any powder-post beetles in the wood. 
CONCLUSIONS 
Results obtained from the foregoing experiments may be briefly summarized 
as follows: 
1. Temperatures below 130° F. are not fatal to the powder-post beetle Lyctus 
planicollis Lee. when the temperature of infested ash and oak lumber is raised to 
these temperatures in a kiln by the use of live steam and are held there for only 
one-half hour, if all parts of the wood have not previously been brought to kiln- 
drying temperature. 
2. Temperatures of 130° F. and upward, maintained for 1% hours, or longer, 
are fatal to these insects if all parts of the wood infested by them have at the 
beginning of the exposure to these temperatures been brought to the minimum 
temperature of 130° F. 
3. The standard kiln-drying schedule for ash and oak, to be used for aircraft 
stock, in a kiln operated by live steam will prove fatal to the powder-post beetle 
and will check all damage that is being done in any infested material. 
