June 7,1924 Temperatures Fatal to Powder-Post Beetle 1035 
sample, noting the condition of the larvae and placing them in vials for future 
observation. Copper tags (PL 1, A, B) furnishing data as to the treatment 
were placed on the remaining pieces, which were put in a heated kiln for further 
observation. Photographs were taken of the samples before and after treat¬ 
ment. After the treatment C. C. Shackford examined the material from time 
to time and noted its condition. A final examination was made four weeks later. 
These tests were conducted in practically an empty kiln. When the kiln is full 
of lumber, time should be allowed for all parts of the wood to reach kiln tem¬ 
perature, at which it should be held for the length of time found to be fatal to 
the insects. 
LOT I 
Because it had been previously determined that dry heat at 120° F. was not 
fatal to the powder-post beetle, indicating that a kiln with a saturated atmos¬ 
phere would require a higher temperature or a longer period of time, no sample 
pieces in Lot I were removed until after an exposure of one and one-half hours to 
a temperature of 130° F. 
The initial treatment of Lot I was similar to that used in commercial opera¬ 
tions for drying lumber. The lot was placed in the kiln at a low temperature, 
which was gradually raised, and the lumber left in the kiln over night. This 
was done to make sure that all parts of the samples were at kiln temperature 
when the temperature of the wood reached the initial point of the experiment. 
At 3 p. m. December 11 the samples were placed in the kiln at a temperature 
of 70° F. By 4 p. m. the temperature had been raised to 100° F., where it 
remained until 3 a. m. December 12. At 8.15 a. m. it reached 110° F. and at 
9.40 a. m. 130° F., where it was held for one and one-half hours. Upon removal 
of the first pieces the temperature was raised 10 degrees and held there for the 
same length of time, this operation being repeated until the last lot was removed 
from the kiln at 160° F. The maximum thermometer showed that the indication 
of the recording thermometer was 4° too low during the work on this lot. 
Table I .—Experiments to determine temperatures fatal to Lyctus planicollis by 
steaming infested ash lumber in a kiln . Lot I 
Sam¬ 
ple 
No. 
Size 
Tempera¬ 
ture and 
time held 
i 
i 
Time 
held at 
accumu¬ 
lated 
tempera¬ 
ture 
starting 
at 130° F. 
Humid¬ 
ity 
Propor¬ 
tion of 
sap- 
wood 
Number 
of piles 
of frass 
noted 
before 
steam¬ 
ing 
Larvae 
chopped out 
immediately 
after steaming- 
number and 
condition 
Final examina¬ 
tion, Jan. 10, 
4 weeks after 
steaming. Piles 
of frass noted; 
larvae chopped 
out where results 
were doubtful « 
Inches. 
°F. 
Hours. 
Hours. 
Per cent. 
Per cent. 
1 
1X12X18- 
! 130 
4 
4 
100 
! 25 
(ft) 
No signs of ac¬ 
1 
| 
tivity. 
2 
1X12X18- 
140 
1* 
3 
100 
1 95 
15 
Do. 
3 
1X12X18- 
! 140 
4 
3 
100 
i 95 
(ft) 
3, darkened_ 
Do. 
4 
1X12X18- 
150 
1* 
4 
100 
! 90 
1 
Do. 
5 
1X12X18- 
150 
4 
4 
100 ! 
95 
3 
c 
Do. 
6 
1X12X18- 
160 
if 
6 
100 
| 100 
(ft) 
Do. 
7 
1X12X18- 
160 
11 
6 
100 s 
100 
(ft) 
Do. 
8 
2X12X18- 
130 
4 
U 
ioo ! 
25 
1 
1, white. 
Do. 
9 
2X12X18- 
130 
4 
4 
100 
95 
15 
12, white; 9, 
Do. 
darkened. 
10 
2X12X18- 
140 
4 
3 
100 
20 
(ft) 
c 
Do. 
11 
2X12X18- 
140 
4 
3 
100 
10 
1 
Do. 
12 
2X12X18- 
140 
4 
3 
100 i 
25 
3 
Do. 
13 
2X12X18- 
140 
4 
3 
ioo ! 
20 
1 
Do. 
14 
2X12X18- 
150 
21 
4 
100 i 
25 
3 
3 larvae (1 
whit 
Do. 
15 
2X12X18- 
150 
21 
41 
100 
15 
1 
W J1A Ivy • 
Do. 
16 
2X12X18- 
150 
21 
41 
100 
15 
1 
Do. 
17 
2X12X18- 
150 
2 1 
41 
100 1 
20 
1 
Do. 
18 
2X12X18 
160 
21 
6 
100 i 
5 
(ft) 
Do. 
19 
2X12X18- 
160 
f 
6 
100 
5 
(ft) 
Do. 
20 
2X12X18- 
160 
6 
100 ! 
20 
7 
Do. 
21 
2X12X18- 
160 
21 
6 
ioo I 
10 
1 
c 
Do. 
« Examined by C. C. Shackford December 15,17, and 21, and January 3; checked by R., A. St. George 
on final examination. 
b No piles of frass noted, but all samples infested. 
« Examined; none found. 
