October, ’23] 
primm & hartley: box leaf miner control 
439 
as in the oil sprays, greatly increased its efficiency. The diminishing power 
of the tobacco extracts is noted on the third day when the relation of 
the number killed by contact to the number successfully emerged, is 
seen to be very much smaller. The maximum emergence was not reach¬ 
ed until two or three days after the last count was made. As the resin 
fish oil soap failed to check them after the third day either by trapping 
the adults or killing by contact, without fresh applications, the workmen 
changed to the oil treatment and further experimental value was there¬ 
fore complicated. The molasses treatment (Treatment B) yielded less 
data for comparison, as most of the plants having a high infestation 
had first been fumigated, or had been fumigated before much emergence 
had taken place. The counts were taken from one small bush, and at a 
time when comparatively few adults had emerged, but would indicate a 
good control. A steady rain through the 17th and 18th washed off the 
spray, however, and on the day following, when the bush was unpro¬ 
tected, swarms of adults emerged and oviposited in the leaves. Two 
more applications were given after an interval of two or three days, but 
only 15.4% control was obtained (See Table 2, Treatment C). The 
hydrocyanic gas treatments (Treatments D and E) yielded very promising 
results, but should not be construed in favor of this treatment without 
qualifications. The high kill in Treatment E is probably due to the 
fact that a large percentage had reached the pupal stage, rather than in a 
perfection of the treatment. The 79 individuals recorded as alive in 
both treatments were larvae. Furthermore, a very high temperature 
was generated in the tent during fumigation, which the operator claimed 
was due to some secret process in connection with the treatment. A 
maximum and minimum thermometer which was placed in one of the 
tents during fumigation, went to its limit, 13U° F. All the tender young 
growth was killed back. Experiments using heat as a treatment prob¬ 
ably would yield some interesting results. 
Table II. 
Exp. No. 
No. of leaves 
infested 
No. of larvae in No. of leaves 
infested leaves uninfested 
Percent 
kill 
2 
150 
200 
3300 
91.0 
Check 
774 
1474 
1389 
3 
189 
262 
2793 
87.1 
Check 
774 
1474 
1389 
4 
646 
1087 
6183 
86.0 
Check 
2381 
5513 
2369 
5 
313 
392 
2776 
92.0 
Check 
1147 
2787 
610 
C . 
588 
920 
1009 
15.4 
Check 
774 
1474 
1389 
The above tabulation shows the counts of newly hatched larvae 
