THE PECAN LEAF CASE-BEAKER. 
23 
cates that the pecan is practically as susceptible to burning as is the 
peach and that the same precautions must be used in order to prevent 
serious injury to its foliage. 
FUMIGATION EXPERIMENTS AGAINST HIBERNATING LARVAE. 
Experiments Against Larvae on Pecan Nursery Trees. 
As the pecan leaf case-bearer may be freely distributed through 
the medium of nursery stock as larvae in hibernacula about the buds, 
it was considered advisable to obtain some data in regard to fumiga- 
tion. A specially constructed box, measuring 10 feet long, 3 J feet 
high, and 3 feet wide, was used for this work. The box was so made 
as to be practically air-tight. In order to test the effect of fumigation 
on the larvae as well as on the plant itself, a number of infested, 
grafted, or budded pecan trees, ranging from 3 to 5 feet in height, 
were used. In order to have the trees in the best possible condition, 
they were dug from the nursery during the afternoon of the day before 
fumigation, and immediately after the fumigation experiments were 
completed the trees were set out in the laboratory yard at Monticello, 
Fla. The method and results of these experiments are shown in 
Table XX. 
Table XX. — Fumigation experiments on pecan nursery trees for destruction of over- 
wintering larvx of the pecan leaf case-bearer at Monticello, Fla., in 1916. 
Experi- 
ment 
No. 
Number 
of trees. 
Treatment. 
Date of 
fumiga- 
tion. 
Results. 
I 
II 
III 
8 
8 
8 
Fumigated for 1 hour with 1 ounce 
of sodium cyanid 1 per 100 cubic 
feet, using formula 1-2-3. 2 
Fumigated for 1 hour with 1| ounces 
of sodium cyanid per 100 cubic 
feet, using formula 1-2-3. 
Check; untreated 
1916. 
Feb. 25 
...do.... 
Larvae were not killed, and these 
larva? destro3'ed the buds. Trees 
were not injured by fumigation. 
All larvae were killed. No ap- 
parent injury to trees by fumi- 
gation. 
Larvae emerged in numbers and 
buds on the trees were badly 
damaged. 
1 Sodium cyanid used was equivalent to 129 per cent potassium cyanid. 
2 Formula: 1 ounce (avoirdupois) sodium cyanid, 2 fluid ounces of sulphuric acid, 3 fluid ounces of water 
to 100 cubic feet of space. 
It will be noted in Table XX that in experiment I, where 1 ounce 
of sodium cyanid per 100 cubic feet was used, the case-bearer 
larvae were not killed, while in experiment II, where 1J ounces of 
cyanid was used, the results were very satisfactory, as no larva? 
emerged from the hibernacula. On May 1, 1916, it was found that 
the buds on trees in experiments I and III were badly damaged by 
the larvae and that the buds and foliage on trees in experiment II 
were not injured. So far as could be determined, the fumigation had 
no effect whatever on the trees, as both the check and fumigated 
