THE PECAN LEAF CASE-BEARER. 
21 
On Plats I and III the case-bearer was satisfactorily controlled, 
while on Plat II, which was left untreated, very serious damage was 
done during the spring by the overwintering larvae. Rather serious 
injury was done to the foliage on Plats I and III, owing in part to 
the showery weather that followed the spraying, which made con- 
ditions favorable for the suspension of free arsenic on the leaves. 
The sprayed trees shed their foliage a little sooner than the checks, 
but defoliation 'did not take place so early as to cause the trees to 
bud out again. 
A series of dosage tests with lead arsenate was carried out for the 
purpose of determining the proper strength necessary to control 
effectively the pest under orchard conditions. The results of this 
work are contained in Table XVIII. 
Table XVIII. — Spraying experiments against the larvae of the pecan leaf case-bearer to 
determine the most effective dosage of lead arsenate; Monticello, Fla., 1914- 
Results. 
Plat 
No. 
Num- 
ber of 
Treatment. 
Date of 
appli- 
trees. 
cation. 
Degree of 
Arsenical injury 
infestation. 
to foliage. 
1914 
I 
26 
Powdered lead arsenate at H pounds to 
50 gallons of water. 
Aug. 20 
Practically none. 
Serious. 
II 
16 
Powdered lead arsenate at 1 pound to 
50 gallons of water. 
...do 
do..... 
Rather serious. 
III 
31 
Powdered lead arsenate at h pound to 
50 gallon of water. 
...do 
Light infestation 
Slight burning. 
IV 
6 
Check; unsprayed 
...do 
Very heavy in- 
festation. 
Light infestation 
V 
37 
Paste lead arsenate at 1 pound to 50 gal- 
lons of water. 
Paste lead arsenate at 1J pounds to 50 
...do 
Slight burning. 
VI 
24 
Aug. 22 
Very light infes- 
Somewhat pro- 
gallons of water. 
tation. 
nounced. 
VII 
21 
Paste lead arsenate at 2 pounds to 50 
gallons of water. 
...do 
Practically none. 
Rather serious. 
VIII 
18 
Paste lead arsenate at 2\ pounds to 50 
gallons of water. 
...do 
do 
Serious. 
IX 
26 
Paste lead arsenate at 3 pounds to 50 
gallons of water. 
...do 
do 
Do. 
X 
24 
Two pounds of paste arsenate of lead 
plus 4 pounds of lime to 50 gallons of 
water. 
...do 
do 
Only a trace of 
burning. 
As is shown in Table XVIII, the powdered lead arsenate at \ pound 
(Plat III), and paste form at 1 pound (Plat V), as well as 1| pounds 
(Plat VI) , to 50 gallons of water were found to be too weak for effec- 
tive work, while the powdered lead arsenate at 1 pound and \\ pounds 
and the paste form at 2, 2h, and 3 pounds gave very satisfactory 
control. It was discovered that pecan foliage was quite susceptible 
to arsenical injury, for on all plats there was some burning. The worst 
burning occurred on Plats I, VIII, and IX, where the stronger dosages 
of lead arsenate were used; but where the weaker dosages were 
employed the injury was considerably lessened. The foliage on Plat 
X, sprayed with lead arsenate to which lime was added, was in the 
best condition, as only a trace of burning occurred. 
