154 
Journal of Agricultural Research 
Vol. XXIX, No. 3 
Table X .—Results of tests to determine residual insecticidal action as well as the 
immediate effect of contact insecticides on eggs of Phlyctaenia rubigalis 
Experi¬ 
ment 
No. 
Date 
Dosage and 
When 
Num¬ 
ber of 
eggs 
Date of— ! 
sprayed 
treatment 
treated 
Deposition 
Hatching 
1921 
| 
I_ 
Apr. 25 
40 per cent nicotine 
Before depo¬ 
sition. 
190 
Apr. 26..., 
May 3 
sulphate, 1-800; 
no soap; entire 
plant dipped. 
II_ 
— .do_ 
Same as in Experi- 
After depo- 
55 
Apr. 24.... 
Apr. 30 
ment I. 
sition. 
Apr. 29_ 
III_ 
...do_ 
Soap solution, 1 
Before depo- 
19 
Apr. 26_ 
May 4 
ounce to 1 gallon 
water; 2 plants 
dipped. 
sition. 
24 
...do.. 
May 5 
IV. 
...do_ 
Same as in Experi- 
After depo- 
110 
Apr. 25.... 
May 3 
ment III. 
sition. 
V_ 
...do_ 
40 per cent nicotine 
Before depo- 
38 
Apr. 26_ 
May 4 
sulphate, 1-800; 
sition. 
45 
Apr. 28.... 
May 7 
soap, 1 ounce to 1 
gallon; plants 
dipped. For egg 
deposition at in¬ 
tervals of 1, 3, and 
40 
Apr. 30_ 
May 10 
5 days, respec¬ 
tively. 
After depo- 
VI.. 
...do_ 
Same as in Experi- 
44 
Apr. 25_ 
May 3 
ment V. 
sition. 
May 1-2. _ 
May 10 
VII_ 
...do_ 
Control; no treat- 
Before depo- 
139 
Apr. 29_ 
May 8 
ment. 
sition. 
VIII-.. 
...do_ 
Control; no treat- 
After depo- 
90 
Apr. 24_ 
Apr. 30 
ment. 
sition. 
Observations and 
results 
May 3, no effect on 
hatching; lower 
leaves died, pos¬ 
sibly owing to 
dipping; larvae 
fed heavily, and 
9 days later plant 
was ruined. 
Apr. 30, eggs 
hatched. 
May 12, all larvae 
developing nor¬ 
mally. 
May 4, no effect on 
hatching; lower 
leaves died; lar¬ 
vae fed heavily. 
May 12, plant ru¬ 
ined as result of 
feeding. 
May 3, eggs 
hatched; noeffect 
on eggs or larvae. 
May 9, larvae fed 
so heavily that 
leaves were bad¬ 
ly spotted. 
May 4-10, no effect 
on hatching; lar¬ 
vae fed and de¬ 
veloped normal¬ 
ly. Eggs depos¬ 
ited Apr. 28-30 
showed tendency 
to scale loose, but 
later hatched. 
May 3-10, eggs 
hatched; lower 
leaves showed 
slight injury; 
larvae develop¬ 
ing normally. 
May 8, all hatched 
and developed 
normally. 
May 8, all hatched 
and developed 
normally. 
TESTS FOR THE DESTRUCTION OF EGGS 
BY DIPPING PLANTS IN CONTACT IN¬ 
SECTICIDES BEFORE AND AFTER EGG 
DEPOSITION 
In some previous experimental work 
(11, p. 17-18) with insecticides, it was 
observed that a residual or continued 
insecticidal action often operates 
against eggs subsequently deposited 
on foliage which has been treated. 
Accordingly plants were dipped both 
before and after deposition of eggs, 
contact poisons being used as indi¬ 
cated in Table X. In this way data 
were obtained on the residual insec¬ 
ticidal action as well as the direct 
effect of contact insecticides on the 
eggs. 
These tests proved negative so far 
as throwing any light on the residual 
or immediate contact effect of in¬ 
secticides on eggs of the greenhouse 
leaf-tyer. 
TESTS FOR THE DESTRUCTION OF EGGS 
BY SPRAYING PLANTS WITH ARSENI - 
CALS BEFORE AND AFTER EGG DEPO¬ 
SITION 
Further tests were then made, 
arsenicals being substituted for the 
contact sprays, as indicated in Table 
XI, it being assumed that the young 
larvae would naturally feed on the 
poisoned foliage after hatching. 
Arsenicals, either alone or combined 
with nicotine sulphate, proved only 
partially effective against the eggs, 
but as soon as the larvae hatched and 
fed on the arsenical-coated foliage, 
they died. Although burning was 
evident in one case, subsequent ex¬ 
periments showed that the plants 
tolerate this treatment. The whitish 
deposit which remains on foliage so 
treated may be objectionable from a 
commercial point of view, but when 
applied to young plants this deposit 
is left behind as growth continues. 
