6 
SOME INSECTS INJURIOUS TO TRUCK CROPS. 
No. 6. The application was much more thorough, although barely 10 
per cent of the amount of mixture used in the previous experiment 
was applied. This would greatly lessen the quantity of the acid- 
producing material, the use of lime as a base for the powdered arsenic 
tending to correct any acidity in the soil instead of increasing the acid 
content. Moreover, the cost of this application is much less, as it 
can be applied at a cost of about $1.20 per acre, while the cost of the 
usual mixture is about $4.20 per acre. The efficiency of the mixtures 
is about equal in either case. 
Experiment No. 8. — In this plat arsenite of copper was applied at 
the rate of 4 pounds to 50 gallons of water. The poison was applied 
without lime. The weather was bright and warm with a northeast 
wind. 
This poison proved equally effective with Paris green used in the 
same quantity but differed in that no damage to the f oliage was noted 
as a result of the application. The larvae were entirely destroyed. 
Experiment No. 9.- — Arsenite of copper, 4 pounds, to 6 pounds of 
lime in solution with 50 gallons of water was sprayed on this plat. 
This application was quite effective and at no time produced burning 
of foliage as an after-effect of the arsenic. 
The check plat was severely defoliated by the beetles and larva? 
and was undoubtedly injured by the neglect of spraying. The yield 
of potatoes from this plat was considerably less than that of the 
properly sprayed plats. 
SUMMARY OF EXPERIMENTS. 
The following table will show the results of experiments with vari- 
ous insecticides: 
H 
Date. 
1 
May 23 
2 
May 27 
3 
May 26 
4 
May 26 
5 
May 27 
6 
May 26 
7 
May 27 
8 
June 17 
9 
June 14 
10 
May 26 
Insecticide used. 
Effect on plant. 
Effect on insect. 
Remarks. 
Arsenite of lime I Badly burned. 
Arsenate of lead with ; None.. 
Bordeaux mixture, j 
Arsenate of lead do. 
Paris green without Slight burning . 
lime. 
Paris green with Bor- j do 
deaux mixture. 
Entirely destroyed in 
24 hours. 
Entirely destroyed in 
48 hours. 
All killed in 48 hours.. 
Very effective. 
....do 
Paris green dust with 
land plaster. 
Paris green dust with 
lime. 
Arsenite of copper 
Arsenite of copper with 
lime. 
None . 
.do. 
.do. 
.do. 
.do. 
.do. 
98 per cent destroyed. 
Very effective 
do 
Check. 
Check. 
Damage to plants too 
great to permit its 
use, although cheap- 
est preparation of 
those employed. 
Excellent yield from 
plat so treated. 
Applied at rate of 6 
pounds to 50 gallons 
water. 
4 pounds to 50 gallons 
water. 
3 pounds Paris green to 
4-6-50 Bordeaux 
mixture. 
4 pounds Paris green to 
ton land plaster. 
1 pound Paris green to 
10 pounds air-slaked 
lime. 
4 pounds arsenite of 
copper to 50 gallons 
water without lime. 
4 pounds arsenite of 
copper with 6 pounds 
lime to 50 gallons 
water. 
Beetles very injurious 
June 14. 
