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 59 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 foliage was noted 
as a result of the application. The larve 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 larvee 
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: 
K+ 
we OD 
os} Date. Insecticide used. Effect on plant. Effect on insect. Remarks. 
og 
Za | 
1 | May 25 | Arsenite of lime........| Badly burned..| Entirely destroyed in | Damage to plants too 
| 24 hours. great to permit its 
| | use, although cheap- 
est preparation of 
those employed. 
2 | May 27 | Arsenate of lead with | None.........-. Entirely destroyed in | Excellent yield from 
Bordeaux mixture. 48 hours. plat so treated. 
3 | May 26 | Arsenate oflead.......|...-- Goss se sass All killed in 48 hours..| Applied at rate of 6 
| pounds to 50 gallons 
water. 
4 | May 26) Paris green without | Slight burning -| Very effective......... 4 pounds to 50 gallons 
lime. water. 
5 | May 27 | Paris green with Bor- !..... O52 Seah 5) see (CUE ee eae 3 pounds Paris green to 
deaux mixture. 46-50 Bordeaux 
mixture. 
6 | May 26 | Paris green dust with |..... (0 (oe ee aaa e (6G eae Paecioe 4 pounds Paris green to 
land plaster. ton land plaster. 
7 | May 27 | Paris green dust with |..... do.........-| 98 per cent destroyed..} 1 pound Paris green to 
lime. 10 pounds air-slaked 
lime. 
8 | June 17 | Arsenite of copper. ....|---.-- dois. -5--2|| Veby.etectivie:.easoaer 4 pounds arsenite of 
copper to 50 galions 
° water without lime. 
9 | June 14 | Arsenite ofcopper with |... -- GOht chee eee ee GOs asc eee 4 pounds arsenite of 
lime. copper with 6 pounds 
lime to 50 gallons 
water. 
LOWEMay. 260 sNones-ccess eee eaee eee @heckas 6 4e-- Cheeks 23 4as20e-se aes Beetles very injurious 
June 14, 
