October, ’20] 
WADLEY: SQUASH BUG 
423 
that would otherwise perish, and encourage hibernation in the vicinity. 
All fruits should be gathered early, the vines cleaned up, field thor¬ 
oughly plowed, and brushy and weedy borders cleaned up. Neglect 
of such measures will greatly increase the number of bugs in the 
vicinity the following season, as observation has shown. 
Hand Picking. —The plan is to prevent development of squash bugs 
by removing all adults and eggs from the plant early in the season. 
The method is very laborious and will not altogether prevent injury; 
but if carried on throughout the season a fair crop can be secured in 
spite of the bugs. 
Test of Contact Insecticides. —In the fall of 1916, squash bugs 
were dipped in various contact insecticides to give an idea as to 
their efficiency. The more effective insecticides were then tested out 
in the field, by spraying a small area on which bugs were congregated, 
and confining them on it with a screen cone. The bugs were given a 
chance to dry, and kept twenty-four hours under favorable conditions, 
as determined by a check, when the living and dead were counted. 
The results are given in Table VII. 
Table VII 
Solution used 
Laboratory 
Field 
No. bugs 
used 
Per cent 
killed 
No. bugs 
used 
Per cent 
killed 
Fish-oil soap, 0.4 to 0.5 pounds per gallon. . . 
Same, plus “Black Leaf 40,” 1 to 1,000. . . . 
Same, plus “Black Leaf 40,” 1 to 500. 
Same, plus “Black Leaf 40,” 1 to 250. 
Same, plus sulphur, 1 or 2 ounces per gallon 
Fish-oil soap, 0.2 pounds per gallon. 
Same, plus “Black Leaf 40,” 1 to 1,000. . . . 
Same, plus “Black Leaf 40,” 1 to 250. 
Same, plus sulphur, 1 or 2 ounces per gallon 
40 
20 
20 
20 
40 
30 
20 
20 
10 
75 
95 
90 
100 
97.5 
60 
95 
85 
60 
47 
68 
12i 
168 
61 
70 
66 
83.5 
91.70 
57 
These figures are for adults, the solutions used all being deadly to 
nymphs. A strong soap solution with sulphur in suspension has given 
the best results of any spray yet tested against the squash bug. Nico¬ 
tine sulphate is less effective in the field, though promising in laboratory 
tests. The sulphur makes trouble by clogging nozzles and settling, 
but its advantages more than offset these drawbacks. Tests in 1917 
confirmed these data, and also showed that nymphs succumbed to 
fish-oil soap at 0.2 pounds per gallon, sometimes to even weaker 
solutions; that sulphur much increased the effectiveness of the soap 
against nymphs as well as adults; that sulphur paste alone will not harm 
squash bugs; that strong soap solutions will not affect the eggs; and 
that squash plants suffer little or no injury from fish-oil soap solutions 
