200 
THE PLUM CURCULIO. 
Table CI. — Summary of results in spraying apples for the plum curculio, in average 
percentages of sound fruit, various localities. 
Localities. 
Treatments. 
Illinois. 
Ander- 
son, Mo. 
West- 
field, 
N. Y. 
North 
East, Pa. 
Siloam 
SDrings, 
Ark. 
Crozet, 
Va. 
Mount 
Jackson, 
Va. 
St. 
Joseph, 
Mo. 
1 application 
86.34 
73.93 
57.90 
36.80 
79.04 
40.82 
91.07 
86.89 
50.10 
5 applications 
82.88 
7 applications (Paris 
45.47 
44.61 
47.80 
44.52 
44.74 
7 applications (arse- 
nate of lead) 
57.45 
7 applications (arse- 
nite of lime) 
8 applications 
10 applications 
13applications(home- 
made dust) 
3.84 
22. 15 
13 applications (com- 
mercial dust) 
62.08 
25.21 
Unsprayed (check)... 
5.51 j 76.21 
25. 44 
9.14 
54. 02 
27. 23 
4.05 
CONCLUSIONS. 
The records above given of results of spraying apples for the con- 
trol of the curculio indicate clearly that the injuries of the pest may 
be in all cases greatly reduced, although the degree of benefit varies 
widely. It is apparent that account must be taken of other factors, 
as the relative abundance of the insects as compared with the amount 
of fruit present on the trees. With a small fruit crop and abundance 
of curculios, the most thorough spraying will not serve to bring 
through a satisfactory amount of sound fruit, as will be noted in the 
results of experiments at St. Joseph, Mo. With a large crop of fruit 
and an abundance of insects, results will likewise be disappointing. 
If the curculios for any cause are scarce and there is a large fruit 
crop, injury is of course much less important. In other words, the 
degree of success in spraying varies with the abundance of the insects, 
and where the latter are numerous thorough treatments seem to fail 
to yield a desired freedom from injury. While spraying is undoubt- 
edly a most important adjunct, and if persisted in from year to year 
may answer for its control, as its effects are cumulative, yet it is 
clear that other control measures should also be employed. In all 
cases which have come under our observations the insects have 
always been found most abundant in orchards which are in sod or 
are poorly cared for and allowed to grow up more or less in weeds 
and trash. Also orchards adjacent to woods always suffer severely, 
especially along the border. (PL XVI.) As opposed to this condition 
is the notably less injury in orchards kept free from weeds and trash. 
In such cases sprayings usually given for other orchard insects, as 
the codling moth, serve to keep this pest well under control. In 
