SPRAYING FOR CURCULTO OX APPLE. 191 
The first attempt, however, to determine the possible value of 
the use of arsenical poisons in the control of the curculio on apple on a 
commercial scale was begun bv Prof. C. S. Crandall, of the Illinois 
Experiment Station, in 1903. His report of operations for that year 
was read before the Illinois State Horticultural Society (vol. 37, pp. 
176-189). Two blocks of sixty 18-year-old trees each in two different 
but adjacent orchards were selected. In the Williams orchard the 
soil was covered for the most part with a bluegrass sod with a heavy 
surface mulch of dead leaves and grass. In the Blair orchard there 
was no sod but a scattered growth of plants, including grasses, and 
the surface mulch of leaves and trash was lighter. From 7 to 16 
applications of an arsenical spray were given to the respective plats, 
including Paris green, arsenate of lead, white arsenic, and arsenite of 
lime, the first three treatments in Bordeaux mixture and the sub- 
sequent ones in water. During the course of the work 29,943 apples 
were examined. In commenting on the results, Prof. Crandall 
states that the spraying did not control the curculio. Apparently 
the frequent spraying had some influence because the percentage ol 
uninjured fruit from the plats sprayed 16 times was a little higher 
than from any other plats. Three reasons were assigned for the 
unfavorable results, namely : 
1. Weather conditions of early spring and their bearing on the 
crop. 
2. Location of the plats directly in the midst of large orchards con- 
tiguous to native woodlands. 
3. Unusual abundance of the insects. 
On the Williams orchard the percentage of sound fruit varied from 
1.26 to 5.29, with an average for all plats of 2.76. Results were 
somewhat better in the Blair orchard, the percentage of sound fruit 
ranging from 2.55 to 16.07, with an average for the several plats 
of 7.13. 
Prof. Crandall continued his work during 1904, as reported for the 
Illinois Horticultural Society (vol. 38, p. 75), and selected a somewhat 
isolated 5-acre orchard, thus eliminating invasion by the insect from 
outside sources. This entire orchard was treated, except the 13 
check trees. The ground was not in sod and the orchard had never 
been sprayed. The spring weather was reasonably favorable and 
the trees bore a fair crop of fruit, and the cuTCulios were much less 
abundant than in 1903. The schedule of applications was the same 
as employed in 1903. A total of 72,922 apples was examined from all 
of the plats, of which 23,956 were windfalls. The treatments and 
results are shown in Table XCTV. 
