6 
BUULETIN 120",, r. S. DKPARTMKXT OF AGRICULTURE. 
During the time this work was under way, about 75 per cent more 
beetles were collected from plat 3, which received no treatments, 
than from plat 2, one of the treated plats. This is very interesting, 
since Table 1 shows that plat 2 had a heavier eurculio infestation 
than plat 3 before any dust was applied. The average number of 
beetles per tree at the close of the experiment in each plat was found 
from Table 1 to be as follows: 
Booties per tree. 
rial I (dusted Aug. 12 and 24) 3.29 
Plat 2 (dusted Aug. 12) 5.18 
Plat 3 (no treatment) 9.07 
Comparing with Table 1, the average decrease on plat 1 was 0.21 
beetle per tree, the average decrease on plat 2 was 0.79 beetle per tree, 
eoo 
S00 
\ 
I 
200 
/00 
3EF0/ZE 
PI/ST///& 
6 S /0 // 
SEPT 
/2 /J/4/S/6/7/0 & 202/22232425262726 29 30 3/ / 2 3 
PlG 2 -Number of plum on rculios col lee tod on dusted and chock plats, 1921. 
and the average increase on plat 3 was 3.72 beetles per tree. (See 
fig. 2 for graphic comparison of the infestation on the three plats.) 
Table 5 gives the summary of results of the held experiments in 
L921. 
