DUSTING AXD SPRAYING CURCTTLIO A.FTEB HARVEST. 5 
of 4.06 beetles per tree on plat 1. 6.29 beetle- per tree on plat 2. and 
10.9 beetles per tree on plat 3. for the period. Plat 1 had increased 
0.56 beetle per tree, plat 2 had increased 0.32 beetle per tree, and 
plat 3 had increased 5.55 beetles per tree after the first dusting was 
applied to plats 1 and 2. Plat 3. the check plat, had, therefore, 2.04 
times as many beetles present per tree during the period August 13 
to 24 as during the period before these dates. This rapid increase 
was due to second-generation adults, which were making their ap- 
pearance in numbers at that time. The figures above show that the 
application of dust applied about four weeks after fruit harvest pre- 
vented a marked increase in the number of adults. Owing to the 
heavy emergence of second-generation curculios during the month of 
August, the increase in the number of beetles collected from each of 
the plats that were dusted would have been very heavy had it not 
been for the dusting. The dust held the infestation about constant 
throughout the period. 
Plat 1 received the second application of dust on August 24. 
During the period from August 26 to September 4, four collections 
were made on each plat. Table 3 gives the number of beetles col- 
lected from the record trees in each plat during the period following 
the second application of dust to plat 1 until the close of the experi- 
ment. 
Table 3. — Xumber of curculios collected during the period following second dusting , 1921. 
Date. 
Plat. 
Date. 
Plat. 
1 
2 3 
1 2 
3 
Aug. 26 
Beetles. 
Beetles. 
Beetles. 
474 
Sept. 2 
Beetles. 
Beetles. 
Beetles. 
202 
Aug. 27 
152 
259 
Sept. 3 
74 
92 
\ug 29 
426 
Total 
Aug. 30... 
145 
270 
467 
2.34 
756 l 356 
Aug. 31 
2-54 
Average per tree . . . 
3.78 6.78 
Sept. 1.. 
96 
135 
1 
These four collections showed the presence of an average of 2.34 
beetles per tree on plat 1, 3.78 beetles per tree on plat 2, and 6.7S 
beetles per tree on plat 3. These figures show for this period a de- 
crease in the number of beetles on plats 1 and 2, and an increase on 
plat 3, as compared with the number of beetles per tree before any 
dust was applied. 
Table 4 gives the total number of beetles collected from the 50 
record trees in each plat during the entire period of the experiment. 
Table 4. — Number of curculios collected during the entire period following first dusting, 
1921. 
Aug. 13. 
Aug. 15. 
Aug. 16. 
Aug. 17. 
Aug. 18. 
Aug. 19. 
Aug. 20. 
Aug. 22. 
Aug. 23. 
Aug. 24. 
Aug. 25. 
Date. 
Plat. 
1 
2 
3 
Beetles. 
Beetles. 
Beetles. 
399 
167 
265 
561 
252 
348 
623 
229 
371 
. . 
552 

206 
311 
590 
161 
278 
Date. 
Aug. 26. 
Aug. 27. 
Aug. 29. 
Aug. 30. 
Aug. 31. 
Sept. 1. 
Sept. 2.. 
Sept. 3. 
Total 
Average per tree... 
Plat. 
Beetles. 
""152* 
145 
"*96 
1,482 
3.29 
Beetles. 
259 
'276' 
136 
5.1S 
Bttth*. 
474 
'254 
4. 061 
