16 BULLETIN 1426, U. S. DEPARTMENT OF AGRICULTURE 
TABLE 2.—Counts of clover root borers caught on a screen 24 inches wide and 50 
feet high, erected April 22, 1916, at the eastern edge of a field of spring-plowed 
clover near Forest Grove, Oreg. 
Height (in feet) of section of screen 
Date of count 0 to 10 10 to 20 20 to 30 30 to 40 40 to 50 Total 
East | West | East | West | East | West | East | West | East | West 
side side side side side side side side | side side 
1916 
AN oe eee cst tale Se 0 2 0 0 0 2 0 0 0 0 4 
WIG Veao eee se ee eee 7 5 8 13 3 3 0 4 2 3 48 
1S Se eeeee se aces 9 35 18 36 13 4 7 2 5 ul 140 
DYN Te lee ie AS chee 4 3 2 5 1 0 ) 0 3 3 21 
iutlliyga dene ee bee 0 1 0 0 0 0 0 0 0 0 1 
Ota on ee see 20 46 28 54 17 9 a. 6 10 17 214 
TABLE 3.—Counts of clover root borers caught on a screen 18 inches wide and 50 
feet high, erected May 1, 1917, at the western edge of a field of spring-plowed clover 
near Forest Grove, Oreg. 
Height (in feet) of section of screen 
0 to 10 10 to 20 | 20 to 30 30 to 40 40 to 50 
Date of counts | Total 
East | West | East | West | East | West | East | West | East | West 
side | side | side | side | side | side side | side side side 
1917 
Vey? se ee 0 0 0 0 0 0 0 0 0 0 0 
SAE a Rater a tee 2 1 0 0 0 0 0 0 0 0 0 1 
A Qi eth SNe ee 5 0 4 1 7 0 6 0 3 0 26 
Dost eet eee 0 0 0 0 0 0 0 0 0 0 0 
Opp, AE 8 Baas apa 11 1 4 0 4 0 2 ] 1 0 24 
a RE So 70 1 27 1 24 1 9 0 uf 0 140 
DOK Rte ia Sa 237 23 147 15 102 23 63 7 on 4 658 
Bile se et 7 1 1 0 2 3 0 0 3 4 21 
June Des = Nae eS 7 ] 28 3 14 2 7 0 11 0 73 
I [eee ay ARTES ER 1 0 0 0 0 0 0 0 2 0 3 
MPotalis sa eae 339 27 211 20 153 29 87 8 64 8 946 
A long screen 24 inches wide and 50 feet high was erected April 
22, 1916, at the eastern edge of a recently plowed clover field near 
Forest Grove, Oreg. To facilitate the counts of borers caught at 
different heights above the ground the screen was divided into sec- 
tions of 1 foot each, beginning at 3 feet (the height of the windlass 
from the ground). A count was made on April 25, only 4 borers 
being found, all on the west side of the screen. When next visited, 
April 29, it was found to have been torn down by a windstorm, and 
was replaced. On May 2, 13, and 24, counts were made, the total 
numbers found on the respective dates being 48, 140, and 21. On 
July 24, two months after the last of these dates, another inspection 
was made; only asingle borer was found on the screen. The counts 
made on this screen, for the season of 1916, are given in greater detail 
in Table 2. The maximum temperatures, read at Forest Grove, 
approximately 214 miles southwest of the screen, on April 24, May 1, 
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