~- 
THE CLOVER ROOT BORER 15 
fence posts; the second of similar width but 50 feet long (fig. 9), 
raised between two wooden poles and reeled in on a windlass (fig. 10) 
for examination. Asa rule counts were taken during the morning 
hours, when root borers were not flying. These experiments afforded 
some of the data on flight which have already been given. Tables 
1 to3®summarize the more important experiments with these two 
types of screens. 
TABLE 1.—Counts of clover root borers caught on screens 24 by 36 inches, erected 
on the four sides of an infested field at Wapato, Wash., on April 2, 1917 
Z North screen| East screen South screen) West screen’ 
Bg) | ; 
Ze | | 
2! | | [as 
Date Time of observation 83) se | | |" 
| x | on) _ 
| scleiz| |sls| (Sis! leis! (s 
a.) 2 | A AS ee ae Paes | Se [ie 
Be ae ls eee |e [eee | ere |e 
cs a = = | ta Bo 3 Em 3 ae a TAN | po ot 
E Cc 5 ° S| iS) SES 3|bO2 ha ©) ES 
Zlalel|Al/EFlei4Z2\a\e\/a/F le | & 
| ea feces] 
1917 oF ee | ee | 
Wiayes === | QDy Mises. Ss Sa 5S Fle OaleOs| te Oslee Or Onl On| 30> |-sl= (211-05 05-0 1— ek 
Fe eS | ao Og Ot peers es eae CSel tele eal (POrf ee ped 2 Seale Or. Be 9 
ete ee Oi) eee ee Haare lero secede seeleebeio ls le SalShel= sac O.| 3, Ae 
pele ee ee eee eas ee B05 lel ete lease | le Pel S| Rela Sa 16 | 25-0 62 | 24 
I QBs os Senses 2 3.00). Peiib=s 2 ASN 4e = be Oeil 1S Gr) 19: 114") 338° 3) OF) 3 4 ol 
tee e oor Dp ani Mee HO NAEAS|: 2.\Ge 691220. | 02/702 Fi7al 25] 9.) 0. |, 0. | 0415 
lig Se enaes Pee i0s il GTA On eet Onl O8|* Onl bole] 76-0 On! 0) ees 
LI oe ae 1230 aime ss DOnEeOnl nO EON Oe |i 2 etal 821-01 051: Oy ee 
1 ae ees O30 ass ans ae GS este! sO eet Os 1F Tat eee |= 351 0517-0" 0| 5 
7A) eae ee ae O30 areMEeae= SSeS jee eee Ore One OS ONS ela 2 | OFS OF250 3 
2 ae in ae tee ea ne enn S (een eon ere oe On a Orles Oble 0: even <2-|-e le a sO: |e ole eet 
DS a ae SOS (psec eee fone lale2e (areal On| -0'1-20 2-04) 2 | 2 1 | Os nal once 
2). Ee ee AND es Se (S05 SOc s0O:2 Ol 2.02122 0-1e OF 2.2: | --05|\- 27) 052.00) -0 2 
Sa ae ee el Foyer ieee es eae cee TOrlesta la lalee eles tt et eR | S| 4-1 05|- 0: |e Oul an 
AibGaXS, jl ee ee ees AS Disease Se ee GOD glade wertstesO: |= 04-0: esd) | Iso 70.) 205 80) leoat 
ae eee AS eee Onl ONE OO) he O81 On OL ob 0) - | 0) Oe Oe ek 
[Gee See SPS asso aa SOREAOe enOn} a Oni On| aO8 sO ale lel’ Ostet | 212 || (Os \eeale eee 
Rees Ser 2:30 DSI Es 22 Seana s ode Oc e201 [O02 12205) 05) 22 )2. 0x) 0-1 04.0) [> 0 (Oe 
Mi priceses te ters See reee cine eee |---= 18 | 21] 39] 8 | 11 | 19| 77 | 46 |123 | 13 | 0 | 13 | 194 
: \ 1 
Table 1 presents the counts of clover root borers caught on screens 
measuring 24 by 36 inches, at Wapato, Wash., in the season of 1917. 
The screens were erected one each on the north, east, south, and west 
sides of an infested field, and were examined (usually) every second 
day from April 2 to June 18, except on May 24. From April 2 to 
May 1 and from June 4 to June 15 no borers were found on the 
screens. The temperatures at the time of examination are recorded 
for the days on which borers were found. During April the tem- 
peratures on the dates of examination ranged from 38° to 64° F. 
From an examination of the table it may be seen that in the case 
of each screen the side turned toward the field collected in the aggre- 
gate more borers than the opposite side, as was to have been expected; 
and that the screen erected at the south side of the field caught 
more than the other three combined. The borers counted on May 
7,8, 10, and 12 total nearly 71 per cent of the entire catch. 
8 The screens at Wapato were examined by E. E. Cowin; those at Forest Grove by C. W. Creel, 
ae ene aH M. Reeher, J. M. Langston, E. J. Taylor, and the writer. The screens were designed 
y C. W. Creel. 
> 
