

REBT pees? i a er 
> oer ue 
he 
hag 
royce 
. s : po 
e ee % gesERetse Fee: 
bs ‘ . -_ ; 
\ a ; 
: of 
s Z a. $] 
- ef 
¢ 
7. 
7 
4 ° 
/ 
f 
s 
e 3 
2 
ry 
6 
se 
« ° 
os 
s 
ee 
e 
. e 
J e 
bY e 
\ * rf 
Nate 
e 
\ 
~ ‘ 
CaN 
‘ 
~ 
: a TOK 
; ee SBE RNS 
} aa ws 
i al 
SH ay ee - 
he é ¥ 
~ 8B) acters 
SS re 
STON 
Wy 
N 
e N 
X 
\ 
\ 
e 
°° 
e 
e 
° 
e 
#6 
6 
° 
s 
e s 
e a 
4 e 
} cd 
\ oe : “ae 
ree 

Figure 12,--Landing pattern of 52 corn earworm moths (Heliothis zea) at- 
tracted to blackbody radiator (8 to 13) in 12-foot? darkroom, (A) Radi- 
ation pattern of blackbody; (B) visible radiation before mercury arc-argon 
discharge tube was blacked out by heavy rubber tape. 
IR ENVIRONMENTAL AND HOST 
PLANTS 
Tanner (1963) pointed out that the thermal 
radiation emissivity of green plants is high-- 
0.95 to 0.97 (table 1)--and thus measured ra- 
diation can be converted to the temperature 
with little error, Plants are normally warmer 
than the air during the day and cooler at night. 
This is, of course, a generality, for the strong 
thermal and solar exchange that occurs during 
the day changes considerably at nighttime. 
170 
Tanner's data (1963) indicated that plant tem- 
perature may be considerably different than 
air temperature. Alfalfa fields measured 5° 
to 10°C, below air temperature at night and 
5° to 10° above during parts of the day. Meas- 
urements by Valli et al. (1964) indicated that 
the temperature of parts of the corn plant 
varied over a 24-hour period. The tempera- 
ture of the corn ear silk, for instance, meas- 
ured 1° to 3° higher than the ambient air 
temperature at both 7 p.m. and again at 2 a.m. 
These periods coincide with the periods of 

