Table 1.--Estimated reduction in average catch per trap of hornworm populations and damage 
at center of light-trap area from population and damage at 12 miles out from center 
Eggs laid 




Plants 
damaged 
Year 



















Percent Percent Percent Percent Percent Percent 
UO OQ oe tede sis 8s Paueue tone 89 59 716 55 58 -- 
MNO Oa teverevever ene oie le atonene 84 65 94 64 83 -- 
NOGA Drovers atecc evavereuateners ie -- fat 15 ide Tal 


NOGA vx .te les Ceres -- -- 89 86 82 

Based on 18 miles, 
The reduction in hornworm populations was field, There was a depression of about 50 per- 
reflected in a reduced use of insecticides, In cent within a few feet of the trap, but this 
1963, the number of applications made against leveled out to zero at about 300 feet, 
hornworms was reduced by 90 percent inside In 1963 and 1964, counts were made of the 
the light-trap area as compared with outside, number of budworms (Heliothis virescens 
In 1964, there was a reduction of 55percent in (Fabricius)) and H, zea found ontobacco plants 
applications made against all insects, and the number of plants damaged, No counts 
In 1963-64, tobacco farmers inthe light-trap of larvae were made in 1963 and differences 
area were told that the light traps were ex- were not significant in 1964, but there was a 
perimental and that they should apply insec- significant reduction in damage, Again, when 
ticides to control hornworms as needed, The results at the center of the area were com- 
sight of large numbers of moths in the light pared with those 12 miles out, the reduction 
traps created an unusual amount of interest in was 92,9 percent in 1963 and 55.8 percent in 
the traps among the local townspeople, as well 1964, As with hornworms, it was not possible 
as among the tobacco farmers, This stimulated to separate the effect of lights from that of 
the farmers to examine their tobacco fields stalk cutting, 
more frequently than usual, Since these frequent 
examinations usually revealed very low horn- 
worm infestations (table 1), most of the 
: : : IMP VEN 5 
growers withheld insecticide applications, MEROVEMENTS IN RIGHT TRAPS 
Some experiments have been run using 
variations of the basic trap, which utilizes a 
15-watt vertically mounted fluorescent black- 
EFFECT OF LIGHT TRAPS AND light lamp and four baffles (see fig, 6). This 
STALK CUTTING ON OTHER design was developed from severalothers em- 
INSECTS ployed in earlier experimental hornworm 
trapping work in Virginia, Indiana, and other 
In 1963, counts were made of the numbers of tobacco-producing States, Limited studies dur- 
corn ears damaged by the corn earworm ing 1963 with other traps equipped with a 
(Heliothus zea (Boddie)) and the fall army- suction fan and greater lamp wattage showed 
worm spodoptera frugiperda (J. E, Smith) ), no improvement in hornworm catches, The 
There was a small but significant difference addition of a fan to the basic trap did increase 
of about 17 percent between the area covered by the catch of corn earworm moths 138 times in 
lights and the area outside, Counts were also one experiment and 1,89 times in another, 
made at 50-foot intervals in cornfields where Hoffman and Lawson (in press) ran a series 
a light trap was located in or on the edge of a of experiments in which virgin females, which 
199 
