and the possibility that the chemical may 
exist in several stereochemical forms, each 
of which may have a different degree of 
attraction (15). 
Ultimately, the best attractants must be 
field tested because laboratory and field tests 
agree only qualitatively. In the field, attract- 
ants must prove themselves in competition 
with a multitude of natural odors, colors, 
light conditions, and weather. 
Trap design is a study in itself for each 
species, The color, type and size of wick, 
amount of chemical, size of openings, and 
trapping technique must be determined (5). 
Even if all works well, unusual interferences 
sometimes occur. Ants were found to be 
stealing the trapped fruit flies, and an ant 
repellent had to be added to the trap. Birds 
also began stealing the trapped flies, and a 
screen, covering half of the trap opening, 
had to be installed, Even with the best design, 
improperly placed traps will not catch. Traps 
placed in hollows or in dense growth do not 
catch well owing to restricted air move- 
ment (5). The height of a trap makes a dif- 
ference. 
I hope that these few examples point up the 
great amount of research involved in using 
attractants successfully. Inasmuch as each 
species must be handled differently, you can 
see that much work awaits us even if our 
future efforts were to be simply a continua- 
tion or extrapolation of the techniques now 
being used for the few species for which we 
do have satisfactory attractants. However, 
what we do learn will undoubtedly speed up 
these future exploits. 
Many insect species have the ability to 
reproduce rapidly and to establish incredibly 
large populations in a short time. Any means 
of depressing this enormous reproductive 
potential directly or indirectly is worth in- 
vestigating. The insect sex attractant in facili- 
tating the mating process falls in this cate- 
gory, and its value in preventing the spread 
of the gypsy moth through detection has already 
been mentioned. There is little doubt that 
sex attractants can help in the direct control 
and eradication of insects, but the very potent 
nature of these exotic materials makes it 
difficult to obtain enough of them for identifi- 
cation. For example, 500,000 abdominal tips 
of virgin female gypsy moths were required 
to get one small drop of pure sex lure, and 
it was only after about 20 years of painstaking 
chemical effort that the attractant was identi- 
fied and synthesized (6). Because of these 
difficulties the identity of very few sex lures 
has been determined. 
Sex attractants among insects may be more 
widespread than is generally realized. For 
example, about 2 1/2 years ago a conference 
on insect sex attractants, called by 
Dr. E, F. Knipling, brought together about 
75 research workers, After receiving a brief- 
ing on what was known, they were asked to 
look for sex attractants among the species 
they worked with. About 25 species, previously 
unknown to have sex lures, turned up having 
thém, and many of these are important pests. 
Again each species had its ownidiosyncracies, 
The peak mating period of one--the southern 
armyworm [Prodenia eridania (Cramer)]--oc- 
curred between 3 and 5 a.m. During our usual 
working hours these insects are indifferent 
to their own sex attractant. The European 
corn borer [Ostrinia nubilalis (Hubner)] had 
to be viewed under infrared light to observe 
its mating habits. It mates in total dark- 
ness (16), 
To date, more than 200 insect species 
have been reported to have sex attractants. 
You do not have to be much of a prophet 
to predict that there will be a great upsurge 
in activity in the sex-attractant field. The 
need is there, we are learning how to use 
these materials, and the results have been 
rewarding. 
Perhaps the greatest impetus to undertake 
such studies comes from the chemical field 
itself. New chemical instrumentation has made 
analyses and identifications of chemicals pos- 
sible at levels down to 1/1000th of those 
previously possible. For example, mass 
spectral analyses with only 0.1 microgram 
have been reported (17). Gas chromatography 
is facilitating the isolation and purification 
of infinitesimal amounts of compound. The 
new instrumentation has also extended the 
range of chemical information that may be 
amassed, and in many analyses the sample 
is recovered completely. This outstanding 
progress in microanalysis has been recent 
and is largely due to the introduction of 
electronics into chemical equipment. We can 
expect our chemical capabilities to increase 
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