Disparlure: A Potential Tool for Gypsy Moth
Population Manipulation
l
By E.
Departmcnt
of Entomology,
ALAN
The Pcnnsylvania
),luch interest and optimism have been generated in
recent years concerning use of pheromones for insect control. Disparlure, the synthl~tic sex attractant tor male
gypsy moths, Por/lre/ria dispar (L.) (Lepidoptera:
Lymantriidae),
has caused as much excitement as any,
especially in the northeast where this destructive insect is
rapidly expanding its range. For the past two years, the
potential of disparlure as a tool with which to manipulate gypsy moth populations has been evaluated in a
series of tests conducted by many people in several cooJlerating agencies.
Recently, Beroza and Knipling
(1972) discussed many of the theoretical aspects of
gYJlSYmoth control using this new material. and they presented a scenario for containment of the insect in the
northeast. It is therefore appropriate at this time to evaluate the results of the various tests and to speculate about
the future use of disparlure,
CAMERON
Statc Uni'l/crsity, University
Park 16802
potent detection tool than was heretofore available.
survey and detection do not constitute control.
But
How may we manipulate populations of adult gypsy
moths using this potent new tool? It may be possible to
use disparlure either as an 'attractant', or as a 'confusant'.
In the former sense, males are directed to predetermined
points where they are 'treated:' currently treatment involves physical capture in traps. Confusion may be
achieved through misdirection of response. This approach
envisions a system in which males are drawn to attractive
points which are not female moths. Confusion may be
achieved also through suppression or disruption of the
male's response to the pheromone. This hypothesis suggests a situation in which such a high background level
of lure is present that either the sensory receptors of
males are unable to detect additional lure produced by a
female, or the additional quantity produced by females
does not exceed the behavioral threshold for male response. Doubtless, other mechanisms also could be postulated.
Briefly, the life history of the gypsy moth is: in
autumn, eggs (containing developed embryos) can be
found in the field. When the weather warms in spring,
these eggs hatch, and the young larvae climb upward apparently seeking food. Some may spin down on a fine
silken thread for a windborne ride. The long hairs clothing the larvae at this stage make them very buoyant. 1£
a suitable food supply is located, feeding begins. Varying
degrees of defoliation may result, depending on insect
populations, host species, and many other factors. Pupation occurs from June through August, depending on location, and adults emerge. The normally flightless female
'calls' to attract the flying males for copulation; egg deposition occurs, and the cycle is repeated.
1£ it can be demonstrated that use of disparlure sufficiently disrupts mating and that populations can, indeed, be
manipulated, it may be possible to use the lure to achieve
one or more of the following:
(1) To establish a barrier zone wide enough to preclude the establishment of new infestations, as a result
of larval blow-in, in currently uninfested lands to the
west and south of the generally infested northeastern
United States.
(2) To eradicate spot infestations
outside the generally infested area.
In addition to the airborne dispersal of young larvae,
larvae, pupae or egg masses may be transported longer
distances by man on commodities such as logs or quarry
stone, or on recreational vehicles.
which are detected
(3) To mop up a residual population after one or more
other agents-parasites,
pathogens, predators, chemical
insecticides, or others-have
reduced the population to a
very low level.
Although it has long been known that the female gypsy
moth produces a material attractive to the male, it is
only recently that disparlure has been available for testing.
Jacobson (1960) identified gyptol as the sex attractant.
An easily synthesized homologue, gyplure, also was reported as a potent attractant. A long series of tests during the 1960's which gave erratic, nonpredictable results,
combined with direct challenges to the validity of the
chemical determination (Eitel' et al. 19(7) resulted ultimately in retraction of these structures as attractants
(Jacobson et al. 1970). Meanwhile, others continued attempts to isolate, identify, and synthesize the attractant
produced by the female moth, and these efforts culminated in a paper by Bieri et al. (1970) reporting success.
(4) To push the infestation back into the northeast,
and to reduce the area of general infestation.
DrSPARLURE
AS AN ATTRACTANT
For a Barrier Zone.-Let
us first examine some experiments which were conducted to evaluate use of disparlure as an attractant.
One of the main reasons for
these tests was to explore the possibility of establishing
a barrier zone of baited traps.
In one test conducted at Penn State in 1971, 300 handplaced Johnson traps in a 16-ha (40 a) block captured
70 of 98 gypsy moth males released, even though 93
virgin females also were in the test block. Fertilization
of female moths was reduced by 470/0 when compared
with the control test. The combination of a very high
(for gypsy moth) percentage recapture of males and a reduction-although
not statistically significant-in
mating
success of females, with only little better than a 3: 1 trapto-female ratio, indicated need of more extensive attractant/trapping tests.
Since mid-1970, disparlure has been used as the bait
in traps deployed for survey and detection. The finding
of male moths in widely scattered States from the southeast to the mid-west in the past two years is undoubtedly
in part, at least, a reflection of the availability of a more
1 Rased nn a contribution
by the same title to the Section B
Symposium, Control of Insect Pests by Pheromones, presented to
the 44th Annual Meeting, Eastern Branch of the Entomological
Society of America, October 18-20, 1972, Atlantic City, N.].
In 1972, our tests were conducted on State Forest lands
15
the end of a test, all remammg pupae and females were
collected for examination. The spermathecae of females
were examined as soon as possible for presence of sperm.
Eggs were held for several weeks, until embryonic development was well advanced and were independently evaluated for fertility. In the tables which follow, mating
success is summarized by numbers of determinations
which were made. Unfortunately, in each separate plot,
5-50% more females than are reported were returned to
the laboratory, but for various reasons we were unable
to assess mating success.
in Huntingdon County, Pa., within the Federally quarantined area but in areas with gypsy moth populations
below detectable levels. Glassine-lined cardboard tube
traps, 7.5 cm long X 2.5 cm diam and coated inside with
Tack- Trap' containing approximately 500 p.g of disparlure
per trap, were used. These were 'distributed by aircraft
over test areas at rates of 1160 or 4640/km" (3000 or
12000/mi').
Gypsy moth pupae, collected from infestations in eastern Pennsylvania, were distributed within the
100-ha (247 a) test blocks in two different patterns: the
first, to which we refer as our "Random" pattern, we believe simulated the situation obtaining as a result of individual wind-blown larvae arriving in a new area. The
second patern, which we called "Aggregate", was designed to simulate a spatial arrangement of insects which
might result from the hatch from one or several egg
masses which had been transported to a previously uninfested area or deposited by moths from larvae previously blown in. Each treatment and control in each
test series was replicated three times. Pupae were used
because, first, we wanted adults to appear over a period
of days, and second, we wanted these adults to have an
opportunity to behave normally from the moment of
emergence. During the summer we ran two tests in each
field block. We refer to these as Test Series 1 and Test
Series 2. All the treatment and untreated control replicates of a test series were run simultaneously.
Results.-First, let us look at the results of tests where
the pupae were placed in the Random configuration to
simulate a distribution pattern from wind-blown larvae.
In test plots which had received 1160 traps/km'
(low
density), 7 of 29 9. (24.1%) were determined to have
been fertilized, while only 6 of 34 (17.6%) of the females
in the untreated control plots were fertile. Where traps
had been dropped at 4640/km' (high density), 12 of
31 (38.7%) of the females were fertile (Table 1). Apparently mating was not inhibited in the treated plots; it
was actually higher than in the controls. Even though
the differences are not statistically significant, the trend
is not particularly encouraging.
In Test Series 2, the same procedures were used except that, instead of 64 ~ and 64 9. per plot, we placed
225 ~ and 225 9.. As is seen in Table 1, mating success
was reduced from 12.5% in the control plots to 10.4% in
the low plots. In the high plots, 11.5% of the females
were mated. Again, the differences are not statistically
significant, and again we see no evidence that the trapping technique we used inhibited mating among very
small numbers of essentially randomly distributed individual gypsy moths.
With the different numbers of insects used in the
various blocks during the several tests, we expected to
test trap to female ratios--or
sources in the form of
traps which competed in attraction with females-varying from a low of approximately 5: 1 t6 a high of approximately 75: 1. In fact, the ratios obtained were considerably higher, because many pupae placed in the field
did not produce adult females for reasons which included
parasitism, disease, predation, handling, or other causes.
At the same time these tests were being conducted we
placed pupae in aggregations to simulate the results not
of this year's blown-in larvae but of adults developing
from an egg mass or masses transported to or laid in a
previously uninfested area. In Test Series 1, in the low
trap density plots, mating success was reduced from
81.3% in the controls to 68.1% in the treated plots, a
difference which is statistically significant (Table 1).
Mating Success was reduced to 74.2% in the high trap
density plots, a reduction from the control which is not
statistically signi ficant.
Every spot at which a pupa was placed was examined
daily for 10-12 consecutive days, and data on the activity
and fate of each insect were collected. Once a male
emerged, of course, it flew off and was lost for further
direct observation.
Female adults, on the other hand,
were more easily followed. As soon as eggs were deposited, both the egg mass and the female were returned
to the laboratory for evaluation of mating success. At
• Animal Repellents, Inc., 1016 Everee Inn Road, Griffin,
Ga. 30223.
Table I.-Mating
success of female gypsy moths in Huntingdon
County trapping test areas. 1972.
J19.
Test
series
2
2
Insect
dispersion
Trap
density·
placed
per plot
No.
plots
Fertile
9.
Infertile 9.
Total
determinedb
%
fertile"
Random
Low
High
Control
64
64
64
3
3
3
7
12
6
22
19
28
29
31
34
24.1
38.7
17.6
Random
Low
High
Control
225
225
225
3
3
3
7
7
7
60
54
49
67
61
56
10.4
11.5
12.5
Aggregate
Low
High
Control
150
150
150
3
3
3
62
121
113
29
42
26
91
163
139
68.1'"
74.2
81.3
Aggregate
Low
High
Control
300
300
300
3
3
3
16
27
26
47
68
42
63
95
68
25.4
28.4
38.2
• Low, 1160/km'; High, 4640/km".
b Totals from 3 replicates (plots).
" Statistically significantreduction from control indicated by asterisk.
16
Table 2.-Mating
success of female gypsy moths in Huntingdon County confusion test areas. 1972.
Test
series'
Insect
dispersion
Disparlure
per ha
~/9placed
per plot
I"
Aggregate
2"
Aggregate
25.0g
7.5g
Control
25.0g
7.5g
Control
150
150
150
300
300
300
3d
Aggregate
5.0 g
Control
Random
5.0g
Control
Total
determined
No.
plots
Fertile
9-
Infertile 9-
7
21
113
2
0
26
13
15
26
10
7
42
20
36
139
12
7
68
16.7
0.0
38.2
135
135
1
1
3
1
1
3
1
1
0
13
28
32
28
45
0.0**
28.9
195
195
1
1
0
15
34
61
34
76
0.0*
19.7
• 6/12~mesh cork used as carrier in Test series 1 and 2; microencapsulated
Statistically significantreductions from controls indicated by asterisks.
" Test insects from wild populations.
%
fertile"
35.0***
58.3u
81.3
formulation used in Test series 3.
b
d
Test insects reared.
In Test Series 2 we doubled the numbers of pupae in
each test plot. Mating success was reduced from 38.2%
in the controls to 25.4% in the low trap density plots and
28.4% in the high trap density plots (Table 1). Neither
reduction is statistically significant.
within the drop zone, each known to contain egg masses,
received three times as many traps, or 8400/km".
Although all our data are not yet summarized, we know
that in 1972 we captured at least 214 ~ moths in 2432
traps which we have examined. We are aware of numerous new egg masses in one part of the block which has
received traps in both years of the test.
An anamoly is apparent in both test series: fewer traps
(in the low density trap drop area) were more effective
in reducing mating than was four times the number of
traps in the high density trap drop area. The results are
unexplained, but possibly they reflect the effect of some
unmeasured physical differences among the various field
plots.
DISPARLURE
AS A CONFUSANT
Results of preseason tests conducted in 1971 and 1972
on Dauphin Island, Ala., and in 1971 at Otis Air Force
Base, Mass., suggested that it might be possible somehow
to confuse male moths and prevent them from finding females (Stevens and Beroza 1972; Cameron unpublished).
In tests conducted in natural populations of the insect in
1971 in eastern Pennsylvania, however, we were unable
to demonstrate mating inhibition (Cameron 1971). I suggested then that, (1) the populations in which we were
working exceeded the levels at which we might eventuatly
be able to use disparlure as a confusant, and (2) that we
needed some method of sticking our lure throughout the
vertical profile of the forest instead of having it all on
the forest floor, as resulted when the paper chips or cork
particles used as carriers in those tests fell through the
canopy to the ground.
From these tests, one other point is strikingly evident.
Results from our control plots demonstrate that when
pupae were placed so many adults would emerge within
a few meters of one another (our aggregates), the probability of successful mating was much higher than where
placement was such that adults emerged at scattered
points throughout 100 ha of forest. These data clearly
demonstrate that establishment of infestations in new
areas as a result of wind-blown larvae is a rather chancy
thing unless there is a sufficient inoculation of individual
insects. On the other hand, once a pocket becomes established, its growth is likely to be rapid.
For Spot Eradication.-Earlier
I referred to the possibility of using disparlure for eradicating spot infestations detected outside generally infested areas. We began
to test this concept in the summer of 1971, in what we
believed was an isolated, very light and very localized
infestation in Somerset County in southwestern Pennsylvania, 125 km W of the closest known infestation. The
test was empirically designed, to consist of dropping baited
traps for three successive years in numbers we hoped
would out-compete the females in the field and, by capturing most of the males, significantly reduce mating success.
Within the trap-drop area of approximately 22 km", we
knew the location of 10-15 egg masses. In the fall of
1971, we located 8 new masses, 5 of these in the area
previously known to have eggs. With so few egg masses
in such a large area, it is very difficult to draw conclusions on what effect, if any, the trap-drop treatment may
have had. Nine egg masses also were discovered a short
distance outside the trap-drop area, so the area which
received traps in 1972 was enlarged to approximately
35 kllll, and the trap density was increased frolll 610 to
2800/km" (1580 to ca 7200/mjl). Three 40-ha areas
Disparlure on Granular Cork.-Further
tests were undertaken in Pennsylvania during the summer of 1972. We
used the same experimental design as described earlier for
our attractant tests with the following exceptions:
(1) Instead of dropping traps over the test areas, we
broadcast 6/12-mesh granular cork, impregnated with disparlure, at a rate of 25 g disparlure/ha over one block;
a second block was treated at a rate of 7.5 g of disparlure/ha. 'In each case, 622 g cork/ha were applied.
(2) Because of limitations on our ability to procure
and treat the quantities of cork required, treatments were
not replicated.
(3) Since our plots were limited in number, and since
we wished to provide a more, rather than less, rigorous
test for our material, we selected the aggregate pattern
for placement of insects instead of the random pattern.
Resu/ts.-The
results are presented in Table 2. In Test
Series 1, in the plot treated with 25 g disparlure/ha,
mating success was reduced from the 81.3% in the con-
17
trol to 35.0%. In the plot treated with 7.5 g disparlure/ha, mating success was 58.3%. Statistically, these
results are very highly significant and highly significant,
respecti vely.
be concerned unless we know that a trap is the equal of
a female. Recalling my earlier comment, to be the equal
of a female, the trap may need to give cues other than
chemical cues-visual,
for example-most
efficiently to
capture males.
In Test Series 2, emergence and recovery of females
was very low. Nevertheless, reductions in mating success
in the treated plots were observed, but these reductions
were not statistically significant when compared with the
control.
There is room to question the efficiency of our traps.
Although the traps started out with 500 ± /Lg of disparlure, the emission ratr of lure from the trap was not
very different than from females. And this rate never
did equal short-term bursts of release which each female
produces at some time during its lifetime (Richerson
1972). Also, all our traps were on the ground. Whether
the micrometeorological conditions were such that good
diffusion of the lure was possible is not known. Finally,
late in the summer we received some evidence that the
sticky Tack-Trap was perhaps too good a keeper for the
lure: that is, too little lure was actually being released
(M. Beroza, personal communication).
Microencapsulated
Disparlure.-After
completion of
Test Series 2, no more wild insects were available. It
was decided to use laboratory-reared
insects to test a
microencapsulated formulation of dis par lure, which had
been developed for the USDA by the National Cash
Register Co., before the weather turned too cold. A water
slurry of microcapsules, stabilized by a thickener and
containing a sticker to adhere the capsules to the foliage
and achieve vertical stratification of the lure, was sprayed
over each of two 100-ha plots at 5 g disparlure/ha.
Pupae
were placed in an aggregate pattern in one plot and a
random pattern in the other; two control plots were run
simultaneously. This constituted Test Series 3.
From our attempted eradication of the spot infestation
in southwestern Pennsylvania, we have learned that with
current techniques we cannot eradicate isolated, incipient
infestations with traps, even if treatment starts the year
after discovery. In this case, we seem not to have been
able even to hold the population static.
The results were very encouraging. We were unable
to detect any evidence of successful mating among the
insects in the two treated plots (Table 2).
The results of our confusant tests show that we were
able consistently to cause some mating inhibition even
though we do not know the mechanism(s) through which
we may be achieving confusion. The results at this point,
are encouraging. Four of our 6 tests showed statistically
significant mating inhibition over their controls, and the
other two tests showed substantial reductions.
Similar results with similar formulations have been obtained in post-season tests conducted at Otis Air Force
Base.
DISCUSSION
Let us first look at our trapping/attractant
tests. There
are several points to be considered. In Test 1, there was
more mating among the randomly distributed insects in
our trap drop areas than in our controls. Unfortunately,
we are woefully ignorant of the full spectrum of behavioral cues and responses which are involved as male
and female gypsy moths detect each other, come together,
and mate, and how, or if, these may be modified by
addition of quantities of disparlure to the picture. I
suspect that the sex attractant is simply one of the
earliest of a sequential set of cues to which males respond.
The message delivered to the male may be no more than,
Start searching: there's a female somewhere. If this is
so, I suggest that the increased mating resulted because
we had many lure emitters, in the form of traps, throughout our test blocks. Consequently, males were stimulated
far more frequently to search for females than was the
case in the controls. Because they were flying more,
searching more, and covering more ground, the probability of encountering subsequent cues from the widely
scattered females was increased, and the proportion of
females mated rose accordingly. In other words, we may
have done more harm than good with the treatment.
Perhaps the increased numbers of females in the plots
in Test Series 2 were sufficient to mask or overcome this
effect, so the phenomenon was not detected.
No adequate testing of integrating use of disparlure
with other treatments has been conducted. Until we know
much more about population levels which can be manipulated, and the methods by which this can be achieved, any
such tests would be empirical at best. The possibility of
reducing the size of the geographical area infested by
gypsy moth is long-range, and it is certainly some years
from testing.
Where does that leave us? How promising do our results really look? Statistical significance is one thing.
Biological significance, and that is the type of significance
with which we must concern ourselves if we are talking
about population manipulation, is quite another. According to Beroza and Knipling (1972), mating suppression
must exceed 93%, i.e., fertility cannot exceed 7% in the
initial year if control is to be achieved. Except in several
of our confusion tests, we do not approach the levels of
mating inhibition required to effect control if we accept
the Beroza-Knipling
model and all of its assumptions
(see Tables 1, 2).
Shorey (1970) concluded from various tests with other
insects that the trapping approach does not appear to hold
much promise when dealing with Lepidoptera. At this
time I tend to agree with him, as this technique relates
to the gypsy moth, but I hasten to add that I feel very
strongly that we must not drop attractant investigations
completely. There may be a simple behavioral key, currently unknown, which could reverse the conclusion.
Other trap designs, placements, and baiting techniques are
possible, and we may yet discover critical population level
limits within which we may be successful with attempts
at manipulation using traps.
In those tests where pupae were placed in the aggregate
patterns we recorded some reduction of mating, but in
only one of the 4 cases was this reduction significant. Why
were we not more successful?
Let us consider the concept of trap: female ratios. As I
indicated earlier, our ratios in these tests varied through
quite a range, but terided to be high, certainly within the
limits postulated as necessary for population suppression
by Bereza and Knipling (1972). I am not entirely convinced that ratios are the standard with which we should
When it comes to confusion, I strongly suspect that our
apparent success is a result of misdirection of moths to
attractive points which are not females. We had some
18
hundreds of thousands of these attracti ve points per hectare in our treated areas, compared with a maximum
potential (never reached) of 30 9 (from 30 pupae placed
in one aggregation)
within a hectare in our tests. We
may have been able to entice males continually to investigate attractive points, cork granules or microcapsules,
each close enough to its neighbor that they seldom if ever
chanced on a female. Unfortunately we have no direct
observations of male behavior in our field-test areas. We
have much to learn about just what is happening in the
field in both treated and control areas.
levels at which disparlure may be effective. (4) Under
no circumstance can I see eradication of the gypsy moth
from North America, and the use of disparlure, in whatever manner, to eradicate local infestations is still open
to question. And, (5) I feel that our attempts to
establish a barrier zone to confine the insect to the Northeast are still premature. Evidence in hand simply does
not support the practicality of this approach.
Disparlure is a potential tool for gypsy moth population manipulation: We still have not been able to determine how to utilize its potential effectively.
There is reason for optimism. In three of the six
confusion tests, mating was totally inhibited, and it was
inhibited in the rather severe condition where several females were present simultaneously in a localized spot in
our aggregations. The fact that we now have a microencapsulated formulation of disparlure which can be adhered
throughout the canopy is in our favor. Formulation seems
to present no serious problems, and application can be
done with standard spray rigs. We are anxiously awaiting the 1973 field season so we can follow up on these
tests.
ACKNOWLEDGMENTS
Most of our studies at Penn State are supported by
Cooperative Agreement 12-14-100-10, (946) 33 between
The Agricultural Experiment Station, PSU, and ERDARS-USDA.
Although I take full responsibility for any
statements or interpretations made here, a large number
of people have participated in the program I have discussed. Many Federal employees in several different
agencies have given us the benefit of their ideas, comments, criticism, and assistance; two Commonwealth of
Pennsylvania Departments have made available manpower
and field-test areas; Drs. J. V. Richerson and R. E. Sandquist, Research Associates in the Department of Entomology, PSU, have been in direct charge of many of the
tests discussed here, and, along with Mr. E. D. Eckess,
APHIS-USDA,
who is stationed at University Park,
have critical1y reviewed this manuscript.
And we are anxiously awaiting 1973 for another very
important reason. The pupae we used in Test Series 1
and 2 were collected just prior to field use from natural
infestations in eastern Pennsylvania. The pupae we used
in Test Series 3 were laboratory-reared
insects supplied
by Wm. Metterhouse of the New Jersey Department of
Agriculture.
Test 3 clearly was our most spectacularly
successful test. But there also have been more or less
spectacular results from tests in Alabama in 1971 and
1972, and at Otis Air Force Base in both years. In
l'1'cry test in which the results were especially exciting,
laboratory-reared
insects wet'e used. In no test so far in
which field-collected insects were used have we been able
to duplicate these results. The fact that laboratory-reared
gypsy moths are somehow different from field insects is
generally accepted. But we usually go blithely ahead in
our work ignoring this very important point for the sake
of convenience. Rarely has anyone attempted to quantify
these differences as has Dr. Richerson. So before we get
our expectations too high, we must wait until we have
given our latest hope a good test with wild insects.
REFERENCES
CITED
Beroza, M., and E. F. Knipling.
1972. Gypsy moth control with the sex attractant pheromone. Science 177:
19-27.
BierI, B. A., M. Beroza, and C. W. Collier. 1970. Potent
sex attractant of the gypsy moth, Porthetria dispar
(L.) : Its isolation, identification, and synthesis. Science 170: 87-89.
Cameron, E. A. 1971. Field Tests of Disparlure in
Pennsylvania. Paper read at Annual Meeting, E.S.A.,
Los Angeles, Calif.
Eiter, K., E. Truscheit, and M. Boness. 1967. Synthesen
von D, L-I0-Acetoxy-hexadecen- (7-cis) -01 (1), 12Acetoxy-octadecen- (9-cis) -01- (1) ("Gyplure")
und
l-Acetoxy-l0-propyl-tridecadien(5-trans. 9) . Justus
Liebigs Ann. Chern. 709: 29-45.
Jacobson, M. 1960. Synthesis of a highly potent gypsy
moth sex attractant. J. Org. Chern. 25: 29-45.
Jacobson, M., M. Schwartz, and R. M. Waters.
1970.
Gypsy moth sex attractants:
A reinvestigation.
J.
Econ. Entomol. 63: 943-945.
Richerson, J. V. 1972. Sex attractant release rates from
female gypsy moths, Porthetria dispar (L.) (Lepidoptera: Liparidae) and disparlure for two different
carriers. Paper read at 44th Annual Meeting, Eastern Branch, E.S.A., Atlantic City, N. J.
Shorey, H. H. 1970. Sex pheromones of Lepidoptera.
[III Control of Insect Behavior by Natural Products,
ed. D. L. Wood, R. M. Silverstein, and M. Nakajima. Academic Press, New York-London.
Stevens, L ].. and M. Beroza. 1972. Mating-inhibition
field tests using disparlure. the synthetic gypsy moth
sex pheromone. J. Econ. Entomol. 65: 1090-95.
To summarize, I evaluate our progress as follows:
(1) Right at the top of any priority list is the need for
good, solid adult behavioral studies. Only as we more
fully understand the insect can we more intelligently attempt to manipulate its populations by altering adult behavior, which is our goal when using disparlure.
For
example, to my knowledge there have not been conducted definitive studies which demonstrate conclusively
that disparlure is the Ollis chemical involved in the behavioral sequence of events during which male and female
perceive each other, come together, and mate. (2) We
do not now have the data which would justify any
operational control programs in 1973; we need at least
one more research field season for extensive testing. (3)
We do not have a panacea; none exist. I seriously doubt
that we ever will be able to manipulate well-established
populations of the gypsy moth solely with disparlure. Its
use is likely to be confined to fringe, newly infested, or
isolated areas with very low populations unless, of
course, other agents can reduce outbreak populations to
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