Method for control of social insects with a hemisalt of a perfluoroalkane sulfonic acid

An aqueous formulation for the control of social insects, especially wasps, and a method for its use. The formulation contains insect attracting ingredients and a toxicant in water. The toxicant is a hemisalt preparation of a perfluoroalkane sulfonic acid which is partially neutralized to a pH of between 2.8 and 6.5.

TECHNICAL FIELD 
This invention relates to the field of insect control and particularly to a 
formulation of a concentration dependent insect toxicant that, when mixed 
with a suitable insect attracting ingredient, will be carried by the food 
gatherers of a group of social insects, such as a colony of wasps, 
whereupon such food is carried back to the wasps' home colony, thereby 
destroying it, as well as a method of use for this preparation. 
BACKGROUND ART 
There are two major passive methods for insect control: traps and toxic 
baits. Both types must incorporate some kind of insect attracting material 
in order to be effective. Food materials are often used as the insect 
attracting material. An example of a material attractive to wasps is U.S. 
Pat. No. 4,851,218 to Hildebrandt et al., "Method for Controlling Insects 
of the Family Vespidae Utilizing Interspecific Bait". Traps, whether of 
the sugar water in a bottle variety or the flypaper variety, are only 
effective on individual insects. Toxicant preparations can be formulated 
with different types of pesticides. Pesticides can be used in two major 
ways, for quick-kill or for so-called "delayed-kill." 
Quick-kill pesticides which kill shortly after contact or ingestion, are 
desirable for control of populations of insects of non-aggregating 
behavior. Quick-kill pesticides are usually used as aerosol and spray 
insecticides which may be dispersed or formulated in aqueous, non-aqueous 
or partially aqueous systems for ease of dispensing. 
Pesticides which have a "delayed kill action" are most useful for a 
different type of insect: the so-called social insect. "Delayed-kill" 
pesticides can derive their delayed kill action from intrinsic properties 
of the chemical, if the toxic moiety of the compound itself has a delayed 
release. Membrane barriers, microencapsulation, or even binding of the 
pesticide to a polymer substrate, have been used as methods for 
accomplishing this delayed release. "Delayed kill" pesticides can also be 
of the type that are not delayed release, but disrupt an insect's internal 
system. Disruption of certain internal systems will cause the insect to 
succumb after a period of days. A different type of "delayed kill" is 
obtained from a concentration dependent toxicant, which, at higher 
concentrations, would provide a quick-kill and at lower concentrations 
would not kill immediately. Such a toxicant, however, has a "delayed 
action kill" effect as the target insect is killed as a result of repeated 
consumption of the toxicant. 
The social insects include such species as ants, termites, wasps and bees. 
(Wasps and bees include both social and non-social types.) Social insects 
by definition have a social hierarchy, with workers and foragers, males, 
and an egg-laying queen. Quick kill of individual forager insects does not 
affect the main colony. However, if a "delayed action" toxicant is mixed 
with an insect attracting ingredient, the foragers will carry the 
toxicant-attractant formulation back to the home colony where it is shared 
by larvae, workers, and queen. If sufficient toxicant is transported back 
into the nest, it is possible to eradicate the entire colony by 
trophallaxis (a mutual exchange of food) within a week or two, (if the 
toxicant is sufficiently effective in the amounts that reach the colony). 
In order to assure that sufficient toxicant is carried back to the nest, 
the toxicant-attractant formulation must not be repellent to the pest and 
must be protected from degradation. 
Wasps, which include such insects as yellowjackets and hornets, as well as 
those commonly called wasps, were considered, in the Old Testament, to be 
a plague upon mankind. Not only do wasps sting, sometimes with fatal 
results, but they also cause damage to fruit crops and they kill 
honeybees. Probably the greatest problem presented to man by wasps, 
however, is their nuisance value. They often are present in large numbers 
around recreational sites or garbage dumps or similar sources of available 
food. Thus effective methods of control are desirable. 
The use and importance of "delayed action" pesticides for the control of 
social insects is known in the art. 
Historically it has been found that the most effective method of wasp 
control is the destruction of the home colony. However, the main drawback 
with this direct approach is the difficulty in locating the home colony. 
Various species of wasps and hornets may have nests that are subterranean, 
within the structure of homes, or "aerial" (in trees, under roofs, etc.). 
A problem in eradicating the home colony for all three types is, as 
stated, locating the home colony. The second type especially presents an 
access problem: it is difficult to introduce an effective amount of a 
toxicant into a nest within an existing home since precautions to protect 
those living there are necessary. 
U.S. Pat. No. 4,540,711 to Bettarini et al, "Method for Combatting 
Infestations of Insects and Acari and Compositions for Use in Said 
Method", discloses the use of a hydroaquinone diether in an insect 
attracting ingredient for control of ants, especially fire ants. The use 
of the compound for termite control is also suggested, since it is 
effective against termites and they are also social insects. The patent 
also points out that such poisoned insect attracting ingredient must still 
be appetizing to the ants, or it will not be eaten or carried back to the 
nest. 
Another "delayed action" toxicant for termite control is disclosed in U.S. 
Pat. No. 4,582,901 to Prestwich, "Fluorinated Cellulose Esters and the Use 
Thereof as Termiticidal Compositions". This patent clearly states the need 
for "delayed action" toxicants for termite control: 
For a pesticide to be effective against termites and related pests it may 
have a somewhat delayed onset of activity. Termites typically feast upon a 
food supply and then return to their nest and regurgitate the food to be 
shared by those occupying the nest. Thus, a pesticide which instantly 
destroys the feeding termites has absolutely no effect upon those hatching 
on the nest. While the feeding termites are affected, those in the nest 
continue to multiply and thus the infestation remains. 
The same considerations apply to any other type of social insect, and the 
Bettarini et al. patent similarly but not as completely discussed the 
"spreading action of delayed action toxicants". 
The problems associated with the presence of wasps, especially around food 
processing and packaging plants, and the successful use of a delayed 
action chlorinated hydrocarbon insecticide for wasp colony destruction has 
been reported in Great Britain. ("Control of Wasps in Food Factories," 
Frank Jefkins, Food Trade Review, May 1961, p. 47). This solid insect 
attracting ingredient has been sold under the name Waspex. Wasp 
toxicant-attractant formulations can also be prepared and dispensed in the 
form of gels, syrups or liquids. 
Since the insect attracting ingredient carrier for any "delayed action" 
toxicant formulation must be appetizing and non-repelling to the target 
insects, different insect attracting ingredients and different types of 
toxicant formulations must be used for different species. 
Carbohydrate insect attracting ingredients are more generally acceptable 
than protein based insect attracting ingredients to wasps. Carbohydrates 
combined with small amounts of protein are also acceptable. Protein insect 
attracting ingredients are preferred by certain scavenging species. 
Protein insect attracting ingredients such as fish, chicken, etc., are 
highly susceptible to spoilage. Although antimicrobials and/or 
preservatives can prevent spoilage of protein insect attracting 
ingredients to some extent, these additives were found to be repellent to 
wasps. Many toxicants added to a insect attracting ingredient are unstable 
(decompose) in sunlight or air over a period of time making the 
toxicant-attractant formulation less effective. Toxicant decomposition 
products are often repellent to wasps and render the insect attracting 
ingredients unacceptable. Certain stabilizing agents such as antioxidants 
and surfactants can be used to stabilize the toxicants to some extent. 
However most of these additives tend to be repellent to wasps. 
Aqueous insecticidal formulations are preferable to solid insecticidal 
formulations because a wasp must first cut a solid insect attracting 
ingredient into a piece of manageable size, then transport the piece back 
to the nest. The time and energy required to imbibe liquid 
toxicant-attractant formulation is less than is required to cut up the 
solid toxicant-attractant formulation. Thus, although transport times are 
the same, more toxicant is delivered to the nest per unit of time with 
liquids than with solids. Aqueous insecticidal formulations also have the 
advantage that they can satisfy the colony's need for water. For these 
reasons a stable water soluble toxicant is preferred. 
Frequently used "delayed action" toxicants such as bendiocarb 
(2,2-dimethyl-1,3-benzodioxol-4-yl methyl carbamate) and Dursban 
(0,0-Diethyl-0-[3,5,6-trichloro-2-pyridyl]-phosphorothioate) are not water 
soluble and must be made water dispersible by the use of surfactants, 
organic solvents, and/or hydrotropes. The addition of such compounds to an 
aqueous insecticidal formulation, however, makes the formulation 
unattractive or even repellent to wasps. Another drawback of the dispersed 
or emulsified insecticide is that it can undergo phase separation in 
storage. The problem of such phase separation is that the insecticide will 
separate into the oil phase at the top, which will create inadequate and 
disproportionate delivery of toxicant-attractant formulation in the 
aqueous phase. 
Although other "delayed action" toxicants such as Dipterex (dimethyl 
[2,2,2-trichloro-1-hydroxy ethyl]phosphonate), acephate (O,S-dimethyl 
acetylphosphoramidothioate) and borax are water soluble, it was found that 
the toxicant-attractant formulation prepared using these were not very 
attractive to wasps. 
A further consideration for an effective "delayed action" toxicant is a 
careful balancing of the concentration and the kill effect. Too great a 
concentration of the pesticide will repel wasps and will produce too quick 
a kill for effectiveness in eradication of the home colony. A smaller 
concentration of toxicant allows a wasp to make repeated visits to the 
source of the toxicant-attractant formulation. After each visit, the wasp 
returns home, carrying some of the toxicant with it. The cumulative effect 
of the toxicant destroys the home colony, an effect that does not occur if 
the initial kill is too quick. 
The fluorinated sulfonamides have been found to be effective "delayed 
action" insecticides for such social arthropods as ants. This is discussed 
in Ch. 21, Fluorinated Sulfonamides, in Synthesis and Chemistry of 
Agrochemicals, Vander Meer et al., (American Chemical Society, Washington, 
D.C., 1987). However, since such compounds are of limited solubility in 
water, they cannot be used with aqueous insect attracting ingredient 
components. 
The Vander Meer et al. chapter also stated that perfluorooctane sulfonic 
acid form and its potassium salt provided good delayed activity on ants. 
The use of various amides of perfluoro compounds for the control of 
arthropods is disclosed by U.S. Pat. No. 4,921,696 to Vander Meer et al. 
U.S. Pat. No. 4,092,110 to Adolphi et al. discloses the use of compounds of 
the formula C.sub.n F.sub.2n+1 SO.sub.3 M where n is an integer from 1 to 
14 and M is hydrogen or a cation for treatment of wood or wood based 
materials from "animal pests," especially termites. 
SUMMARY DISCLOSURE OF THE INVENTION 
The present invention is an aqueous concentration dependent toxicant 
formulation for the control of social flying insects, especially wasps, 
and a method for its use. The preparation includes both toxicant and 
insect attracting ingredient components. 
It has been found that the perfluoroalkane sulfonic acid salts are 
generally insoluble in water and thus unsuitable for use with an aqueous 
insect attracting ingredient composition by itself. Perfluoroalkane 
sulfonic acid is water soluble, but such solutions have very low pH (a 1% 
solution of the acid in water has a pH of 1 or less), creating problems 
with the insect attracting ingredient and in handling the solution. A 
toxicant-attractant formulation produced using perfluoroalkane sulfonic 
acid has such a low pH that the preparation is not readily taken by wasps 
and appears to repel them. The acidic preparations are not preferred 
either for consumer or for pest control use due to the hazardous nature of 
highly acidic preparations. 
A partially neutralized preparation of perfluoroalkane sulfonic acid, 
however, is not very acidic and has sufficient water solubility for such 
use and produces a toxicant-attractant formulation that is very attractive 
to wasps. Perfluoroalkane sulfonic acid can be partially neutralized to 
raise pH by incremental addition of a base to produce a sufficiently water 
soluble and attractive toxicant-attractant formulation. Sufficient water 
solubility and higher pH can be achieved by using a hemisalt preparation 
of perfluoroalkane sulfonic acid. It has been found that the hemisalt 
preparation of perfluoroalkane sulfonic acid is an effective concentration 
dependent toxicant The hemisalt preparation is also stable in carbohydrate 
solutions, the preferred insect attracting ingredient for such insects. 
Solubility of the toxicant in water is one problem solved by the present 
invention; effective concentration limits for such a preparation is 
another. It was found that very low toxicant concentrations of the 
hemisalt of perfluoroalkane sulfonic acid (approximately 0.001%) were 
effective, although sufficient kill of a home colony for adequate 
population control was much slower than for higher concentrations. 
Concentrations of 1.0% proved to kill so effectively that the wasps did 
not live long enough to transport to and share sufficient toxicant with 
the home colony to destroy it.

BEST MODE FOR CARRYING OUT THE INVENTION 
A preferred method of use of the toxicant-attractant formulation of the 
present has been found to be to place the formulation into a covered 
container. Liquid toxicant-attractant formulation can be dispensed through 
a wick extending into the liquid and protruding through and above the 
container cover. (Other dispensing means, such as a humming bird 
feeder-type station with permeable membrane, absorbent pads, or any 
seepage device may also be used.) To be effective, the container should be 
placed in an area frequented by the wasps, preferably above ground level 
to prevent access by children or animals. 
SELECTION OF FORMULATIONS TO BE FIELD TESTED 
Preparations were first tested in the laboratory to screen out those 
formulations that did not have the desired combination of attractancy (or 
non-repellency) and "delayed kill" effect. 
Mortality of toxicants/additives, etc. of wasps and repellency were studied 
under controlled conditions in the laboratory. Laboratory tests were 
conducted with standard insecticides such as bendiocarb, Dursban, 
Dipterex, acephate, and borax (described before). It was found that all 
were ineffective as concentration dependent toxicants for wasps. Then 
various toxicant-attractant formulations with perfluoroalkane sulfonic 
acids and perfluoroalkane sulfonic acid salts were tested. It was found, 
as discussed before, that both concentration levels and pH were important 
variables. Wasps were trapped and brought to the lab. Ten worker wasps 
were placed in a 1 cubic foot wire mesh cage and given access to a 10% 
sucrose solution and acclimated overnight. The next day the sugar solution 
was removed and was replaced by two solutions, one with a particular level 
of toxicant in the insect attracting ingredient and the other one without 
toxicant (insect attracting ingredient solution alone). The number of dead 
wasps was recorded at various time intervals, up to 24 hours. Four 
replicate cages were used for each concentration of each toxicant. 
Generally, three concentrations of two toxicants were tested in each 
experiment. If mortality occurred at moderate concentrations of a 
particular toxicant, but not a higher concentrations it was concluded that 
the test toxicant was toxic to wasps. It was also assumed that the test 
toxicant was a repellent to wasps at higher concentrations. 
Since wasps under laboratory or forced-feeding (no other food sources 
available) would consume toxicant-attractant formulations that they might 
normally avoid in the open, preliminary, non-controlled field tests were 
conducted to select formulations to be thoroughly tested for colony and 
nest destruction under extensive and controlled conditions in three 
regions. 
Next, fields with wasp problem/population were identified and insect 
attracting ingredient stations were established there. Containers with the 
insect attracting ingredient alone (no toxicant) and with formulations 
containing the insect attracting ingredient and different levels of 
concentrations of toxicant were placed on bait stations close to each 
other. The number of wasps feeding from each container was counted at 
various time intervals. Materials which had shown little repellency in the 
laboratory often showed repellency in the field. This phenomenon is 
probably due to the fact that, as said earlier, wasps in the open field 
(in their natural habitat) had free choice of food sources, while wasps in 
the cages had no such choice. Toxicant-attractant formulations frequently 
visited and fed by wasps in the field were considered non-repellent and 
those which were not visited and fed by wasps were considered repellent. 
PREATION OF AQUEOUS HEMISALT 
Perfluoroalkane sulfonic acids were prepared by ion exchange from 
commercially purchased potassium perfluoroalkane sulfonates. A 
representative batch of these potassium perfluoroalkane sulfonates was 
tested and found to contain perfluoroalkane chain lengths ranging from 
C.sub.4 F.sub.9 to C.sub.8 F.sub.17. A hemisalt of perfluoroalkane 
sulfonic acids can be made by mixing an aqueous solution of a base with an 
aqueous solution of the acid to prepare an aqueous formulation having a pH 
between 2.8 and 6.5, preferably pH 4.0 to 6.5, most preferably pH 5.0 to 
6.0, and optimally approximately pH 5.5. The base can have any suitable 
base, such as metal hydroxides of sodium, potassium, lithium, calcium, 
magnesium, zinc, aluminum or zirconium; ammonium hydroxide; primary, 
secondary or tertiary amines; primary, secondary or tertiary 
alkanolamines; or tetra alkylammonium hydroxides (alkyl being methyl, 
ethyl, propyl, or butyl). 
PREATION OF AQUEOUS FORMULATIONS 
An insect attracting ingredient preparation of carbohydrates in water, 
preferably containing a mixture of corn syrup, sucrose, maltodextrine, a 
protein, and optionally a preservative, was made up. The optimal 
preparation contained 10% to 20% corn syrup, 5% to 15% sucrose, 0.5% to 5% 
maltodextrine, 1% to 10% commercially available proteins, and 0.001% to 
0.20% of Kathon (preservative), the balance being water. To this was added 
the hemisalt preparation of perfluoroalkane sulfonic acid, preferably 
0.001% to 1.5% of the total weight, and most preferably 0.02% to 0.03%. 
Gel formulations were also prepared by addition of a suitable gelling agent 
to the preparation. 
Suitable gelling agents would include such things as cellulose fibers, 
polysaccharides, or clays (natural or synthetic). Such an agent would be 
preferably present in from 0.5% to 10% by weight of the total weight of 
the formulation. 
A preparation of the formulation in a gel form provides several advantages. 
It provides necessary water for the foragers and the colony, it minimizes 
water loss through evaporation (which would happen in open field on a 
sunny day) and it provides packaging flexibilities for the finished 
product. 
FIELD TEST EXPERIMENTAL METHODOLOGY 
For wasp population abundance studies, three bait stations were placed out 
at each of several sites, preferably near known wasp nests. Each station 
was kept filled with the aqueous insect attracting ingredient with no 
toxicant added. Each day, the number of insects feeding at the insect 
attracting ingredient station was counted and recorded. This indicated 
when populations were abundant enough for testing. It also gave baseline 
abundance for toxicity tests. Such testing was carried out at least a week 
in advance of toxicant testing. 
This allowed yellowjacket foragers to be trained to the stations. (Similar 
results to those reported below were obtained without such training, but 
initial wasp visitations were lower). Individual wasps were netted and 
then marked with a small drop of paint. Wasps readily returned to the 
station after marking. All wasps visiting the same station were marked 
with the same color. Each station had a different color. The number of 
marked and unmarked wasps feeding at each station was recorded. Also, the 
number of marked and unmarked wasps leaving the nest cavity in 5 minutes 
was recorded. This constituted the precount. 
After precounts were established, actual toxicant testing was begun. The 
formulation with the insect attracting ingredient alone was, at some 
sites, then replaced with a formulation containing toxicant as well as the 
insect attracting ingredient. Other sites continued to have only the 
formulation without the toxicant to serve as controls. Periodically 
afterwards, the number of marked and unmarked wasps feeding at the 
stations and the number exiting the nests were recorded. A decline 
indicated mortality. At longer intervals, nests were excavated to 
determine the number of workers alive in the nest, status of the brood 
with the nest, and whether the queen was alive. 
The presence of marked wasps leaving the nest indicated that at least some 
wasps from that nest had been feeding on a station containing toxicant and 
insect attracting ingredient. Movement of wasps between stations was also 
tracked with the marked wasps. 
Testing was carried out at sites in Hawaii, Wisconsin and Georgia. At each 
test site, three different concentrations of toxicant were tested and 
population densities both at the insect attracting ingredient stations and 
at the home nests were monitored over time. The wasps present at each 
location were species of yellowjackets. The toxicant-attractant 
formulations field tested were all previously screened, as discussed 
above, and it was found that they were well taken by wasps under 
choice-feeding conditions. 
Approximately 100 different formulations were tested, using slightly 
different proportions of insect attracting ingredients, preservatives, 
bases, and many different levels of toxicant. All formulations were within 
the parameters discussed above. Four of the formulations tested are given 
below: 
______________________________________ 
1 2 3 4 
______________________________________ 
Tap Water 73.96185 73.9614 70.9535 
70.9615 
Animal protein 
-- -- 3.0000 -- 
Hydrolyzed 
(Polypro 5000) 
Wheat Protein 
-- -- -- 3.0000 
Hydrolyzed 
(Hydrotriticum) 
Maltodextrin 
3.00000 3.0000 3.0000 3.0000 
(Star Dry 10) 
Sucrose 8.00000 8.0000 8.0000 8.0000 
(C & H Sugar) 
Corn Syrup 15.00000 15.0000 15.0000 
15.0000 
(Cornsweet 95) 
Kathon LX 0.00800 0.0080 0.0160 0.0080 
(Preservative) 
Perfluoroalkane 
0.02990 0.0279 0.0293 0.0293 
sulfonic acid 
Sodium Hydroxide 
0.00025 -- 0.0012 0.0012 
Tetramethyl -- 0.0027 -- -- 
ammonium 
hydroxide 
Total 100.00000 
100.0000 100.0000 
100.0000 
______________________________________ 
The acid, bases and Kathon were used from dilute water solutions and water 
corrections adjusted accordingly. 
Over 300 individual observations were made at the sites. Three 
concentrations of toxicant (0.03%, 0.014% and 0.007%) were tested at each 
station to allow for field observation of wasp feeding preferences. All 
concentrations proved effective. The results of the observations for each 
toxicant concentration were averaged. 
In Lake Herrick, Ga., the wasp species tested was Vespula maculifrons. 
Locations for the stations were selected near known nests. Zero hours 
marks the beginning of the test, when the toxicant-attractant formulation 
solution was placed in the station. Negative time counts are precounts. 
The results of these tests for the stations are: 
______________________________________ 
Average Number of Wasps Per Station 
% Concentration of Toxicant 
Time 0.03 0.014 0.007 
(hrs) (6 stations) (9 stations) 
(9 stations) 
______________________________________ 
-3.6 44.0 31.7 38.1 
1.2 38.9 45.2 64.0 
2.4 25.0 36.2 61.2 
20.6 1.8 2.7 2.4 
24.2 1.6 0.7 1.4 
______________________________________ 
As the numbers show, the stations with the lower toxicant concentrations 
showed an increase in wasp concentration over the precount figure. It is 
assumed that this increase reflects the fact that additional wasps located 
and visited the station after the precount. Wasps partaking of the lower 
toxicant concentration formulations were able to revisit the stations 
before their deaths. Wasps having visited the station with higher toxicant 
concentrations began to die off sooner than those who visited and fed on 
the lower toxicant level compositions. Thus, stations with higher toxicant 
levels showed no visitation increase after precount. 
As discussed before, wasps visiting a station were marked. No wasps marked 
at one station were ever found at another station. At 20.6 hours and 24.2 
hours, no marked wasps were found at any station, at any concentration, 
indicating that, by that time, all wasps that had visited a station had 
died. 
The number of wasps leaving a nest was also monitored. Five nests were 
observed, the five nests containing wasps that were marked as having 
visited three different stations. Nest activity showed a decline 
comparable to that observed on the stations. 
______________________________________ 
# Exits 
Time per 5 min. 
(hrs) (averaged) 
______________________________________ 
-2.8 83.500 
1.7 117.500 
3.0 91.000 
20.0 14.125 
21.3 19.375 
24.8 17.125 
______________________________________ 
After 20.0 hours, no marked wasps were observed exiting the nests. 
Excavation of two nests after the 24.8 hour count showed that worker 
populations had been reduced, but some workers and the queen were still 
alive. Presumably, the nest excavations were performed before the toxicant 
had spread to the queen and remaining workers. Excavation of the remaining 
nests after five days showed that none of the workers nor the queen were 
alive. 
In order to test the effectiveness of the toxicant-attractant formulation 
in areas without nearby nests, stations, one for each toxicant 
concentration, were set up at three locations, chosen at random, away from 
identified nests. Similar wasp populations visiting the stations were 
noted. 
______________________________________ 
Average Number of Wasps per Station 
Time % Concentration of Toxicant 
(hrs) 0.03 0.014 0.007 
______________________________________ 
-0.2 22.3 31.3 22.0 
1.0 15.3 22.3 35.0 
2.7 15.3 22.3 29.0 
3.9 3.0 14.0 16.3 
4.8 2.3 10.7 8.7 
5.8 3.3 6.0 7.0 
7.2 6.3 3.0 4.0 
23.3 0.0 1.0 5.3 
24.3 1.0 1.7 3.7 
25.1 2.3 1.7 6.3 
27.1 1.0 1.3 6.0 
______________________________________ 
The numbers showed a similar pattern of decline, both in numbers of marked 
and unmarked wasps, as in the other tests. 
To study the effect of toxicant concentration on bait palatability, three 
stations (each with one toxicant concentration) were set up at four sites 
and monitored. Three stations with no toxicant present but only the insect 
attracting ingredient were set up at two sites to serve as a check on the 
effects of external factors such as weather or natural population decline. 
The data showed that the decline in the number of wasps was attributable 
to the presence of the toxicant, for no decline (only a variation) showed 
for the stations without toxicant. 
Since wasps returning to a particular colony could have fed from stations 
with any of these toxicant concentrations, results were pooled for final 
reporting in the table that follows. 
______________________________________ 
Average Number of Wasps Per Station 
Time With Toxicant 
(hrs) (Average of all concentrations) 
No Toxicant 
______________________________________ 
-26.4 20.8 5.3 
48.0 1.6 11.2 
100.6 0.0 4.5 
115.6 0.0 7.3 
141.7 0.1 14.8 
165.9 0.8 36.2 
______________________________________ 
Excavation of nine nests in the vicinity of the toxicant-containing 
stations, performed at eleven days, found all wasps within the nest dead. 
It should be understood that this figure does not mean that any nest would 
be destroyed in less than two weeks. Total kill time will vary, depending 
upon the size and population of a home nest and the amount of toxicant 
being carried back to that nest. 
The amount of toxicant being carried back to a nest, as discussed, depends 
not only on the number of wasps visiting the site and then returning to 
the nest, but also on the concentration of the toxicant in the station. 
Similar studies were carried out in Racine, Wisconsin, with Vespula 
germanica and in Hilo, Hi., with Vespula pensylvanica. 
The results were similar, with the exception of the fact that to destroy 
entire extensive colonies (colonies of very high population such as tens 
of thousands) requires a large quantity of toxicant-attractant formulation 
and several days. 
OTHER INSECTS 
Similar studies were conducted in Racine, Wis., on honeybees (Apis 
mellifera), with almost identical results. All bees within a hive were 
found to be dead within 24 hours after access to the aqueous insecticidal 
formulation of the present invention. Studies were conducted on honeybees, 
not because honeybees are considered a nuisance insect, but to ascertain 
if the formulation would be effective against a non-desirable bee species, 
the so-called Africanized honeybee or killer bee. Field tests with such 
bees were not feasible to conduct, due to the ferocity of the bees and the 
possibility of lethal venom dosages to field personnel. 
INDUSTRIAL APPLICABILITY 
Toxicant-attractant formulation preparations according to the present 
invention can be used to control populations of wasps (including hornets 
and yellowjackets) wherever such insects create a problem. Picnic and park 
areas frequently have yellowjacket problems, as do any areas where garbage 
is stored. Food processing or production areas also have wasp problems. 
The formulation appears also useful for eradication of killer bee 
colonies.