Environmentally safe insecticide

An environmetally safe, broad spectrum insecticidal composition is disclosed. The composition combines a mixture of monocarboxylic acids (such as oleic and linoleic) and their alkali metal salts, and a pyrethroid compound. In a concentrated form of the composition, the monocarboxylic acid mixture comprises about 50 percent by weight monocarboxylic acids and their salts, at least 70 percent of which comprise oleic acid and at least 6 percent comprise linoleic acid. The pyrethroid compound is present in the concentrate at about 0.2 to 2.0 percent by weight.

BACKGROUND OF THE INVENTION 
This invention relates to an environmentally safe insecticidal composition. 
More particularly, the invention features a specific insecticide 
formulation combining certain fatty acid soaps and pyrethroids. 
The use of insecticides has greatly enhanced agricultural productivity, but 
it has become apparent that there are limits to the amount of 
petrochemical-based materials that safely can be absorbed into the 
environment. Catastrophic, unanticipated, relatively long term effects 
experienced with materials such as DDT have increased awareness of the 
potentially dangerous environmental impact of widespread use of 
synthetics, contributed to the creation of regulatory agencies charged 
with protecting the environment, and promoted the development of potent, 
but apparently less dangerous insecticidal materials made from 
petrochemicals. These new insecticides are nevertheless far from ideal 
from the point of view of environmental safety, and sometimes collect in 
food and fresh water resources. 
Recently, natural insecticidal materials such as bacterial preparations 
lethal to insects have been available commercially. However, the potential 
of non-bacterial, natural materials having insecticidal properties has 
largely been ignored, presumably because of the higher cost and lower 
insecticidal activity of such known natural substances. 
Salts of fatty acids, primarily sodium or potassium fatty acid soaps, 
recently have been used commercially as insecticides. Compositions having 
excellent insecticidal properties which exploit these salts are available 
commercially under the trademark SAFER INSECTICIDAL SOAP. This product 
accordingly constitutes an exception to the trend noted above. These fatty 
acid soaps are naturally occurring materials having no known long term 
environmental effects. They are very effective against soft bodied insects 
such as aphids and whiteflies, but less effective against other types of 
insects. 
Pyrethrum was used commercially many years ago as an insecticide, primarily 
in the form of "oleoresin of pyrethrum". Oleoresin of pyrethrum is an 
archaic pharmaceutical term for an ether extract of the cinerariaefolium 
variety of chrysanthemum. It contains volatile oils and components having 
insecticidal properties, called pyrethrins and cinerins. These materials 
are known to be toxic to insects, but essentially non-toxic to mammals. 
Pyrethrins also lack persistence in the environment, and are characterized 
by negligible biological magnification in the food chain. 
One major problem with the use of these pyrethrins as insecticides is their 
high cost per unit dose. Attempts to extend the efficacy of the pyrethrins 
to provide economic feasibility have not been commercially successful. An 
example of such a composition comprising a mixture of saponified organic 
acids, i.e., salts of coconut oil, and pyrethrins was once sold 
commercially under the trademark Red Arrow. However, these compounds were 
still not economically feasible because of their high pyrethrin content 
(about 40% by weight), and because the coconut oil soaps contributed 
little to their insecticidal efficacy. In fact, most commercially 
available fatty acid soap compositions contain an excess of alkali which 
is believed to promote hydrolysis and inactivation of pyrethrins. 
Pyrethrin-based insecticides also degrade rapidly in the presence of 
sunlight and during storage. 
Other materials which have been used to extend the efficacy of pyrethrins 
are toxic not only to insects but also to a variety of plants and animals. 
One material often suggested for use with pyrethrins is piperonyl 
butoxide. While this type of composition can produce a very potent 
insecticide, high doses can cause nausea in many animals including man, 
and the compositions are significantly phytotoxic. Other combinations of 
insecticides and pyrethrins have either presented similar toxicity 
concerns or loss of effectiveness due to inactivation of the pyrethrins. 
U.S. patent application Ser. No. 148,961 discloses an insecticidal 
formulation which combines pyrethrins and salts of fatty acids. Although 
this composition is environmentally safe and demonstrates improved 
insecticidal properties, it is still relatively expensive and may be 
susceptible to degradation during storage or use because of the presence 
of pyrethrins. 
Accordingly, it would be advantageous to provide an environmentally safe 
and effective insecticidal composition which has improved storage 
properties and is not particularly prone to degradation upon exposure to 
sunlight. 
It is thus an object of this invention to provide an insecticide 
formulation comprising natural, biodegradeable materials which are 
relatively inexpensive, non-toxic to a wide variety of plants and animals, 
and effective against a broad spectrum of insect life. Another object is 
to provide a specific, environmentally safe insecticidal formulation which 
has a commercially acceptable shelf life, low, acceptable phytotoxicity, 
and relatively low cost. 
These and other objects and features of the invention will be apparent from 
the description and the claims which follow. 
SUMMARY OF THE INVENTION 
The present invention features an aqueous insecticidal solution comprising 
a combination of active, readily biodegradeable insecticidal materials. 
This combination of active insecticidal materials has been observed to 
enhance the effectiveness of the individual insecticidal materials. The 
insecticidal solution is effective in protecting a variety of plants 
against a variety of insects and related pests. Moreover, the insecticide 
is economical to use and substantially non-toxic to plants and animals. 
The insecticidal formulation comprises a first insecticidal component 
comprising a mixture of carboxylic acids and the alkali metal salts of the 
acids. The carboxylic acids of this mixture comprise oleic acid, and its 
alkali metal salts, as a major component, and linoleic acid, and its 
alkali metal salts, as a minor component. Other carboxylic acids, and 
their salts, having less than 21 carbon atoms may also be present in the 
mixture. A second insecticidal component of the insecticidal formulation 
comprises a pyrethroid compound. Although virtually any insecticidally 
active pyrethroid compound may be used with the invention, the currently 
preferred pyrethroids include cypermethrin, fenvalerate, fluvalinate and 
permethrin. A solvent for the pyrethroid, such as an alcohol having 
between 2 and 6 carbon atoms (e.g. ethanol or isopropanol), may be 
included in the insecticidal formulation to help solubilize the fatty acid 
salts at higher concentrations (e.g., greater than 20%). 
A concentrated formulation may be diluted from between 25:1 to 500:1 with 
water to yield a ready-to-use formulation. The ready-to-use formulation is 
effective on application to a plant at a dilution in water such that the 
applied solution contains at least about 0.05-2.0 percent by weight of the 
monocarboxylic acid mixture and at least 0.001 percent of an 
insecticidally active pyrethroid compound. 
This insecticidal formulation provides protection against plant damage from 
infestation from insect species from at least the orders Homoptera; 
Coleoptera; Dermaptera; Hemiptera; and Lepidoptera; and from crustacea 
species from the order Isopoda. More specifically, application of the 
solutions is effective against species from the families Homoptera 
aphididae; Homoptera aleyrodidae; Homoptera coccidae; Homoptera psyllidae; 
Coleoptera chrysomelidae; Coleoptera tenebrionidae; Lepidoptera arctiidae; 
Lepidoptera lasiocampidae; Lepidoptera tortricidae; Lepidoptera pieridae; 
and Lepidoptera noctuidae. These orders and families include essentially 
all northern hemisphere insects which damage ornamental plants, trees, and 
vegetable crops. The insecticidal solutions also are effective in the 
control of mosquitoes, fleas, lice, and ticks, and accordingly may be 
used, for example, to protect pets and their resting places in the home. 
The insecticide of the invention is useful in protecting apples, avocados, 
grapefruits, lemons, oranges, tangerines, peaches, nectarines, apricots, 
pears, almonds, pecans, walnuts, kiwi fruit, blackberries, logan berries, 
raspberries, strawberries, and grapes, against insects including Japanese 
beetles, flea beetles, weevil adults, caterpillars, aphids, leaf hoppers, 
psyllids, scale crawlers, and sawfly larvae. In addition to commercial or 
vegetable garden protection, the insecticide of the invention can be used 
to protect lawns, turf grass, ornamental trees and shrubs, flowers, and 
house plants against a variety of insects. For example, the insecticide 
protects lawns against chinch bugs, lawn moth, sod webworm and army ants, 
and ornamental trees and shrubs against aphids, beetles, caterpillars, 
lace bugs, box elder bug, treehoppers, psyllids, sawflies, scales, and 
woolly aphids. Essentially complete insect protection is provided for 
ornamental trees and shrubs including azaleas, camellias, cacti, dogwood, 
rhododendrons, evergreens, and broad-leafed shade trees. The insecticide 
of the invention has been shown to provide effective protection for 
flowers including asters, carnations, chrysanthemums, geraniums, 
marigolds, petunias, and roses against attack by aphids, flea beetles, 
Japanese beetles, caterpillars, and whitefly.

DETAILED DESCRIPTION OF THE INVENTION 
As noted previously, the insecticidal formulation of this invention 
combines two insecticidally active materials (fatty acid soaps and 
pyrethroids) to obtain insecticidal effectiveness which is superior to the 
effectiveness of either of the two components alone. Generally, it is 
possible to combine the insecticidal components of the invention in 
varying amounts to form an aqueous solution. However, as pyrethroid 
compounds are more insecticidally potent than the fatty acid soaps, the 
pyrethroid component generally may be present in smaller amounts. 
The insecticide of the invention is preferably prepared as a concentrate 
and is subsequently diluted for use to a ready-to-use form. A preferred 
formulation, in concentrate form, comprises (1) approximately 50 percent 
by weight of an aqueous solution of carboxylic acids and the alkali metal, 
preferably potassium, salts thereof; (2) approximately 0.2 to 2.0 percent 
by weight of a pyrethroid compound; (3) about 30 percent by weight of an 
alcohol having between 2 and 6 carbon atoms; and (4) water. The 
concentrate may be diluted from between 25:1 to 500:1, and preferably from 
about 50:1 to about 100:1, with water to yield a ready-to-use formulation 
comprising about 1.0 percent by weight carboxylic acids and at least 0.001 
percent by weight of a pyrethroid compound. Preferably, the pyrethroid 
compound is present from about 0.002 percent by weight to 0.04 percent by 
weight. 
In a currently preferred embodiment the carboxylic acid mixture comprises, 
in an aqueous solution, approximately 10 to 50 percent by weight, and most 
preferably about 49 percent, of a mixture of the alkali metal salts of 
fatty acids and unneutralized fatty acids. 
A suitable carboxylic acid solution is available commercially from Safer, 
Inc. of Wellesley, Mass. under the trademark "Safer Insecticidal Soap". 
The composition of this product varies slightly from batch to batch, but 
its carboxylic acid component always includes at least about 70% salt (or 
acid) form of oleic acid, and at least about 6% salt (or acid) form of 
linoleic acid. The remainder of the solutes comprise other fatty acids or 
salts having between 12 and 20 carbon atoms. The soap component is present 
in the concentrate at levels in the range of 10 to 50, preferably about 
49, percent by weight. 
The pyrethroid component comprises about 0.2-2.0 percent, by weight of the 
concentrate. Upon dilution to a ready-to-use formulation the pyrethroid 
component is present at between about 0.001 to 0.04, and preferably 
between about 0.009 and 0.025 percent by weight. The pyrethroid compounds 
useful with this invention are esters which have been developed in 
response to the high cost and rapid breakdown of natural pyrethrins. These 
synthetic compounds have the insecticidal activity associated with that of 
the naturally occurring pyrethrins, without their high cost, erratic 
supply or low environmental stability. 
Virtually any known pyrethroid compound having insecticidal activity is 
useful with the practice of this invention. Such useful pyrethroids 
include, but are not limited to alfoxylate, cyfluthrin, cyhalothrin, 
cypermethrin, cyphenothrin, deltamethrin, esfenvalerate, fenfluthrin, 
fenopropathrin, fenpyrithrin, fenvalerate, fluorocythrin, furamethrin, 
fluvalinate, permethrin, phencyclate, phenothrin, tetrallethrin, 
tralocythrin and tralomethrin. Currently, the most preferred pyrethroids 
are cypermethrin, fenvalerate, fluvalinate and permethrin. 
Preferred cypermethrin compounds are available from BASF (India) under the 
trademark "Basathrin"; from FMC, Agri. Chem. Group under the trademarks 
"Ammo", "Arrivo", and "Cynoff"; from ICI Americas, Inc., Agri. Chem. Div. 
under the trademark "Cymbush"; from IGI Agrochemicals (U.K.) under the 
trademarks "Cymbush", "Kafil Super" and "Cymperator"; from Mitchell Cotts 
Chem. Ltd. (U.K.) under the trademark "Cyperkill"; from Shell Int'l Chem. 
Co., Ltd. (London) under the trademarks "Barricade", "Flectron", "Folcord" 
and "Ripcord"; and from United Phosphorous, Ltd. (India) under the 
trademarks "Ustaad 10EC" and "Cyroxy 25EC". 
Fenvalerate compounds are available from E. I. du Pont de Nemours & Co., 
Inc. Agri. Products Dept. under the trademark "Pydrin"; from Fermenta 
Animal Health under the trademark "Ectrin"; from Rallis India Ltd. under 
the trademark "Sumicidin"; from Shell Intl. Chem. Co., Ltd. (London) under 
the trademark "Belmark"; from Sumitomo Chem. Co., Ltd. (Japan) under the 
trademark "Sumicidin"; and from United Phosphorus Ltd. (India) under the 
trademark "Fenkill". 
Fluvalinate compounds are available from Sandoz Crop Protection Corp. under 
the trademark "Mavrik". 
Permethrin compounds are available from FMC Agri. Chem. Group under the 
trademarks "Cellutec", "Dragnet", "Pounce" and "Pounce Peach"; from ICI 
Americas Inc., Agri. Chem. Div. under the trademarks "Ambush" and 
"Torpedo"; from ICI Agrochemicals (U.K.) under the trademarks "Ambush", 
"Dragon", "Imperator", "Kafil" and "Perthrine"; from Mitchell Cotts Chem. 
Ltd. (U.K.) under the trademark "Permasect"; from Penick-Bio UCLAF Corp. 
under the trademark "Pramex"; from Shell Int'l Chem. Co., Ltd. (London) 
under the trademarks "Outflank" and "Talcord"; from Sumitomo Chem. Co., 
Ltd. (Japan) under the trademark "Eksmin"; from Wellcome Foundation Ltd. 
(U.K.) under the trademarks "Coopex" and "Qamlin". 
The concentrate may also include an alcohol having between 2 and 6 carbon 
atoms, which acts to dissolve the soap in the concentrate if the soap 
concentration exceeds about 20 percent. Preferred alcohols include ethanol 
and isopropanol, present at approximately 30 percent by weight. The 
balance of the concentrated formulation consists of water. 
The composition is manufactured by mixing together a solution of salts of 
fatty acids, water and alcohol, which acts as a carrier and solvent for 
the pyrethroid. 
A currently preferred embodiment of the concentrated formulation is made by 
combining and gently agitating the components of the mixture. An 
insecticidal solution utilizing fenvalerate as the pyrethroid is prepared 
by combining approximately 200 parts of potassium fatty acid soaps as 
previously described, 7 parts fenvalerate, 73 parts water, and 120 parts 
ethanol. This formulation is diluted 50:1 to 100:1 with water before 
application. 
An insecticidal solution utilizing permethrin as the pyrethroid compound is 
prepared in the same way, utilizing 200 parts potassium fatty acid salts 
as previously described, 8 parts permethrin, 72 parts water and 120 parts 
ethanol. This formulation is likewise diluted 50:1 to 100:1 with water 
before application. 
A concentrated insecticidal formulation having cypermethrin as the 
pyrethroid is prepared in the same way as the fluvalinate-containing 
formulation. In this formulation, however, 200 parts potassium fatty acids 
salts as previously described, 4 parts cypermethrin, 76 parts water and 
120 parts ethanol are combined. This formulation is diluted 50:1 to 100:1 
with water before application. 
An insecticidal solution utilizing fluvalinate as the pyrethroid compound 
is prepared in the same way, utilizing 200 parts potassium fatty acid 
salts as previously described, 8 parts fluvalinate, 72 parts water and 120 
parts ethanol. This concentrated formulation is diluted 50:1 to 100:1 with 
water before application. 
Insecticidal products having the above formulations exhibit a combination 
of insecticidal activity, spectrum response, low vertebrate and 
phytotoxicity, and ready biodegradeability unavailable in any composition 
known to applicants. Furthermore, the storage and environmental stability 
of both the ready-to-use and the concentrate are improved, relative to the 
combination of soap and the natural pyrethrin. 
The following example illustrates the efficacy and synergy of the 
insecticidal composition of the invention. 
EXAMPLE 
In this Example, a comparison of kill effectiveness was made between a 
fatty acid based insecticide (Safer Insecticidal Soap) alone, the 
pyrethroid extract alone, and an insecticide comprising a combination of 
the fatty acid mixture and various pyrethroids, formulated in accordance 
with the ratio disclosed herein. The experimental procedure involved 
applying the same amount of the sample to potato plants and measuring 
mortality percentages of the Colorado potato beetle. Table A shows the 
results of this experiment. As is obvious from the Table, the insecticidal 
formulation of the present invention does not show purely additive 
insecticidal properties with respect to this particular insect pest, but 
rather an unexpected, synergistic kill ratio. 
TABLE A 
______________________________________ 
Safer Insecticidal Soap (Conc.) 
0% 0.75% 1.0% 
______________________________________ 
distilled H.sub.2 O 
3.1 0 12.5 
0.017% fenvalerate 
25.0 56.7 48.7 
0.021% permethrin 
13.6 20.0 15.9 
0.009% cypermethrin 
42.9 90.0 90.0 
______________________________________