HK1038157B - Microencapsulation formulations of cadusafos - Google Patents

Description

Microcapsule formulation of cadusafos

Technical Field

The present invention relates to organophosphate pesticide formulations. In particular, the present invention relates to microencapsulated formulations of the pesticide/nematicide, cadusafos, which are equivalent to conventional formulations but have reduced toxicity.

Background

The organophosphate compound S, S-di-sec-butyl-O-ethyl dithiophosphate (cadusafos) is an effective pesticide and nematicide. However, the toxicity of cadusafos impairs its safe use. For example, the current aqueous microemulsion formulation of cadusafos at 100g/l in commercial use recommends that the user should wear a full protective suit to handle and apply the formulation. The label also indicates that the formulation is highly toxic to mammals, fish, arthropods and birds.

Accordingly, there is a need to develop a cadusafos formulation that maintains the effectiveness of cadusafos as a pesticide or nematicide, but has reduced toxicity to mammals, birds, fish, and other non-target organisms. These formulations will increase safety to humans and minimize any adverse environmental effects of using the compounds.

Brief description of the invention

In accordance with the present invention, pesticidally effective, microencapsulated cadusafos formulations are provided which have low or moderate toxicity to non-target organisms, among other advantages.

According to one aspect of the invention, the formulation comprises a suspension of microcapsules having a polyurea layer around a cadusafos core. The polyurea layer is interfacially polymerized from a polyisocyanate and one or more polyfunctional amines, and is substantially impermeable to cadusafos, thereby resulting in a formulation having reduced toxicity to mammals as compared to known aqueous microemulsion cadusafos formulations (having equivalent or lower concentrations of cadusafos).

According to another aspect of the present invention there is provided cadusafos granules comprising the aforementioned microcapsules containing cadusafos immobilised on a particulate carrier.

According to the present invention, there is also provided a process for preparing the aforementioned water-soluble Capsule Suspension (CS) or particulate microencapsulated cadusafos formulation.

The microencapsulated cadusafos of the invention has lower toxicity to the skin, oral administration and inhalation of mammals, thereby being capable of safer carrying and using the pesticide. According to the guidelines of the united states environmental protection agency ("EPA"), the formulations of the present invention are rated as class II (warning) or class III (caution) compositions, at twice the concentration of the non-microencapsulated liquid formulation of the same active ingredient, which is rated as class II. The microencapsulated formulation does not have reduced pesticidal activity or physical and chemical stability compared to non-microencapsulated formulations. In addition, the microencapsulated formulation of the present invention is consistent in color and, unlike aqueous microemulsion formulations of the compound, can remove unpleasant odors for commercial use if previously treated with copper salts.

Detailed Description

The microencapsulated cadusafos of the invention was prepared according to the following basic steps: (a) providing an aqueous phase (also preferred herein as a "continuous" phase) containing an emulsifier and an anti-foaming agent; (b) providing a water immiscible phase (also referred to herein as a "discontinuous" phase) comprising cadusafos and a first polyfunctional compound; (c) emulsifying the aqueous phase with a water-immiscible phase to form a dispersion of water-immiscible phase droplets in the aqueous phase; and (d) adding a second polyfunctional compound, neat or in an aqueous solution, to the dispersion to form a layer of polymer, referred to herein as microcapsules, around the water-immiscible droplets; i.e. to form cadusafos microcapsules. The first polyfunctional compound may be any suitable compound having two or more reactive groups, such as, but not limited to, an isocyanate monomer. The second polyfunctional compound is any suitable compound having two or more reactive groups, such as, but not limited to, a polyfunctional amine; wherein the first and second polyfunctional compounds are different. The suitability of the first and second polyfunctional compounds is that they have the ability to form a heteromeric structure at the interface between the dispersed cadusafos and the liquid phase. These compounds will include hydrophobic and hydrophilic groups between the two compounds, such that these groups can be present in each compound, or may be absent from one or the other. The final step is referred to as interfacial polymerization, since the polyurea layer is formed by polymerization of first and second polyfunctional compounds, which are preferably an isocyanate and a polyfunctional amine at the interface of the water-immiscible phase (droplets) and the aqueous phase, thereby forming the preferred polyurea layer.

Once the microcapsules are formed, the suspension is preferably matured, i.e., gently heated to complete the polymerization, and then one or more modifiers, such as propylene glycol, xanthan gum, urea, germicides, amphoteric surfactants, inert dyes, or ionic dispersants (e.g., alkyl naphthalenesulfonates) can be added.

The addition of materials after encapsulation and curing to adjust viscosity, stability and suspension/dispersion characteristics preferably does not affect the reduction of formulation toxicity or efficacy of the pesticide. Another preferred step is to adjust the pH of the formulation to neutral, i.e., from about pH6.5 to about pH7.5, to increase its stability. As used herein, "approximately" using a modifier according to pH indicates a deviation of about at least 1/2 per pH unit, and preferably a deviation of 1/2 per pH unit. In the remainder of this document, the modifier "approximately" is used to assess the non-logarithmic units, and "approximately" will mean a deviation of ± 15%, and more preferably a deviation of ± 10%.

The aqueous phase generally contains from about 0.3 to about 3.0, preferably from about 0.7 to about 2.5 weight percent of one or more emulsifiers. Polyvinyl alcohol is preferably used in the present invention. Other suitable emulsifiers for use in the present invention include, but are not limited to: nonylphenol ethoxylates, sorbitol mono-and trioleate, and ethoxylated oleates.

The aqueous phase also contains from about 0.1 to about 1.0, preferably from about 0.3 to about 0.9 weight percent of one or more anti-foaming agents. Anti-foaming agents suitable for use in the present invention include, but are not limited to: silicon-based anti-foaming agents, such as Dow Corning anti foam DC1500 and DC 1520.

The aqueous phase may also optionally include a viscosity modifier and/or stabilizer, such as from about 0.05 to about 0.50, preferably from about 0.06 to about 0.40 weight percent xanthan gum, and one or more biocides from about 0.02 to about 0.10, preferably from about 0.03 to about 0.05 weight percent. Fungicides suitable for use in the present invention include, but are not limited to: legend MK (Rohm & Haas Co.), Proxel GXL (Zeneca, Inc.) and Dosidide A (Dow chemical).

The water-immiscible phase (also referred to in the examples as a polyisocyanate solution) generally contains about 50 to 98, preferably about 53 to 92 weight percent of cadusafos, and about 2 to about 35, preferably about 4 to about 25 weight percent of a first polyfunctional compound, preferably an isocyanate monomer. Polymethylene Polyphenyl Isocyanates (PMPPIs) are particularly suitable for use in the present invention; such as Mondur MT (Miles, Inc.), Papi27 or 135(Dow Chemical) and Desmodur (Bayer). Other suitable first polyfunctional compounds may also be used in accordance with the present invention if they have suitable chemical and physical properties (e.g., chain length, functionality) to enable the polymer layer formed around the cadusafos to act as a barrier to the liberation of the cadusafos from the microcapsules. Suitable first polyfunctional compounds will be apparent to those skilled in the art.

The water-immiscible phase may also contain a hydrocarbon solvent, such as vegetable oil. However, this solvent is optional in the preparation of microencapsulated formulations of cadusafos, especially in formulations containing more than about 240 grams per liter of cadusafos. Hydrocarbon solvents useful in the practice of the present invention include, but are not limited to, petroleum hydrocarbons such as Aromatic 200, Aromatic 150, and Exxate1000 (all from Exxon Chemicals), or vegetable oils such as corn oil. If any solvent is desired, about 15 to about 30, preferably about 20 to about 25 weight percent of solvent is present in the water-immiscible phase.

An advantage of the present invention is that the formulation can be prepared with either untreated cadusafos or cadusafos treated with an already copper salt. Copper salts are added to cadusafos to remove its odor. Typically, copper salts prevent interfacial polymerization to form microcapsules, but are not found in this process.

The second polyfunctional compound solution generally contains from about 10 to about 100, preferably from about 20 to about 70, weight percent of the second polyfunctional compound or mixture of such second polyfunctional compounds. Examples of suitable second polyfunctional compounds suitable for use in the practice of the present invention include various polyfunctional amines such as, but not limited to: diethylenetriamine (DETA), triethylenetetramine (TETA), and 1, 6-Hexanediamine (HDA).

Using PMPPI as the first polyfunctional compound and an amine-like compound as the second polyfunctional compound, the interfacial polymerization of the first and second polyfunctional compounds forms a polymer microcapsule surrounding the cadusafos, according to the following exemplary chemistry: O-C-R-N-C-O + H₂N-R’-NH₂--NHCONH-R-NHCONH-R’-NHCONH-R-

A B wherein A is PMPPI having an average functionality of about 2.3 to about 2.6 and B is a polyfunctional amine.

Several parameters of the process of the invention have an effect on the properties of the final formulation. The emulsification step is preferably effected with high shear mixing to obtain small droplets of immiscible phases. The average size of the microcapsules of the present invention is from about 5 to about 25 microns. Factors that affect the size of the microcapsules, as well as the stability of the emulsion, include: (1) the amount of shear force applied during emulsification; (2) the type or amount of the discontinuous phase, such as the use of a surfactant or hydrocarbon solvent; (3) the temperature or viscosity of the mixture; and (4) if xanthan gum or alkyl naphthalene sulfonate dispersant is present in the mixture, its amount.

The relative percentages of the first and second polyfunctional compound monomers (e.g., PMPPI and amine) in the discontinuous phase are selected to achieve suitable microencapsulation, requiring a balance between competing factors. In general, increasing the percentage of monomer in the discontinuous phase can reduce the toxicity of the final formulation. Likewise, decreasing the percentage of monomer results in a higher toxicity in the final formulation. In the most preferred general formulation of the present invention, a balance of high potency and low toxicity is achieved by incorporating about 5 to about 35, preferably about 7 to about 30 weight percent in the discontinuous phase. The operating conditions required to obtain microcapsules from the appropriate monomer concentration depend on the emulsifying equipment used; the determination of these conditions is well within the skill of the art.

In contrast to the vigorous conditions required for the emulsification step, the agitation during the addition of the second polyfunctional compound should be low shear, such as by using a mechanical paddle stirrer. After the second polyfunctional compound has been added, the suspension may be stirred for an additional period of about 1 to 10 hours, preferably about 3 to about 4 hours, for example, by heating to about 20 to about 60℃, preferably from about 30 to about 50℃, for maturation.

One or more substances generally selected from the following may be added to the formulation after encapsulation, although other substances not specifically listed will also be apparent to those skilled in the art: (1) propylene glycol, preferably from about 1.3 to about 6.0 weight percent; (2) urea, preferably from about 5.0 to about 5.5 weight percent; (3) xanthan gum, preferably from about 0.003 to about 0.30 weight percent; (4) one or more biocides having a total weight percent of about 0.01 to about 0.10; (5) one or more dyes in a total weight percent of up to about 0.05; and (6) one or more surfactants, up to about 7.0 total weight percent; each weight percentage is relative to the weight of the formulation after addition of the additive.

Preferably, after curing the microcapsules, the agent is neutralized, e.g., with phosphoric acid, acetic acid or hydrochloric acid, although other acid neutralizing agents may be used. The post-encapsulation additive is then added and the formulation is continuously stirred at a slightly hot temperature (e.g., 50 ℃) for about 4 hours.

The Capsule Suspension (CS) formulation of cadusafos prepared by the above method has the following general composition characteristics: they contain from about 150 to about 360 grams of cadusafos per liter of formulation and comprise a suspension of microcapsules forming a polyurea layer surrounding a cadusafos core, and optionally a hydrocarbon solvent, and further comprise an emulsifier, such as about 0.3 to about 3.0 weight percent polyvinyl alcohol, and an anti-foaming agent, from about 0.05 to about 0.5 weight percent. The formulation may also optionally contain about 0.06 to about 0.4 weight percent xanthan gum or other viscosity modifiers/stabilizers, about 0.02 to about 0.10 weight percent one or more bactericides, and about 1.2 to about 5.8 weight percent propylene glycol or urea, or combinations thereof. Preferred formulations contain about 200g/l of cadusafos, and contain about 53 to about 92 weight percent cadusafos and about 4 to about 25 weight percent PMPPI in a water-immiscible phase, and utilize DETA, TETA or HDA as the polyfunctional amine.

In other aspects of the invention, the CS cadusafos formulation described above is used to prepare a granular microemulsion (G-ME) formulation of cadusafos. A G-ME formulation was prepared by the following steps: (a) providing a homogeneous mixture of a microencapsulated or Capsule Suspension (CS) cadusafos formulation and a binder; b) dispersing the mixture onto a carrier, and c) drying the carrier, thereby forming a granular formulation.

The G-ME formulation will generally contain from about 5.0 to about 30.0, preferably from about 10.0 to about 20.0 weight percent of the cadusafos CS formulation, from about 60.0 to about 95.0, preferably from about 70.0 to about 80.0 weight percent of the carrier, and from about 0.05 to about 5.0, preferably from about 0.1 to about 2.0 weight percent of the binder.

Useful binders for practicing the present invention include, but are not limited to: calcium or sodium lignosulfonates, polyalkylene glycols, and other polymer solutions, such as resins, as well as other suitable binders known to those skilled in the art.

Examples of vectors that can be used in the present invention include, but are not limited to: cellulose complexes, attrapt clays, silica complexes and plant materials such as corn cobs. Other suitable vectors are known to those skilled in the art.

The time required for the CS formulation and binder mixture to reach homogeneity is not critical, but is typically about 1 to 10 minutes. Dispersion to the support continued until the entire mixture was used up. The granular formulation is then dried for several hours.

The following examples are provided to illustrate embodiments of the present invention. They are not intended to limit the invention in any way.

Example 1

Preparation of 200g/l cadusafos Capsule Suspension (CS) preparation (preparation PP)

20% (wt/wt) partially hydrolyzed poly (ethylene glycol) was prepared by stirring and heating appropriate amounts of polyvinyl alcohol and water at about 80-90 deg.C for 1 hourVinyl alcohol (Airvo)^203) To prepare an aqueous solution. The cooled solution is stored for later use.

In a 4 liter stainless steel beaker, 92 grams of a 20% aqueous solution of polyvinyl alcohol, 68.6 grams of 2% xanthan gum (Kelzan)^S) aqueous solution, and 8.2 g of polydimethylsiloxane anti-foaming agent (Dow Corning)^1520) The aqueous phase of the microcapsules was prepared by mixing in 1832 g of water. 332.5 grams of this mixture was then transferred to a 1 liter beaker. The mixture was mixed at high speed for 1 minute, and then a premixed 140.0 grams of cadusafos solution (previously treated with 2.5% copper naphthenate), 60.0 grams of white spirit (C) were rapidly added₉-C₁₅A mixture of naphthalene-removed aromatics, hydrocarbons, a flash point of 95 deg.C, Aromatic 200ND), and 43.0 grams of PMPPI (Mondur)^MR), the mixture was emulsified for 1 minute. The mixture was then placed in a 1 liter 3-neck round bottom flask equipped with a mechanical stirrer and 27.0 grams of 70% aqueous HDA dissolved in 10.0 grams of water was added over 30 seconds. After the addition was complete, the mixture was heated to 50 ℃ and maintained for 4 hours. Thereafter, the mixture was cooled to 30 ℃, 35.0 grams of urea was added, followed by 25.0 grams of 2% xanthan gum (Kelzan)^S) an aqueous solution. The formulation was then gently stirred for 1 hour and stored. The formulations described in tables 1 and 2 were prepared in this manner.

Example 2

Mass production of 200g/l cadusafos Capsule Suspension (CS) formulation (formulation PB-8PG)

A solution of 2.09 pounds of polyvinyl alcohol, 0.16 pounds of a 2% aqueous solution of xanthan gum, 0.9 pounds of a polydimethylsiloxane anti-foaming agent, 7.62 pounds of the sodium salt of an alkyl naphthalene sulfonate, and 0.07 pounds of a 1, 2-benzisothiazol-3-one fungicide dissolved in 226.2 pounds of water was placed in a 120 gallon stainless steel container and stirred at 80 ℃ for 1 hour. Thereafter, the solution was cooled to 20 ℃ and placed in a 120 gallon stainless steel batch homogenizer. The homogenizer was brought to a speed of about 3,500rpm and then a premixed of 82.6 pounds of technical grade cadusafos (which had been treated with 2.1 pounds of copper naphthenate) and 15.1 pounds of PMPPI were fed into the homogenizer at a pressure of 10 pounds per square inch. The mixture was homogenized for about 1 minute. After homogenization, the mixture was quickly added dropwise to a 100 gallon stainless steel reactor while stirring with a cross-over agitator blade. An amine mixture consisting of 9.4 pounds of 70% aqueous HDA dissolved in 4.4 pounds of water was added rapidly. After the addition of the amine was complete, the mixture was stirred vigorously for 10 minutes, then heated to 50 ℃ and allowed to mature for 3 to 4 hours with slow stirring at this temperature. At the end of the maturation, the mixture was cooled to 35 ℃ and then neutralized to a pH of 6.5 to 7.5 with 2.2 lbs of concentrated phosphoric acid. After the addition was complete, 15.51 pounds of a 2% aqueous solution of xanthan gum, 22.0 pounds of propylene glycol, 0.14 pounds of 1, 2-benzisothiazol-3-one fungicide and 0.81 pounds of polydimethylsiloxane anti-foaming agent were added to the formulation. The formulation after stirring for 1 hour had a viscosity of 325cps, and a suspensibility of 98%.

Example 3

Mass production of 200g/l cadusafos Capsule Suspension (CS) preparation (preparation PB-C14U-ND)

Premixed 172.6 lbs of technical grade cadusafos (treated with 4.21 lbs of copper naphthenate), 53.0 lbs of PMPPI, and 74.1 lbs of white spirit (C)₉-C₁₅The naphthalene-removed aromatic hydrocarbon, hydrocarbon mixture, having a flash point of 95 deg.C) solution was added to a 120 gallon stainless steel batch homogenizer, stirred, with 7.24 pounds of polyvinyl alcohol dissolved in 391.3 pounds of water, 0.32 pounds of a 2% aqueous solution of xanthan gum, and 3.33 pounds of polydimethylsiloxane anti-foaming agent (Dow Corning)^1520) 7.53 pounds of the sodium salt of an alkyl naphthalene sulfonate ester, and 0.20 pounds of a 1, 2-benzisothiazol-3-one fungicide. After the addition was complete, the mixture was stirred in a homogenizer at about 3,500rpm for about 10 minutes. After homogenization was complete, the amine mixture consisting of 33.3 lbs 70% aqueous HDA dissolved in 12.3 lbs water was added quickly. After the addition of the amine was complete, the mixture was stirred for 10 minutes and then heated to 50 ℃ and aged at this temperature for 3 to 4 hours. At the end of the maturation, the mixture was cooled to 35 ℃ and then neutralized to ph6.5 to 7.5 with 7.47 lbs 85% phosphoric acid. After addition was complete, 32.04 pounds of a 2% aqueous solution of xanthan gum, 44.6 pounds of urea, and 0.17 pounds of an inert dye (Tricon green 18800) were added to the formulation. The formulation was then stirred for 1 hour and stored.

Example 4

Mass preparation of 200g/l cadusafos capsule suspension (200 CS) preparation (preparation PB-C14U-ND)

Stirred 1.77% polyvinyl alcohol, 0.08% xanthan gum, 0.81% polydimethylsiloxane anti-foaming agent (Dow Corning) to provide a 14.6 pound per minute flow^1520) 1.84% sodium salt of alkyl naphthalene sulfonate (Lomar)^LS-1), 0.05% 1, 2-benzisothiazol-3-one fungicide (Proxel)^GXL) and 95.46% water with 10.9 pounds per minute of liquid premixed 57.55% technical grade cadusafos, 17.75% PMPPI, and 24.70% white spirit (C)₉-C₁₅The mixture of the naphthalene-removed aromatic hydrocarbon and the hydrocarbon, the flash point of which is 95 ℃) is combined. The combined stream is added to an in-line homogenizer, which generates sufficient shear to achieve the desired particle size. 1.6 pounds per minute of a stream of amine mixture consisting of 73% of 70% HDA in water dissolved in 27% water was fed into the homogenizer discharge stream and the resulting stream was fed into a stirred reactor set at 35 ℃. The mixture was continuously discharged from the reactor into a second 100 gallon reactor and maintained at a steady residence time of 20-30 minutes. When the second 1000 gallon reactor (5420 lbs) was filled, the mixture was heated to 50 deg.C and aged at that temperature for 3 to 4 hours. At the end of the maturation, the mixture was cooled to 35 ℃ and then neutralized to pH6.5 to 7.5 with 75.0 lbs 85% phosphoric acid. After addition was complete, an aqueous solution of 230.6 pounds of 2% xanthan gum, 321.6 pounds of urea, and 1.3 pounds of an inert dye (Tricon green 18800) was added to the formulation. The formulation was then stirred for 1 hour and stored. The formulations described in tables 3 and 4 were prepared in the manner of examples 2, 3 and 4.

Example 5

Preparation of 3% w/w Encapsulated granular (3G-ME) formulation of cadusafos

Place 83.0 grams of the above-prepared suspension in a 1 liter beaker200CS of cadusafos, and 10.0 grams of calcium lignosulfonate (Norlig)^A) In that respect The mixture was mixed until homogeneous (about 10 minutes) and then sprinkled with 417 grams of a cellulose composite (made from filter paper, kaolin, calcium carbonate and titanium dioxide (Biodac)^20/50) until the entire mixture is exhausted. After the mixture was used, the tumbler/mixer was stopped and the formulation air dried for 16 hours.

Example 6Toxicity Studies

Laboratory tests conducted in the following manner showed that the cadusafos Capsule Suspension (CS) formulation attenuated mammalian skin toxicity. For each formulation to be tested (referred to as test material), 6 Sprague-Dawley rats (3 males, and 3 infertile, non-pregnant females) were treated with the cadusafos CS formulation at dosage levels of 50, 200, 400, and 2000 mg/Kg. The day before applying the test material, the trunk of each rat was clipped free and at least 10% of the body surface of the rat was exposed. The test material was applied to a 4-layer 2 x 2 inch mesh pad and mounted on the rat test site. A strip of self-adhesive, elastic bandage lined with plastic was wrapped around the rat torso to ensure that the test material remained in contact with the skin. After about 24 hours, the bandage and the mesh pad were removed, and a clean mesh pad moistened with tap water was wiped to remove any residual test material. Mortality was observed twice daily. Rats were observed once daily for about 3 hours after administration on day 0, and 14 days thereafter. The nature, onset and duration of all gross or visible toxicological or pharmacological effects are recorded daily. The time to death (or the time at which death was found) was also recorded. Body weights of rats were recorded prior to dosing and on days 7 and 14. Animals that cannot survive the observation period should be weighed as soon as possible after the death is found. All animals that died in the trial were necropsied. All animals were sacrificed past the observation period (day 14) and observed visually. All internal exceptions are recorded. Estimation of LD from dose level₅₀. The results shown in table 5 indicate that the CS formulations of the present invention are effective in reducing the mammalian skin toxicity of cadusafos. While all formulations showed reduced skin toxicity, formulations K, KK, LL, MM, PB-9PG, and PB-11PG reduced toxicity to IClass II, while the preparation PB-14U-ND attenuated toxicity to class IV. See below for definitions of classes I-IV.

Laboratory tests performed in a similar manner as described above showed that the cadusafos Capsule Suspension (CS) formulation reduced oral toxicity in mammals. The test was different in that the test material was administered at 25, 50, 200 and 500mg/kg instead of 50, 200, 400 and 2000mg/kg oral gavage using a ball-end gavage needle and the rats were starved for 18 hours prior to testing. The results shown in table 6 indicate that the CS formulations of the present invention are effective in reducing the mammalian oral toxicity of cadusafos. While all formulations showed reduced oral toxicity, formulations B, PP, Q and PB-14U-ND reduced toxicity to class III.

The attenuation of the mammalian inhalation toxicity of the attenuated formulations PB-8PG and PB-C14U-ND was also tested in the laboratory in the following manner. 6 Sprague-Dawley rats (3 males, and 3 infertile, non-pregnant females) were exposed to the test material air for 4 hours in the inhalation chamber of 11 liters nose only under dynamic air flow conditions. The concentration of the test material was 0.5mg/l or more and 0.05mg/l or more. Toxicity and mortality were observed at least once daily during the exposure period, hourly, after removal from the chamber, and for 14 days thereafter. The respective body weights were recorded before exposure (day 0) and on days 7 and 14. Animals that cannot survive the observation period are weighed as soon as possible after the death is found. All animals that died in the trial were necropsied. All animals were anesthetized and sacrificed past the observation period (day 14) and then visually observed. All internal exceptions are recorded. Estimation of LD from dose level₅₀. The results of the inhalation study showed that formulations PB-8PG and PB-C14U-ND had 4 hr L estimated to be greater than 1.04mg/L and 3.87mg/L, respectively₅₀' s. These results show a reduction in inhalation toxicity from class I to class III. Rat acute inhalation of 100ME formulation of known cadusafos (100g/l aqueous solution of cadusafos microemulsion) is 0.026mg/l/4 hr.

The terms "class I", "class II", "class III" and "class IV" refer to the classes designated by EPA for compounds based on their toxicity. Criteria for classifying a compound as "class I", "class II", "class III", or "class IV" are as follows:

hazard indicator class I, class II, class III, class IV

Oral LD₅₀Greater than or equal to > 50 to > 500 to > 5000mg/kg

50mg/kg 500mg/kg 5000mg/kg

Cutaneous LD₅₀Greater than or equal to more than 200 to more than 2000 to more than 5000mg/kg

200mg/kg 2000mg/kg 5000mg/kg inhalation LD measured for 4 hour exposure greater than or equal to > 0.05 to > 0.5 to 5mg/L > 5mg/L₅₀0.05 mg/L0.5 mg/L (actual) chamber concentration

Example 7

Study of drug efficacy

The general formulations of the present invention have been found to be effective against a wide variety of pests. The following procedures are representative of the efficacy of the formulations of the present invention and are not intended to limit the scope of the invention in any way.

Formulations AA to FF (except DD) were tested for efficacy against root wart nematode (RKN) on tomato (i.e. Meloidogyne incognita) and for persistence in soil. 3 weeks old tomato (Lycopersicon esculentum, variety "Rutgers") were planted in 10 cm square pots containing a sterile 50: 50 sand to soil mixture. For each ratio of application of the test formulation, 10 replicate pots (5 replicates each of the two sets of tests) were prepared. Ready-to-use dispersions of each test formulation were prepared by dispersing sufficient amounts of the test material in 100 ml of water to give application rates of 0.25, 0.5, 1 and 2kg actives/hectare. Each pot received 10 ml of the appropriate suspension on the surface adjacent to the periphery of the tomato forThe control treatment received only water for each set of test pots. Pots were also prepared as above with the same ratio of 100ME cadusafos formulation and technical grade cadusafos. The RKN eggs used in the experiments were separated from the gelatin matrix by vigorously shaking the severely infested tomato plant roots in 1% aqueous sodium hypochlorite for 4 minutes. The resulting egg suspension was quickly poured onto 60, 325 and 500 mesh sieves nested together. Eggs on a 500 mesh screen were collected and rinsed gently with water to remove any excess sodium hypochlorite. The eggs were placed in water and the resulting aqueous solution was diluted appropriately with water to give about 2000 eggs per plant, resulting in an effective inoculation level of about 1000 infectious larvae per pot. Eggs were counted using a dissecting microscope. All pots were infected with nematodes by pricking the inoculum onto previously treated tomato transgenic plants. The pots infected with nematodes 48 hours after soil treatment are referred to herein as "set 1". Prior to nematode infection, pots, referred to herein as "set 2", were treated and tested for residual activity and were kept in the greenhouse for 7 days. After nematode infection, the pots were maintained in the greenhouse for 28 days and monitored for phytotoxic symptoms. At the end of 28 days, soil was washed from the tomato roots and evaluated according to the following table:

damage assessment

Description of the invention

0	Intact and healthy root system without infection
		1	Careful examination can detect very small amounts of small lesions
2	Such as radicular lesions in "1", but more so, are also easier to detect.
		3	Root systems are characterized by many small lesions, some of which may even grow together, but root function is not severely affected.
4	In addition to many small lesions, there are some large lesions, but most of the roots are still functional.
		5	Due to severe damage, about 25% of the roots do not function.
6	Due to severe damage, up to 50% of the roots do not function.
		7	Approximately 75% of the roots are severely damaged and lose fruiting function.
8	Healthy roots are not left, plant nutrition is interrupted, but the plant remains green.
		9	The completely damaged root system is decaying and the plant is dying.
10	The plants and roots have died.

The test results shown in tables 7 and 8 indicate that all cadusafos CS formulations are effective for controlling nematodes on tomatoes, with no significant difference between the formulations. In table 7, only two lower rates of application are shown, since all treatments completely control nematodes at 1 and 2kg of active ingredient per hectare.

Formulations B, E, F, G and H were tested against cucumber beetle (SCR) larvae, the initial and residual soil activity of the cadusafos CS formulation. Each formulation was evaluated with three 5000 gram samples of two types of soil (clay soil and sandy loam). Sandy fertile soil contains 30% clay, 30% sand and 3% organic material, while clayey soil contains 87% sand, 3% clay and 0.9% organic material. Prior to treatment, the soil was placed in 5 gallon buckets, air dried, and then adjusted to 50% soil moisture retention capacity. Each formulation was sprayed onto the screened soil at 20psi at a rate of 0.1, 0.2, 0.5 and 1.5ppm in sandy loam and 0.1 and 0.2ppm in clayey soil. Two soil buckets were also sprayed with the cadusafos 100ME formulation in the same ratio as above. After treatment, the soil was mixed for 5 minutes and then transferred to a 2.84 liter container. The soil was covered and maintained at 26 ℃ and 40-50% soil humidity in the greenhouse until needed for testing. At each loading period, 50 grams of treated soil was added to a 113.4 gram plastic cup containing two days germinated corn seed kernels, which completely covered the seed. 15 second instar later stage SCR larvae were added to each cup. The cups were closed with a tightly attached lid and placed in an ambient chamber at 24-26 ℃. After 96 hours, a cup of 226.8 grams of paper corresponding to each soil container was filled to a depth of about 1.27 cm with soapy water. A funnel with a plastic mesh at the bottom was placed in each paper cup. Each 50 grams of extracted soil was then placed in a funnel in a corresponding paper cup. The soil was left in the funnel until completely dry and all live larvae had climbed into the cup below. The number of SCR larvae on the bottom of the cup was scored as alive. From these data, the percent mortality in each soil sample can be determined.

The test results show that the cadusafos formulations of the invention are equally active or slightly more sustained in activity than cadusafos 100ME formulation. For example, at 0.2ppm in clay soil, formulation G resulted in 97% death after 84 days of treatment, while cadusafos 100ME resulted in 40% death. These data are shown in tables 9 and 10.

The invention is not intended to be limited to the embodiments described herein but may be varied or modified within the scope of the appended claims. These variations include, but are not limited to, mixtures of one or more pesticides, whether encapsulated or not, wherein the microencapsulated cadusafos of the present invention is part of the mixture.

TABLE 1

Preparation of cadusafos Capsule Suspension (CS) formulation (ingredients and amounts)

Weight (G) formulation (G/L) AB C D E-1E-2F G H J

(240) (200) (180) (200) (200) (200) (200) (200) (240) (220) (270)Composition (I) Aqueous solutionWater 430.7430.7430.7316.0394.11182.32364.6394.1394.1394.1394.1 PVA 4.04.04.04.03.9811.9823.883.983.983.983.98 xanthan gum 0.30.30.3-0.280.841.680.280.280.280.28 antifoaming agent 1.81.81.81.81.644.929.841.641.641.641.64Isocyanate solutionLiquid sulfur-phosphorus 170.0140.0140.0140.0140.0420.0840.0140.0140.0140.0140.0 petroleum solvent-30.030.0 30.0 30.0 90.0 180.0 30.0 30.0 30.0 --PMPPI 36.0 30.0 30.0 30.0 30.0 90.0 180.0 15.0 7.5 12.0 30.0Amine solutionTETA 19.019.019.019.0-DETA-19.057.0114.09.54.757.228.5 Water 31.031.031.031.031.093.0186.015.57.7511.78- -After encapsulation StabilizerPolyethylene glycol 9.39.39.027.054.09.09.09.09.0 xanthan gum 0.030.021.01.01.03.06.01.01.01.01.0 water 1.470.98-concentrated phosphoric acid 18.0-18.054.0108.011.04.0-concentrated hydrochloric acid 15.5-11.9 sodium sulfonate-5.015.030.05.05.05.05.0 bactericide A-0.3-1.80.30.30.3-

TABLE 1 (continuation)

Weight (g) preparation (g/L)K(200) L(240) M(240) N(240) 0(250) P(250) Q(250) R(250) S(250) T(250) Composition (I) Aqueous solutionWater 207.06281.01319.8319.8325.38261.29239.6261.29239.6288.6 PVA 19.322.628.768.763.042.442.232.442.232.23 xanthan gum 1.450.20.210.210.230.180.170.180.171.17 antifoaming agent 8.611.171.231.231.351.091.01.091.01.0Isocyanate solutionThiamine phosphorus 840.0140.0140.0140.0170.0140.0140.0140.0140.0140.0 white spirit 180.0-PMPPI 180.015.015.015.015.015.024.015.024.024.0Amine solutionDETA 114.010.09.59.59.59.515.65.714.4414.44 Water 186.0- -15.515.515.515.525.49.323.5623.56Stabilization after encapsulation Agent for treating cancerPolyethylene glycol 60.028.028.028.028.028.028.028.028.028.0 xanthan gum 6.01.01.01.01.01.01.01.01.0-water 294.049.0- — 49.049.049.049.0-concentrated phosphoric acid 99.011.011.06.846.848.511.42.511.411.4-concentrated hydrochloric acid 6.01.01.01.01.01.01.01.01.0-sodium sulfonate 30.05.05.05.05.05.05.05.04.04.0 bactericide A1.00.30.30.30.30.30.30.30.30.3 amphoteric surfactant-15.0- -

TABLE 1 continuation

Weight (g) preparation (g/L)U V W-1 W-2 W-3 X Y Z AA BB BB-1

(250) (250) (360) (360) (360) (250) (250) (250) (250) (250) (200) Composition (I) Aqueous solutionWater 264.1264.14270.42270.42270.42261.14261.22261.29251.42374.68384.54 PVA 2.232.215.05.05.02.212.352.442.353.53.59 xanthan gum 0.670.670.220.220.220.670.380.180.180.260.27 sodium sulfonate 1.00.982.282.282.280.981.051.091.051.561.6 anti-foaming agent 5.05.05.05.0Isocyanate solutionThiotepa 140.0140.0289.8289.8289.8140.0140.0140.0140.0140.0140.0 white spirit-31.231.231.2-PMPPI 24.015.062.562.562.515.015.015.015.015.012.0 copper naphthalene-1.40.70.7Amine solutionDETA 14.449.52525259.59.59.59.59.50.4 Water 23.5615.5- - -15.515.515.515.515.519.6Encapsulated stabilizersPolyethylene glycol28.028.0-40.028.028.028.028.035.035.0 xanthan gum-0.50.520.520.520.50.50.50.70.70.7 water-24.525.6825.6825.6824.524.524.534.334.334.3 concentrated phosphoric acid 11.48.5-concentrated hydrochloric acid-16.016.016.022.011.810.412.012.012.0 sodium sulfonate 4.05.054.454.459.412.512.57.57.57.57.5 bactericide A-0.3-fungicide B-0.40.30.30.30.30.30.3 ampholytic surfactant-25.0-26.026.0-anti-foaming agent-2.02-fungicide

TABLE 1 continuation

Weight (g) preparation (g/L) CC D(150) E(200) FF GG HH JJ KK LL MM NN

(150) (200) (200) (200) (200) (200) (200) (200) (200) Composition (I) Aqueous solutionWater 606.39591.6354.96374.68374.68374.68369.771109.261123.221123.221123.22 PVA 5.665.523.313.53.53.56.7810.3510.3610.3610.36 xanthan gum 0.430.420.250.260.260.260.30.780.820.820.82 anti-foaming agent 2.522.461.481.561.561.563.094.614.594.594.59 sodium sulfonate 5.05.05.05.05.012.512.5637.537.9237.9237.92 bactericide A- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Isocyanate solution Liquid for treating urinary tract infectionCadusafos 140.0140.0140.0140.0140.0137.86136.5409.5409.5409.5409.5 PMPPI 12.015.025.010.015.015.015.060.045.045.090.0 copper naphthalene 0.70.70.70.71.43.543.510.510.510.510.5Amine solutionDETA 7.69.515.26.19.53.8- -28.5- -HDA- -6.5126.0419.5- -39.06 Water 12.415.524.89.915.56.218.4948.9655.546.536.74After encapsulation StabilizerPolyethylene glycol 35.035.035.035.035.035.035.0105.0105.0105.0105.0 xanthan gum 0.70.70.70.70.50.50.51.51.51.51.5 water 34.334.334.334.324.524.573.573.573.573.573.5 concentrated phosphoric acid- -0.11.0-20.0 concentrated hydrochloric acid 12.012.017.017.012.00.6- -sulfonic acidSodium 7.57.57.57.57.5-fungicide B0.30.30.30.30.30.3-1.01.01.0- -

Preparation (g/L) PP(200) QQ(200) RR(200)

Composition (I)

Aqueous solution

Water 327.85327.85607.15

PVA 3.06 3.06 5.63

Xanthan gum 0.230.230.45

Anti-foaming agent 1.361.362.39

Sodium sulfonate- -20.42

Bactericide B- - -0.21

Isocyanate solution

Cadusafos 136.5136.5221.63

Naphthalene copper 3.53.55.52

60.0- -

Corn oil-60.0-

PMPPI 43.0 43.0 40.64

Amine solution

HDA 18.9 18.9 25.11

Water 18.118.111.73

Encapsulated stabilizers

Concentrated phosphoric acid- -5.11

Water 24.524.539.98

Xanthan gum 0.50.50.80

Urea 35.035.053.24

Anti-foaming agent 1.361.361.99

Inert dye- -0.21

·PVA-Airvol^203 polyvinyl alcohol

Xanthan Gum-Kelzan^M and Kelzan^S yellowVirgin rubber, except that S has been surface treated to ease dispersion. Aqueous solutions of formulations A to R were prepared with M, while formulations S to Z were prepared with S. The xanthan gum used in the post-encapsulation stabilization was Kelzan^S。

Anti-foaming agent Dow Corning^1500 is 100% polydimethylsiloxane. Dow Corning  1520 is a 20% solution. 1500 was used in formulations a and B; 1520 in all other formulations.

Petroleum solvent-Aromatic 200ND, a C₉-C₁₅A mixture of decalin aromatics, hydrocarbons, boiling point 95 ℃, or Exxate  1000, an acetic acid, C₉-C₁₁A branched alkyl ester. Exxate1000 was used only in formulation RR.

PMPPI-polymethylene polyphenyl isocyanate, Mondur  MR or Papi 27. Papi27 was used for formulation QQ, while Mondur  MR was used for the other formulations.

TETA-triethylenetetramine; DETA-triethylenediamine; HDA-1, 6-hexanediamine

Sodium sulfonate-sodium alkyl naphthalene sulfonate, Lomar  PW, Emery  5355, or Lomar  LS-1. Formulations A to GG used Lomar PW, formulation HH used Emery 5355, and formulations JJ to ZZ used Lomar  LS-1.

A mixture of fungicide A-2-methyl-4-isothiazol-3-one, Legend  MK; fungicidal B-1, 2-benzisothiazol-3-ones, Proxel  GXL

Amphoteric surfactant Dodecaneiminedipropionate Mirataine^TM H2-C-HA

Inert dye-Tricon Green 18800

TABLE 2

Cadusafos Capsule Suspension (CS) formulations (ingredients and weight/weight percent)

Percent (weight/weight) formulations A (240) B (200) C (180) D (200) E and E-2E-1F (200) G (240) H (220) J (270)Composition (I)PVA 0.580.580.560.670.580.580.630.660.640.66 xanthan gum 0.050.050.180.170.190.190.200.210.210.21 anti-foaming agent 0.260.260.250.300.240.240.260.270.260.27 thiotepa 24.4920.3519.5823.4320.4920.5022.0023.1322.5723.13 petroleum solvent-4.364.205.024.394.394.714.964.84-PMPI 5.194.364.205.024.394.392.361.241.934.96 TETA 2.742.762.663.18-DETA-2.782.78.1490.781.161.40 propylene glycol-1.301.561.321.321.411.491.451.49 concentrated phosphoric acid-2.52-2.632.641.73-0.64-concentrated hydrochloric acid-2.59- - -1.97 sodium sulfonate- -0.730.730.790.830.810.83 Fungicide A- -0.04- -0.050.050.05- -Water 66.6967.2864.5558.0662.2262.2464.3766.3865.4465.08 Total 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00

TABLE 2 continuation

Percent (weight/weight) formulation K (200) L (240) M (240) N (240) O (240) P (250) Q (250) R (250) S (250) T (250)Composition (I)PVA 0.470.471.581.590.520.450.410.470.410.41 xanthan gum 0.180.210.220.220.210.220.220.230.220.22 anti-foaming agent 0.210.210.220.220.230.200.180.210.190.19 thiotepa 20.5425.0325.2125.4029.2526.0825.8026.8825.9925.99 petroleum solvent 4.40-PMPPI 4.402.682.702.722.582.794.422.884.464.46DETA 2.791.791.711.721.631.772.871.092.682.68 propylene glycol 1.475.015.045.084.825.225.165.385.205.20 concentrated sodium phosphate 2.421.971.981.241.181.582.100.482.122.12 sodium sulfonate 0.730.890.900.910.860.930.920.960.740.74 Fungicide A0.020.050.050.050.050.060.060.060.060.06 amphoteric-2.68-water 62.3759.0160.3960.8558.6760.7057.8661.3657.9357.93 Total 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00

TABLE 2 continuation

Percent (weight/weight) formulation U (250) V (250) W-1W-2W-3X (250) Y (250) Z (250) AA BB BB-1Composition (I)PVA 0.430.410.640.620.580.410.450.470.450.530.55 xanthan gum 0.130.220.090.090.090.220.170.130.170.150.15 cadusafos 27.2726.0837.0135.8233.8426.2826.7926.8626.7121.3621.29 petroleum solvent- -3.983.863.64- -PMPPI 4.672.797.987.737.302.822.872.882.862.291.83 copper naphthalene- -0.270.110.11 DETA 2.811.773.193.092.921.781.821.821.811.450.06 propanediol 5.455.22- -4.675.265.365.375.345.345.32 concentrated phosphoric acid 2.221.58- -concentrated hydrochloric acid- -2.041.981.874.132.262.002.291.831.83 sodium sulfonate 0.780.936.956.726.942.352.392.402.381.911.90 fungicide A- -0.06- - - -0.06- -fungicide B- -0.050.060.060060.060.050.05 amphoteric- -4.66- -3.213.04- -anti-foaming agent 0.190.180.290.280.500.180.200.210.200.240.24 water 56.0556.1037.8336.6034.5656.5157.6357.8057.4664.7466.67 in total 100.00100.00100.00100.00100.00100.00100.00100.00100..00 100.00 100.00

TABLE 2 continuation

Percent (weight/weight) formulation CC DD EE FF (200) GG HH JJ (200) KK LL MMComposition (I)PVA 0.640.630.500.540.540.561.070.540.550.540.53 xanthan gum 0.130.130.140.150.120.120.130.120.120.120.12 anti-foaming agent 0.290.280.220.240.240.250.490.240.240.240.24 sulfur phosphorus 15.8615.9921.0421.6621.6722.2421.5821.5621.5721.3421.07 PMPPI 1.361.71.376.1552.322.422.373.162.372.354.63 copper naphthalene 0.080.080.110.110.220.570.550.550.550.550.54 DETA 0.861.092.280.941.470.610.000.000.001.490.00 HDA 0.000.000.000.000.000.001.031.371.030.002.01 propylene glycol 3.974.005.265.415.425.655.535.535.535.475.40 concentrated phosphoric acid 0.000.000.000.000.000.000.020.050.001.040.00 concentrated hydrochloric acid 1.361.372.552.631.860.100.000.000.000.000.00 sodium sulfonate 1.421.431.881.931.932.021.991.972.001.981.95 Fungicide A- -0.030.030.03 Fungicide B0.030.030.050.050.050.05- -0.050.050.05- -Water 74.0073.2662.2164.7964.1665.4165.2464.8665.9664.8063.48 in total 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00

TABLE 2 continuation

Percent (weight/weight) formulation (g/L)PP(200) QQ(200) RR(200) Composition (I)PVA 0.460.460.54 xanthan gum 0.110.10.12 anti-foaming agent 0.200.200.42 thiotepa 20.3020.3021.27 copper naphthalene 0.520.520.53 petroleum solvent 8.92- -corn oil 8.92- -PMPPI 6.396.393.90 HDA 2.812.812.41 urea 5.205.205.11 concentrated phosphoric acid- -0.49 sodium sulfonate1.96 Fungicide B- -0.02 inert dye- -0.02 Water 55.0955.0963.21 Total 100.00100.00100.00

TABLE 3

Mass preparation (ingredients and amounts) of 200g/l cadusafos CS formulation

Weight (pounds) of formulation PB-1 PB-2 PB-3 PB-4 PB-5PG PB-5U PB-6PG PB-6U PB-7PG PB-7UComposition (I) Isocyanate solutionSulfathion 189.2165.8165.8113.783.382.683.382.683.382.6 copper naphthenate 4.74.14.12.82.12.12.12.12.12.1 PMPPI 24.024.024.025.09.19.19.19.112.212.1Aqueous solutionWater 449.0449.3454.6454.6229.2227.3229.4227.6225.3223.6 PVA 4.144.144.224.222.112.092.112.092.082.06 xanthan gum 0.330.330.330.330.170.160.170.160.170.16 sodium sulfoacid 1.801.801.901.900.900.900.920.910.900.90 antifoaming agent 15.1015.1015.3015.300.280.280.230.237.587.52 Bactericide B0.150.150.150.150.070.070.070.070.070.07Amine solutionHDA 10.510.513.215.8-5.35.2 DETA-5.85.75.85.7-water 19.719.713.714.99.49.49.49.49.99.8Encapsulated additivesConcentrated phosphoric acid 2.94.33.77.43.53.43.53.41.21.2 water 0.50.80.71.30.60.60.60.60.20.2 xanthan gum 0.590.610.860.610.300.300.300.300.300.30 water 29.029.942.229.914.914.814.714.814.714.7 propylene glycol 42.542.542.542.521.0-21.0-22.0-urea- - - - - - - - - - - - - - - - - -20.0 bactericide B0.270.270.390.270.14-0.14-0.140.14 anti-foaming agent 1.561.561.561.56- - - - - - - - - - -0.78 preparation PB-PB-PB-PB-PB-13U-PB-PB-PB- -

8PG 8U 9PG 9U 11PG 11U 12PG 12U ND C14U-ND C18UComposition (I) Isocyanate solutionCadusafos 82.683.281.983.982.683.283.382.6165.8172.61254.68 copper naphthenate 2.12.12.02.12.12.12.12.14.14.21-PMPPI 15.115.318.018.515.115.39.19.156.553.0386.86 white spirit-73.074.1538.47Aqueous solutionWater 226.2227.8224.2229.8234.1235.7227.9226.1397.9391.32795.06 PVA 2.092.112.072.132.092.112.12.13.77.2451.71 xanthan gum 0.160.170.160.170.150.150.20.20.260.322.27 antifoaming agent 0.900.900.890.910.910.910.90.91.83.3323.76 sodium sulfonate 7.627.687.567.747.627.687.77.6-7.5353.6 bactericide B0.070.070.070.080.050.050.10.1-0.201.4Amine solutionHDA 6.66.67.88.06.66.64.03.932.833.3166.52 DETA- -Water 7.27.27.37.56.86.911.111.012.112.3159.48Encapsulated additivesConcentrated phosphoric acid 1.91.92.12.11.91.91.71.74.26.3463.75 Water 0.30.30.40.40.30.30.30.30.81.1311.25 Xanthan Gum 0.310.30.310.300.30.310.310.30.610.644.6 Water 15.214.715.214.714.715.215.214.729.931.4226.0 propylene glycol 22.0- -22.0- -20.0- -22.0- - -urea- -22.0- -22.0- -20.0- -22.042.544.6321.6 Bactericide B0.140.140.140.14- - -anti-foaming agent 0.810.750.810.750.760.80.80.8- - -inert dye- - -0.171.3- - -inert dye- - -

TABLE 4

Mass preparation of 200g/l cadusafos CS formulation (ingredients and weight/weight percentages)

Percent (weight/weight) formulation (g/L) PB-1 PB-2 PB-3 PB-4 PB-5PG PB-5U PB-6PG PB-6U PB-7PG PB-7UComposition (I)Cadusafos 23.7721.421.0115.3821.7521.821.7521.7921.4421.55 copper naphthenate 0.590.540.530.390.540.550.540.550.540.54 PMPPI 3.013.103.043.412.392.392.392.393.143.16 PVA 0.520.530.530.580.550.550.550.550.540.54 xanthan gum 0.120.120.150.130.120.120.120.120.120.12 antifoaming agent 0.420.430.440.470.240.240.240.240.430.44 HDA 1.321.351.67.216- - -1.361.36 TETA- - -1.511.51.1511.51- - -propylene glycol 5.345.485.385.805.49- - -5.49- - -5.67- - -urea- - -5.28- - -5.22 concentrated phosphoric acid 0.360.560.471.010.900.910.900.900.320.32 sodium sulfonate 1.901.951.942.090.070.070.070.061.951.96 bactericide B0.050.050.070.060.060.020.050.020.050.02 water 62.6064.4964.7768.3866.3866.5666.4066.5964.4464.75 Total 100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00 preparation PB-PB-PB-PB-PB-PB-13U-PB-C14U-PB- (g/l) 8PG 8U 9PG 11U 12PG 12U ND N D12N D ND C18UComposition (I)Thiotepa 21.1121.2720.8421.0320.8620.7421.4221.5420.0820.4620.7 copper naphthenate 0.530.530.520.530.520.520.540.540.500.50- -PMPPI 3.873.904.594.633.823.802.352.366.846.286.38 white spirit- -8.848.788.88 PVA 0.530.540.530.530.530.530.540.550.450.860.85 xanthan gum 0.120.120.120.120.110.110.120.120.110.110.04 anti-foaming agent 0.440.420.430.420.420.430.440.440.220.390.39 HDA 1.681.691.992.011.651.65.1021.033.973.953.92 propylene glycol 5.62- -5.60- -5.05- -5.66- -urea- -5.11- -5.01- -5.48- -5.225.145.295.30 concentrated phosphoric acid 0.490.490.530.540.480.480.440.440.510.761.24 sodium sulfonate 1.951.961.921.941.921.911.991.99- -0.890.89 bactericide B0.050.050.050.050.010.010.020.02- -0.020.02 inert dye- -0.020.02 water 63.6163.9262.8863.1964.6364.3465.4665.7553.3451.6951.37 total 100.00100.00100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

TABLE 5

Acute mammalian skin toxicity of cadusafos CS formulations

Preparation LD₅₀(mg/kg) approximate EPA Classification

B ＞1000 II

F > 2000 and < 5000 II

G > 200 and < 2000 II

K ＞2000 III

KK ＞2000 III

LL¹ ＞2000 III

MM ＞2000 III

PB-8PG¹ ＜2000 II

PB-8U ＜2000 -

PB-9PG ＞2000 III

PB-11PG ＞2000 III

PB-12PG > 400 and < 2000 II

PB-C14U-ND ＞5000 IV¹Preparation testTwo trials were performed. Rat acute skin toxicity LD of known cadusafos 100ME preparation₅₀761mg/kg, or class II.

TABLE 6

Acute mammalian oral toxicity of cadusafos CS formulations

Preparation LD₅₀(mg/kg) approximate EPA Classification

B ＞500 III

G > 50 and < 500 II

PP¹ ＞500 III

QQ ＞500 III

PB-8PG ＜500 -

PB-8U ＜500 -

PB-9PG > 200 and < 500 II

PB-11PG > 50 and < 200² II

PB-12PG > 50 and < 200² II

PB-C14U-ND > 500 and < 5,000 III

¹The formulation was tested twice.

²Toxicity is based on the more sensitive females. Rat acute oral toxicity LD of known cadusafos 100ME preparation₅₀371mg/kg, or class II.

TABLE 7

After 48 hours of treatment with CS preparation of cadusafos, the nematode, which is a root wart,

mean rating of root damage caused on tomato

Mean root wart injury rating

Proportioning (Kg/Ha) 0.25 0.5

Preparation

AA 0 0

BB 0.8 0

BB-1 1.8 0

CC 0.4 0

EE 0 0

FF 0.2 0

100ME 0 0

Industrial products 2.41.2

TABLE 8 Microrowed root knot nematodes on tomatoes, on nematode soil infected with nematode soil 7 days before infection with cadusafos CS formulation

Mean rating of resulting root damage

Mean root wart injury rating

Proportioning (kilogram) 0.25 0.5 1.0 2.0

Hectare)

Preparation

AA 1.2 0 0 0

BB 0.8 0 0 0

BB-1 0.6 0.2 0 0

CC 0.8 0 0 0

EE 0.6 0 0 0

FF 0.8 0 0 0

100ME 0 0 0 0

Industrial products 4.43.00.60.4¹And (3) damage rating: 0 injury, 10 deep injury.

TABLE 9Residual soil activity of cadusafos CS preparation in clay soil against cucumber beetle larvae

Percent mortality in the residual phase (day)PreparationProportioning (ppm)0 1 4 7 14 21 35 42 63 84B 0.2 63 72 75 47 78 89 47 35 49 --E 0.2 77 33 55 43 75 60 51 30 35 9F 0.2 90 98 92 63 88 78 33 68 33 --G 0.2 98 98 85 60 95 96 75 52 75 97H 0.2 100 82 60 63 83 73 47 42 22 --PB-C14U-ND 0.2 -- 3 23 23 30 28 -- -- -- --100 ME 0.2 93 92 83 67 78 85 49 30 31 40Biodac 10G 0.2 -- 14 55 15 5 30 -- -- -- --

Watch 10

Residual soil activity of cadusafos CS formulation against cucumber Stephania elegans larvae in sandy fertile soil

Percent mortality in remaining period (days)PreparationProportioning (ppm)0 1 4 7 21 35 49 70 84 112B 1.5 100 100 100 97 97 98 98 97 100 62E 1.5 100 100 100 100 100 98 100 100 100 70F 1.5 100 100 100 97 97 98 98 97 100 62G 1.5 100 100 100 97 100 98 100 100 100 75H 1.5 100 100 100 100 97 98 100 100 100 73100 ME 1.5 100 100 100 100 100 100 100 100 100 33

Claims (14)

1. A process for preparing a microencapsulated cadusafos formulation, the process comprising the steps of:

a) providing an aqueous phase containing one or more emulsifiers and an anti-foaming agent;

b) providing a water-immiscible phase containing up to 98 weight percent cadusafos and 2 to 35 weight percent of an isocyanate monomer;

c) emulsifying a water-immiscible phase in an aqueous phase to form a dispersion of water-immiscible phase droplets in the aqueous phase;

d) an effective amount of an aqueous solution of one or more polyfunctional amines is added to the dispersion to effect interfacial polymerization with the isocyanate monomer to form the cadusafos microcapsules.

2. The method of claim 1, wherein the water-immiscible phase further comprises a hydrocarbon solvent.

3. The method of claim 1, further comprising curing the microcapsules.

4. The method of claim 3, further comprising neutralizing the pH of the microencapsulated cadusafos formulation.

5. The method of claim 4 wherein said aqueous phase further comprises a xanthan gum viscosity modifier/stabilizer and a biocide; the water-immiscible phase further comprises 1.3 to 6.0 weight percent propylene glycol, 5.0 to 5.5 weight percent urea, 0.003 to 0.30 weight percent xanthan gum, 0.01 to 0.10 weight percent of one or more biocides, up to 0.05 weight percent inert dye, and up to 7.0 weight percent of one or more surfactants, each relative to the weight of the formulation after addition of the additive.

6. A pesticide formulation prepared according to the method of claim 1.

7. A process for preparing a microencapsulated cadusafos formulation, the process comprising the steps of:

a) an aqueous phase is provided comprising 0.3 to 5.0 weight percent of one or more emulsifiers, and 0.1 to 1.0 weight percent of an anti-foaming agent, and further optionally comprising 0.05 to 0.50 weight percent of a xanthan gum viscosity modifier/stabilizer and optionally, 0.02 to 0.1 weight percent of a biocide;

b) a water-immiscible phase comprising 50 to 98 weight percent of cadusafos, optionally pretreated with a copper salt, 2 to 35 weight percent of polymethylene polyphenylisocyanate and, optionally, 15 to 30 weight percent of a hydrocarbon solvent is provided;

c) emulsifying a water-immiscible phase in the aqueous phase to form a dispersion of water-immiscible phase droplets throughout the aqueous phase;

d) agitating the dispersion while adding to said dispersion 10 to 100 weight percent of an aqueous solution of one or more polyfunctional amines;

e) curing the microcapsules by heating the dispersion at a temperature in the range of 20 to 60 ℃ for 1 to 10 minutes while continuing to stir; and

f) optionally, the pH of the formulation is neutralized with an acid.

8. A pesticide formulation prepared according to the method of claim 7.

9. A pesticidal formulation of cadusafos, which is a suspension of microcapsules comprising a polyurea shell surrounding a cadusafos core, the polyurea shell being formed by interfacial polymerization of an isocyanate and one or more polyfunctional amines, the polyurea shell being sufficiently impermeable to cadusafos to reduce toxicity to a mammal as compared to an unemulsified formulation having an equivalent or lower concentration of cadusafos.

10. The pesticidal formulation of claim 9, further comprising:

d) optionally, 0.06 to 0.4 weight percent xanthan gum viscosity modifier/stabilizer;

e) optionally, 0.7 to 6.7 weight percent of one or more surfactants; and

g) optionally, 1.2 to 5.8 weight percent propylene glycol or urea.

11. A pesticidal particulate formulation of cadusafos comprising carrier particles coated with microcapsules according to claim 9.

12. The granular formulation according to claim 11, wherein the formulation comprises 5 to 30 weight percent microcapsules, 60 to 95 weight percent carrier, and 0.05 to 5.0 weight percent of a binder.

13. A pesticidal formulation characterized in that it is 150 to 360 grams of cadusafos per liter, 0.7 to 2.5 weight percent polyvinyl alcohol and 0.3 to 0.9 weight percent of an anti-foaming agent, the formulation comprising a suspension of microcapsules, said microcapsules comprising a polyurea layer surrounding a core of cadusafos, said polyurea layer being formed by interfacial polymerization of polymethylene polyphenylisocyanate and one or more polyfunctional amines, wherein the weight percent of cadusafos is 53 to 92% of an interfacially polymerized water-immiscible phase, the weight percent of polymethylene polyphenylisocyanate is 4 to 25% of a water-immiscible phase, and the polyfunctional amine is selected from the group consisting of TETA, DETA, HDA, and a combination of one or more of TETA, DETA and HDA.

14. A pesticidal particulate formulation of cadusafos comprising carrier particles coated with microcapsules according to claim 13.