JP5185547B2 - Insecticide / nematicide composition and pest control method - Google Patents

Description

  The present invention relates to an insecticide / nematicide composition effective for simultaneous control of various nematodes and insects such as soil pests, and a method for controlling pests.

  S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate is a compound disclosed in US Pat. No. 4,590,182. O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate is a compound disclosed in US Pat. No. 5,405,961. S, S-di-sec-butyl O-ethyl phosphorodithioate is a compound disclosed in US Pat. No. 4,535,077. They are active ingredients of known organophosphorus nematicides. Until now, organophosphorus insecticides are known. However, it is not well known that when a specific organophosphorus nematicide and a specific organophosphorus pesticide are combined, they exhibit a synergistic effect on pest control. JP-A-1-238505 discloses an organophosphorus nematicide containing the above S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate and an organophosphorus insecticide. There is a disclosure about the combination.

U.S. Pat. No. 4,590,182 US Pat. No. 5,405,961 U.S. Pat. No. 4,535,077 JP-A-1-238505

  Rather than controlling each of the known nematicides and insecticides alone, there is a need for insecticides and nematicides in which the control effects of both are synergistically enhanced.

  As a result of repeated investigations to solve these problems, the present inventors have obtained an effect more than expected by combining a specific organophosphorus nematicide and a specific insecticide. As a result, the present invention was completed.

  That is, the present invention relates to S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate, O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazo At least one organophosphorus nematicide selected from the group consisting of lysine-1-yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate, and an organophosphorus insecticide The present invention relates to an insecticidal / nematicide composition characterized by containing The present invention also relates to a method for controlling pests, characterized by treating those active ingredients in pests or pest habitats.

  S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate has optical isomers and includes (−) and (+) isomers in addition to racemates. It is. The racemic (R, S) -S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate is a compound known by the generic name Fosthiazate. .

  O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate also has an optical isomer, and in addition to the racemate, the (−) and (+ ) The body is included. Racemate is a compound known by the general name Imicyafos.

  S, S-di-sec-butyl O-ethyl phosphorodithioate is a compound known by the general name cadusafos.

  Examples of organophosphorus insecticides include pyridaphenthion, isoxathion, diazinon, chlorpyrifos, fenitrohion, cyanophos, profenofos, acephete, and acephate. Dichlorvos, Fenamiphos, EPN, Chlorpyrifos-methyl, Prothiofos, Phosphocarb, Dislufoton, Demeton-S-methyl, Dimethoate ( Dimethoate, Methamidophos, Isofenphos, Ethion, Etrimfos, Quinalphos, Dimethylvinphos, Sulprofos, Thiometon, Vamidothion, Vamidothion Pila Chlophos (Pyraclofos), Pirimiphos-methyl, Propaphos, Phosalone, Formothion, Malathion, Tetrachlovinphos, Chlorfenvinphos, Trichlorfone (Chlorfenvinphos) Trichlorfon, Methidathion, Phenthoate, ESP, Azinphos-methyl, Fenthion, Heptenophos, Methoxychlor, Paration, Monocrotophos, Parathion Examples thereof include methyl (Parathion-methyl), terbufos (Terbufos), phosphamidon (Phospamidon), phosmet (Phosmet), and holate (Phorate). These are compounds described in The Pesticide Manual (13th edition; BRITISH CROP PROTECTION COUNCIL) and the like. Among these, soil damage such as pyridafenthion (Pyridaphenthion), isoxathion (Isoxathion), diazinon (Diazinon), chlorpyrifos (Chlorpyrifos), fenitrothion (Fenitrohion), cyanophos (Cyanophos), profenofos (Acfenate) and insect pest control A good insecticide is desirable. In combination with S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate, it is particularly desirable to use pyridaphenthion. The group consisting of O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate In combination with at least one organophosphorus nematicide selected from the group consisting of Pyridaphenthion, Isoxathion, Diazinon and Chlorpyrifos among these organophosphorus insecticides It is particularly desirable to use at least one selected from the group.

  The composition of the present invention has an excellent control effect against various pests such as insects and nematodes.

  In the composition of the present invention, the mixing ratio of the specific organophosphorus nematicide and organophosphorus insecticide is usually a ratio of 10: 1 to 1:50, preferably 5: 1 to 1:30 by weight. The ratio is more preferably 2: 1 to 1:20.

  The composition of the present invention contains an auxiliary agent in addition to the active ingredient. The blending ratio of the active ingredient may be 0.05 to 75% by weight. Examples of the auxiliary agent include a carrier, an emulsifier, a suspending agent, a dispersing agent, a spreading agent, a penetrating agent, a wetting agent, a thickening agent, a stabilizer, and the like. The carrier is divided into a solid carrier and a liquid carrier, and the solid carrier includes starch, activated carbon, soybean flour, wheat flour, wood flour, fish flour, powdered milk and other animal and vegetable powders; talc, kaolin, bentonite, calcium carbonate, zeolite, Examples include mineral powders such as diatomaceous earth, white carbon, clay, alumina, and sulfur powder. Examples of liquid carriers include water, alcohols such as methyl alcohol and ethylene glycol; ketones such as acetone and methyl ethyl ketone; dioxane, tetrahydrofuran, and the like. Ethers; aliphatic hydrocarbons such as kerosene and kerosene; aromatic hydrocarbons such as xylene, trimethylbenzene, tetramethylbenzene, cyclohexane and solvent naphtha; halogenated hydrocarbons such as chloroform and chlorobenzene; dimethylformamide Acid amides; nitriles such as acetonitrile; ethyl acetate, esters such as glycerin esters of fatty acids such as sulfur-containing compounds such as dimethyl sulfoxide. Various surfactants are used as the emulsifier, suspending agent, dispersing agent, spreading agent, penetrating agent, wetting agent and the like. Also, if necessary, it can be mixed with other agricultural chemicals such as insecticides, acaricides, nematicides, fungicides, antiviral agents, attractants, herbicides, plant growth regulators, etc. In this case, a more excellent effect may be exhibited.

  The composition of the present invention can be used in various forms such as emulsions, powders, fine granules F, fine granules, granules, tablets, wettable powders, liquids, aerosols, pastes, flowables, dry flowables, and microcapsules. Can be formulated. Of these, forms such as emulsions, fine granules, wettable powders, liquids, powders, granules, tablets and the like are more desirable, and forms such as emulsions, fine granules, granules, wettable powders and liquids are most desirable. A preferable blending ratio in the emulsion is 5 to 75 parts by weight of the active ingredient, 90 to 10 parts by weight of the carrier, and 5 to 15 parts by weight of the surfactant. Moreover, the preferable mixture ratio in a powder agent, a granule, and a tablet is 0.1-10 weight part of active ingredients, 85-99 weight part of support | carriers, and 0.5-5 weight part of surfactant. In actual use of these preparations, they can be used as they are or diluted to a predetermined concentration with a diluent such as water.

  The composition of the present invention is generally applied at an active ingredient concentration of 0.1 to 10,000 ppm, preferably 1-1000 ppm. The concentration of these active ingredients can be appropriately changed depending on the form of the preparation and the method of application, purpose, time, place and occurrence of pests. The application amount per unit area is about 1 to 5000 g, preferably 10 to 1000 g as an active ingredient compound per 10a. However, in special cases, it is possible to deviate from these ranges. Examples of the application method of the composition of the present invention include soil admixing treatment, planting hole treatment, grooving treatment, irrigation treatment, and soaking treatment and dressing treatment for seeds.

  In addition to the method of treating the composition of the present invention with pests, the present invention includes a method of treating the organophosphorus nematicide and organophosphorus insecticide at the same time in a pest or a pest habitat, and the organophosphorus A method of treating one of a nematicide and an organophosphorus insecticide in a pest or a pest habitat and then treating the other pest in the pest or pest habitat is included.

  Examples of the pests to which the present invention can be applied include nematodes, isopods, Coleoptera pests, lepidopterous pests, gastropods, orthoptera pests, plant parasitic mites, thrips pests, diptera pests, hymenoptera Various insect pests such as insect pests, octopus insects, lice insects, and the like are lepidopterous insects, semilepidopterous insects, rotifers, centipedes and millipedes. In particular, the present invention is a pest that harms agricultural and horticultural crops and trees in the soil, and a pest that harms agricultural and horticultural crops and tree seeds, such as the above nematodes, isopods, Coleoptera, Lepidoptera pests, It is effective for gastropods, straight-nosed insect pests, and plant parasitic mites. Specific examples of various pests to which the present invention can be applied are shown below.

  As nematodes, Negrass nematodes (Pratylenchus coffeae), Nepalese nematodes (Pratylenchus fallax), Chanegesu nematodes (Pratylenchus loosi), Negresa nematodes (Pratylenchus vulnus), etc .; soybean Heterodera glycines, cyst nematodes such as potato cyst nematodes (Globodera rostochiensis); root-knot nematodes such as Meloidogyne hapla and Meloidogyne incognita; Aferenchoides such as: Ishku nematodes; Wasenchus; Pin nematodes; Longidorus; Trichodols; Strawberry mesenchus; It is. In addition, examples of isopods include corundum moths and slats.

  Crustacea pests include corn rootworms such as Western corn room worms (Diabrotica virgifera virgifera) and Southern corn root worms (Diabrotica undecimpunctata howardi); Bill (Sitophiluszeamais), Echinocnemus squameus, Cylas formicarius, Lissorhoptrus oryzophilus, Alfalfa weevil (Hypera pastica), Callosobruchuys chiensis; Callosobruchuys chiensis; okinawensis), Agriotes ogurae fusciollis, bark beetles such as Melanotus legatus; Tenebrio molitor, Tribolium castaneum, etc .; leaf beetles (Aulacophora femoralis), horned beetles (Phyllotreta striolata), potato beetles (Leptinotarsa decemlineata), etc .; (Paederus fuscipes).

  The lepidopteran pests include Chilo suppressalis, Cnaphalocrocis medinalis, European corn borer (Ostrinia nubilalis), Parapediasia teterrella, Cotton moth (Notarcha derogata), Pelodia Spodoptera litura, Pseudaletia separata, Mamestra brassicae, Agrotis ipsilon, Trichopulcia, Heliotis, Helicoberpa, etc .; Tortoises such as Grapholita molesta, Cydia pomonella; Sinkigas such as Carposina niponensis; Anemones such as Rionetia; Rimantria, Euproctinis, etc. Sugas such as Puga (Plutellaxylostella); Swabs such as Pectinophora gossypiella; Higgriats such as Hyphantria cunea; Hirosukoga such as Tinea translucens and Tineola bisselliella Can be mentioned.

  Examples of gastropods include maimai and slugs.

  Examples of the direct insect pest include kerat, grasshopper, German cockroach (Blattella germanica), black cockroach (Periplaneta fuliginosa), American cockroach (Periplaneta americana), black cockroach (Periplaneta brunnea), and British cockroach (Blatta orientalis).

  Examples of plant parasitic mites include nymph mites, moss mites, citrus mites, and mites.

  The thrips of the order Thrips palmi, Thrips tabaci, Thrips hawaiiensis, Scirtothrips dorsalis, Frank ella An example of this species is Ponticulothrips diospyrosi.

  Diptera: Culex pipiens pallens, Culex tritaeniorhynchus, etc .; Aedes genus, such as Aedes aegypti, Aedes albopictus; Anopheles genus, such as Anopheles sinensis; House flies such as Muscina stabulans; black flies; powder fly; Butterfly species; flyfish; abu species;

  Examples of the Hymenoptera pest include ants; wasps; hornets; scallops;

  Examples of the pests include cat fleas (Ctenocephalides felis), dog fleas (Ctenocephalides canis), human fleas (Pulex irritans) and the like.

  Examples of the lice insects include pediculus humanus corporis, white lice (Phthirus pubis), and human lice.

  Examples of isopods include Yamato termites and termites.

Hemiptera pests include Japanese brown planthoppers (Laodelphax striatellus), brown planthoppers (Nilaparvata lugens), white planthoppers (Sogatella furcifera), etc .; Nephotettix cincticeps; gossypii), peach aphid (Myzus persicae), citrus aphid (Aphis citricola), black-headed aphid (Lipaphis pserudobrassicae), nippolachnus piri, citrus aphid (Toxoptera aurantiera), citrus Aphids such as Nezara antennata, Cletus punctiger, Riptortus clavetus, Platya stali, etc .; Whiteflies such as Trialeurodes vaporariorum, Tobacco whitefly (Bemisia tabaci), Silverleaf whitefly (Bemisia argentifolii); Aonidiella aurantii; Pseudaulacaspis pentagona), Saissetia oleae, Lepidosaphes beckii, Ceroplastes rubens, Icerya purchasi, and other insects;

  Examples of the barley beetles include Porcellio scaber, Porcellionides pruinosus, Armadillidium vulgare, and the like.

  Examples of centipedes include Tobism cadets (Scolopendra subspinipes mutilans), Aosude cadets (Scolopendra subspinipes japonica), Akasumi cadets (Scolopendra subspinipes multidens), Geji (Thereuopoda hilgendorfi), and the like.

  Millipedes include oyster millipede (Oxidus gracilis), obibaya millipede (Parafontarialaminata laminata) and the like.

  The compositions and methods of the present invention have a synergistic effect on pest control. This synergistic action is based on a synergistic effect that cannot be predicted from various pest control properties of each drug, and the usefulness of the present invention is more than the pest control effect than using each drug alone. In particular, it can be said that the pest control power in the soil is clearly enhanced and an immediate effect is imparted.

Desirable embodiments of the present invention will be described below, but the present invention is not limited thereto.
(1) The above insecticide, wherein the organophosphorus nematicide is S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate, and the organophosphorus insecticide is pyridafenthion. Nematicide composition.
(2) Consists of O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate The insecticidal / nematicidal composition comprising at least one organophosphorus nematicide selected from the group and an organophosphorus insecticide as active ingredients.
(3) The insecticidal / nematicidal composition according to (2), wherein the organophosphorus insecticide is at least one selected from the group consisting of pyridafenthion, isoxathione, diazinon, chlorpyrifos, fenitrothion, cyanophos, propenofos and acephate.
(4) The insecticidal / nematicidal composition according to (2), wherein the organophosphorus insecticide is at least one selected from the group consisting of pyridafenthion, isoxathione, diazinon and chlorpyrifos.
(5) S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate, O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidine-1 -Yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate selected from the group consisting of at least one organophosphorus nematicide and an organophosphorus insecticide Alternatively, a method for controlling pests characterized by treating the pests in a habitat.
(6) The organophosphorus nematicide is S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate, and the organophosphorus insecticide is pyridafenthione (5) The method described in 1.
(7) Organophosphorus nematicides are O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate and S, S-di-sec-butyl O -The method according to (5), wherein the organophosphorus insecticide is at least one selected from the group consisting of pyridafenthion, isoxathione, diazinon and chlorpyrifos, wherein the organophosphorus insecticide is at least one selected from the group consisting of ethyl phosphorodithioate.

  Next, examples of the present invention will be described.

Test example 1
Add water to the onion powder at a ratio of 1:10 and stir well. 8cm filter paper is dipped in a powder suspension, air-dried, packed in 3 pieces on an 8cm petri dish, and 2ml of a predetermined concentration of organophosphorus nematicide and / or organophosphorus insecticide is added. Inoculate 50 female mite mites per petri dish, cover and place in a constant temperature room at 25 ° C. Observe under a stereomicroscope 48 to 72 hours later, make a life / death determination and determine the death rate.
Mortality (%) = {1- (number of surviving animals / number of insects)} × 100
Also, the theoretical value (%) of the death rate can be calculated by the Colby equation. When the experimental value (%) of mortality is higher than the theoretical value (%), the composition of the present invention has a synergistic effect on the control of mites.
The organophosphorus nematicide: organophosphorus pesticide = within the range of 10: 1 to 1:50, the experimental value of mortality is higher than the theoretical value.

Test example 2
Create test soil mixed with loam soil 3: sand 1: corrosive soil 1, put 200g of soil into a 300ml plastic container, add organophosphorus nematicide and / or organophosphorus pesticide at a predetermined concentration and mix To do. 10 larvae immediately after hatching of the beetle are released and allowed to stand in the dark at 25 ° C in a constant temperature room for 5 to 10 days. Then, the soil is demolished and the number of surviving larvae is counted to determine the mortality rate.
Mortality (%) = {1- (number of surviving animals / number of insects)} × 100
Also, the theoretical value (%) of the death rate can be calculated by the Colby equation. When the death rate (%) is higher than the theoretical value (%), the composition of the present invention has a synergistic effect on the control of scarab beetles.
The organophosphorus nematicide: organophosphorus pesticide = within the range of 10: 1 to 1:50, the experimental value of mortality is higher than the theoretical value.

Test example 3
Paddy soil 4: 3 liters of sand loam mixed with sand 1 was placed in a 1 / 5000a pot, and an organophosphorus nematicide and / or organophosphorus insecticide was added and mixed at a predetermined concentration. Immediately after the addition of the drug, 500 cc of nematode (Meloidogyne incognita) -contaminated soil was inoculated into each pot, and after mixing well, a tomato (cultivar: strong rice life) seedling was transplanted. 44 days after transplantation, the degree of nematode formation (0-100%) of nematodes was investigated. The results are shown in Table 1. Further, the theoretical value (%) of the degree of cat root formation was calculated by the Colby equation. The composition of the present invention has a synergistic effect on the control of nematodes when the degree of root formation (%) is lower than the theoretical value (%). The theoretical values (%) in these cases are also shown in parentheses in Table 1. The test was conducted in two consecutive systems.

Test example 4
The test was conducted in the same manner as in Test Example 3 except that the degree of nematode formation on the nematode was investigated 49 days after the transplantation, and that the test was conducted in triplicate. The results are shown in Table 2.

Test Example 5
Paddy soil 4: 3 liters of sand loam mixed with sand 1 was placed in a 1 / 5000a pot, and an organophosphorus nematicide and / or organophosphorus insecticide was added and mixed at a predetermined concentration. Immediately after the addition of the drug, 500cc of nematode (Pratylenchus fallax) contaminated soil was inoculated into each pot, and after mixing well, transplanted burdock (variety: Takinogawa Gyudon) seedling. The degree of damage (0 to 100% damage) was investigated, and the results are shown in Tables 3 and 4. The theoretical value (%) of the negre index was calculated using the Colby equation. %) Is lower than the theoretical value (%), the composition of the present invention has a synergistic effect on the control of nematodes.The theoretical value (%) in these cases is shown in Tables 3 and 4. Also shown in parentheses.

Test Example 6
Forty-eight sweet potato root nematode second stage larvae were immersed in a chemical solution diluted to a predetermined concentration with distilled water and kept in a thermostatic chamber at 25 ° C. for 48 hours. Under the microscope, the total number of sweet potato root nematodes in the drug solution (A) and the number of individuals that did not move in the drug solution for 15 seconds (B) were examined. In addition, the total number of individuals (A ′) and the number of individuals that did not move for 15 seconds (B ′) were also investigated in the control group using distilled water instead of the chemical solution. From these values, the motor inhibition rate was determined by the following equation. The results are shown in Tables 5-7.
Movement inhibition rate (%) = [1-{(1-B / A) / (1-B ′ / A ′)}] × 100
In addition, the theoretical value (%) of the movement inhibition rate was calculated by the Colby equation. When the movement inhibition rate (%) is higher than the theoretical value (%), the composition of the present invention has a synergistic effect on nematode control. The theoretical values (%) in these cases are also shown in parentheses in Tables 5-7.

Formulation Example 1
(1) Phosthiazet active substance 1.7 parts by weight (2) Chlorpyrifos active substance 1.2 parts by weight (3) Newkalgen EX-70 (Dioctylsulfosuccinate; Takemoto Yushi Co., Ltd.)
1.0 parts by weight (3) Silver W (fine powdered calcium carbonate; manufactured by Shiraishi Calcium Co., Ltd.) 10.0 parts by weight (4) 86.1 parts by weight of calcium carbonate To the mixture of (1) to (4) above, 1% serogen 703A (carboxymethylcellulose) Soda salt (Daiichi Kogyo Seiyaku Co., Ltd.)) Aqueous solution was added and kneaded, then extruded and granulated with a dome type granulator equipped with a 0.8mmφ screen (DG-L1; manufactured by Fuji Powder Co., Ltd.). After drying with air flow at 70 ° C., the particles are sized to a size of 0.3 mm to 1.00 mm to obtain granules.

Formulation Example 2
(1) 11 parts by weight of phostiazate base (2) 22 parts by weight of chlorpyrifos base (3) Solpol 4296A
(Nonionic and anionic compound surfactant: manufactured by Toho Chemical Co., Ltd.) 12 parts by weight (4) Solvesso 150 (aromatic solvent; manufactured by ExxonMobil) 55 parts by weight The above (1) to (4) are mixed Dissolve to make an emulsion.

Formulation Example 3
3.4 parts by weight of a mixed solution of 50 parts by weight of a phostiazate base and 50 parts by weight of a diazinon base is oil-absorbed and mixed with 96.6 parts by weight of 16-50 mesh silica stone (manufactured by Tokai Kogyo Co., Ltd.) to obtain a granule.

Formulation Example 4
(1) Phosthiazate base 16 parts by weight (2) Diazinon base 27 parts by weight (3) Solpol T-15 (nonionic surfactant; manufactured by Toho Chemical Co., Ltd.) 12 parts by weight (4) Rhodacal 70 (anionic) Surfactant; Rhodia Nikka Co., Ltd.) 2 parts by weight (5) Solvesso 150 43 parts by weight The above (1) to (5) are mixed and dissolved to obtain an emulsion.

Formulation Example 5
2.9 parts by weight of a mixture of 60 parts by weight of phosthiazate base and 40 parts by weight of isoxathion base is oil-absorbed and mixed with 97.1 parts by weight of silica stone particles (manufactured by Tokai Kogyo Co., Ltd.) with a particle size of 180-710 μm. To do.

Formulation Example 6
(1) Kazusafos bulk 3.5 parts (2) Chlorpyrifos bulk 1.2 parts (3) Topcoperlite # 54 (manufactured by Toko Perlite Industry) 7 parts (4) Bentonite 10 parts (5) Clay 78.3 parts Part To the mixture of (1) to (5) above, an aqueous solution of sun extract C (lignin sulfonate; manufactured by Nippon Kokusaku Pulp Co., Ltd.) diluted to 20% is added and kneaded, and a dome-shaped structure equipped with a 0.8 mmφ screen. Extruded and granulated with a granulator (DG-L1), further dried by air flow at 70 ° C, and then sized to a size of 0.3 mm to 1.00 mm to obtain granules.

Formulation Example 7
A mixture of 75 parts by weight of kazusafos and 25 parts by weight of isoxathione is absorbed and mixed in 95.3 parts by weight of pumice (Ishikawa Light No.3; Ishikawa Light Industry Co., Ltd.), and contains kazusafos and isoxathione. Use granules.

Claims (2)

Selected from the group consisting of O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate An insecticide / nematicide composition comprising at least one organophosphorus nematicide and chlorpyrifos as active ingredients. Selected from the group consisting of O-ethyl-Sn-propyl (2-cyanoimino-3-ethyl-imidazolidin-1-yl) phosphonothiolate and S, S-di-sec-butyl O-ethyl phosphorodithioate A pest control method comprising: treating at least one organophosphorus nematicide and chlorpyrifos in a pest or a pest habitat.