FR2577555A1 - NEW PESTICIDE COMPOUND - Google Patents

Abstract

S, S-DITERTIOBUTYL ETHYLPHOSPHONODITHIOATE. USE AS AN INSECTICIDE AND NEMATICIDE FOR EXAMPLE FOR THE CONTROL OF CORN ROOTWORM (DIABROTICA SP.). APPLICATION FOR CROP PROTECTION.

Description

The invention relates to S, S-ditertiobutyl ethylphosphonodithioate,

  pesticide compositions containing it as an active ingredient and its use

as an insecticide and nematicide.

  The compound of the invention is of the formula CH 3 CH 2 -P (= O) [-SC (CH 3) 3] 2 (Formula 1) and has a broad spectrum of insecticidal and nematicidal activity and excellent stability and stability.

  long afterglow, especially in the soil.

  The compound can be used, in particular, in agriculture, against adults, larvae and eggs of Lepidoptera (butterflies and moths), for example Heliothis spp such as Heliothis virescens (tobacco budworm), Heliothis armigera and Heliothis zea, spodoptera such as S. exempta, S. littoralis (cotton caterpillar), S. eridania (southern armyworm), Mamestra configurata (bertha armyworm); Earias spp, eg E. insulana (cotton spiny caterpillar), Pectinophora spp. for example Pectinophora gossypiella (pink worm), Ostrinia spp. such as 0. nubilalis (corn borer), Trichoplusia ni (cruciferous looper), Pieris spp (cabbage buckthorn),

  Laphygma spp. (armyworms), Agrotis and Amathes spp.

  cutworms), Wiseana spp. (porina mothe), Chilo spp. (Rusty rice moth), Tryporyza spp. and Diatraea spp. (white rice moths and sugar cane borers), Sparganothis pillerinia (vine borer), Cydia pomonella (codling moth), Archips spp. (fruit tree tortrix moths), Plutella xylostella (cruciferous moth), against adults and larvae of Coleoptera, eg Hypothenemus hampei (coffee berry borer), Hylesinus spp. (bark beetles),

  Anthonomus grandis (cotton borer), Acalymma spp.

  (cucumber beetles), Lema spp., Psylliodiodes spp., Leptinotarsa decemlineata (Colorado potato beetle), Diabrotica spp. (corn rootworms), Gonocephalum spp. (false wire worm), Agriotes spp. (wireworms), Dermolepida, Lepidiota and Heteronychus spp. (white grubs), Phaedon cochleariae (watercress beetle), Lissorhoptrus oryzophilus (aquatic rice weevil), Meligethes spp. (cruciferous meligenes), Ceuto rhynchus spp., Rynchophorus and Cosmopolites spp. (root weevils) Sitona spp (pea and bean weevils); against Hemiptera, for example Psylla spp., Bemisia spp., Aphis spp., Myzus, Megoura viciae, Phylloxera spp, Adelges spp. Phorodon humuli (hop aphid), Aeneolamia spp., Nephotettix spp. (Scallops), Empoasca spp., Nilaparvata spp., Perkinsiella spp., Pyrilla spp., Aonidiella spp. (for California red), Coccus spp., Pseudococcus spp., Helopeltis spp. (mosquito bugs), Lygus spp. Dysdercus spp., Oxycarenus spp., Nezara spp .; the

  Hymenoptera, for example Athalia spp. and Cephus spp.

  (cephes), Atta spp. (ant cut leaves); Diptera, for example Hylemyia spp. (root flies), Atherigona spp. and Chlorops spp. (shoot flies), Phytomyza spp. (Leafminers), Ceratitis spp. (fruit fly); Thynasoptera such as Thrips tabaci; Orthoptera such as Locusta and Schistocerca spp. (locusts) and locusts for example Gryllus spp. and Acheta spp. and gryllotalpidae (mole crickets); Collembola for example Sminthurus spp. and Onychiurus spp. (springtails), for example Isoptera Odontotermes spp. (termites), Dermaptera eg Forficula spp. (earwigs) and also other arthropods of agricultural importance such as

  mites, for example Tetranychus spp., Panonychus spp.

  and Bryobia spp. (spiders), Eriophyes spp. (phytoptes), Polyphagotarsonemus spp .; Blaniulus (centipedes), Scutigerella spp. (symphilids), Oniscus spp. (sowbugs) and Triops (crustaceans) and also plant-parasitic nematodes, infesting both roots and stems, such as root nematodes (Heterodera spp., Globodera spp.), (Meloidogyne spp.) "nematode lesion" (Xiphinema spp) and "stem and bulb eelworms" (Ditylenchus

spp).

  Because of its good activity against corn rootworm (Diabrotica sp.) And its great remanence in the soil, the compound according to the invention is particularly interesting for the fight against corn rootworm. The duration of the residual activity of the compound in the soil against corn rootworm is unexpectedly greater than that of compounds of neighboring chemical structures, as shown by the following experiment described in Example 1:

Example 1

  EXPERIMENT The compounds tested are of formula:

R (X) P (= X1) (X2R1) (X3R)

  Compound R (X) X 1 X 2 R 1 X 3 R 2 A Et - 0 S t -butyl S t -butyl B Et - 0 S npropyl S t -butyl C Et - 0 S iso-propyl S t -butyl D Et - 0 S isobutyl S-tert-butyl and n-butyl-tert-butyl, n-butyl, t-butyl, n-butyl, n-propyl, t-butyl, and tert-butyl and n-butyl. S-butyl S-butyl I and S-butyl S sec-butyl Compound A is the compound according to the invention B is the compound No. 2 of US Patent No. 4,472,390 C is compound No. 7 U.S. Patent No. 4,472,390 D is Compound No. 9 of U.S. Patent No. 4,472,390. E is Compound No. 10 of U.S. Patent No. 4,472,390. F is Compound No. 12 of U.S. Patent No. 4,472,390. G is Compound No. 8,298,508 H is a compound A congenere included in U.S. Patent No. 4,268,508. It is PCT Application Compound No. 11. WO 83/000870 J is PCT Compound No. 10 n WO 83/000870 Residual activity and persistence test against corn rootw orm (Diabrotica spp.) - Method: A clay-loam mixture having a water content of about 23% of the oven-dried weight (determined by drying a sample for 24 hours at 1100 C) is used as the soil. . All doses of the tested product of treatments are expressed in parts per million (ppm) of the weight of soil dried in an oven. Before treatment with the

  compound to be tested, the soil is screened with a sieve at 3.5 mm.

  The product to be tested is dissolved in dimethylketone so as to provide concentrations such that the addition of amounts of 1 ml of solution to soil samples corresponding to 100 g of oven-dried soil, gives concentrations of 0, 05, 0.1 and 0.5 ppm

  and in some cases, 0.05 ppm of the product to be tested.

  Soil samples corresponding to 500 g of oven-dried soil are placed in polyethylene bags into which 5 ml of solution, in dimethylketone, of the product to be tested at the desired concentration is added. The contents of the bags are then thoroughly mixed. Then, the bags are opened for one hour to

  allow the dimethylketone vapor to disperse.

  Soil samples taken from the bags are tested immediately for activity against Diabrotica undecimpunctata (day 0). The remaining sol is then stored at 240C in sealed glass jars and other examples are taken and tested on the 7th, 14th, 21st, 28th, 42nd, 56th, 70th and 84th days after treatment with the product to be tested ( days 7, 14, 21, 28, 42, 56, 70 and 84), the soil being remixed before

  sampling of each sample.

  The activity against Diabrotica is determined as follows: Diabrotica larvae are raised to 250C on

corn seeds.

  About 20 g of treated soil is placed in a 25 x 75 mm glass vial containing 2.5 ml of distilled water and a germinated corn seed with well developed roots. Five 5-day-old Diabrotica larvae are placed on the ground and any larvae that do not sink into the soil after a few minutes are replaced until all the larvae have sunk into the soil. The tube is covered with a mesh lid and held at 250C for four days. Each treatment is made up of four replicates, up to and including day 42, and two replicates for days 56, 70 and 84. After four days, the samples are examined, the number of dead and live larvae counted, and Mean larval mortality calculated as a percentage for the four replicates compared with controls

untreated.

  A mean percentage mortality of at least 90 indicates a satisfactory level of efficacy against

larvae of Diabrotica.

  The results obtained are given in the following Tables I and II. 04 OO 0 (NO _- ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo 0E0DCOa D C D 1 WH I IIO OIo o oII '0t

4) HHHH H H

(U - - - - - - - - - - -

  ## EQU1 ## where: ## STR2 ## is a compound of the following groups: ## STR1 ## wherein: ## STR2 ## CDaCI DC 0CCi) 14C D00 <Ju) aI,) CDC

0V4-3 4

Mp - - ----

O.) VC

r-1, -4- CN404 Kr-

0 CL C

E4U) C (O Ln OD Ln OD Ln OCD

HH N N,

TABLE (II)

  Persistence of the average mortality in I Compound I percentage of at least 90 against the test larvae Diabrotica (days) II Concentration of the product to be tested (ppm) II ___ I 0,5 i 0,1 I 0,05 IAI gt 84 42-56 i 1421 II 'i II

I B | 28-42 0-7

I I

I C 56-70 0-7 + I

D 21-28 +

I E 0-7 + I I

I .. I

I F 7-14 +

I - I - I

I G + + -

I H! + + -

I -I --- I I I

I I 42-56 + I - I

I T, I

J I 7-14 + I - I

I._ _ I _ _ _ _ _ _ _ _ _ _ _ _ I

  "gt" means "greater than" "-" means "not tested" "+" means that the average percentage mortality did not reach 90 on day 0 'A range for example "42-56" means that mortality percentage average fell below 90 between

these days.

  From the above results, it appears that: 1) At the concentration of 0.1 (ppm) the compound A has a satisfactory efficacy against the larvae of Diabrotica for more than six times longer than the compound B, the effectiveness Compound A is satisfactory until day 42, whereas compound B no longer has satisfactory efficacy on day 7. Even at a concentration five times higher (0.5 ppm), compound B has no further satisfactory efficiency between day 28 and day 42. In addition, compound A still has satisfactory efficacy at low level of 0.05 ppm at day 14, whereas, as indicated above, the compound has not more satisfactory efficiency on day 7 even at a

double concentration (0.1 ppm).

  2) At a concentration of 0.1 ppm, compound A has a satisfactory efficacy against the Diabrotica larvae for more than six times longer than compound C, the efficacy of compound A being satisfactory until day 42 , while compound C no longer gives a mean percentage mortality of 90% at day 7. At the half dose (0.05 ppm), compound A has satisfactory activity until day 14 while compound C

  does not reach this level of efficiency even at day 0.

  3) Even at a concentration of 0.5 ppm, compound D does not give a satisfactory activity against the larvae of Diabrotica at day 28, whereas, on the contrary, compound A has satisfactory efficacy twice as long until day 42, at a concentration five times lower (0, 1 ppm). At a concentration of 0.1 ppm, compound D has no satisfactory efficacy even at day 0, while compound A has satisfactory efficacy at this concentration until day 42 and. even at a concentration five times lower (0.05 ppm), has a

  satisfactory efficiency until day 14.

  4) At the concentration of 0.5 ppm, the compound E no longer has a satisfactory efficacy against the larvae of Diabrotica at day 7, whereas even at a concentration five times lower (0.1 ppm) the compound A has a satisfactory efficacy for more than six times longer, until day 42. Even at a concentration ten times lower (0.05 ppm) compound A has a two-fold efficiency.

  times longer at day 14 than compound E at 0.05 ppm.

  At a concentration of 0.1 ppm, compound E is little or not effective even at day 0, whereas at this concentration compound A has satisfactory efficacy until day 42 and, even at a concentration of half (0, 05 ppm), has a

  satisfactory efficiency until day 14.

  At a concentration of 0.5 ppm, the compound F no longer has a satisfactory efficacy against the larvae of Diabrotica at day 14, whereas at a concentration five times lower (0.1 ppm) the compound A has an efficacy. satisfactory for at least three times longer, until day 42 and even at a concentration ten times lower (0.05 ppm) compound A has an efficiency that lasts twice more, until day 14. At a at a concentration of 0.1 ppm, compound F has no satisfactory efficacy even at day 0, whereas at this concentration compound A has satisfactory efficacy until day 42 and even at half concentration (0, 05 ppm) is effective

satisfactory until day 14.

  6) Neither compound G nor compound H has satisfactory activity against Diabrotica larvae even at day 0 at concentrations of 0.5 ppm and 0.1 ppm, whereas compound A has satisfactory activity up to at days 42 and 14, respectively, at concentrations only one-fifth or one-tenth of the highest concentration (0.05 ppm) of compound G and

H compound tested.

  7) At a concentration of 0.1 ppm, compound I does not have satisfactory efficacy against Diabrotica larvae even at day 0, whereas at this concentration compound A has satisfactory efficacy until day 42 and, even at a concentration five times lower (0.05 ppm), compound A has satisfactory efficacy until day 14. At a concentration of 0.5 ppm, compound I no longer has satisfactory efficacy. at day 56, while at this concentration compound A has satisfactory efficacy until day 84 and even at a concentration five times lower (0.1 ppm) has a satisfactory efficacy for a period comparable to that obtained with the compound I at a concentration five

times higher (0.5ppm).

  8) At a concentration of 0.5 ppm, compound J is no longer effective against Diabrotica larvae at day 14, while compound A at a concentration five times lower (0.1 ppm) has an efficacy at least three times longer, at day 42 and at a concentration ten times lower (0.05 ppm) compound A has a satisfactory efficiency twice as long, until day 14. At a concentration of 0 , 1 ppm compound J has no satisfactory efficacy even at day 0, while at this concentration, compound A has a satisfactory efficacy until day 42 and even at a concentration five times lower (0, 05 ppm) has a

  satisfactory efficiency until day 14.

  9) At a concentration of 0.1 ppm, compound A has a satisfactory efficacy on Diabrotica larvae six times more persistent, ie at least until day 42, than the most persistent of the comparison compounds in 0.1 ppm (compound B and compound C), which at this concentration no longer has satisfactory efficacy on Diabrotica at day 7, whereas none of the other seven comparative compounds has satisfactory efficacy.

on Diabrotica even at day 0.

  ) Expressed as mean percentage mortality of Diabrotica at days 21, 28 and 42, at a concentration of 0.1 ppm, the results reported in Table (I) show that at day 21, compound A is six times more active compound C and nine times more active than compound D and that on day 28, compound A is nine and a half times more active than compound C and nineteen times more active than compound D, the seven compounds of comparison the remaining days are no longer active at these days, whereas at day 42, compound A gives a mean percentage mortality of 90% Diabrotica, while none of the nine

comparison is active at day 42.

  The results reported in Tables (I) and (II) clearly demonstrate the essential and unexpected advantage of compound A over the nine comparative compounds both from the point of view of the persistence of a satisfactory level of efficacy on Diabrotica and activity against Diabrotica at given times after application of test compounds. This appears particularly well by examining the results obtained at a concentration of 0.1 ppm of product to be tested, for which is obtained with compound A satisfactory efficacy on Diabrotica at least until day 42, while a comparison compound at this concentration (compound C)) no longer satisfactory on day 14 a comparison product, compound B is no longer satisfactory on day 7 and the other seven comparison compounds have no satisfactory efficiency at day 0. Even at a concentration five times higher (0.5 ppm), only two of the comparison compounds (compound C and compound I) have satisfactory efficacy as long or slightly longer than that of compound A to the concentration five times lower (0.1 ppm) and even there the compound C and the compound I have no satisfactory efficiency respectively at day 56, while the compound A has a satisfactory activity at

  beyond day 84 at a concentration of 0.5 ppm.

  Example 2: Control of Diabrotica on Field Corn Compound A, formulated in 10% granulate, is applied in a strip, at the time of sowing, on the soil of a plot of a cornfield infested with Diabrotica larvae . The maize plans were then uprooted and their roots observed to assess the damage caused by Diabrotica spp using a standard assessment scale, in which 6.0 represents an attack.

  maximum of the parasite and 1.0 of no visible damage.

  The application rates given below are those of compound A in kilograms per hectare (kg / ha). The following results are obtained: IDose Root notation Application I I (kg / ha) I repeat plots I average I IComposed A I A B C O I

0.84 2.1 2.2 2.1 1.8 2.05

0.56 2.6 2.1 2.4 1.9 2.25

0.28 2.8 2.8 2.9 2.3. 2.70

  Non-treated control 5.9 5.9 4.9 3.6 5.08 The low root notations obtained with compound A compared to untreated controls demonstrate the high efficacy of this compound against

Diabrotica spp.

  Example 3: Control of Hylemyia platura on but in the field Compound A, formulated in granules at 20%, is applied in strip or in furrow, on the soil of a field of corn in the field infested by the fly gray, at a rate of 1.12 kg / ha of A domed, both

  treatments being carried out at the time of sowing.

  The effectiveness of treatment against the gray fly (Hylemia platura) is determined by counting the

  fly pupae on given lengths of seedling line.

  The following results are obtained: Compound AI pupes found, in percentage 1.12 kg / ha of those in the control. Treatment in strip I Treatment in seedling row I The reduction of the pupae respectively of 85% and% proves the high activity of compound A against

gray fly.

  Example 4: Control of mole crickets Compound A, formulated as 20% granules, and applied to grass infested with mole crickets (gryllotalpid species) at doses equivalent to 5.56 and 11.2 kg / ha. compound A. Mounds of soil produced by insects are observed before and after treatment. The following results are obtained: I Compound A number of (kg / ha) | control Imonticles 5.6 11.2 untreated washing treatment 1 13.8 7.3 after treatment 1 2.8 8.3 washing treatment 1 10.3 15.0 after treatment 1 1.5 17.0

1 1

  The significant reduction in the number of mounds between the counts before and after treatment proves the usefulness of compound A in the fight against

crickets.

  Example 5: Control of larvae of (Sitona spp) pea and bean weevil in bean fields Compound A, formulated as a 10% granule, is applied, in two experiments, to the soil surrounding the emergence of sown beans. in spring, in the field, in a plot infested with pea and bean weevils, at 1 kg / ha of compound A. The plots are subject to four replicates in experiment 1 and three replicates in experiment 2. About seven weeks later, the plants are uprooted and weevil larvae are counted on the roots. The results are expressed as an average percentage reduction in the number of

  larvae in comparison with the plants, untreated controls.

  The following results are obtained: I Compound A I% reduction in the number of larvae I (kg / ha) I Experiment 1 I Experiment 2

i I I-

1 2 1 90.2 I 92

1 1 53.3 1 93.75

  III The large reduction in larval populations obtained with compound A, in particular at the dose of 2 kg / ha in experiment 1 and experiment 2 and 1 kg / ha in experiment 2, proves the effectiveness of this compound

  against pea and bean weevil larvae.

  Example 6: Efficacy test against Lepidiota frenchi Compound A is dissolved in acetone and this solution is used to treat soil samples to have a scale of known concentrations of the compound in the soil. After evaporation of the solvent, the treated soil is placed in glass jars (about 1 g of soil per jar). Twenty jars are prepared for each concentration. Each jar then receives a larva

  in the third stage of Lepidiota frenchi (cane white grub).

  The larval mortality is evaluated twenty-eight days later.

  The following results are obtained: Application dose of% mortality corrected for compound A in mg / kg of dead larvae of soil in controls

1 I

1 0.5 47

I 1.0 89

2.0 95

1 4.0 100

8.0 100

  The results obtained prove the high insecticidal activity of compound A against Lepidiota frenchi Example 7: Tests on nematicidal activity a) Ditylenchus dispsaci (stem and bulb ellworm) The nematodes are raised on alfalfa plants (cv of the well) in a greenhouse . Two or three months after the initial infection, the plants are harvested, washed and the eggs and larvae of the nematodes are removed by soaking in the water of the torn stems and leaves. After sieving, an inoculum suspension containing about 150 larvae per milliliter is prepared in distilled water. Equal parts of contaminated soil are mixed

  particle size of 1 to 2 mm, and river sand.

  To the lots of this earth is added the compound A to be tested, previously dispersed in distilled water with Tween 80, to obtain the necessary range of dilutions of

chemical in the earth.

  Plant pots of 200 ml capacity are partially filled with untreated coarse sand on which are sown 100 alfalfa seeds per pot. The pots are then filled with chemically treated soil, except in the case of untreated controls or untreated soil. Each pot is watered from above with 5 ml of nematode suspension, so that each pot receives about 750 larvae. The pots are kept at optimum moisture content for germination of

  seeds and plant growth.

  Twelve to fourteen days later, alfalfa seedlings are harvested and examined. The effectiveness of each treatment is determined by the percentage of reduction

  of the attack in comparison with untreated controls.

  The following results are obtained: I Dose i% reduction of the attack Id'application l __ compared to the controls

I of the compound A I -

  I (kg / ha) I Experiment 1 I Experiment 2 I I I i

1,100 1,100 I _

50 100 100

80,100

50 - 70

I 5 I 50 80

  i - i 60 (- "means untested at this dose in this experiment) b) Meloidogyne incognita (root nematode) The culture is maintained on tomato plants in the greenhouse A suspension of nematode root inoculum approximately 1500 eggs per milliliter of distilled water is prepared from macerated and sieved washed roots at least 10 to 15% of the eggs are at a stage

embryonic larvae.

2S577555

  The soil for the experiments is composed of a mixture of equal parts of river sand, peat and uncontaminated soil prepared by manual mixing. This soil is inoculated with enough egg suspension to yield about 30,000 eggs per liter of soil. Compound A is dissolved in acetone and absorbed on a small amount of attapulgite, the acetone being removed by evaporation. Except for the untreated control earth, the soil lots are then manually mixed with the treated attapulgite to provide the necessary range of dilutions of the test chemical in the final batches.

earthen.

  With each lot of soil we fill two repetitions of pots. These are then watered and kept in a humid atmosphere for two weeks. Two small tomato plants (variety Marmande) are then transplanted each into a pot, these being maintained in

  squeeze again for 4 weeks.

  The plants are then harvested, washed and root galls are counted. The effectiveness of each treatment is determined on the percentage reduction of the galls compared to the untreated controls. The following results are obtained in the two experiments: Dose I% reduction in attack I = application in comparison with controls I of compound A I (kg / ha) I Experiment 1 1 Experiment 2

I I I

100 I 100

100 100

100 100

100 90

50 0

1 - O 0

  I '_ _ _ _ _ I__ ___ _ _ _ _ _ i ("-" means not tested at this application rate in this experiment) The above results prove the high level of activity cont - {itylenchus dipsaci and the very high level of activity against Meloidogyne incognita of compound A. The compound according to the invention can be prepared according to methods known per se (by the term "process").

  known in the present description means

  processes used hitherto or described in the chemical literature). Preferably, the compound according to the invention is prepared from a starting material which is an ethylphosphonic acid halide. This ethylphosphonic acid halide is reacted with methyl 2 propane thiol-2 in the presence of a base. to get the

compound according to the invention.

  According to one characteristic of the invention, the compound of formula I is prepared according to the process consisting in reacting an ethylphosphonic acid halide of general formula CH 3 CH 2 --P (= O) (- X) -X (general formula II), wherein X represents a halogen atom, preferably chlorine, and X1 represents a halogen atom, preferably chlorine, or a tert-butyl group [SC (CH3) 3], with, when X1 represents an atom of halogen, generally two molar equivalents or, when X1 represents a tert-butyl group, generally a molar equivalent of 2-methylpropane

thiol-2, in the presence of a base.

  The process is carried out according to the following Reaction Schemes A and B: Reaction Scheme A: (X1 represents a halogen atom)

  CH3 CH2 -P (= O) (-X) -X + 2CH3C (SH) (CH3) CH3 (IIA) 2.bases CH3 CH2 -P (= O) [SC (CH3) 3] 2 + 2 base HX / HX1 Schematic

  Reaction B: (X1 represents S-C (CH3) 3)

  CH3CH2-P (= O) (-X) -SC (CH3) 3 + CH3C (SH) (CH3) CH3

3 2 3 3 3 3.

  (IIB) base at CH3 CH2 - P (= O) [- SC (CH3) 3] 2 + base HX

(2) 3 2332

  in which X and X are as defined above. The reaction according to Reaction Scheme A is preferred to prepare the compound of Formula I. The process is conveniently carried out at a temperature of about OOC at 100 ° C in an organic solvent with an alkali thiolate prepared from the thiol and a metal. alkali, for example sodium, or an alkali metal hydroxide, for example sodium hydroxide. Suitable organic solvents include, for example, benzene, toluene, cyclohexanone, tetrahydrofuran, dimethylformamide, butanone-2 and

acetone (dimethylketone).

  The compounds of general formula II may be prepared according to methods known per se. For example, the compounds of general formula IIA can be prepared according to the methods described by Morita et al, Tetra Hedron Letters 28, 2522-6 (1978), Morita et al, Chemistry Letters (1980), 435-8, British Patent 1 374,757 and Pianfetti and Quin, J. Amer Chem. Soc., 84 851 (1962) and the compounds of general formula IIB can be prepared according to the process described in published British Patent Application No. 2,087,891 A. 2-methylpropane thiol-2 can be prepared according to the method described by Dobbin, J. Chem.

Soc., 57,641.

  The compound according to the invention is effective as an insecticide and / or nematicide at low concentrations. Because of the low doses to obtain a satisfactory efficiency, it is in general practically impossible to apply the compound as it is. For this reason, it is desirable that the compound be applied in the form of insecticidal or nematicidal compositions comprising diethylobenzodithioate of diethylobenzylate in combination with, and preferably dispersed in a homogeneous manner, at least one diluent or carrier and / or agent. agriculturally acceptable and compatible surfactant (i.e., extenders or carriers and / or surfactants known in the art as suitable for use in insecticidal compositions and

  nematicides and which are compatible with the active ingredient.

  The compositions to be applied comprising the active ingredient according to the invention may be dispersions or liquid emulsions, containing from 0.001% to approximately 1% w / v (weight / volume) of active material. Since the active ingredient is essentially insoluble in water, it is desirable to add a non-phytotoxic inert organic solvent to obtain a concentrate which preferably comprises about 2 to 75% by weight of active ingredient and can be easily dispersed. in an aqueous medium to obtain a uniform dispersion of the active ingredient for application. The compositions usually comprise a surfactant. For example, an effective liquid composition can be prepared with the active ingredient, acetone or ethanol, water, and a surfactant such as Tween-20 (polyoxyethylene sorbitan monolaurate) or each of

other well-known surfactants.

  The compositions containing the active ingredient may be in solid form, for example in powder or granular form. For example, the active compound may be mixed with a suitable solid support such as kaolinite bentonite, talc or the like, or incorporated into granules for example mineral clays, eg attapulgite, montmorillonite, diatomite or sepiolite. Preferably, the powder compositions comprise from about 0.5% to 25% w / w (w / w) and the granule compositions preferably from about 1% to 25% w / w of the

active ingredient.

  Compositions containing the active ingredient may also comprise other agrochemical compounds, for example insecticides, nematicides and fungicides, for example thiofanox, carbofuran, aldicarb and benomyl. For the control of insects and nematodes, the active ingredient is usually applied where the infestation is to be fished, at a rate of about 0.1 to 25 kg of active ingredient per hectare treated. Under ideal conditions, depending on the parasite to be controlled, the lower dose may provide adequate protection. In addition, adverse climatic conditions, parasite resistance and other factors may require that the active ingredient be used in

higher.

  When dealing with a soil parasite, the formulation containing the active ingredient is distributed evenly over the surface to be treated by any suitable means. The application can be made, if necessary, on the ground or the culture surface generally on or very similar to the seed or the plant to be protected. The active ingredient can be washed in the soil by spraying in the field with water or the natural action of rain can be allowed to take place. During or after application, the formulation may, if necessary, be mechanically distributed into the soil, for example by plowing or passing discs. Application can be made before sowing, at sowing, after sowing

  but before emergence or after emergence.

  The following example illustrates the preparation of

  compound according to the present invention.

Example 8

  Preparation of S, S-ditertiobutyl ethylphosphonodithioate Sodium hydride (3.0 g, 0.125 mol) is suspended in tetrahydrofuran (70 ml) at 0 ° C. Then 2-methylpropane thiol-2 is added dropwise over 15 minutes ( 14.1 ml, 0.125 mol), keeping the temperature below 5 ° C. The mixture is then stirred at room temperature overnight, and ethylphosphonic acid dichloride (7.35 g, 0.05 g) mole) in tetrahydrofuran (10 ml) is added for 30 minutes with cooling below 35 C in a water bath. The mixture is stirred at room temperature for 5 hours and then allowed to stand

until the next day.

  After addition of toluene (200 ml), then water

  (200 ml) the layers separate. The toluene layer is -

  washed with 2N sodium hydroxide solution (100 ml), and water (100 ml), then dried, filtered and evaporated to give S, S-diethylbutylphosphonodithioate under

  form of an oil (8.72 g, 69% yield).

  The structure of the compound is confirmed by its phosphorus NMR (nuclear magnetic resonance) spectrum (a single peak at 65.0 ppm corresponding to 85% of the phosphonic acid), and by its proton NMR (with tetramethylsilane as internal reference): singlet at 1.6 ppm [SC (CH3) 3], two triplets at 1.1 ppm and 1.3 ppm

  (P-CH 2 CH 3) and a multiplet at 2.2 ppm (P-CH 2 CH 3).

  The integration of the proton magnetic spectrum is coherent

with the indicated structure.

  The following example illustrates compositions according to the present invention:

Example 9

  A composition containing S, Sditertiobutyl ethylphosphonodithioate is prepared. 10% w / w (weight / weight) propylene glycol ................

  ................ 5% w / w attapulgite 24/48 mesh granules .................. DTD: 85% p by mixing S, S-ditertiobutyl ethylphosphonodithioate and propylene glycol and spraying the mixture with a flat-blast nozzle at a pressure of 2 bar on the attapulgite granules, the mixing being carried out in a horizontal drum . After the end of the spraying on the granules, mixing is continued for about 10 minutes until the liquid has been completely absorbed and the granules are homogeneous. The granules thus obtained can be applied at a dose of 3 kg at .DTD: the hectare at a place infested by Diabrotica sp.

Claims (4)

  1) S, S-ditertiobutyl ethylphosphonodithioate.   2) A method of controlling insects and nematodes by applying to themselves or their habitat an effective pesticidal amount of S, S-ditertiobutyl ethylphosphonodithioate. 3) A method of controlling Corn rootworm (Diabrotica sp.) Which comprises introducing into the soil an effective pesticidal amount of S, Sditertiobutyl ethylphosphonodithioate. 4) Composition comprising S, S-ditertiobutyl ethylphosphonodithioate in an effective amount as an insecticide or nematicide and an organic solvent   inert, non-phytotoxic or a solid carrier.   A process for the preparation of S, Sditertiobutyl ethylphosphonodithioate which comprises reacting an ethylphosphonic acid halide of the general formula: CH3 CH2 - P (= O) (X) -X1   in which: X represents a halogen atom; X 1 represents a halogen atom or a tert-butyl group with, when X 1 represents a halogen atom, two molar equivalents or, when X 1 represents the tert-butyl group, a molar equivalent; of 2-methylpropane thiol 2, in presence of a base.