Nematocide

Abstract

A nematocide comprises S-methyl-N,N-di-C.sub.1-2 alkyl thiolcarbamate as an active ingredient.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nematocide for controlling nematode in soil to prevent nematode.

2. Description of the Prior Art

It has been important to control soil pests, for perennial crops such as fruit trees and tea tree. Recently, a concentrated utilization of up-lands, a greenhouse culture and a special production of vegetables have been developed to cause an injury by continuous cropping caused by soil nematode and disease germs. In an up-land which is not suitable for culturing crop plants, it has been known that soil nematode affect to the troubles.

The damages caused by the soil nematode are found in various forms and are usually a poor initial growth, a death and a reduction of yield caused by the poor growth or the death. In the case of a root crop plants, the soil nematode remarkably damage a market value of root crops by a deformation or a surface damage. Once, a damage caused by nematode is given in an up-land, it is impossible to attain a continuous cropping. It is not easy to consider a rotation cropping system under a concentrated agriculture system. Therefore, it has been required to find a safety economical nematocide which can be easily applied.

The known nematocides are mainly halogenohydrocarbon fumigants such as chloropicrin, methyl bromide, D-D(1,3-dichloropropene), EDB(ethylene dibromide), DCIP(bischloroisopropyl ether) and DBCP(1,2-dibromo-3-chloropropane) etc.

These nematocides are not easily used in view of a mucous stimulation and a metal corrosion. Although phytotoxicity is not found by using DBCP and DCIP, serious phytotoxicity is caused by using the other nematocides. Most of the nematocides are used in liquid forms, and accordingly, it is necessary to provide a water-seal of a soil surface for a while or to cover with a polyethylene film in order to impart the nematocidal effect and it is also necessary to discharge the nematocide in the atmosphere by a cultivation for a gas discharge after the treatment in the soil treatment. Thus, remarkable inconvenience is caused in the processing. DBCP can be granulated, however, the production of DBCP is inhibited in view of toxicity to human-body and a long residue of DBCP in a soil and underground water. DCIP has a low nematocidal effect.

In USA, certain contact nematocides as organophosphorus agents such as Fensulfothion (O,O-diethyl-O-(4-methylsufynyl)phenylphosphorothioate), Ethoprop(O-ethyl S,S-dipropylphosphorodithioate) and Phenamiphos[ethyl 3-methyl-4-(methylthio)phenyl(1-methylethyl)phosphoroamidate]; and carbamate agents such as Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methyl carbamate), and Aldicarb[2-methyl-2-(methylthio)propionaldehyde O-(methylcarbomoyl)oxime] have been used.

These contact namatocides have remarkable toxicity and can be used in a form of granule only by a special expert.

The following nematode diseases have been known. Leaf nematode disease (Aphelenchoides ritzema-bosi. Aphelenchoides fragariae); Stem and bulb namatode disease (Ditylenchus dipsaci); Root knot nematode disease (Meloidogyne incognita var. acrita) and Meloidogyne hapla); Stem nematode disease (Ditylenchus dipsaci); Root lesion nematode disease (Pratylenchus coffcae, Pratylenchus penetraus); Cyst namatode disease (Heterodera glycines and Globodera rostochiensis).

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a nematocide especially a soil nematocide which is safe and effective and can be easily applied.

The foregoing and other objects of the present invention have been attained by providing a nematocide especially a soil nematocide which comprises S-methyl-N,N-di-C.sub.1-2 alkyl thiolcarbamate as an active ingredient.

DETAILED DESCRIPTION OF THE PREFERRED EMODIMENTS

The active ingredient can be S-methyl-N,N-dimethyl thiolcarbamate (b.p. 117.degree. C./90 mmHg) or S-methyl-N,N-diethyl thiolcarbamate (b.p. 100.degree. C./25 mmHg).

The compounds can be easily produced at a low cost by reacting methylthiochloroformate with dimethylamine or diethylamine and then reacting the resulting carbamate with methyl chloride or dimethyl sulfuric acid.

The active ingredient can be applied as a desired composition such as an emulsifiable concentrate, a wettable powder, a granule, a dust and an oil solution which is formed by mixing with suitable adjuvants in view of the application. The liquid or solid carrier or a combination thereof can be used.

Suitable solid carriers include bentonite, talc, kaolin, zeolite, clay and diatomaceous earth. Suitable liquid carriers include inert organic solvents such as xylene, o-chlorotoluene, methyl naphthalene, isophorone and kerosen.

In the preparation of the composition, it is preferable to incorporate a surfactant for imparting emulsifiability, dispersibility and spreadability. The composition can be prepared by the known technology.

The content of the active ingredient is in a range of 5 to 40 wt.% in the form of a granule or a dust and 5 to 90 wt.% in the form of an oil solution, an emulsifiable concentrate, a wettable powder.

The content of the surfactant is in a range of 0.5 to 30 wt.% preferably 2 to 20 wt.%.

The active ingredient and the surfactant are diluted with the liquid or solid carrier.

The active ingredient of the present invention is not only used as a single active ingredient but also can be used by mixing another agricultural chemical such as herbicides, germicides and insecticides, other pesticides and fertilizers.

It is especially preferable to apply the active ingredient in the form of the granule or a fine granule. In the preparation, the active ingredient is absorbed or adsorbed on a carrier for granule which has high oil absorption such as diatomaceous earth and fine silica with water if necessary with the other adjuvants.

The following is a list of certain compositions.

TABLE 1__________________________________________________________________________GranuleActive ingredient 5 10 15 20 25 30 35 40__________________________________________________________________________Solid carrier 93 -- 88 -- 83 -- 78 -- 73 -- 68 -- 63 -- 58 --Liquid carrier -- 93 -- 88 -- 83 -- 78 -- 73 -- 68 -- 63 -- 58Surfactant 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2__________________________________________________________________________

EXAMPLE 1

Granule:

______________________________________S--methyl-N,N--diethylthiolcarbamate 10 wt. partsGranular diatomaceous earth 90 wt. parts______________________________________

The active ingredient was immersed in the granular diatomaceous earth to obtain a granule.

EXAMPLE 2

Granule:

______________________________________S--methyl-N,N--diethylthiolcarbamate 15 wt. partsFine silica (Carplex: Shionogi) 15 wt. partsBentonite (Na Salt) 65 wt. partsNonionic surfactant 2 wt. parts(Surfinol TGE: Air Prod. and Chem.)Dispersant 3 wt. parts(Lapizol B-80: Nippon Oil & Fat)______________________________________

The components were mixed and ground and 15 wt. parts of was added and the mixture was kneaded and granulated and dried to obtain a granule.

EXAMPLE 3

Oil solution:

______________________________________S--methyl-N,N--diethylthiolcarbamate 10 wt. partso-Chlorotoluene 90 wt. parts______________________________________

The active ingredient was dissolved to obtain an oil solution.

EXAMPLE 4

Emulsifiable concentrate:

______________________________________S--methyl-N,N--diethylthiolcarbamate 80 wt. partsXylene 10 wt. partsNonionic surfactant 10 wt. parts(Sorpol 800A: Toho Chem.)______________________________________

The active ingredient was dissolved to obtain an emulsifiable concentrate.

EXAMPLE 5

Granule:

______________________________________S--methyl-N,N--dimethylthiolcarbamate 25 wt. partsGranular diatomaceous earth 75 wt. parts______________________________________

The active ingredient was immersed in the granular diatomaceous earth to obtain a granule.

EXAMPLE 6

Granule:

______________________________________S--methyl-N,N--dimethylthiolcarbamate 25 wt. partsDispersing agent (surfactant) 5 wt. parts(Newcol 565 Nippon Emulsifier)Granular diatomaceous earth 70 wt. parts______________________________________

A mixture of the active ingredient and the surfactant was immersed into the granular diatomaceous earth to obtain a granule.

EXAMPLE 7

Granule:

______________________________________S--methyl-N,N--diethylthiolcarbamate 10 wt. partsGranular zeolite 90 wt. parts______________________________________

The active ingredient was immersed in the granular zeolite to obtain a granule.

EXAMPLE 8

Granule:

______________________________________S--methyl-N,N--dimethylthiolcarbamate 15 wt. partsButyl carbitol 15 wt. partsCalcined granular diatomaceous earth 70 wt. parts______________________________________

A mixture of the active ingredient and butyl carbitol was immersed in the sintered granular diatomaceous earth to obtain a granule.

EXAMPLE 9

Granule:

______________________________________S--methyl-N,N--diethylthiolcarbamate 15 wt. partsDipropylene glycol 15 wt. partsCalcined granular diatomaceous earth 70 wt. parts______________________________________

A mixture of the active ingredient and dipropyleneglycol was immersed in the calcined granular diatomaceous earrh to obtain a granule.

EXAMPLE 10

Granule:

______________________________________S--methyl-N,N--dimethylthiolcarbamate 10 wt. partsCastor oil 10 wt. partsGranular zeolite 80 wt. parts______________________________________

A mixture of the active ingredient and castor oil was immersed in a granular zeolite to obtain a granule.

EXAMPLE 11

Granule:

______________________________________Bentonite (Na salt) 45 wt. partsUncalcined diatomaceous earth 54.5 wt. partsNonionic surfactant 0.5 wt. parts(Rapisol Nippon Oil & Fat)______________________________________

These components were mixed with water and treated by a wet granulation and dried to obtain a granular carrier. In 90 wt. parts of the carrier, 10 wt. parts of S-methyl-N,N-diethylthiolcarbamate was immersed to obtain a granule.

EXAMPLE 12

Granule:

______________________________________Bentonite (Ca salt) 80 wt. partsUncalcined diatomaceous earth 20 wt. parts______________________________________

A mixture was mixed and ground and kneaded with water and granulated and dried to obtain a granular carrier. In 85 wt. parts of the active ingredient, 15 wt. parts of S-methyl-N,N-dimethylthiolcarbamate was immersed to obtain a granule.

EXAMPLE 13

Granule:

______________________________________Bentonite (Ca salt) neutralized 90 wt. partswith phosphoric acidS--methyl-N,N--diethylthiolcarbamate 10 wt. parts______________________________________

The bentonite (Ca salt) neutralized with phosphoric acid (pH=7 in a concentration of 2 g/100 g of water) was kneaded with water and was granulated by a wet granulation and dried to obtain a granular carrier. In the carrier, S-methyl-N,N-diethylthiolcarbamate was immersed to obtain a granule.

EXAMPLE 14

Granule:

______________________________________Bentonite (Ca salt) 68 wt. partsUncalcined diatomaceous earth 30 wt. partsVinyl acetate emulsion 2 wt. parts(non-volatile matter)______________________________________

The components were mixed and ground and kneaded with water and granulated by a wet granulation and dried to obtain a carrier. In 85 wt. parts of the carrier, 15 wt. parts of S-methyl-N,N-dimethylthiolcarbamate was immersed to obtain a granulate.

EXAMPLE 15

Aqueous solution:

In water 10 wt. parts of S-methyl-N,N-dimethylthiolcarbamate was dissolved to obtain an aqueous solution.

EXAMPLE 16

Granule:

______________________________________S--methyl-N,N--dimethyldithiocarbamate 25 wt. partsPyrophylite (Fubasamiclay: Onuki Kozan) 50 wt. partsFine silica (Carplex: Shionogi) 25 wt. parts______________________________________

The active ingredient was adsorbed on fine silica and pyrophylite was mixed to obtain a granule.

EXAMPLE 17

Emulsifiable concentrate:

______________________________________S--methyl-N,N--dimethyldithiocarbamate 10 wt. partsXylene 85 wt. partsNonionic surfactant 5 wt. parts(Sorpol 800A: Toho Chemical)______________________________________

The active ingredient was mixed with xylene and the nonionic surfactant to obtain an emulsifiable concentrate.

The effects of the nematocide compositions of the present invention will be illustrated by certain experimental tests.

TEST 1

Test for controlling meloidogyne incognita in tomato

A soil infected by meloidogyne incognita multiplicated on sweet potato as a host plant was filled in a 1/10000 a pot having a height of 14 cm. Each granule prepared in accordance with the composition of Example 1 was mixed at a predetermined ratio. As a reference, the commercially available nematocidal compositions; 30% DCIP granule or 20% DBCP. Granule was also mixed. Seven days after the treatment, 10 seeds of tomato were sowed in each pot.

The test was performed in a glass greenhouse at 25.degree. to 30.degree. C. One month after the sowing, each degree of root knot caused by parasitism, each phytotoxicity and each weight of stem and leaf were measured. The tests were repeated for 3 times. Average data are shown in Table 2.

The same tests were performed by using the active ingredient in various forms of compositions such as those of Example No. 5, No. 16 and No. 17. The results are shown in Table 2.

The degree of root knot caused by parasitism and the phytotoxicity were shown by the following rating.

______________________________________Degree of Percent Number ofroot knot Infection root knots______________________________________0 0 none1 1-25% 1-82 25-50% 9-203 51-75% 21-304 76-100% >30______________________________________

Phytotoxicity

- none .+-. slight damage + damage ++ serious damage +++ death without germination TABLE 1______________________________________ Dosage of Weight formulated Degree of stem product of root leaf Phyto-Composition (kg/10 a) knot (g/seedling) toxicity______________________________________ ##STR1## 4 2 1 0.00 0.21 0.92 0.87 0.81 0.90 - - - ##STR2## 4 2 1 0.12 1.31 2.75 0.84 0.88 0.67 - - - ##STR3## 4 2 1.14 2.56 0.84 0.65 +*.sup.1 .+-.*.sup.1 ##STR4## 4 2 1.63 3.00 0.71 0.49 ++*.sup.2 +*.sup.1 ##STR5## 4 2 2.47 3.83 0.29 0.32 +++*.sup.3 ++*.sup.2DBCP 4 0.29 0.73 .+-.20% granuleDCIP 9 3.32 0.42 -30% granuleNon-treatment -- 3.93 0.18 -______________________________________ *.sup.1 Stem discoloring *.sup.2 Leaf edge drying *.sup.3 Leaf drying, stem discoloring TABLE 2'______________________________________ Dosage of Weight formulated Degree of stem product of root leaf Phyto-Composition (kg/10 a) knot (g/seedling) toxicity______________________________________ ##STR6## 20 10 0.00 0.98 0.99 1.01 - - ##STR7## 20 10 1.62 3.33 0.95 0.66 - - ##STR8## 20 times dil. 1000 l/10 a 40 times dil. 1000 l/10 2.87 3.54 0.51 0.34 - - ##STR9## 20 10 0.89 2.17 0.94 0.70 +*.sup.1 .+-.*.sup.1 ##STR10## 20 10 1.25 2.15 0.85 0.63 ++*.sup.2 +*.sup.1 ##STR11## 20 10 1.99 2.83 0.67 0.46 ++*.sup.2 +*.sup.1 ##STR12## 20 10 3.22 3.84 0.58 0.27 +*.sup.2 +*.sup.1 ##STR13## 20 times dil. 1000 l/10 a 40 times dil. 1000 l/10 3.21 3.86 0.42 0.12 +*.sup.1 .+-.*.sup.1 ##STR14## 20 10 2.19 3.52 0.28 0.30 +++*.sup.3 ++*.sup.2DBCP 20 0.50 0.75 .+-.20% granuleDCIP 30 3.32 0.46 -30% granuleNon-treatment -- 4.00 0.08 -______________________________________

TEST 2

Test for controlling meloidogyne incognite in tomato by oil solution and emulsifiable concentrate of invention

Each oil solution prepared in accordance with the composition of Example 3 or each emulsifiable concentrate prepared in accordance with the composition of Example 4 to contain each predetermined content of the active ingredient was diluted with water to 4 times, 8 times or 16 times and each diluted solution was poured at a center in a depth of 8 cm in each at a rate of 15 liter/10 a or 20 liter/10 a. Then, each pot was sealed with 50 ml. of water.

As a reference, the commercially available D-D, and EDB were also applied in the same manner. Five days after the treatment, the soil was cultivated for the gas discharge. Eight days after the treatment with the composition, seeds of tomato were sowed as Test 1. One month after the sowing, each degree of root knot caused by parasitism and phytotoxicity were measured. The results (average) are shown in Table 3.

TABLE 3______________________________________ Dosage of Weight formulated Degree of stem product of root leaf Phyto-Composition (kg/10 a) knot (g/seedling) toxicity______________________________________ ##STR15## 3 2 1 0.64 1.06 1.39 1.10 0.82 0.94 - - - ##STR16## 3 2 1 0.50 1.12 1.53 0.88 1.03 0.86 - - -DD 16.5 1.43 0.85 -55% oil sol.EDB 9 1.32 0.88 -30% oil sol.Non-treatment -- 3.93 0.18 -______________________________________

TEST 3

Test for controlling pratylenchus penetrans in burdock by granule of invention

A soil infected by pratylenchus penetrans multiplicated on kidney bean as a host plant was filled in a 1/10000 a pot having a height of 14 cm. Each granule prepared in accordance with the Example 2 was mixed at a predetermined ratio. As a reference, the commercially available nematocidal compositions. Seven days after the treatment, 5 seeds of burdock were sowed in each pot. The test was performed in a glass greenhouse at 25.degree. to 30.degree. C. Fifty days after the sowing, each degree of root damage caused by parasitism, each phytotoxicity and each weight were measured. The results are shown in Table 4. The degree of root damage was tested as the rating in Test 1.

______________________________________ Number ofDegree of brown colored Percentroot damage lesions infection______________________________________0 0 01 1-5 1-25%2 6-10 26-50%3 11-15 51-75%4 >16 76-100%______________________________________

The same tests were performed by using the active ingredient in various forms of compositions such as those of Example No. 5 and No. 16. The results are shown in Table 4'.

TABLE 4______________________________________ Dosage of formulated Degree Total product of root weight Phyto-Composition (kg/10 a) damage (g/piece) toxicity______________________________________ ##STR17## 6 3 0.89 1.78 2.62 2.25 - - ##STR18## 6 3 1.63 2.36 2.46 2.03 - - ##STR19## 6 3 2.14 3.14 1.81 1.77 + .+-. ##STR20## 6 3 2.59 3.25 1.73 1.75 + .+-.DBCP 6 1.46 2.48 -20% granuleNon-treatment -- 3.31 1.80 -______________________________________ TABLE 4'______________________________________ Dosage of formulated Degree Total product of root weight Phyto-Composition (kg/10 a) knot (g/piece) toxicity______________________________________ ##STR21## 30 20 0.83 1.61 2.41 2.31 - - ##STR22## 30 20 2.05 2.74 1.81 1.96 + .+-. ##STR23## 30 20 1.87 2.80 2.24 1.83 - -DBCP 30 1.39 2.36 -20% granuleNon-treatment -- 3.20 1.70 -______________________________________

TEST 4

Test for controlling meloidogyne incognita in cucumber in paddy field

On a paddy field infected by meloidogyne incognita in the preceding cropping of a sweet potato, a predetermined amount of each granule prepared in accordance with the process of Example 1 was sprayed on all surface and the soil was cultivated to mix the granule. The reference compositions were also applied in the same manner. Five days after the treatment, 16 cucumber seedlings at 5 leaf stage were transplanted in each section of 4 m.sup.2. The test was repeated twice. The irrigation and the pesticidal treatment were perforemed. The tests were performed from June 16 to August 14th. On August 14th, each degree of root knot caused by parasitism each phytotoxicity and length of cucumber including branches were measured in accordance with Test 1. The results (average) are shown in Table 5.

TABLE 5______________________________________ Dosage of Length of formulated cucumber product Degree of (cm/ Phyto-Composition (kg/10 a) parasitism seedling) toxicity______________________________________ ##STR24## 2 3 0.92 0.50 315 308 - - ##STR25## 2 3 2.83 1.83 231 299 - -DBCP 4 1.19 312 -20% granuleNon-treatment -- 3.10 194 -______________________________________ TABLE 5'______________________________________ Dosage of Length of formulated cucumber product Degree of (cm/ Phyto-Composition (kg/10 a) parasitism seedling) toxicity______________________________________ ##STR26## 30 20 0.13 0.64 291 303 - - ##STR27## 30 20 2.22 2.86 219 234 .+-. - ##STR28## 30 20 1.18 1.99 280 262 - -DBCP 20 0.75 297 -20% granuleNon-treatment -- 3.45 205 -______________________________________

As shown in Tests, S-methyl- or ethyl-N,N-diethylthiolcarbamate imparts remarkably high effects for controlling meloidogyne incognite and pratylenchus penetrans which cause serious damages to crops. Moreover, the active ingredient does not cause phytotoxicity to tomato, cucumber and burdock.

Claims

1. A formulation for a parasitic-nematocidal composition comprising 5-40% of S-methyl-N,N-di C.sub.1-2 alkyl-thiocarbamate as an active ingredient of said composition; and an inert carrier; wherein the improvement comprises:

formulating said nematocidal composition in the form of granules.

2. The formulation according to claim 1, wherein said carrier is silica, bentonite, pyrophylite, talc, kaolin, zeolite, clay or diatomaceous earth.

3. The formulation according to claim 1, wherein said composition further comprises 0.5 to 30 wt. % of a surfactant.

4. The formulation according to claim 1, wherein said active ingredient is S-methyl-N,N-dimethylthiolcarbamate.

5. The formulation according to claim 1, wherein said active ingredient is S-methyl-N,N-diethylthiolcarbamate.

6. The formulation of claim 4, wherein the amount of S-methyl-N,N-dimethylthiolcarbamate is between about 15 and 25% of said composition.

7. The formulation of claim 5, wherein the amount of S-methyl-N,N-diethylthiolcarbamate is 10% or more of said composition.