CONTROL OF CORN BORERS BY 1-ARYL PYRAZOLE OR 1-HETEROARYL PYRAZOLE COMPOUNDS

Abstract: Method of control of corn borers attacking or susceptible or expected to attack corn plants whereby an effective amount of a 1-aryl pyrazole insecticidally active ingredient is applied near the corn sown seed. Method of protection of corn plants against European corn borer, whereby an effective amount of a 1-aryl pyrazole insecticidally active ingredient is applied near the corn sown seed.

Description: CONTROL OF CORN BORERS BY 1-ARYL PYRAZOLE OR 1-HETEROARYL PYRAZOLE COMPOUNDS The present invention relates to a method of protection of maize. There is a need for protection of maize against com borers, especially those of the Pyralid moth family such as European com borer [Latin name : Ostrinia spp. e.g. Ostrinia nubilalis (hereafter referred to as European com borer)], Southwestern com borer and Lesser comstalk borer. These various com borers are creating similar problems. Com borer larvae can consume up to 40% of total plant leaf tissue, thus substantially reducing photosynthesis and subsequent yield. Consumption of ears by late-season infestations further reduces yield. European com borer also feeds by tunneling into the stalk; tunneling causes the stalk to weaken and break under stormy or windy conditions, resulting in yield losses. Furthermore, attacks are not apparent because feeding occurs unobserved in whorls and in tunnels in the stalk, therefore insecticidal treatments may be deemed unnecessary, or may be incorrectly timed so as to fail to control the larvae before they enter the whorl cluster or penetrate into the hard stalk of the plant. The hidden effects of European com borer and the difficulty of correctly timing foliar insecticide applications create a need to have a long and continuous protection of maize against European com borer in order to avoid unpredictable introduction of said European com borer in the whorl and stem of the plant. However, existing insecticides that must be applied to foliage for control of European com borer provide a duration of protection effectively no longer than one or two weeks. The difficulty in correctly timing applications could be overcome by an at-plant soil application, but this method is hardly expected to be highly effective against European com borer with moderate amount of active ingredient, due to the interval between application of product to the soil and infestation of European com borer (two to four months), and the distance from the soil to the foliage where the European com borer larvae feed (0.7 m to 2.5 m). The words "maize" and "com" are equivalent in the description and claims. The words "maize," "com," "com plants," and "com seed" comprise all the states of development and parts of the plant, including seed, leaves, stalks and the com ears and kernels. It is known that com plants may protected by some heterocyclic insecticides such as those described in patent applications WO 87/3781, 93/6089, 94/21606 as well as in European patent application 295117. An object of the instant invention is to provide an effective method of treatment of com against European com borer despite all the existing bias against such a method. Another object of the instant invention is to provide a highly effective method of treatment of com against European com borer. Another object of the instant invention is to provide a method of treatment of com against European com borer which is effective during a long period of time. These and other objects will better appear during the description of the invention. It has now been found that the object can be fitted and met by mean of the instant invention. The invention is now directed to a method of control of com borers (such as European com borer) attacking or susceptible to attack or expected to attack com plants, as well as a method of protection of com plants against com borers (such as European com borer), whereby an effective amount of a 1 -aryl pyrazole insecticidally active ingredient is applied on, near or around the previously planted com seed. The invention is also directed to a method to reduce and/or prevent tunnels formation in com stalks, whereby an effective amount of a 1-aryl pyrazole insecticidally active ingredient is applied on, near or around the previously planted com seed. The invention is still further directed to a method of control of com borers (such as European com borer) attacking or susceptible to attack or expected to attack grown com plants, as well as a method of protection of grown com plants against com borers (such as European com borer), whereby an effective amount of a 1-aryl pyrazole insecticidally active ingredient is applied near the com sown seed at the time of sowing. The 1-arylpyrazole compounds which can be used according to the instant invention are compounds of formula (I) : (I) wherein: Rj is CN or methyl; R 2 is S(O) n R 3 ; R3 is alkyl or haloalkyl; R4 is selected from the group comprising a hydrogen atom, a halogen atom, and a radical which may be -NR5R6, C(O)ORy, -S(O) m R7, alkyl, haloalkyl, -ORg, or -N=C(R 9 )(R 10 ); R5 and R6 are independently selected from a hydrogen atom, alkyl, haloalkyl, - C(O)alkyl, -S(O) r CF3; or R5 and Rg form together a divalent radical which may be interrupted by one or more heteroatoms; R7 is selected from alkyl or haloalkyl; Rg is selected from alkyl, haloalkyl or the hydrogen atom; R9 is selected from the hydrogen atom and alkyl; RjO selected from phenyl or heteroaryl that is optionally substituted by one or more hydroxy, a halogen atom, -O-alkyl, -S-alkyl, cya o, or alkyl or combinations thereof; X is selected from the Nitrogen atom and the radical C-Rj2 . R\ i and Ri 2 are independently selected from a halogen atom or the hydrogen atom; Rl3 is selected from a halogen atom, haloalkyl, haloalkoxy, -S(0)qCF3, -SF5; m,n,q,r are independently selected from 0,1, and 2; provided that when R\ is methyl, R3 is haloalkyl, R4 is NH2, Ri 1 is Cl, R13 is CF3, and X is N. The proviso in Claim 1 is included for reasons of biological efficacy. The alkyl and alkoxy groups of the formula (I) are preferably lower alkyl and alkoxy groups, that is, radicals having one to four carbon atoms. The haloalkyl and haloalkoxy groups likewise preferably have one to four carbon atoms. The haloalkyl and haloalkoxy groups can bear one or more halogen atoms; preferred groups of this type include -CF3 and -OCF3. A preferred group of 1-aryl pyrazoles for use in the present invention are those of formula (I) wherein: R\ is CN; and/or R4 is -NR5R ; and/or R5 and Rg are independently selected from the hydrogen atom, alkyl, haloalkyl, -C(O)alkyl, C(O)OR 7 ; and/or X is C-R12, and/or Rl3 is selected from a halogen atom, haloalkyl, haloalkoxy, or -SF5. A particularly preferred group of 1-aryl pyrazoles for use in the present invention are those of formula (I) wherein: Ri is CN; R4 is -NR5R6; R5 and Rβ are independently selected from the hydrogen atom, alkyl, haloalkyl, -C(O)alkyl, C(O)OR 7 ; X is C-R12; Rl3 is selected from a halogen atom, haloalkyl, haloalkoxy, or -SF5. Specific pyrazole derivatives usable in the method for controlling European com borer falling within the scope of the present invention include 5-amino-3-cyano- 1 -(2,6-dichloro-4-trifluoromethylphenyl)-4- trifluoromethylsulfinylpyrazole. This especially preferred insecticide for use in the present invention is hereafter called compound A. The preparation of compounds of formula (I) can be effected according to any process described in International Patent Publications No. WO 87/03781, WO 93/06089 and WO 94/21606, as well as in European Patent Publication numbers 0295117, 0403300, 0385809, and 0679650, German Patent Publication 19511269 and United States Patents 5,232,940 and 5,236,938. As already said, the 1-arylpyrazoles of this invention have to be applied near the sown com seed. Practically, this means that the active ingredient should be applied either on the com seed to be sown (application before sowing, optionally as a direct com seed treatment), or as a soil treatment after sowing the said com seed. The application of active ingredient to the soil at or after com seed sowing is advantageously done so as to provide on the soil a rate of active ingredient of from about 0.01 kg/ha to about 1 kg/ha of active ingredient, preferably between 0.02 and 0.3 kg/ha. Advantageously, the above-said 1-arylpyrazoles may be formulated as flowable compositions, wettable powders, microemulsions and the like, all of which lend themselves to soil, water and/or foliage application and provide the requisite plant protection. Such formulations include the compounds of the invention admixed with inert, agronomically-acceptable solid or liquid diluents. The preferred formulations for soil applications are granules or liquids. A description of possible formulations may be found in patent applications WO 87/3781, 93/6089, 94/21606 as well as in European patent application 295117. For example, wettable powders, dusts and dust concentrate formulations of the active ingredient of the invention can be prepared by grinding together an 1-arylpyrazole compound of formula (I), with about 1% to 20% by weight of a solid anionic surfactant. One suitable anionic surfactant is a dioctyl ester of sodium sulfosuccinic acid. About 85% to 99%, by weight, of an inert solid diluent, such as montmorillonite, attapulgite, chalk, talc, kaolin, diatomaceous earth, limestone, silicates or the like is also included in such formulations, as well as other adjuvants as previously indicated. As already said, the 1-arylpyrazoles of this invention may also be effective for controlling European com borer when applied to the com before sowing. The com may be treated, especially by coating or embedding or impregnation or soaking or dipping in liquid or paste formulations which are known per se and are subsequently dried. Com comprising 2 to 1000 gram per quintal, preferably 5 to 800 g/q are particularly appropriate. The invention is especially advantageous because of the long treatment it provides. Protection for a duration corresponding to a growth of about 2 to 3 meters of the stem of the com plant may be obtained according to the invention. The following examples are presented as illustrations of the present invention. EXAMPLE 1 Com was sown in 3.5 1. pots, and grown in a greenhouse. Compounds A granules (1.5 % w/w) were applied on the soil surface at sowing time at a rate equivalent to 120 g/ha of active ingredient. European com borer egg masses were pinned to the foliage 3 to 4 weeks after plant emergence. Numbers of tunnels in stalks caused by European com borer larvae were counted 4 to 5 weeks after infestation (plants were then higher than 2 m.). Untreated controls, and plants treated with Terbufos (1120 g ha) and Imidacloprid (500 g/ha) granules averaged 5.3, 5.5, and 5.6 tunnels/stalk, respectively. Plants treated with compound A averaged 0.4 tunnel/stalk. EXAMPLE 2 Com seeds were treated with compound A at a rate of 500 g. of compound A per quintal of seed. The experiment was then done as described in Example 1. Plants had at the end an average of 1.3 tunnel/stalk. Untreated plants had an average of 4.1 tunnel/stalk. EXAMPLE 3 Com seed was treated with compound A at a rate of 500 g per quintal of seed. The seed was then planted, allowed to grow and after 90 days, assessed for damage against European com borer. Untreated controls averaged 20.3 tunnels/10 stalks, with 72.5% of stalks damaged. Plants grown from seed treated with Compound A averaged 6.5 tunnels/10 stalks (68% control) with 32.5% of stalks damaged. EXAMPLE 4 Com was sown in a field and allowed to grow. Compound A granules were applied on the soil surface at sowing time at a rate equivalent to 120 g AI/Ha of active ingredient both as an in-furrow treatment and as a banded treatment on a portion of the plants. All plants were infested 48 days after planting with European com borer eggs at a rate of 50 to 100 eggs per plant. Samples were removed and inspected at 77 days after planting for the numbers of tunnels per ten plants and the percentage of infested plants. Data are presented in Table 1. The percentage (%) control is calculated as: % control = [(% untreated plants that are infested) - (% treated plants that are infested )]/(% untreated plants that are infested) Table 1 Tunnels per 10 % Plant Treatment stalks infested % Control Compound A-banded 1.0 8 82 Compound A-furrow 1.5 15 67 Untreated control 8.5 45 - EXAMPLE 5 Com was sown in a field and allowed to grow. Compound A granules were applied on the soil surface at sowing time at a rate equivalent to 120 g AI/Ha of active ingredient both as an in-furrow treatment and as a banded treatment on a portion of the plants. All plants were infested 74 days after planting with European com borer eggs at a rate of 50 to 100 eggs per plant. Samples were removed and inspected at 103 days after planting for the numbers of tunnels per ten plants and the percentage of infested plants. The percentage (%) control is calculated as in EXAMPLE 4. Results are in Table 2 Table 2 Tunnels per 10 % Plant Treatment stalks infested % Control Compound A-banded 0.3 3 96 Compound A-furrow 2.5 18 75 Untreated control 9.8 73 - EXAMPLE 6 Com was sown in a field and allowed to grow. Compound A granules were applied on the soil surface at sowing time at a rate equivalent to 120 g AI/Ha of active ingredient both as an in-furrow treatment and as a banded treatment on a portion of the plants. All plants were infested 91 days after planting with European com borer eggs at a rate of 50 to 100 eggs per plant. Samples were removed and inspected at 127 days after planting for the numbers of tunnels per ten plants. Untreated plants averaged 4.3 tunnels/10 ear shanks. Plants treated with Compound A banded and in-furrow averaged 2.8 and 2.3 tunnels/ 10 ear shanks respectively.

Claims: What is claimed is: 1. A method of control of com borers attacking or susceptible to attack or expected to attack com plants comprising applying on, near or around previously planted com seed an effective amount of a compound having the formula: wherein: R\ is CN or methyl; R 2 is S(O) n R 3 ; R3 is alkyl or haloalkyl; R4 is selected from the group comprising a hydrogen atom, a halogen atom, and a radical which may be -NRsRg, C(O)OR7, -S(O) m R7, alkyl, haloalkyl, -ORg, or -N=C(R 9 )(Rιo); R5 and Rg are independently selected from a hydrogen atom, alkyl, haloalkyl, - C(O)alkyl, -S(O) r CF3; or R5 and Rg form together a divalent radical which may be interrupted by one or more heteroatoms; R7 is selected from alkyl or haloalkyl; Rg is selected from alkyl, haloalkyl or the hydrogen atom; R9 is selected from the hydrogen atom and alkyl; RlO selected from phenyl or heteroaryl that is optionally substituted by one or more hydroxy, a halogen atom, -O-alkyl, -S-alkyl, cyano, or alkyl or combinations thereof; X is selected from the Nitrogen atom and the radical C-R12; R\ \ and Rj2 are independently selected from a halogen atom or the hydrogen atom; Rj3 is selected from a halogen atom, haloalkyl, haloalkoxy, -S(0)qCF3, -SF5; m,n,q,r are independently selected from 0,1, and 2; provided that when R\ is methyl, R3 is haloalkyl, R4 is NH2, Ri 1 is Cl, R13 is CF 3 , and X is N. 2. A method of protection of com plants against com borer, comprising applying on, near or around previously planted com seed an effective amount of a compound of formula: (I) wherein the substituents are defined as in Claim 1. 3. A method according to claim 1 of reducing and/or preventing tunnel formation in com stalks comprising applying on, near or around previously planted com seed an effective amount of a compound of formula (I)- 4. A method according to any one of the foregoing claims comprising applying a compound of formula (I) at the time of sowing the said com seed. 5. A method according to any one of the foregoing claims comprising applying a compound of formula (I) as a soil treatment after sowing the said com seed. 6. A method of protection of com plants against com borer according to claim 1 which comprises applying a compound of formula (I) on the said com seed before sowing. 7. A method according to any one of the foregoing claims whereby the com borer is Ostrinia nubilalis. 8. A method according to any one of the foregoing claims wherein: R\ is CN; and/or R4 is -NRsRg; and/or R5 and Rg are independently selected from the hydrogen atom, alkyl, haloalkyl, -C(O)alkyl, C(O)OR 7 ; and/or X is C-R12. and/or Rj3 is selected from a halogen atom, haloalkyl, haloalkoxy, or -SF5. 9. A method according to any one of the foregoing claims wherein: Rl is CN; R4 is -NRsRg; R5 and Rg are independently selected from the hydrogen atom, alkyl, haloalkyl, -C(O)alkyl, C(O)OR 7 ; X is C-Rι 2 ; Rj3 is selected from a halogen atom, haloalkyl, haloalkoxy, or -SF5. 10. A method according to any one of the foregoing claims wherein the compound of formula (I) is 5-amino-3-cyano-l-(2,6-dichloro-4- trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole. 11. A method according to any one of the foregoing claims wherein the active ingredient is applied so as to provide on the soil a rate of active ingredient of from about 0.01 kg/ha to about 1 kg/ha. 12. A method according to any one of the foregoing claims wherein the active ingredient is applied so as to provide on the soil a rate of active ingredient between 0.02 and 0.3 kg/ha. 13. A method according to any one of the foregoing claims wherein the active ingredient is applied so as to provide com seed comprising 2 to 1000 gram per quintal of active ingredient. 14. A method according to any one of the foregoing claims wherein the active ingredient is applied so as to provide com seed comprising 5 to 800 g/q of active ingredient. 15. Compositions which are to be used in a method according to any one of the foregoing claims which comprise 0.0001 to 95 % by weight of an active ingredient of formula (I) as defined in said foregoing claims.

Inventors: HAMON NICHOLAS MARK, MILES VERNON L, PILATO MICHAEL THOMAS, ROYALTY REED NATHAN, HAMON, NICHOLAS, MARK, MILES, VERNON, L., PILATO, MICHAEL, THOMAS, ROYALTY, REED, NATHAN
Applicants: HAMON NICHOLAS MARK, MILES VERNON L, PILATO MICHAEL THOMAS, RHONE POULENC AGROCHIMIE, ROYALTY REED NATHAN, HAMON, NICHOLAS, MARK, MILES, VERNON, L., PILATO, MICHAEL, THOMAS, RHONE-POULENC AGROCHIMIE, ROYALTY, REED, NATHAN
Application year: 1996
Main classification: A01N47
IPC codes: A01N43, A01N47