FR2765774A1 - USE OF BENZYLURACILS FOR CONTROLLING WEEDS IN CEREAL CROPS - Google Patents

Abstract

The present invention relates to a method for controlling Papaver, Matricaria, Viola and / or Polygonum weeds in cereal crops, which comprises the step of applying, to the site where it is desired to control the weeds, of a herbicidally effective amount of a composition comprising a benzyluracil of the formula: (CF DRAWING IN BOPI) wherein V is chlorine; W is chlorine or the methoxy radical; X is hydrogen; Y is chlorine or the methoxy radical; and R is methyl or amino. Preferred benzyluracils are those for which R is the methyl radical.

Description

USE OF BENZYLURACILES FOR CONTROLLING

  WEEDS IN CEREAL CROPS

  Field of the Invention The present invention relates generally to a method for controlling the growth of

  unwanted plants in cereal crops.

  More particularly, the invention relates to a method for controlling weeds Papaver, Matricaria, Viola and / or Polygonum in cereal crops by application of a compound chosen from certain substituted benzyluracils on the site where weed control is desired. . In particular, the invention relates to a method for controlling these weeds by application to the

  benzyluracil 3- site (2,5-dichloro-3-

  methoxyphenylmethyl) -6-trifluoromethyl-2,4-

  (1H, 3H) 1-substituted or 3- (2,3-dichloro-) pyrimidinedione

  5-methoxyphenylmethyl) -6-trifluoromethyl-2,4-

  (1H, 3H) 1-substituted pyrimidinedione o the substituent in position 1 is a methyl or amino radical. Benzyluracils unexpectedly control weeds of each genus at use doses that are not harmful to

  cereal crops such as wheat.

  Certain herbicides are known to exercise their herbicidal activity by inhibiting the enzyme

  protoporphyrinogen oxidase, also called "PPO".

  PPO is an enzyme necessary for the synthesis of porphyrin in the pathway of chlorophyll biosynthesis in plants. In susceptible plant species, inhibition of PPO eventually disrupts the cell membrane and causes desiccation. As a class of herbicides, PPO inhibitors have been shown to be very

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  effective in controlling the Galium and Veronica weed species, but have generally not been shown to control other weeds that are commonly found in cereals such as Papaver, Matricaria, Viola and Polygonum. The high use rates that are normally required for PPO inhibitors to control these weeds usually cause unacceptable damage to the grain crop you wish to protect. This activity and selectivity profile of PPO inhibitors is generally indicated by way of example by carfentrazone-ethyl from

  FMC, which is described in US Patent No. 5,125,958.

o CHF2

F U-N

  N'N CI CO2And carfentrazone-ethyl More recently, US Patent No. 5,391,541 indicated the herbicidal efficacy of certain benzyluracils which are also inhibitors of PPO. These compounds are represented by formula I:

V O

W N / NNJN 'CH3

X X CF3

  y U.S. Patent No. 5,391,541 indicates that the compounds of formula I are useful against a variety of species

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  weeds that appear in cereal crops, but it does not describe anything about the use of the weed compounds Papaver, Matricaria, Viola or Polygonum. Surprisingly, we have now found that certain benzyluracils can be effectively used to control the weeds Papaver, Matricaria, Viola and / or Polygonum in cereal crops such as wheat, barley, oats and rye. These benzyluracils have been shown to be selective in controlling weeds of each genus at use doses which cause relatively little damage to the grain crop that is to be protected. SUMMARY OF THE INVENTION An effective method has now been found for controlling the Papaver, Matricaria, Viola and / or Polygonum weeds in cereal crops, by applying certain benzyluracils to the site where it is desired to control the weeds. Benzyluracils are represented by formula II

presented below.

  Detailed description of the invention

  This invention relates to a method for controlling Papaver, Matricaria, Viola and / or Polygonum weeds in cereal crops, which comprises the step of applying, on the site where it is desired to control weeds, a effective amount, from a herbicidal point of view, of a composition comprising a benzyluracil of formula:

SR 15237 US / MDT

V 0

N N '

X O CF 3

  Y y II in which V is chlorine; W is chlorine or the methoxy radical; X is hydrogen; Y is chlorine or the methoxy radical; and R is the methyl or amino radical, in admixture with an agricultural acceptable vehicle. Preferred benzyluracils are those for which R is the methyl radical. More preferred benzyluracils are those for which (a) V and Y are chlorine, W is the methoxy radical, and R is the methyl radical; and (b) V and W are chlorine, Y is

  the methoxy radical, and R is the methyl radical.

  The method of this invention is useful for controlling the Papaver, Matricaria, Viola and / or Polygonum weeds. Some species of these weeds are also known by the names

following common and abbreviations.

  Common name Species name Abbreviation Field violet Viola arvensis Vioar Maritime matrix Matricaria maritima Matma Odorless matrix Matricaria inodora Morning Knotweed Polygonum convolvulus Polco Kochia Kochia scoparia Kchsc Poppy J Papaver rhoeas Paprh

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  Table 1 below presents the

  benzyluracils of the present process.

Table 1 Benzyluracils

V O

N N'R

Y y

N_ V W X Y R

1 CI CI H OCH3 CH3

2 CI OCH3 H CI CH3

3 CI CI H OCH3 NH2

  4 ci OCH3 H CI NH2 Benzyluracils can be prepared in the manner described in US Pat. No. 5,391,541 (where R is the methyl radical) or in the manner described in the international patent application bearing the number of

  publication WO 97 / 01.543 (where R is the amino radical).

  Herbicidal compositions are prepared by combining herbicidally effective amounts of benzyluracils with adjuvants and vehicles normally employed in the art to facilitate the dispersion of the active ingredients for the desired particular use, recognizing that the formulation and the mode of application of the herbicide may affect its activity in a given application. Useful formulations include, but are not limited to, granules, emulsifiable concentrates, emulsifiable fluid powders, solutions, dispersions, powders

  wettables, suspensions and suspension concentrates.

  In the test of the present process, a 5% suspension concentrate (CS) (50 g of benzyluracil / liter) is used, indicated in the

Table 2.

  Table 2 CS formulation Component% w / w Active ingredient (99%) 5.05 Antimicrobial agent 0.05 Antifoaming agent 0.10 Emulsifier 2.60 Wetting agent 0.40 Thickening agent 1 0.45 Thickening agent 2 0, 35 Propyleene glycol 6.00 Water 85.0 The present method can generally be used to control Papaver, Matricaria, Viola and / or Polygonum weeds in cereal crops which are not significantly damaged at the use rates which are effective against weeds. We can also use the process to control Veronica species such as

  Veronica persica (speedwell), from Galium spp.

  such as Galium aparine (skyscraper), from Kochia spp.

  such as Kochia scoparia, and Sinapis spp. such as Sinapis arvensis (wild mustard). Cereal crops which can be treated in accordance with this process include, but are not limited to, wheat, barley, oats and rye. It should be noted that to achieve selective weed control in barley, it is best not to use a

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  nonionic surfactant as an adjuvant in the

herbicide composition.

  The amount of benzyluracil that is needed to be effective, from a herbicidal standpoint, for a given weed will vary depending on the formulation, application method and variations in field conditions. In general, a herbicidally effective amount of benzyluracil is in the range of about 20 to 120 grams per hectare (g / ha). We prefer a quantity

  benzyluracil 40 to 70 grams per hectare.

  Trial We evaluate herbicidal formulations against weed species which are grassy and broadleaf weeds found in cereal crops in North America and Europe. 1. Planting Cereal and weed species are planted in standard 10.16 cm (4 inch) plastic pots containing approximately 550 ml of pasteurized sieved potting soil which contains 1.2% organic matter and has a pH of 6, and they are covered with approximately 1 cm of a 1/1 mixture by volume of soil and sand. Table 3 shows the treatment scheme for cultivated species and weeds, which includes the quantity of seeds (cm3) and the interval between planting and chemical applications ("interval"). Both quantity and interval can be adjusted based on batch quality

of seeds.

  Table 3 Plant species and treatment scheme Seeds Interval Common name Scientific name (crn3) (weeks) Barley Hordeum vulgare 1.0 2 Wheat Triticum aestivum 0.7 2 Wild oats Avena fatua 10 2 seeds Chickweed Stellana media 0.15 3 Field violet Viola arvensis 2.2 4 Odorless matrix Matricaria inodora 0.7 3 Knotweed Polygonum convolvulus 0.5 3 Wild mustard Sinapis arvensis 0.3 2 The seeds are measured using a graduated powder measure or counting the number of seeds. About 90 pots of each species are planted to allow replication and untreated controls. Then the pots are placed in a greenhouse set at 20/15 C (day / night temperature) with a day / night diurnal cycle

from 14/8 hours.

  2. Dilution The benzyluracils, used as technical chemicals, are diluted in a 1/1 base of acetone and water with 0.25% by volume of Tween 20. The appropriate quantity of technical product is dissolved first in ml of acetone / Tween and then 80 ml of water / Tween 20 are added. The samples are diluted successively by removing an 80 ml aliquot and adding 80 ml of base to reach the dose.

desired application.

  3. Application Each of the plant species is placed in two separate plastic trays, 21 x 12 inches (53.34 x 30.48 cm). The two trays are placed on a moving belt sprayer which has been calibrated to deliver 1000 l of spray / ha. The sprayer is equipped with a TeeJet 8004E SS nozzle, a mesh screen, and a pattern control assembly. The spray pressure is 40 psi. The nozzle height is adjusted to a minimum height of 26.67 cm

  (10.5 inches) above the weed ridge.

  Benzyluracils, formulated as described above, are sprayed successively from the high dose to the low dose. For each new chemical sample, the body of the sprayer is rinsed three times, twice with acetone and once with

the water.

  4. Experimental configuration The treatments are arranged according to a configuration in divided plots, the main plot concerning the chemical and the secondary plots concerning the doses. Crop and weed species are placed on greenhouse carts depending on the chemical used. The species are aligned in column with the untreated controls at the rear of the cart. Plant foliage is not wetted for about 24

  hours after applying the chemicals.

  Then we wet the plants according to what is

  necessary for optimal growth.

  5. Crop tolerance and efficacy The effect on crop and weed species is assessed visually using a scale from 0 to 100., where O% indicates that there is no reduction in biomass green and 100% indicates a total reduction in biomass or complete destruction. Crops are evaluated 7 and 21 days after treatment (JAT), while weeds are not evaluated until 21 JAT. Table 4 shows the comparative greenhouse trials of benzyluracils selected jointly with carfentrazone-ethyl. For the greenhouse test, benzyluracils are used as technical material.

  In the table, carfentrazone-ethyl is identified by "carf" and the compounds bearing the numbers "1" and 1 "2" are as described in Table 1.

  1i Table 4 Benzyluracil herbicide activity on weeds in greenhouses% compared to the control Compound N Dose, g / ha TRIAE 'MORNING VIOAR POL CO Carf 4 15 5 70 55 i1 4 20 15 98 85

2 4 5 20 88 70

Carf 8 30 20 50 63

1 8 33 33 96 99

2 8 12 43 97 84

Carf 16 43 23 80 83

1 16 40 48 99 99

2 16 17 50 100 93

Carf 32 55 40 84 93

1 ... 32 45 70 100 99

2 32 30 55 100 97

Carf 64 68 58 87 99

1 64 60 97 100 100

2 64 43 63 100 99

Carf 128 80 95 100 100

1,128 70 98 100 100

  2 d 128 45 98 100 98 Notes 1 The percentage compared to the control is the average of two trials for the rates of 8, 16, 32 and 64 g / ha. The percentage relative to the witness is taken

  in a single trial for the rates of 4 and 128 g / ha.

  2 Damage to wheat at 7 instead of 21 days.

  TRIAE: wheat; MORNING: odorless matrix; VIOAR:

  wild violet: POLCO: knotweed.

  The weeds Matricaria, Viola and Polygonum are represented respectively by the last three columns of Table 4. The results show the higher selectivity of benzyluracils when compared to carfentrazone-ethyl for the control of these weeds compared to damage to wheat in the greenhouse test. We observe the

  better overall selectivity with compound 2, 1-

  methyl-3- (2,5-dichloro-3-methoxyphenylmethyl) -6-

  trifluoromethyl-2,4- (1H, 3H) pyrimidinedione.

  We also compare compound 2 and carfentrazone-

  ethyl under field conditions. For the field test, carfentrazone-ethyl is formulated as 40% water dispersible granules and Compound 2 is formulated as a 5% suspension concentrate. Results of the field trial show that benzyluracils achieve significant control (> 70%) of the weeds Papaver, Matricaria and Viola at use rates of 20 to 120 g / ha, which are generally harmless to wheat . On the contrary, carfentrazone-ethyl is much less effective in controlling these weeds at the use doses for which wheat is little affected. It is obvious that various modifications can be made to the formulations and to the application of the compounds of the present invention, without departing from the inventive concepts contained therein, as defined in

the revendications.

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Claims (7)

RESELL I CATIONS   1. Method for controlling weeds Papaver, Ma tricaria, Viola and / or Polygonum in cereal crops, comprising the step of applying, on the site where we wish to control weeds, an effective amount , from a herbicidal point of view, of a composition comprising a benzyluracil of formula: V O WNff / 'N R X O 'CF3   Y in which V is chlorine; W is chlorine or the methoxy radical; X is hydrogen; Y is chlorine or the methoxy radical; and R is the methyl or amino radical, mixed with a vehicle acceptable from the point of view agricultural.   2. Method according to claim 1, where R is methyl radical.   3. Method according to claim 2, where W is   chlorine and Y is the methoxy radical.   4. Method according to claim 2, where W is   methoxy radical and Y is chlorine.   5. Method according to claim 1, o the culture is wheat.   6. Method according to claim 1, 2, 3, 4 or 5,   in which the weed is Papaver.   7. Method according to claim 1, 2, 3, 4 or 5,   in which the weed is Viola. SR 15237 US / MDT