IL30291A - Selective herbicidal compositions containing n-aryl ureas - Google Patents

Description

Selective herbicidal compositions containing ureas BAYER A 68 2 The present relates to selective herbicidal compositions for the control of weeds in cereal crops or cotton comprising as an active ingredient an aryl urea of the formula 0 in which is hydrogen or an alkyl radical with carbon atoms and alkyl radical with carbon toms preferably 1 or 2 carbon alone or in admixture with solid or liquid It is known that ureas can be used as It is further known urea and urea can be used as selective herbicides British Patent Specification 914 The ureas of formula I above exhibit strong selective herbicidal the selectivity the same or higher herbicidal is generally m than that of They can therefore be used for the control of weeds in cereal such as barley and maize and also in urea has especially good 3 The present invention is especially concerned with which grow in Examples of weeds which in cereals and which are difficult to control but which are destroyed by the active compounds used in ance with the invention include such as common mayweed speedwell deadnettle and such as silky spica and annual bluegrass The selectivity of the ureas of formula I in cereals or cotton is a genuine occurs not only when the ureas are applied according to emergence method but also when they according to the that is when the herbicide is contacted directly with the This selectivity is because quite similar compounds with similar herbicidal sho no selectivity in cereals or 4 Thus the compounds described in Patent Patent Specification Specification the general formula X in which R represents an group containing 1 to 4 carbon represents a hydrogen atom or an group containing 1 to 4 oarbon X represents an gen or sulphur atom and n is the whole 1 or in which the substltuents of the benzene ring are not in the same positions as in the compounds used in the sitions according to the present do not have such selective herbicidal The active compounds used in the compositions according to the present invention can be converted into the usual such as pastes and These 6 or ground synthetic such as silicic acid or Preferred examples of emulsifying agents include and anionic such as fatty acid alcohol for example alkylarylpolyglycol alkyl sulphonates and and preferred examples of dispersing agents include sulphite waste liquors and methyl The active compounds can he used in admixture with other active The compositions normally contain from to of the active preferably from to 90 The active compounds can be used as such or in the form of their compositions or application forms prepared for example suspensions powders pastes or They may be applied by the usual such as atomising or The ureas can be applied before the emergence of the cultivated plants as well as after their that according to the or according to the The used actual application may be varied wide in they are from to 5 of active compound per preferably from to 3 The herblcidal compositions usually contain as active in redient a com ound of a I above in admixture 7 with a solid diluent or carrier on in admixture with a liquid diluent or carrier containing a The invention also provides a method of combating in cereal crops or cotton weeds comprises applying to the weeds or a weed habitat a compound of formula I alone or in the form of a composition containing as active ingredient a compound of formula I in admixture with a solid or liquid diluent or The present invention further provides a method of providing a harvested cereal crop or harvested cotton which comprises applying a compound of formula I or a sition containing such compound to area of cultivation of the crop or cotton whereby the latter is protected from damage by and harvesting the crop or The herblcidal activity of the compositions of the invention is Illustrated by Examples Example A powder Inert carrier parts by weight kaolin and silicic acid Protective parts by weight lignin sulphate Dispersing parts by weight sulphonic acid formaldehyde condensate To produce a suitable preparation of active 1 part by weight of active compound was mixed with the stated amounts of formulation auxiliaries and the concentrate was then diluted with water to the desired Outdoor plots with test plants which had a height of about cm were sprayed with such an amount of the re aration of active com ound that a uniform wettin of the 7a plants The amount of active compound applied per unit area is After three weeks the degree of damage to the plants was determined and characterised by the values which have the following 0 no effect 1 a few slightly burnt spots 2 marked damage to leaves 3 some leaves and part of stalks partially dead 4 plant partially destroyed 5 plant completely The active the amounts used and the results can be seen from the following Tables 1 and Example B powder Inert carrier materia parts by weight and silicic acid 3 Protective parts weight lignin sulphate Dispersing by weight phonic acid formaldehyde condensate To produce a suitable preparation of active 1 part by weight of active compound was mixed with stated amount 0 formulation auxiliaries and the concentrate was then diluted with water to desired Shortly after sowing of the test plants the individual plots were watered with such an amount of the active as was necessary a uniform wetting 5 of the surface of the The concentration of the active pound in the is of no only the amount of active compound per unit area is After 5 the degree of to the test plants was determined and characterised by the which have the 0 following no effect slight damage or delay in growth marked damage or inhibition growth heavy damage and only deficient 5 development or only emerged 4 plants partially destroyed after germination or only emerged 5 plants completely dead or not The active the amounts used and the results can 0 be seen from the following Tables 3 and 4 Example test 5 parts weight acetone part by weight alkylaryl polyglycol ether To produce a suitable preparation of active part by weight of active compound is mixed with the stated amount the stated amount of emulsifier is trate is then diluted with water to the desired Test plants have a about sprayed the preparation of the compound just dew After three degree of damage to the plants is mined and characterised by the values which have the wing 0 no effect a slightly burnt spots 2 marked damage leaves some leaves and parts of stalks dead plant partially destroyed 5 plant completely The active their concentrations and the results obtained can be seen from the followin Table L A 10 Example D test 5 parts Weight acetone 1 part by weight alkylaryl polyglycol ether To produce a suitable preparation of active 1 part by weight of active compound is mixed with the stated amount the stated amount of emulsifier is added and the trate is then diluted with water the desired Seeds of the test plants are sown in normal soil 24 watered the preparation of the active It is expedient to keep constant the amount water unit The concentration of the active compound in the tion of no only the amount of active compound applied per unit area being After three the degree of damage the test plants is determined terised by the values which have the following 0 no effect slight damage1 in growth marked damage or inhibition of growth heavy damage and only deficient developmen or only emerged 4 plants partially after germination only 5 plants dead or not active the amounts applied and results obtained can be see from the following Table Barley C 0 0 insufficientOCRQuality

Claims (12)

1. Selective herbicldal compositions for the control of weeds in cereal crops or cotton containing as active ingredient a compound of the formula in which Is hydrogen or an alkyl radical with 1-4 carbon atoms and R2 is an alkyl radical with 1-4 carbon atoms, alone or in admixture with a solid diluent or carrier, or with a liquid diluent or carrier containing a surface-active agent.

2. Compositions according to Claim 1, wherein a compound of formula I in which R2 is 3X1 alk 1 radical of 1 or 2 carbon atoms is used as the active ingredient.

3. A composition according to Claim 1, wherein a compound of the formula is used as the active compound.

4. A composition according to Claim 1, wherein a compound of the formula 0 HH.C II-NH-CH3 - 18 - 30291/3 is used as the active compound.

5. Compositions according to any of Claims 1 to 4 containing from 0.1 to 95$ of the active compound.

6. Selective herbicidal compositions according to Claims 1 to 5 substantially as described herein with reference to the Examples.

7. A method of combating weeds in cereal crops or cotton which comprises applying to the weeds or a weed habitat a compound of formula I in Claim 1 alone or in the form of a composition according to any of Claims 1 to 6.

8. A method according to Claim 7 in which the compound is applied to an area of cereal crop cultivation or cotton cultivation in an amount of 0.1 to 5 kg, and preferably 0.5 to 3 kg per hectare.

9. A method according to Claim 8 in which the weeds are any of those hereinbefore mentioned.

10. A method according to any of Claims 7 to 9 in which the active compound is one according to any of Claims 2 to 4.

11. A method of providing a harvested cereal crop or harvested cotton which comprises applying a compound of formula I in Claim 1 alone or in the form of a composition according to Claims 1 to 6, to the area of cultivation of the cereal crop or the cotton whereby the latter is protected from damage by weeds, and harvesting the cereal crop or the cotton. - 19 - 30291/3

12. A method according to Claim 11 in which the compound is one according to any of Claims 2 to 4. PC/rb