FR2648674A1 - PROCESS FOR INHIBITING GERMINATION OF POTATOES - Google Patents

Abstract

The present invention relates to the use of carbetamide to inhibit the germination of potatoes, for example during storage.

Description

The object of the present invention is the limitation

  tion and inhibition of the germination of potatoes and, more specifically, the chemical inhibition of this

  germination by application of carbetamide.

  Carbetamide is the compound of formula:

C6H5-NH-COO-CH (CH3) -CO-NH-C2H5

  It is also known as

  D-N-ethyl-lactamide or N-phenyl-1- phenylcarbamate

  (ethylcarbamoyl) ethylcarbamate (D isomer).

  0 Potatoes (Solanum tuberosum) may be subjected to extended storage periods between harvest and consumption. During these periods, the harvested crop tends to germinate. This germination results in a certain rotting, which it is desirable to avoid. A number of chemical agents are known

  which inhibit this germination (e.g. chlorpropha-

  me, prophame, tecnazène>, but all these agents have various drawbacks. Carbetamide has now been found to be an effective inhibitor of germination, which further reduces moisture loss and maintains turgor and has several advantages by

  in relation to the substances currently used.

  In addition to inhibiting germination during storage, it has also been found that carbetamide can be used to delay the germination of these potatoes before planting, with release taking place

after planting.

  Inhibition of germination means a reduction in the number of sprouts per tuber and / or a reduction in the average length of the sprouts. Consequently, the present invention provides a method for inhibiting the germination of potatoes which consists in applying to these potatoes a quantity of carbetamide sufficient to inhibit the germination of

these potatoes.

  Carbetamide can be applied, for example, before or during storage to inhibit the germination of stored potatoes. Carbetamide is preferably applied at the time of, or after, the usual storage period, after lifting the crop and before storage. Preferably, the tubers should not be washed before treatment (although washing in water at carefully adjusted temperatures is achievable). 24 Carbetamide is a known selective herbicide which has been widely used in the cultivation of fodder, cruciferous vegetables or cultivated for their seeds, vegetables and other very diverse crops. It is also used to control weeds

  in fallows, orchards, vineyards and nurseries

  res. Carbetamide also has plant growth regulating activity and can be used as an effective greedy inhibitor in tobacco plants where it blocks or inhibits bud growth

  axillary by modification of meristematic activity.

  However, the mode of action of the present invention is different, all germination being inhibited in an already harvested crop while, in tobacco, the main action is the selective inhibition of the growth of particular buds (c is to say no

  terminals) in the growing plant.

  The process of the present invention for the treatment of potatoes can use any of the known compositions of carbetamide. Compositions suitable for use in the process of the present invention include carbetamide in combination with a diluent or carrier. These compositions can be prepared in the form, for example, of wettable powders, dusting powders, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols, and generally comprise 1 to% by weight of substance active; other ingredients which may be present include surfactants and other acceptable adjuvants such as absorbents, binders, penetrating agents, stabilizers and other active ingredients, for example fungicides and insecticides. The term "support" denotes an organic or inorganic, natural or synthetic material, to which the carbetamide is mixed in order to facilitate its application, its transport, its handling or its adhesion to the potato. Support can be solid

  (for example a natural or synthetic clay or silicate

  ) or fluid (e.g. water or organic solvents

  ques, comprising ketones such as acetone, acetophenone, and cyclic ketones such as cyclohexanone; dimethylformamide; lower alkanols such as methanol or denatured ethanol; chlorinated hydrocarbons, such as methylene chloride; aromatic solvents, such as toluene and xylene; and petroleum fractions). The preferred solid supports are soluble in water and of food grade such as for example polyvinyl alcohol (PVA)

and sugar products.

  The surfactant can be an emulsifying, dispersing or wetting agent and can be ionic or non-ionic. Suitable emulsifiers include

  cationic, anionic, nonionic or zwit-

  commonly used terionics such as, for example,

  the salts of polyacrylic acids, of lignosulfonic acids

  ques, and the condensation products of ethylene oxide

  with fatty alcohols, acids and amines.

  Other adjuvants which can be incorporated into the composition for simultaneous application are fungicides and insecticides. Examples of fungicides that can be applied with carbetamide are

imazalil and iprodione.

  It is preferred to apply the carbetamide in the form of a dispersion in or on liquid or solid media, conventionally at concentrations of 0.01% to 80%,

  for example from 0.5% to 50% by weight.

  Carbetamide is soluble in water in the proportion of about 3.5 g / liter. In 2t liquid media, the carbetamide is therefore preferably applied in the form of an emulsified dispersion in water by emulsification of a concentrated solution in a suitable solvent. Carbetamide can also be applied as an aqueous suspension formed from a wettable powder. The solvents, the active agent and the surfactants are prepared in the form of emulsifiable concentrates which are then diluted with water, before

  application, at the appropriate concentration. Compounds

  Concentrated liquids are preferred for preparation.

  tion of dispersions intended to be applied by spraying. However, these concentrates can be

  modified for the application of dispersions via the

  medium of aerosols, nebulisates or mists. These

  modification techniques are well known.

  Liquid carbetamide formulations can be applied by manual methods such as manual spraying, use of spray tanks, soaking, etc., but, in large-scale operations, a conventional apparatus (e.g., apparatus mounted on roller tables) can be used. Liquids can also be dispensed by

nebulizers.

  Carbetamide can also be applied in solid form, that is to say by means of wettable powders, powders for dusting or granules. These powders or granules are applied by dusting or dispersing the solid materials, in the required quantities, on the stored culture to be treated, for example by means of dispersing powder granules. Wettable powders or granules are

  preferred for the application of solid agents.

  The concentrated compositions, in the liquid, solid or semi-solid state, are diluted before application to guarantee a uniform distribution. The degree of dilution required depends on the mode of application. When carbetamide is sprayed in liquid form via an aqueous dispersion or suspension, the concentration of active ingredient may be in the range of

  0.01 to 80%, for example 4.5 to 50% by weight.

  Wettable powders comprising about 65% by weight of carbetamide are preferred, as are solutions of carbetamide comprising 100 to 300 g / l of carbetamide. Solid compositions are used for

  administer an approximate active ingredient concentration

  identical to that of liquid compositions.

  As mentioned above, carbetamide is compatible with other active substances, such as fungicides and insecticides, and it can therefore be applied to crops stored in association with these active substances. This app can be done

  separately, sequentially or simultaneously.

  The amount of carbetamide applied generally ranges from 17 to 200 g of i.a. (active ingredient) / tonne

potatoes.

  In the temporary inhibition of germination of seed potatoes after planting, an amount of 17 to 50 g of a.i./tonne is preferably

  used. Carbetamide is considered to be subject to-

  degradation in the soil: the higher the amount of

  betamide used is strong, the longer the delay in germination

is important.

  In the inhibition of the germination of stored potatoes, an amount of 17 to 200 g of a.i./tonne is advantageously used, preferably

70 g a.i./tonne.

  In general, the lower the temperature, the lower the amount of carbetamide required to inhibit germination. The amount of carbetamide required may also vary depending on the variety of potato, some varieties being more likely to germinate

that others.

  By way of example, the following compositions can be used in the process according to

present invention.

  Wettable powders (percentage by weight) carbetamide 70 50 nonylphenol oxyethyl-17 (wetting agent) 2 2 polycarboxylate (dispersing agent) 2 2 silica (support) 26 25 calcium carbonate (support) 0 21 Emulsifiable carbetamide concentrate 300 g acetophenone (support) 180 g nonylphenyl oxyethyl-7 (wetting agent) 200 g cyclohexanone (support) qs per 1000 cm3 Carbetamide has an acute LD50 in rats equal to 11000 mg / kg of body weight of the animal and is practically devoid of chronic toxicity . Topical applications in the rabbit eye (5 mg) and rabbit skin (5% cream) also demonstrate

the absence of irritant effects.

  Thus, carbetamide is less toxic or irritating to mammalian species than the germination inhibitors previously used and is safer to use for an inexperienced worker. In addition, in the absence of significant toxicity, the residues

  present on the tubers present a significant danger-

  inferior to the health and environment of

  preparers and end consumers.

  Carbetamide also causes less deterioration of the treated tubers, making these

  latter more acceptable for consumption.

  In addition, carbetamide is much less volatile than the germination inhibitors currently used. This therefore allows treatment selectivity and avoids cross contamination, the zone of effectiveness of a treatment not extending. As a result, there is no need to separate treated tubers from untreated tubers or other stored crops, or use complex separation procedures during processing, as required with the inhibitors currently in use. . The very weak

  volatility also avoids any risk of exposure

  steamers for warehouse workers

potatoes.

  Treatment according to the present invention

  also results in weight loss not greater than

  lower than those of conventional treatments.

  The following example illustrates the use of

  carbetamide according to the present invention.

EXAMPLE

  Four varieties of potato were treated with different amounts of a wettable powder

  containing 65% w / w carbetamide. Degree.

  inhibition of germination was determined, by comparison with untreated potatoes, after three months of storage. The results were as follows:

  Variety of pcome Inhibition application rate (for-

  of land caposition (g / ton) centering) after 3 months 5 months Squire 50 69 99

96 99

99 99

300 99 99

Romano 50 * 75

100 * 93

* 96

300 * 97

Desiree 50 71 98

/ Z 100 97 98

99 99

300 100 99

Cara 50 88 87 0loo 98 98

150 100 99

300 100 99

  * Variety with late germination In comparative experiments, a similar test was carried out, except that the treatment was carried out with BYGRAN S (a commercial composition based on tecnazene) at a rate of 1300 g / ton. The results were as follows: Apple variety Inhibition (percentage) of earth after 3 months 5 months Squire 78 92 Romano * 75 Desiree 93 83 Cara 85 82 The weight losses of the potatoes subjected to the various treatments were also measured. . evaluated and compared with those resulting from conventional treatment and those of untreated controls. The average values for all the varieties of potatoes tested are as follows: Treatment Weight loss (%) after 3 months 5 months None (control) 1.8 3.3 Carbetamide 50 g / ton 1.4 2, 8 g / ton 1.5 2.8 "150 g / ton 1.3 '2.2" 2 g 300 g / ton 1.5 2.3 Bygran S 1300 g / ton 1.9 3.5 l1

Claims (10)

  1. A method for inhibiting the germination of potatoes, characterized in that it consists in applying to it a quantity of carbetamide sufficient to inhibit germination. 2. Method according to claim 1, characterized in that the carbetamide is applied before or during storage to inhibit germination during of storage.   3. Method according to claim 1 or 2, characterized in that the carbetamide is applied after a certain storage time depending on the removal of the potatoes.   4. Method according to claim 1, 2 or 3, characterized in that the potatoes are not   washed before application of carbetamide.   5. Method according to any one of   previous claims, characterized in that the   amount of carbetamide is in the range of   2'0 17 to 200 g / tonne of potatoes.   6. Method according to claim 5, characterized in that the amount of carbetamide is in the range from 30 to 70 g / ton of potatoes. 7. Procedure according to any one of   previous claims, characterized in that the   carbetamide is applied by spraying a dispersion   or an aqueous suspension of carbetamide.   8. Method according to claim 1, characterized in that the carbetamide is applied to potatoes before planting in order to delay germination. 9. The method of claim 1 or 8, characterized in that the amount of carbetamide is in the range of 17 to 50 g / tonne of potatoes. 10. Composition characterized in that it comprises carbetamide and a diluent or carrier acceptable for use in inhibiting the germination of potatoes.