Agricultural crops are often subjected to a variety of biotic and abiotic threats, that can be induced by weeds, pathogens, temperature, drought, light etc.. These stress factors can affect the yield and/or quality of the product.

In addition, it is generally appreciated by consumers to buy produce of high quality without stress symptoms, such as leaf yellowing, wilting, chlorosis or colour changes.

Control of weeds is an important problem in agriculture. In common agricultural practice a great variety of herbicides are used to reduce adverse effects of weeds on crop yield. The world pesticides sales in 2000 amounted to US$ 31 billion. More than half of the costs that are spend by farmers on crop protection are for weed control. These costs have an effect on the price of agricultural products.

Since herbicide applications often negatively affect the environment, governmental policies aim at reducing the use of herbicides. In several European countries policy documents have been drafted in which farmers are being forced to achieve substantial reductions in the use of herbicides.

Organic farming is of growing importance in Europe.

An organic farmer is not allowed to use any chemical herbicides. Since mechanical methods like hoeing often do not result in sufficient weed control, very expensive hand-weeding is required to solve weed problems on organic farms. Agro-economic studies have shown that the presently

required amount of hand-weeding is one of the major constraints for a further increase of organic farming in countries like the Netherlands.

An important factor to achieve reductions in the use of herbicides is the development of preventive or alternative methods for weed control. Possibilities to prevent weed germination and establishment are essential components of modern strategies for weed control or what is called"integrated weed management". Moreover, insights in the competitive relation between crop and weeds have led to the conclusion that a complete elimination of the weeds is often not necessary. Negative effects occur only above a minimum weed development. Also the crop itself can play a role in weed control, provided that the development of the crop is ahead of the growth of weeds.

Weed growth can be inhibited by establishing a top- layer on the soil or substrate that has a sufficient mechanical strength to prevent weeds from emerging. The top- layer can be either formed after emergence of the crop plants or before sowing depending on the ability of the crop plants to penetrate this layer. The formation of a top-layer inhibiting weed emergence is for example described in the international patent application WO-01/35747 of the same applicant.

WO-01/35747 discloses the use of lignosulfonates for the formation of a top-layer. However, the obtained top- layer can be further improved.

It is thus a first object of the present invention to provide a new top-layer forming composition for effectively controlling weed growth which is environmentally friendly and relatively cost-effective.

Plants are also threatened by various pathogenic micro-organisms like fungi, viruses and bacteria. To

overcome the problem of infections with these micro- organisms, large quantities of anti-microbial compounds (in particular fungicides and bactericides) are applied. Because of the lack of natural, environmentally acceptable crop protection products that are also highly efficient this results in the use of large quantities of classical synthetic anti-microbial compounds.

It is known that certain compounds of natural origin can protect the plant against pathogenic micro-organisms.

The use of these natural crop protection compounds (NCP's) is becoming more and more preferable since governments world-wide aim for a reduction in the use of synthetic anti- microbial compounds.

However, these natural crop protection compounds often have limited usefulness, because they may be phytotoxic at effective concentrations. Furthermore, some of these compounds are not stable enough due to environmental conditions in the field like temperature, pH, inactivation by other compounds in soil or substrate, and their susceptibility to sun light, especially UV-light.

Therefore, it is a further object of the invention to provide compositions comprising natural crop protection compounds, which compositions are less phytotoxic and more stable.

Another threat encountered in agriculture worldwide consists of plant-parasitic nematodes, which attack almost all crops. Damage estimates range from 5-25 % yield reduction, but 100 % losses occur locally, due to plant death or quality loss.

Nematodes are conventionally managed by crop rotation and chemical control. Crop rotation often is not an efficient tool for nematode management, due to the large

host range of some of the nematode species and the lack of resistant crops or plant varieties.

Chemical control often uses compounds that are hazardous to the environment and the user. Many effective nematicides have been banned due to these risks. A widely used and effective nematicide, methyl bromide, is banned in the USA and will be banned in the EU shortly, leaving the farmers with very little management options for solving nematode problems. Biological control could be an alternative to chemical control, but at the moment no effective commercial nematode bio-control products are available on the European or American market.

It is therefore another object of the invention to provide compositions for the control of nematodes.

Yet another problem encountered in the agricultural industry is bad quality of produced products. Examples are apples with pale colour, tomatoes and grapes with little taste, flowers without scent etc. These quality problems are often related to the very controlled and optimized conditions of production. Induction of the right level of stress at a certain time point during crop development will optimally induce the secondary metabolism related to colour, taste or scent.

Therefore, it is also an object of the present invention to provide a composition for inducing a higher quality of crop products.

In the research that lead to the present invention it was surprisingly found that the above-identified problems can be solved by compositions that comprise one or more poly- phenols and one or more other active ingredients. The use of one or more poly-phenols is the common concept of all compositions according to the invention. The other active ingredient determines the particular utility.

Examples of suitable sources of poly-phenols are lignosulfonates, humic acids, fulvic acids, and compost tea's (i. e. water extracts of compost). Lignosulfonates are particularly preferred.

Lignosulfonates are a derivative of lignin and the commercially available form thereof. Lignin is a naturally occurring component of plant cell walls (e. g. in wood), and one of nature's most plentiful and renewable resources. The lignosulfonate molecule is complex and can enter into many types of chemical reactions. This versatility allows it to be modified into a whole family of special chemicals.

Lignosulfonates are a by-product of the manufacture of paper. Because lignosulfonates are a waste product of the paper industry they are generally available and can be used in the composition at relatively low costs. In addition, lignosulfonate is a natural product and safe for agricultural use.

According to a first aspect of the present invention, compositions are provided for controlling weed growth by forming a surface layer on soil or substrate which composition comprises one or more poly-phenols and small particles of organic material as the other ingredient.

Preferably, the organic material is fibrous organic material, selected from the group consisting of saw dust, wool, cotton, rock wool, finely grinded dry plant material, such as grass, cellulose. Such organic material may have received a heat treatment to increase its resistance to microbial decay.

Because of its fibrous nature a structure is formed wherein the fibres are randomly dispersed providing a matrix of maximal strength. The second component, the poly-phenols, in particular lignosulfonates, provide the adhesion component of the randomly dispersed fibrous material thereby making the matrix resistant to environmental conditions like rain, wind,

etc. In addition, the poly-phenols provide additional mechanical strength to the matrix. Compared to known top- layers that consist solely of lignosulfonates, it is found that the combination with small particles of organic material leads to a better distribution. Moreover, the lignosulfonates are washed out to a lesser extent.

The ratio between lignosulfonates and organic material is between 1: 5 and 5: 1 by weight, preferably between 1: 4 and 4: 1, more preferably between 1: 3 and 3: 1 and even more preferably between 1: 2 and 2: 1 by weight, most preferably 1: 1 by weight. Using this ratio, a matrix is obtained with excellent mechanical strength and minimal volume.

Preferred fibrous organic material is pulverized plant material or pulverized processed plant material. The use of plant materials as fibrous material provides a generally available source of fibrous material. In addition, plant material is biodegradable providing an extra source of nutrients to the growing crop plants. The use of processed plant materials provides an additional advantage because it is a by-product of other processes used to obtain valuable compounds or extracts and thus an economically attractive source of fibrous waste material.

According to a particular embodiment of the present invention pulverized grass is used as a fibrous material.

Grass is usually readily available and because it can be obtained locally, transportation costs are generally low.

According to another embodiment saw dust is used as a fibrous material. Saw dust is a waste product of the wood industry, can easily be obtained in large quantities and can be handled in a simple manner.

Both grass and saw dust may have been heat-treated to increase the durability of the protective top-layer.

In addition to the protective function of lignosulfonates, these compounds show an allelopathic effect by inhibiting weed germination and growth while not affecting the crop. Thus, they further enhance the effectivity of the composition.

Lignosulfonate is in general complexed with Ca2+, but can also be complexed with other organic and inorganic cations.

In one embodiment of the invention, the lignosulfonate component of the composition comprises at least in part ammonium lignosulfonate and/or potassium lignosulfonate. These two cations are valuable nutrients for crop plants. Because lignosulfonate is an ion exchange material it can be used to add these nutrients to the soil by exchanging the ions with less desirable ions present in the soil or substrate. This way, nutrients can be easily added.

Since ammonium and potassium are thus slowly released from the top-layer a sustained-release formulation is provided to the growing crop plants.

Because the top-layer functions as a sustained- release matrix also other compounds can be added to the formulation which enhance the growth of crop plants like trace elements like copper, molybdenum, boron; plant nutrients, such as nitrogen, potassium, magnesium; anti- microbial agents like carvacrol, azadirachtin.

The present invention also provides a method for controlling weed growth which method comprises applying the composition to the soil or substrate in which the crop plants are or will be growing. The composition can be applied in solution. Suitable solvents are solvents such as water, ethanol, essential oils, etc.

The solution can be applied onto the soil or substrate using methods known to the person skilled in the

art, but is preferably applied by spraying. Spraying allows for an even distribution of the solution resulting in a top- layer with an evenly distributed thickness.

The top-layer can also be formed using a solid composition. The top-layer is then formed after the solid composition has been in contact with water, such as rain. The solid composition is less susceptible to biodegradation than the solution and can therefore be stored during a prolonged period of time. The solid can also be applied by hand and is lighter than the solution since it contains no solvent. This is advantageous in areas with less mechanized agriculture or in areas which are difficult to reach with machines.

Effective weed control is obtained by applying the composition according to the invention in an amount of 200, 500,1200, 190,2400, 3100 and 4000 kg/ha, thus in the range of 200-4000 kg/ha, preferably 400,700, 900,1100, and 1200 kg/ha, thus in the range of 400-1200 kg/ha, more preferably 900,950, 1050, and 1100 kg/ha, thus in the range of 900-1100 kg/ha. The According to another embodiment, the external threat is abiotic stress, such as drought, salt, heat, cold, nutrient deficiency, and the composition comprises lignosulfonates and one or more compounds that induce stress tolerance, for example selected from the group consisting of abscisic acid, chitosan, ethylene, salicylate, jasmonate, nonanoic acid.

Alternatively, the composition comprises lignosulfonates and one or more compounds that stimulate wound repair and growth, for example selected from the group consisting of cytokinins, gibberellins, brassinosteroids, auxins.

It is also possible to combine the lignosulfonates with one or more compounds that induce stress tolerance as

defined above and one or more compounds that induce wound repair and growth as defined above.

Also part of the invention is the use of lignosulfonates alone, i. e. without other active ingredients, to induce stress tolerance. Additional compounds may further increase the stress tolerance and are therefore preferred but are not essential for inducing stress tolerance.

According to a further aspect of the present invention, the external threat consists of biotic stress caused by microorganisms and the composition comprises lignosulfonates and one or more natural crop protection compounds.

The one or more natural crop protection compounds are for example selected from a first group of plant protection compounds consisting of natamycin, blasticidin-S, kasugamycin, mildiomycin, oxytetracycline, polyoxins (polyoxin B and polyoxorim), streptomycin, and validamycin.

Natamycin is especially preferred. The one or more natural crop protection compounds are alternatively selected from a second group of plant protection compounds consisting of carvone, carvacrol, Citrex Liquid (an organic compound, derived from natural organic acids mixed with ascorbic acids), chitosan, thyme oil, azadirachtin, eucalyptus oil, harpin, potassium phosphite, nisin, lactoperoxidase, and nerolidol. In a preferred embodiment, one or more compounds from both groups are combined.

The above listed compounds are so-called natural crop protection compounds having an anti-microbial activity against bacteria, viruses, fungi etc.. These compounds may be phytotoxic when used in effective amounts. It was now surprisingly found that lignosulfonates lower the phytotoxicity of NCP's.

Lignosulfonates protect the anti-microbial compounds in the composition against degradation thus allowing for their use in agriculture.

In a particular embodiment, the NCP is natamycin which is very sensitive to light. The combination with lignosulfonates allows natamycin to be applied to leaves, while retaining its activity.

Furthermore, lignosulfonates provide an synergistic effect by making the plant less susceptible to the anti- microbial compounds and increasing the effect of such compounds.

In a particular embodiment of the present invention either titanium and/or silver lignosulfonates are used. The use of titanium and/or silver further enhances the anti- microbial effect of the composition. In an aqueous environment the titanium is slowly released from the titanium lignosulfonates thereby forming TiO2. In (sun)-light TiO2 catalyses the reaction: UV + 02 + H2O-> HO2* + *OH. The radicals produced have a biocidal effect on pathogens. TiO2 is not toxic for humans (it is for instance present in tooth paste). Silver lignosulfonates release Ag-ions in an aqueous environment. Ag-ions are toxic for micro-organisms and therefore contribute to the effectivity of the composition.

Compositions of the invention may further comprise compounds which facilitate the spreading, the effectivity, stability, etc. of the compositions. Examples of such compounds are detergents, buffers, chelators, spreading agents, preservatives or boric acid.

The composition with anti-microbial function can be applied to plants as a solid, but can also be applied in solution. The solution can be applied onto the crop plants using methods known to the person skilled in the art but is

preferably applied by spraying. Spraying allows for an even distribution of the composition.

Because of the excellent anti-microbial characteristics of the composition of the present invention, the composition can be used for protection of growing crop plants but can also be used for decontamination and subsequent preservation and protection of plant parts, such as seeds and bulbs, against pathogenic micro-organisms.

According to yet another aspect thereof, the invention relates to compositions for improving the quality of the products of the crop, which composition comprises lignosulfonates, a chelator and optionally a terpene. The chelator is preferably EDTA or EDDHA (ethylenediaminedi (o- hydroxyphenylacetic) acid).

The terpene can be selected from pentene, carvacrol.

It was surprisingly found that when applied to fruits, like apples, the composition induces an improvement of the <BR> <BR> quality of this fruit. "Improved quality"as used herein is intended to mean any improvement in colour, taste, scent, and structure of the fruit as compared to the untreated fruits. With respect to apples, it was found that when applying a composition comprising lignosulfonates, a chelator, such as EDTA, and a terpene, such as pentene, to apple fruits four weeks and two weeks before harvest results in a strong increase in the formation of red colour on the skin of the apples. Also, it was found that the uniformity of the harvested product was largely increased. This leads to a better price of the product and reduced harvesting.

Pentene and EDTA allow for the equal spreading of the composition on fruits thereby enhancing the quality improving effects of the composition according to the invention.

In addition, a composition is provided for the protection of plants against nematodes, comprising lignosulfonates in combination with a cellulose containing material, such as cellulose, compost or finely grinded plant material. This composition is applied into the substrate in which the plant is growing, usually soil or artificial substrates. Application of the composition will be most efficient in systems where final yield is highly determined by plant establishment and by the first period of growth.

Specific situations in which lignosulfonates and cellulose containing materials can be used are described hereinbelow.

These examples are, however, not intended as limitations.

Protection of sugar beet seedlings against nematode attack (for instance against Heterodera schachtii and Paratrichodorus teres) can be obtained by in-furrow application of lignosulfonates and cellulose slurry at seeding.

For potatoes, it is possible to coat seed potatoes with lignosulfonates and cellulose or apply lignosulfonates and cellulose slurry at planting of the tubers. This will protect the potato plant against early attack by Pratylenchus, Paratrichodorus, Globodera, Meloidogyne and other nematodes, that are most harmful during the first period of potato growth.

Protection of tulips against tobacco rattle virus, which is transmitted by Paratrichodorus and Trichodorus nematodes, can be achieved by coating of tulips or application of lignosulfonate slurry with compost upon planting. Tulip is sensitive to tobacco rattle virus transmission only for a limited period after planting and the strong effect of lignosulfonates on the vector nematode Paratrichodorus teres shows that virus transmission will be inhibited.

A further application of lignosulfonates and cellulose is for amelioration of replant problems. Replant problems are often caused by nematodes, that attack young trees or shrubs that are replanted at a site were the same crop was grown before. Addition of lignosulfonates and cellulose slurry in the plant hole will inhibit nematode (Pratylenchus, Meloidogyne and others) attack and give the young plant a better chance of establishing a vital root system.

(Re) planting can take place in soil but also in other substrates, such as potting soil, vermiculite, coconut fibres etc. These substrates can also be pre-treated with the composition of lignosulfonates and cellulose containing material. Such pre-treated substrates for plant growth are also part of this invention.

The invention furthermore relates to the use of lignosulfonates and cellulose containing materials in the applications described above and to compositions that contain lignosulfonates and are intended for the above identified use.

Compositions according to the invention for controlling nematodes comprise lignosulfonates (LS) in an amount to meet the desired goal as described above. An optimal amount lies usually around 0.05 kg/m2. The compositions take usually the form of a solution or slurry that can be sprayed or poured. Such solution contains about 10-55%, preferably around 30% LS. LS does usually not dissolve above an amount of 55% without additional measures.

Effective nematode control is obtained by applying the composition according to the invention in an amount of 100,250, 600,950, 1200,1550 and 2000 kg/ha, thus in the range of 100-2000 kg/ha, preferably 200,350, 450,550, and 600 kg/ha, thus in the range of 200-600 kg/ha, more

preferably 450,475, 525, and 550 kg/ha, thus in the range of 450-550 kg/ha.

The invention further relates to methods for protecting plants and plant parts against weeds, pathogens and other stresses wherein compositions of the invention are applied to soil, substrate, plant or plant part.

Lignosulfonate is typically a mixture of more or less degraded lignin residues of different sizes. This mixture can be fractionated and/or treated chemically. When used in this application the terms"lignosulfonate"and"lignosulfonates" are intended to mean both crude, untreated forms of lignosulfonate as well as more or less purified and/or chemically modified lignosulfonate or fractions thereof.

Lignosulfonates can thus be either a mixture or isolated lignosulfonate molecules. Usually a crude mixture is used, but the invention may in some applications, such as immunization, benefit from the use of pure LS. Crude mixtures still contain 5 to 10% reducing sugars that may lead to stickiness of plant parts, such as leaves, when a solution thereof is sprayed onto the plant or applied to the plant otherwise. Crude mixtures are however more cost-effective as they do not require a further fractionation to remove the sugars. Lignosulfonates used according to the invention are usually Ca-lignosulfonates or NH4-lignosulfonates.

As used in this application the term"active ingredient"is intended to mean any ingredient that contributes to the function of the composition.

The invention will be further exemplified with reference to the following figures and examples. However it should be understood that these figures and examples are not intended to limit the invention in any possible way.

The figures show:

Figure 1: Effect of LS and natamycin on development of Botrytis on lily leaf tips.

Figure 2: Effect of Titanium-LS on growth of Botrytis on petri dishes with nutrient broth growing medium.

Figure 3: Effect of Silver-LS on growth of Botrytis on petri dishes with nutrient broth growing medium.

EXAMPLES EXAMPLE 1 Protection of Solanum niger plants from stress induced by low dosages of herbicides In an experiment Solanum niger plants were grown for 6 weeks after sowing. The plants were then sprayed with a sub-optimal level of herbicide (either with 6% of the recommended dosage of Round up, containing the active compound glyphosate, or with 10 % of the dosage recommended on the label of 2,4 D, respectively). Groups of plants were sprayed with a mixture of the low dosage of the herbicide and different concentrations and types of LS (see table).

The results from table 1 show that LS induces stress tolerance to the low dosages of herbicides.

Table 1 Treatment Round up 2,4-D Percentual increase in dry weight (glyphosate) compared to low herbicide application Dry weight (g) 6 weeks Round up 2,4-D after treatment control untreated 2.4 g 2.4 g normal herbicide dosage plants died plants died low herbicide dosage 1.15 g 1.05 g low herbicide dosage + 1.9 g 1.85 g 65% 76% 2g/1 calcium-LS

low herbicide dosage + 1.6 1.3 39% 24% lOg/1 calcium-LS low herbicide dosage + 2.35 1.1 104% 5% 25g/l calcium-LS low herbicide dosage + 2.05 1.25 78% 19% lOg/1 iron-LS EXAMPLE 2 Effect of NH4-LS and a NCP, carvacrol, on infection (lesions) of Botrytis elliptica on lily leaf tops In all incubations the amount of NH4-LS was 5 g/1 (the amount of carvacrol is given in the table).

In a test system, leaf tops of lily were used. For infection with pathogens, leaf tops were placed into special square plastic trays (10 cm x 10 cm x 2 cm) which were divided in 25 small sections of 2 x 2 cm (see figure 1). At the start of the experiments the trays were filled with water (4 ml per small section). Then the leaf tops were placed in the trays and finally the leaf tops were sprayed with the different LS-NCP combinations. In the table the combination of LS with carvacrol in a formulation of pentene and EDTA is given.

Twenty-four hours after treatment the leaf tops in the trays were infected with 2 pl of Botrytis elliptica spore suspension (approximately 500 spores/» l, see below).

Subsequently, the plastic trays were put in a transparent container with high humidity. This container was placed in a temperature and humidity controlled greenhouse (12 hours of light, 20°C, and 400-600 ppm of CO2).

Each tray contained 15 leaf tops and all experiments were performed in triplicate.

For Botrytis spore production, the fungus was grown on 25 ml sterile solid medium containing liquid broth. The

spores were applied to the leaves in Gamborg B5 medium (Gamborg 3.16 g/1, Na-phosphate 10 mM pH=6.5, sucrose 10 Mm).

After 3,5 and 7 days incubation the size (mm) of the Botrytis lesions was measured.

Table 2 shows the results.

Table 2 Treatment Lesion size Lesion size Lesion size (mm) after 3 (mm) after 5 (mm) after 7 days days days Control 6.8 8.6 14.2 (untreated) Control 5.3 7.5 12.5 formulation NH4-LS/0. 9 1.8 2.7 carvacrol 0. 2% NH4-LS/0. 2 0.3 0.3 carvacrol 0. 8% NH4-LS/0. 1 0.5 1.2 carvacrol 1. 6% EXAMPLE 3 Effect of LS and natamycin on development of Botrytis on lily leaf tips The same method was used as in Example 2. The leaf tops in the left tray were treated with water, the leaf tips in the middle were treated with the LS formulation without

natamycin and the leaf tips in the incubator on the right were treated with LS-natamycin combination.

Figure 1 demonstrates that natamycin formulated with LS protects very well against Botrytis. Natamycin-LS also protected against other fungi. Treatment with natamycin alone did provide adequate protection but also resulted in some leaf damage. The combination with LS is thus better.

EXAMPLE 4 Effect of Titanium-LS on growth of Botrytis on petri dishes with nutrient broth growing medium Botrytis spores were incubated on sterilized growing medium containing different concentrations of Ti-LS. The spores were placed on the middle of the petri dish and the infection size (diameter of the Botrytis-colony) was measured after 5 days. Figure 2 shows the results.

The outcome of the experiment was that at a concentration lower than 1.6 g/1 of Ti-LS development of Botrytis was already completely blocked.

EXAMPLE 5 Effect of Silver-LS on growth of Botrytis on petri dishes with nutrient broth growing medium Botrytis spores were incubated on sterilized growing medium containing different concentrations of Ag-LS. The spores were placed on the middle of the petri dish and the infection size (diameter of the Botrytis colony) was measured after 5 days.

Figure 3 shows that at a concentration of lower than 1 g/l of Ag-LS development of Botrytis was completely blocked.