WO2010031787A1

WO2010031787A1 - Grass seeds different from cereal seeds comprising at least one insecticide and their use as baits for combating harmful social insects

Info

Publication number: WO2010031787A1
Application number: PCT/EP2009/062006
Authority: WO
Inventors: Keith A. Holmes; Cletus Youmans; Thomas J. Holt
Original assignee: Basf Se
Priority date: 2008-09-17
Filing date: 2009-09-16
Publication date: 2010-03-25

Abstract

The present invention relates to grass seeds different from cereal seeds comprising at least one insecticide, to the use of grass seeds different from cereal seeds which have been treated with at least one insecticide as baits for combating harmful social insects, and to a method for combating harmful social insects, which method comprises applying to the habitat or food supply of the social insects, or to the soil, area, material or environment in which the harmful social insects are staying at least temporarily, or to the materials, soils, surfaces or spaces to be protected from insect attack or infestation grass seeds different from cereal seeds which have been treated with at least one insecticide.

Description

Grass seeds different from cereal seeds comprising at least one insecticide and their use as baits for combating harmful social insects

Description

The present invention relates to grass seeds different from cereal seeds comprising at least one insecticide, to the use of grass seeds different from cereal seeds which have been treated with at least one insecticide as baits for combating harmful social insects, and to a method for combating harmful social insects, which method comprises apply- ing to the habitat or food supply of the social insects, or to the soil, area, material or environment in which the harmful social insects are staying at least temporarily, or to the materials, soils, surfaces or spaces to be protected from insect attack or infestation grass seeds different from cereal seeds which have been treated with at least one insecticide.

Social insects, which are best exemplified by all termites (Isoptera) and ants (Formici- dae) and also by various bees and wasps (Hymenoptera), are known for their high degree of cooperation and complex social organisation that have enabled them to form colonies with millions of individuals and underground cities with tunnel networks span- ning many kilometres. They manifest three characteristics: group integration, division of labour, and overlap of generations. Social insects are differentiated in structure, function, and behaviour into castes, the major ones being the reproductives (e.g., the queen) and the steriles (workers and soldiers). Besides carrying out the basic function of reproduction, the members of the reproductive caste generally select the site for a new colony and excavate the first galleries. The workers care for the eggs and larvae, collect food for other members of the colony, and construct and repair the nest, while the soldiers defend the colony against predators.

However, some of these social insects destroy growing and harvested crops, pasture land, turf and lawns and attack wooden dwelling and commercial structures, causing large economic loss to the food supply and to property. Some of them, such as fire ants, are quite aggressive and attack persons and animals stepping into their mounts and cause painful stings. The same applies to Africanized honey bees ("killer bees"), which are characterized by greater defensiveness in established hives than European honey bees. They are more likely to attack a perceived threat and, when they do so, attack relentlessly in larger numbers ("hyper-defensive behaviour"; this defensiveness has earned them the nickname "killer bees"). Red imported fire ants ("RIFEs") are not only aggressive when coming into conflict with humans, but also attack and kill newborn domestic animals, pets and wildlife and destroy seeds and crops. They can even remove bands of bark from young trees, especially citrus trees, thus often killing the whole tree. Their nests (mounds) can grow up to 60 cm high and are hazards in yards, parks and other recreational areas. These types of social insects which cause human economic loss or loss in human life quality are called in the terms of the present invention "harmful social insects".

Control of harmful social insects is a difficult agricultural and non-agricultural pest con- trol problem. Control methods are tedious and labour intensive and therefore expensive. Termites and ants are ubiquitous and forage constantly for new food sources. Wood or wood products in homes provide an inviting target if foraging termites are undeterred or not removed. Ants are even less fastidious.

For combating undesired social insects, efforts have been made to increase the effectiveness and selectivity of insecticides. One approach is the combination of insecticides with bait formulations, often including insect attractants, such as pheromones. In theory, less insecticide is used and over a narrower area because the insects are attracted to a specified location. However, in practice the attractant effect is generally insufficient for non-confined areas, such as crop fields or pasture land or large turf areas. Moreover, the initiating period of most bait formulations, i.e. the time from bringing out the bait formulation until the insecticide starts showing an effect, is rather long.

It is an object of the present invention to provide an insecticidal composition which overcomes the disadvantages of the prior art.

The object is achieved by grass seeds different from cereal seeds comprising at least one insecticide.

"Comprising at least one insecticide" signifies that the at least one insecticide is for the most part on the surface of the seed at the time of application, although a greater or lesser part of the at least one insecticide may penetrate into the seed, depending on the method of application. According to one embodiment, such a grass seed comprising the at least one insecticide has a coating, wherein the coating comprises the at least one insecticide. According to a further embodiment, such a seed comprising the at least one insecticide is a seed whose germinable part and/or natural sheath, shell, pod and/or integument comprise(s) the at least one insecticide. Also, the at least one insecticide can be present in both the coating and the germinable part and/or natural sheath, shell, pod and/or integument of the seed.

The invention further relates to the use of grass seeds different from cereal seeds which have been treated with at least one insecticide as baits for combating harmful social insects.

The invention also relates to a method for combating harmful social insects which method comprises applying to the habitat or food supply of the social insects, or to the soil, area, material or environment in which the harmful social insects are staying at least temporarily, or to the materials, soils, surfaces or spaces to be protected from insect attack or infestation grass seeds different from cereal seeds which have been treated with at least one insecticide.

"Applying to the habitat or food supply of the social insects, or to the soil, area, material or environment in which the harmful social insects are staying at least temporarily, or to the materials, soils, surfaces or spaces to be protected from insect attack or infestation grass seeds" means making available the seeds to the insects to be combated by any suitable method, for example by spreading/broadcasting/distributing the seeds in the respective site or by planting them.

The remarks made below as to suitable and preferred insecticides, grass seeds and harmful social insects as well as to how the use and the method according to the invention are best put into practice and as to how the grass seeds comprising the at least one insecticide are prepared apply both to the use and to the method of the invention as well as to the grass seeds of the invention as such.

In terms of the present invention, halogen is fluorine, chlorine, bromine or iodine.

Ci-C4-Alkyl is an aliphatic saturated straight-chain or branched hydrocarbon radical having 1 to 4 carbon atoms. Examples are methyl, ethyl, propyl, isopropyl, butyl, 1- methylpropyl (sec-butyl), 2-methylpropyl (isobutyl) and 1 ,1-dimethylethyl (tert-butyl).

Ci-C4-Haloalkyl is a Ci-C4-alkyl radical as defined above, where some or all of the hy- drogen atoms in these groups may be replaced by halogen atoms as mentioned above. Examples are chloromethyl, bromomethyl, dichloromethyl, trichloromethyl, fluoro- methyl, difluoromethyl, trifluoromethyl, chlorofluoromethyl, dichlorofluoromethyl, chloro- difluoromethyl, 1-chloroethyl, 1-bromoethyl, 1-fluoroethyl, 2-fluoroethyl, 2,2- difluoroethyl, 2,2,2-trifluoroethyl, 2-chloro-2-fluoroethyl, 2-chloro-2,2-difluoroethyl, 2,2- dichloro-2-fluoroethyl, 2,2,2-trichloroethyl, pentafluoroethyl, 1 ,1 ,1-trifluoroprop-2-yl, heptafluoropropyl and 1-, 2-, 3 or 4-chlorobutyl.

For the grass seeds of the invention as well as in the use and the method according to the invention in principle all insecticides known to be effective against the insects to be combated can be used. One condition is however that the insecticides be not repellent to the insects to be combated. Moreover, advantageously the insecticide shall exhibit delayed kill, preferably over at least a ten-fold and more preferably over at least a 100- fold dosage range. Furthermore, the insecticide shall be rapidly transferred from one insect to another, e.g. via trophallaxis or grooming, and kill the recipient. In view of the above essential and desired properties, the insecticide is preferably selected from GABA-antagonists and nicotonic receptor agonists/antagonists. Mixtures of two or more of these insecticides can be used, too.

The GABA-antagonists are preferably selected from acetoprole, endosulfan, va- niliprole, pyrafluprole, pyriprole, the phenylpyrazole compound of the formula Il

where each R^c independently is Ci-C4-alkyl or Ci-C4-haloalkyl; or an agriculturally acceptable salt thereof; and the phenylpyrazole compound of the formula III

or an agriculturally acceptable salt thereof.

Preferably, the GABA antagonists are selected from compounds of formula II.

In compounds II, R^c is preferably ethyl or trifluoromethyl. The compound where R^c is ethyl is also known under the common name ethiprole and the compound where R^c is trifluoromethyl is known under the common name fipronil. More preferably, R^c is trifluoromethyl. Accordingly, fipronil is the most preferred GABA-antagonist.

The nicotinic receptor agonists/antagonists are preferably selected from acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid and thiamethoxam, more preferably from acetamiprid, clothianidin, imidacloprid and thiamethoxam and in particular from imidacloprid and thiamethoxam. GABA antagonists, nicotinic receptor agonists/antagonists and methods for producing them are generally known. For instance, the commercially available compounds may be found in The Pesticide Manual, 13^th Edition, British Crop Protection Council (2003) among other publications.

Preferably, the insecticide is selected from GABA antagonists. Reference is made to the above-mentioned preferred embodiments of the GABA antagonists. In particular, the insecticide is fipronil.

The method and the use of the present invention serve for combating harmful social insects. As already explained, social insects are best exemplified by all termites (Isop- tera) and ants (Formicidae) and also by various bees and wasps (Hymenoptera). Social insects representing a nuisance to men and domestic animals are termed "harmful". Preferably, the use and the method according to the invention serve for combating termites and/or fire ants and in particular for combating fire ants. The fire ants may be domestic or imported fire ants, such as red imported fire ants (RIFEs; Solenopsis in- victa Buren).

Examples for termites are Calotermes spp, e.g. Calotermes flavicollis, Coptotermes spp., e.g. Coptotermes acinaciformis, Coptotermes formosanus, Coptotermes havilandi or Coptotermes lacteus, Cryptotermes spp., e.g. Cryptotermes brevis, Heterotermes spp., e.g. Heterotermes aureus or Heterotermes indicola, Leucotermes spp., e.g. Leu- cotermes flavipes, Mastotermes spp., e.g. Mastotermes darwiniensis, Reticulitermes spp., e.g. Reticulitermes arenicola, Reticulitermes flavipes, Reticulitermes hageni, Re- ticulitermes hagenus, Reticulitermes hesperus, Reticulitermes lucifugus, Reticulitermes santonensis, Reticulitermes speratus, Reticulitermes tibialis or Reticulitermes virgini- cus, Schedorhinotermes spp., e.g. Schedorhinotermes intermedius, Termes spp., e.g. Termes natalensis, and Zootermopsis spp., e.g. Zootermopsis nevadensis.

Fire ants, also sometimes referred to as red ants, are stinging ants with over 280 species worldwide. Non-limiting examples are Solenopsis abdita Thompson, Solenopsis africana Santschi, Solenopsis albidula Emery, Solenopsis alecto Santschi, Solenopsis altinodis Forel, Solenopsis amblychila Wheeler, Solenopsis andina Santschi, Solenopsis angulata Emery, Solenopsis atlantis Santschi, Solenopsis aurea Wheeler, Solenopsis avia, Solenopsis azteca Forel, Solenopsis balachowskyi Bernard,

Solenopsis banyulensis Bernard, Solenopsis basalis Forel, Solenopsis belisarius Forel, Solenopsis blanda, Solenopsis brasiliana SantschiSo/enops/s brazoensis, Solenopsis brevicornis Emery, Solenopsis brevipes Emery, Solenopsis bruchiella Emery, Solenopsis bruesi Creighton, Solenopsis buck! Kempf, Solenopsis canadensis Forel, Solenopsis capensis Mayr, Solenopsis carolinensis Forel, Solenopsis castor Forel, Solenopsis celata, Solenopsis clarki Crawl ey, Solenopsis clytemnestra Emery, Solenopsis conjurata Wheeler, Solenopsis cooper! Donisthorpe, Solenopsis corticalis Forel, Solenopsis crivellarii Menozzi, Solenopsis daguerrei, Solenopsis dalli, Solenopsis decipiens Emery, Solenopsis delta, Solenopsis deserticola Ruzsky, Solenopsis duboscqui Bernard, Solenopsis dysderces Snelling, Solenopsis egregia, Solenopsis electra Forel, Solenopsis emeryi Sa ntschi, Solenopsis eximia, Solenopsis fairchildi Wheeler, Solenopsis foersteri Theobald, Solenopsis franki Forel, Solenopsis froggatti Forel, Solenopsis fugax, Solenopsis fusciventris Clark, Solenopsis gallardoi Santschi, Solenopsis gallica Santschi, Solenopsis gayi, Solenopsis geminata, Solenopsis georgica Menozzi, Solenopsis germaini Emery, Solenopsis globularia, Solenopsis gnomula Emery, Solenopsis goeldii Forel, Solenopsis granivora Kusnezov, Solenopsis hammari Mayr, Solenopsis hayemi Forel, Solenopsis helena Emery,

Solenopsis hostilis, Solenopsis iheringi Forel, Solenopsis ilinei Santschi, Solenopsis indagatrix Wheeler, Solenopsis insculpta Clark, Solenopsis insinuans Santschi, Solenopsis insularis, Solenopsis interrupta Santschi, Solenopsis invicta Buren, Solenopsis jacoti Wheeler, Solenopsis jalalabadica Pisarski, Solenopsis japonica Wheeler, Solenopsis joergenseni Santschi, Solenopsis juliae, Solenopsis kabylica Santschi, Solenopsis knuti Pisarski, Solenopsis /croc/cow/ Wheeler, Solenopsis laevi- ceps Mayr, Solenopsis laevithorax Bernard, Solenopsis latastei Emery, Solenopsis latro Forel, Solenopsis leptanilloides Santschi, Solenopsis longiceps Forel, Solenopsis loretana Santschi, Solenopsis lotophaga Santschi, Solenopsis lou Forel, Solenopsis lusitanica Emery, Solenopsis macdonaghi Santschi, Solenopsis macrops Santschi, Solenopsis madara Roger, Solenopsis major Theobald, Solenopsis maligna Santschi, Solenopsis mameti Donisthorpe, Solenopsis marxi Forel, Solenopsis maxillosa Emery, Solenopsis maxima , Solenopsis megera Santschi, Solenopsis megergates Trager, Solenopsis metanotalis Emery, Solenopsis metatarsalis, Solenopsis minutissima Eme- ry, Solenopsis moesta, Solenopsis molesta, Solenopsis monticola Bernard, Solenopsis mozabensis, Solenopsis nicaeensis Bernard, Solenopsis nickersoni Thompson, Solenopsis nigella Emery, Solenopsis nitens Bingham, Solenopsis nitidum, Solenopsis normandi Santschi, Solenopsis novemmaculata Wheeler, Solenopsis occipitalis Santschi, Solenopsis oculata Santschi, Solenopsis oraniensis Forel, Solenopsis orbula Emery, Solenopsis orbuloides Andre, Solenopsis overbecki Viehmeyer, Solenopsis pachycera, Solenopsis papuana Emery, Solenopsis parabiotica Weber, Solenopsis parva Mayr, Solenopsis patagonica Emery, Solenopsis pawaensis Mann, Solenopsis pergandei Fore\, Solenopsis photophila Santschi, Solenopsis picea Emery, Solenopsis picquarti Forel, Solenopsis picta Emery, Solenopsis pilosa, Solenopsis pilosula Wheeler, Solenopsis pollux Forel, Solenopsis privata, Solenopsis provincialis Bernard, Solenopsis punctaticeps Mayr, Solenopsis puncticeps MacKay & Vinson, Solenopsis pusillignis Trager, Solenopsis pygmaea Forel, Solenopsis pythia Santschi, Solenopsis quinquecuspis Forel, Solenopsis reichenspergeri Santschi, Solenopsis richardi Bernard, Solenopsis richteri Forel, Solenopsis robusta Bernard, Solenopsis rugiceps Mayr, Solenopsis rugosa Bernard, Solenopsis sabeana, Solenopsis saevissima, Solenopsis salina Wheeler, Solenopsis santschii Forel, Solenopsis schilleri Santschi, Solenopsis schmalzi Forel, Solenopsis scipio Santschi, Solenopsis sea, Solenopsis seychellensis Forel, Solenopsis silvestrii Emery, Solenopsis solenopsidis, Solenopsis soochowensis Wheeler, Solenopsis spei Forel, Solenopsis stricta Emery, Solenopsis substituta Santschi, Solenopsis subterranea MacKay & Vinson, Solenopsis subtilis Emery, Solenopsis succinea Emery, Solenopsis sulfurea, Solenopsis superba, Solenopsis tar- guia Bernard, Solenopsis tennesseensis Smith, Solenopsis tenuis Mayr, Solenopsis terricola Menozzi, Solenopsis tertialis Ettershank, Solenopsis tetracantha Emery, 1906 , Solenopsis texana Emery, Solenopsis tipuna Forel, Solenopsis tonsa Thompson, Solenopsis tridens Forel, Solenopsis trihasta Santschi, Solenopsis truncorum Forel, Solenopsis ugandensis Santschi, Solenopsis valida, Solenopsis virulens, Solenopsis vorax Santschi, Solenopsis wagneri Santschi, Solenopsis wasmannii Emery ,

Solenopsis weiseri Forel, Solenopsis westwoodi Forel, Solenopsis weyrauchi Trager, Solenopsis wolfi Emery, Solenopsis xyloni McCook, Solenopsis zambesiae Arnold, and Solenopsis zeteki Wheeler.

Grass is a common word that generally describes monocotyledonous green plants. The plants belonging to the family Gramineae (Poaceae) are the "true grasses" and include most plants grown as grains, for pasture, and for lawns (turf). They include some more specialised crops such as lemongrass, as well as many ornamental plants. They also include plants often not recognized to be grasses, such as bamboos or some species of weeds called crab grass. More then 650 genera encompassing over 10,000 species belong to the Poaceae familiy.

The grass seeds used in the present invention are the seeds of grass different from cereal seeds. Cereals in turn are the cultivated forms of grasses (Poaceae) and include for example wheat (inclusive spelt, einkorn, emmer, kamut, durum and triticale), rye, barley, rice, wild rice, maize (corn), millet, sorghum, teff and oats.

Preferably, the grass seeds used in the present invention are the seeds of grass from the family Gramineae (Poaceae), with the exception of cereals.

In the use and the method of the invention, the grass seeds to be used are preferably chosen according to their geographic distribution. In other words the grass seeds used according to the invention are preferably chosen so that they correspond to endemic grasses of the respective application site. Moreover they are preferably chosen so that they represent a food source for the insect to be combated. The person skilled in the art is aware of the species of grass seeds being accepted as a food source for the respective insect and of the geographic distribution of the respective grasses.

More preferably, the grass seeds used in the present invention are selected from rye- grass, bermudagrass, centipedegrass, switchgrass, indiangrass, bluegrass, or- chardgrass, big bluestem grass, little bluestem grass and fescue seeds. Even more preferably, the grass seeds used in the present invention are selected from ryegrass, bermudagrass and centipedegrass seeds. In particular, the grass seeds are selected from bermudagrass seeds and ryegrass seeds. Specifically, the grass seed is ryegrass seed.

For the treatment with the at least one insecticide, the grass seed can be used in any physiological state, but of course it is preferred that the seed be in a sufficiently durable state that it incurs no significant damage during the treatment process. Typically, the seed is one that has been harvested from the grassland/field; removed from the plant; and/or separated from the any pod, stalk, outer husk, and other non-seed plant mate- rial. In one embodiment, for example, the treatment can be applied to grass seed that has been harvested, cleaned and dried to a moisture content below about 15% by weight. In an alternative embodiment, the seed can be one that has been dried and then primed with water and/or another material and then re-dried before or during the treatment with the at least one insecticide.

The "grass seed that has been treated with at least one insecticide" or the "grass seed that comprises at least one insecticide" has suitably been subjected to a seed treatment with the at least one insecticide.

The term "seed treatment" comprises all suitable seed treatment and especially seed dressing techniques known in the art, such as seed coating (e.g. seed pelleting), seed dusting and seed imbibition (e.g. seed soaking). Here, "seed treatment" refers to all methods that bring seeds and the at least one insecticide into contact with each other, and "seed dressing" to methods of seed treatment which provide the seeds with an amount of the at least one insecticide, i.e. which generate a seed comprising the at least one insecticide. In principle, the treatment can be applied to the seed at any time from the harvest of the seed to the application of the seed according to the invention (e.g. by spreading the seed in the desired place). The seed can be treated immediately before, or during, the application of the seed according to the invention, for example using the "planter's box" method. However, the treatment may also be carried out several weeks or months, for example up to 12 months or longer, before applying the seed according to the invention (e.g. by spreading it in the desired place), for example in the form of a seed dressing treatment.

By applying the treatment to the seed prior to its application according to the invention the operation is simplified. In this manner, seeds can be treated, for example, at a central location and then dispersed for application (e.g. by spreading/planting). This permits the person who applies the seeds to avoid the handling and use of the at least one insecticide and to merely handle the treated seeds in a manner that is conventional for regular untreated seeds, which reduces human exposure. In principle, all customary methods of treating and in particular dressing such as coating (e.g. pelleting) and imbibing (e.g. soaking) seeds can be employed. Specifically, the seed treatment follows a procedure in which the seed is exposed to the specifically desired amount of a preparation comprising the at least one insecticide. The prepara- tion may be a formulation that is applied as such or after previously diluting it, e.g. with water; for instance, it may be expedient to dilute seed treatment formulations 2-10 fold leading to concentrations in the ready-to-use compositions of 0.01 to 60% by weight active compound by weight, preferably 0.1 to 40% by weight.

Usually, a device which is suitable for this purpose, for example a mixer for solid or solid/liquid components, is employed until the preparation is distributed uniformly on the seed. Thus, the preparation can be applied to seeds by any standard seed treatment methodology, including but not limited to mixing in a container (e.g., a bottle, bag, mixer or tumbler), mechanical application, tumbling, spraying, and immersion. If appro- priate, this is followed by drying.

Particular embodiments of the present invention comprise seed coating and imbibition (e.g. soaking). "Coating" denotes any process that endows the outer surfaces of the seeds partially or completely with a layer or layers of non-plant material, and "imbibi- tion" any process that results in penetration of the active ingredient(s) into the ger- minable parts of the seed and/or its natural sheath, (inner) husk, hull, shell, pod and/or integument. The treatment thus encompasses a treatment of seeds which comprises providing seeds with a coating that comprises the at least one insecticide, and also a treatment of seeds which comprises imbibition of seeds with the at least one insecti- cide.

Coating is particularly effective in accommodating high loads of the at least one insecticide.

Coating may be applied to the seeds using conventional coating techniques and machines, such as fluidized bed techniques, the roller mill method, rotostatic seed treat- ers, and drum coaters. Other methods such as the spouted beds technique may also be useful. The seeds may be pre-sized before coating. After coating, the seeds are typically dried and then transferred to a sizing machine for sizing. Such procedures are known in the art. Seed coating methods and apparatuses for their application are disclosed in, for example, US 5,918,413, US 5,891 ,246, US 5,554,445, US 5,389,399, US 5,107,787, US 5,080,925, US 4,759,945 and US 4,465,017.

In another embodiment, the solid at least one insecticide, for instance as a solid fine particulate formulation, e.g. a powder or dust, can be mixed directly with seeds. Optionally, a sticking agent can be used to adhere the solid, e.g. the powder, to the seed surface. For example, a quantity of seed can be mixed with a sticking agent (which increases adhesion of the particles on the surface of the seed) and optionally agitated to encourage uniform coating of the seed with the sticking agent. For example, the seed can be mixed with a sufficient amount of sticking agent, which leads to a partial or complete coating of the seed with sticking agent. The seed pretreated in this way is then mixed with a solid formulation containing the at least one insecticide to achieve adhesion of the solid formulation on the surface of the seed material. The mixture can be agitated, for example by tumbling, to encourage contact of the sticking agent with the solid insecticide, thereby causing the insecticide to stick to the seed.

Another particular method of treating seed with the at least one insecticide is imbibition. For example, seed can be combined for a period of time with an aqueous solution comprising from about 1 % by weight to about 75% by weight of the at least one insecticide in a solvent such as water. Preferably the concentration of the solution is from about 5% by weight to about 50% by weight, more preferably from about 10% by weight to about 25% by weight. During the period in which the seed is combined with the solution, the seed takes up (imbibes) at least a portion of the insecticide. Optionally, the mixture of seed and solution can be agitated, for example by shaking, rolling, tumbling, or other means. After the imbibition process, the seed can be separated from the solution and optionally dried in a suitable manner, for example by patting or air-drying.

In yet another embodiment, the at least one insecticide can be introduced onto or into a seed by use of solid matrix priming. For example, a quantity of the insecticide can be mixed with a solid matrix material, and then the seed can be placed into contact with the solid matrix material for a period to allow the insecticide to be introduced to the seed. The seed can then optionally be separated from the solid matrix material and stored or used, or, preferably, the mixture of solid matrix material plus seed can be stored or distributed directly.

As described above, the at least one insecticide and optionally the further active ingre- dient(s) can be used as such, that is, without any auxiliary agents present. However, the at least one insecticide and the further active ingredient(s) are typically applied to the seeds in the form of a composition.

As used herein, a "composition" comprises at least one active ingredient and at least one auxiliary agent.

The term "auxiliary agent" refers to a compound or combination of compounds which do not exert a biologically relevant effect of their own, but support the effects of the active ingredient(s). When auxiliary agents are used, their choice will depend on the active ingredients and on the procedures selected for seed treatment. Usually, the compositions thus comprise an active ingredient component ("A") and an auxiliary agent component ("B"). The active ingredient component ("A") of the composition comprises at least one insecticide ("A1 ") and optionally one or more further active ingredient(s) ("A2"). The auxiliary agent component ("B") comprises one or more auxil- iary agent(s). Specifically, the composition comprises fipronil, optionally at least one further insecticide and at least one auxiliary agent.

In general, the compositions comprise from 0.005% by weight to 95% by weight, preferably from 0.1 % by weight to 90% by weight, in particular from 5% by weight to 50% by weight, of the active ingredient component "A", the balance being formed by component "B". In this context, the active ingredients are employed in a purity of 90% to 100%, preferably 95% to 100% (according to NMR spectrum).

In a particular embodiment of the invention, the composition may additionally comprise one or more repellents for warm-blooded animals, e.g. birds, dogs and hedgehogs, for example nonanoic acid vanillyl amide. The amount of repellent will preferably range from 0.1 to 5% by weight, based on the total weight of the composition.

According to one embodiment, the composition is a seed treatment formulation. A seed treatment formulation according to the present invention comprises at least one auxiliary agent that is specifically suited for the seed treatment, i.e. an auxiliary agent which in particular promotes adhesion of the at least one insecticide to and/or penetration into the seeds and/or otherwise improves stability and/or manageability of the composition or the seeds treated therewith. Thus, the present invention also relates to a seed treatment formulation, which comprises the at least one insecticide, at least one seed treatment auxiliary agent(s), and optionally one or more further auxiliary agents.

In particular, seed treatment auxiliary agents are selected from the group consisting of agents suitable for seed coating materials, agents suitable for solid matrix priming ma- terials, penetration enhancers suitable for promoting seed imbibition, colorants, antifreezes, and gelling agents.

According to a preferred embodiment, the seed coating material comprises a binder (or sticker). Optionally, the coating material also comprises one or more additional seed treatment auxiliary agents selected from the group consisting of fillers and plasticizers.

Binders (or stickers) are all customary binders (or stickers) which can be employed in seed treatment formulations. Binders (or stickers) that are useful in the present invention preferably comprise an adhesive polymer that may be natural or partly or wholly synthetic and is without phytotoxic effect on the seed to be coated. Preferably, the binder (or sticker) is biodegradable. Preferably the binder or sticker is chosen to act as a matrix for the at least one insecticide.

The binder (or sticker) may be selected from polyesters, polyether esters, polyanhy- drides, polyester urethanes, polyester amides; polyvinyl acetates; polyvinyl acetate copolymers; polyvinyl alcohols and tylose; polyvinyl alcohol copolymers; polyvinylpy- rolidones; polysaccharides, including starches, modified starches and starch derivatives, dextrins, maltodextrins, alginates, chitosanes and celluloses, cellulose esters, cellulose ethers and cellulose ether esters including ethylcelluloses, methylcelluloses, hydroxymethylcelluloses, hydroxypropylcelluloses and carboxymethylcellulose; fats; oils; proteins, including casein, gelatin and zeins; gum arabics; shellacs; vinylidene chloride and vinylidene chloride copolymers; lignosulfonates, in particular calcium Ng- nosulfonates; polyacrylates, polymethacrylates and acrylic copolymers; polyvinylacry- lates; polyethylene oxide; polybutenes, polyisobutenes, polystyrene, polyethylene- amines, polyethylenamides; acrylamide polymers and copolymers; polyhydroxyethyl acrylate, methylacrylamide monomers; and polychloroprene. In a particular embodiment, the binder is a thermoplastic polymer.

In a particular embodiment of the invention the seed treatment formulation contains at least one polyester, which, in particular, is selected from polylactides, partially aromatic polyesters (copolymers of terephthalic acid, adipic acid and aliphatic diols), polygly- colides, polyhydroxyalkanoates and polytartrates.

The amount of binder (or sticker) in the formulation can vary, but will be in the range of about 0.01 to about 25% of the total weight, more preferably from about 1 to about 15%, and even more preferably from about 5% to about 10%.

As mentioned above, the coating material can optionally also comprise a filler. The filler can be an absorbent or an inert filler, such as are known in the art, and may include wood flours, cereal flours, tree bark mill, wood meal and nut shell meal, sugars, in particular polysaccharides, activated carbon, fine-grain inorganic solids, silica gels, silicates, clays, chalk, diatomaceous earth, calcium carbonate, magnesium carbonate, dolomite, magnesium oxide, calcium sulfate and the like. Clays and inorganic solids which may be used include calcium bentonite, kaolin, china clay, talc, perlite, mica, vermiculite, silicates, quartz powder, montmorillonite, attapulgite, bole, loess, limestone, lime and mixtures thereof. Sugars which may be useful include dextrin and mal- todextrin. Cereal flours include wheat flour, oat flour and barley flour. The filler may also comprise fertilizer substances such as, for example, ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas and mixtures thereof.

The filler is selected so that it will provide a proper microclimate for the seed, for example the filler is used to increase the loading rate of the active ingredients and to adjust the control-release of the active ingredients. The filler can aid in the production or process of coating the seed. The amount of filler can vary, but generally the weight of the filler components will be in the range of about 0.05 to about 75% of the total weight, more preferably about 0.1 to about 50%, and even more preferably about 0.5% to 15%.

It is preferred that the binder (or sticker) be selected so that it can serve as a matrix for the at least one insecticide. While the binders disclosed above may all be useful as a matrix, it is preferred that a continuous solid phase of one or more binder compounds is formed throughout which is distributed as a discontinuous phase the insecticide. Op- tionally, a filler and/or other components can also be present in the matrix. The term "matrix" is to be understood to include what may be viewed as a matrix system, a reservoir system or a microencapsulated system. In general, a matrix system consists of the at least one insecticide and a filler uniformly dispersed within a polymer, while a reservoir system consists of a separate phase comprising the insecticide that is physi- cally dispersed within a surrounding, rate-limiting, polymeric phase. Microencapsulation includes the coating of small particles or droplets of liquid, but also to dispersions in a solid matrix.

Especially if the at least one insecticide used in the coating is an oily type composition and little or no inert filler is present, it may be useful to hasten the drying process by drying the composition. This optional step may be accomplished by means well known in the art and can include the addition of calcium carbonate, kaolin or bentonite clay, perlite, diatomaceous earth, or any absorbent material that is added preferably concurrently with the at least one fungicide coating layer to absorb the oil or excess moisture. The amount of absorbent necessary to effectively provide a dry coating will be in the range of about 0.5 to about 10% of the weight of the seed.

Optionally, the coating material comprises a plasticizer. Plasticizers are typically used to make the film that is formed by the coating layer more flexible, to improve adhesion and spreadability, and to improve the speed of processing. Improved film flexibility is important to minimize chipping, breakage or flaking during storage, handling or sowing processes. Many plasticizers may be used; however, useful plasticizers include polyethylene glycol, oligomeric polyalkylene glycols, glycerol, alkylbenzylphthalates, in particular butylbenzylphthalate, glycol benzoates and related compounds. The amount of plasticizer in the coating layer will be in the range of from about 0.1 % by weight to about 20% by weight.

Agents suitable for solid matrix priming materials which are useful in the present invention include polyacrylamide, starch, clay, silica, alumina, soil, sand, polyurea, polyacry- late, or any other material capable of absorbing or adsorbing the at least one insecticide for a time and releasing that insecticide into or onto the seed. It is useful to make sure that the at least one insecticide and the solid matrix material are compatible with each other. For example, the solid matrix material should be chosen so that it can release the at least one insecticide at a reasonable rate, for example over a period of minutes, hours, or days.

Penetration enhancers suitable for promoting seed imbibition include agriculturally acceptable surface active compounds. The amount of penetration enhancers will usually not exceed 20% by weight, based on the total weight of the formulation. Preferably, the amount of penetration enhancers will be in the range from 2% to 20% by weight.

Colorants according to the invention are all dyes and pigments which are customary for such purposes. In this context, both pigments, which are sparingly soluble in water, and dyes, which are soluble in water, may be used. Examples which may be mentioned are the colorants, dyes and pigments known under the names Rhodamin B, C. I. Pigment Red 112 and C. I. Solvent Red 1 , Pigment Blue 15:4, Pigment Blue 15:3, Pigment Blue 15:2, Pigment Blue 15:1 , Pigment Blue 80, Pigment Yellow 1 , Pigment Yellow 13, Pigment Red 48:2, Pigment Red 48:1 , Pigment Red 57:1 , Pigment Red 53:1 , Pigment Orange 43, Pigment Orange 34, Pigment Orange 5, Pigment Green 36, Pigment Green 7, Pigment White 6, Pigment Brown 25, Basic Violet 10, Basic Violet 49, Acid Red 51 , Acid Red 52, Acid Red 14, Acid Blue 9, Acid Yellow 23, Basic Red 10, Basic Red 108. The amount of colorants will usually not exceed 20% by weight of the formulation and preferably ranges from 1 to 15% by weight, based on the total weight of the formulation. It is generally preferred if the colorants are also active as repellents for warmblooded animals, e. g. iron oxide, Tiθ2, Prussian blue, anthraquinone dyes, azo dyes and metal phtalocyanine dyes.

Antifreezes which can be employed especially for aqueous formulations are in principle all those substances which lead to a depression of the melting point of water. Suitable antifreezes comprise alcohols such as methanol, ethanol, isopropanol, butanols, glycol, glycerine, diethylenglycol and the like. Typically, the amount of antifreeze will not exceed 20% by weight and frequently ranges from 1 to 15% by weight, based on the total weight of the formulation.

Gelling agents which are suitable are all substances which can be employed for such purposes in agrochemical compositions, for example cellulose derivatives, polyacrylic acid derivatives, xanthan, modified clays, in particular organically modified phyllosili- cates and highly-dispersed silicates. A particularly suitable gelling agent is carrageen (Satiagel^®). Usually, the amount of gelling agent will not exceed 5% by weight of the formulation and preferably ranges from 0.5 to 5% by weight, based on the total weight of the formulation. Further auxiliary agents that may be present in the seed treatment formulation include solvents, wetters, dispersants, emulsifiers, surfactants, stabilizers, protective colloids, antifoams, and preservatives.

Examples of suitable solvents are water or organic solvents such as aromatic solvents (for example Solvesso^® products, xylene), paraffins (for example mineral oil fractions), alcohols (for example methanol, butanol, pentanol, benzyl alcohol), ketones (for example cyclohexanone, gamma-butyrolactone), pyrrolidones (N-methylpyrrolidone, N-octylpyrrolidone), acetates (glycol diacetate), glycols, fatty acid dimethylamides, fatty acids and fatty acid esters. In principle, solvent mixtures may also be used. However, according to a particular embodiment, the formulations of the present invention contain less than 10% by weight and preferably less than 6% by weight of said organic solvents.

Surface active compounds are all those surfactants which are suitable for formulating agrochemical actives, in particular for the at least one insecticide, and which may be nonionic, cationic, anionic or amphoteric. According to their action, surfactants - sometimes referred to as "additives" - may be divided into wetters, dispersants, emulsifiers or protective colloids; however, these particular groups may overlap and cannot be divided strictly. Typically, the amount of surfactants will not exceed 20% by weight and frequently ranges from 1 to 15% by weight, based on the total weight of the formulation.

Suitable wetters are all those substances which promote wetting and which are con- ventionally used for formulating agrochemical active ingredients. Alkylnaphthalenesul- fonates such as diisopropyl- or diisobutylnaphthalenesulfonat.es can be used preferably.

Dispersants and/or emulsifiers which are suitable are all nonionic, anionic and cationic dispersants or emulsifiers conventionally used for formulating agrochemical active ingredients. The following can preferably be used: nonionic or anionic dispersants and/or emulsifiers or mixtures of nonionic or anionic dispersants and/or emulsifiers.

Suitable nonionic dispersants and/or emulsifiers which may be employed are, in par- ticular, ethylene oxide/alkylene oxide block copolymers, alkylphenol polyglycol ethers and tristyrylphenol polyglycol ethers, for example polyoxyethylene octylphenol ether, ethoxylated isooctylphenol, octylphenol, nonylphenol, alkylphenol polyglycol ether, tributylphenyl polyglycol ether, tristearylphenyl polyglycol ether, alkylarylpolyether alcohols, alcohol and fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ether, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters and methyl cellulose. However, according to a particular embodiment, the formulations of the present invention contain less than 10% by weight and preferably less than 6% by weight of ethylene oxide/alkylene oxide block copolymer, and, more particularly, less than 10% by weight and preferably less than 6% by weight of said nonionic dispersants and/or emulsifiers.

Suitable anionic dispersants which and/or emulsifiers which may be employed are, in particular, alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acid, phenolsulfonic acid, dibutylnaphthalenesulfonic acid, alky- larylsulfonates, alkyl sulfates, alkylsulfonates, fatty alcohol sulfates, fatty acids and sulfated fatty alcohol glycol ethers, furthermore arylsulfonate/formaldehyde condensates, for example condensates of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensates of naphthalene or of naphthalenesulfonic acid with phenol and formaldehyde, ligninsulfonates, lignin-sulfite waste liquors, phosphated or sulfated derivatives of methylcellulose, and salts of polyacrylic acid.

Protective colloids are typically water soluble, amphiphilic polymers. Examples include proteins und denatured proteins such as casein, polysaccharides such as water soluble starch derivatives and cellulose derivatives, in particular hydrophobic modified starch and celluloses, furthermore polycarboxylates such as polyacrylic acid and acrylic acid copolymers, polyvinylalcohol, polyvinylpyrrolidone, vinylpyrrolidone copolymers, polyvi- nyl amines, polyethylene imines and polyalkylene ethers.

Antifoams which can be employed are all those substances which inhibit the development of foam and which are conventionally used for formulating agrochemical active ingredients. Silicone antifoams, i.e. aqueous silicon emulsions (e.g. Silikon® SRE by Wacker or Rhodorsil® by Rhodia), long chain alcohols, fatty acids and salts thereof, e.g. and magnesium stearate are particularly suitable. Usually, the amount of antifoam will not exceed 3% by weight of the formulation and preferably ranges from 0.1 to 2% by weight, based on the total weight of the formulation.

Preservatives which can be employed are all preservatives used for such purposes in agrochemical compositions. Examples which may be mentioned are dichlorophene, isothiazolenes and isothiazolones such as 1 ,2-benzisothiazol-3(2H)-one, 2-methyl-2H-isothiazol-3-one-hydrochloride, 5-chloro-2-(4-chlorobenzyl)-3(2H)- isothiazolone, 5-chloro-2-methyl-2H-isothiazol-3-one, 5-chloro-2-methyl-2H-isothiazol- 3-one, 5-chloro-2-methyl-2H-isothiazol-3-one-hydrochloride, 4,5-dichloro-2-cyclohexyl- 4-isothiazolin-3-one, 4,5-dichloro-2-octyl-2H-isothiazol-3-one, 2-methyl-2H-isothiazol-3- one, 2-methyl-2H-isothiazol-3-one-calcium chloride complex, 2-octyl-2H-isothiazol-3- one and benzyl alcohol hemiformal. Usually, the amount of preservatives will not exceed 2% by weight of the formulation and preferably ranges from 0.01 to 1 % by weight, based on the total weight of the formulation. The skilled person is essentially familiar with agricultural compositions of active ingredients. Examples include water-soluble concentrates (SL, LS), dispersible concentrates (DC), emulsifiable concentrates (EC), emulsions (EW, EO, ES), suspensions (SC, OD, FS), water-dispersible granules (WG, SG), water-dispersible or water-soluble powders (WP, SP, SS, WS), dusts or dustable powders (DP, DS), granules (GR, FG, GG, MG), ULV solutions (UL) and gel formulations (GF). The skilled worker is familiar with such compositions, for example from Ullmann's Encyclopedia of Industrial Chemistry, Fungicides Chapter 4, 5th ed. on CD-ROM, Wiley-VCH, 1997 and Mollet, H., Grubemann, A., Formulation technology, Wiley VCH Verlag GmbH, Weinheim (Federal Republic of Germany), 2001. For seed treatment purposes, such compositions may be applied as such or after addition of a suitable liquid, in particular water, in order to dissolve, emulsify, disperse, suspend or dilute the composition. The type of the ready-to-use preparation applied to the seeds thus depends on the type of composition used and the method used for treating the seeds.

Such compositions can be prepared in the known manner (see e.g. for review US 3,060,084, EP-A 707 445 (for liquid concentrates), Browning, "Agglomeration", Chemical Engineering, Dec. 4, 1967, 147-48, Perry' s Chemical Engineer' s Handbook, 4th Ed., McGraw-Hill, New York, 1963, pages 8-57 and et seq. WO 91/13546, US 4,172,714, US 4,144,050, US 3,920,442, US 5,180,587, US 5,232,701 ,

US 5,208,030, GB 2,095,558, US 3,299,566, Klingman, Weed Control as a Science, John Wiley and Sons, Inc., New York, 1961 , Hance et al., Weed Control Handbook, 8th Ed., Blackwell Scientific Publications, Oxford, 1989 and Mollet, H., Grubemann, A., Formulation technology, Wiley VCH Verlag GmbH, Weinheim (Germany), 2001 , 2. D. A. Knowles, Chemistry and Technology of Agrochemical Formulations, Kluwer Academic Publishers, Dordrecht, 1998 (ISBN 0-7514-0443-8)), for example by extending the active ingredient component with one ore more auxiliary agents.

The following examples simply illustrate said compositions:

A Water-soluble concentrates, solutions (SL, LS)

10 parts by weight of active ingredient are dissolved in 90 parts by weight of water or a water-soluble solvent. As an alternative, wetters or other auxiliaries are added to the phenylsemicarbazone of formula (I) or the agriculturally acceptable salt thereof. The active dissolves upon dilution with water, whereby a formulation with 10% (w/w) of the at least one insecticide is obtained.

B Dispersible concentrates (DC)

20 parts by weight of active ingredient are dissolved in 70 parts by weight of cyclohex- anone with addition of 10 parts by weight of a dispersant, for example polyvinylpyrrolidone. Dilution with water gives a dispersion, whereby a formulation with 20% (w/w) of the active ingredient is obtained. C Emulsifiable concentrates (EC)

15 parts by weight of active ingredient are dissolved in 7 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). Dilution with water gives an emulsion, whereby a formulation with 15% (w/w) of the active ingredient is obtained.

D Emulsions (EW, EO, ES)

25 parts by weight of active ingredient are dissolved in 35 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). This mixture is introduced into 30 parts by weight of water by means of an emulsifier machine (e.g. Ultraturrax) and made into a homogeneous emulsion. Dilution with water gives an emulsion, whereby a formulation with 25% (w/w) of the active ingredient is obtained.

E Suspensions (SC, OD, FS)

In an agitated ball mill, 20 parts by weight of active ingredient are comminuted with addition of 10 parts by weight of dispersants, wetters and 70 parts by weight of water or of an organic solvent to give a fine active compound(s) suspension. Dilution with water gives a stable suspension of the active ingredient, whereby a formulation with 20% (w/w) of the active ingredient is obtained.

F Water-dispersible granules (WG, SG)

50 parts by weight of active ingredient are ground finely with addition of 50 parts by weight of dispersants and wetters and made as water-dispersible or water-soluble granules by means of technical appliances (for example extrusion, spray tower, fluid- ized bed). Dilution with water gives a stable dispersion or solution of the active compound^), whereby a formulation with 50% (w/w) of the active ingredient is obtained.

G Water-dispersible and water-soluble powders (WP, SP, SS, WS)

75 parts by weight of active ingredient are ground in a rotor-stator mill with addition of 25 parts by weight of dispersants, wetters and silica gel. Dilution with water gives a stable dispersion or solution of the active compound(s), whereby a formulation with 75% (w/w) of the active ingredient is obtained.

H Dusts and dustable powders (DP, DS)

5 parts by weight of active ingredient are ground finely and mixed intimately with 95 parts by weight of finely divided kaolin. This gives a dustable product having 5% (w/w) of the active ingredient.

J Granules (GR, FG, GG, MG), 0.5 part by weight of active ingredient is ground finely and associated with 95.5 parts by weight of carriers, whereby a formulation with 0.5% (w/w) of the active ingredient is obtained. Current methods are extrusion, spray-drying or the fluidized bed. This gives granules to be applied undiluted for foliar use.

K ULV solution (UL)

10 parts by weight of active ingredient are dissolved in 90 parts by weight of an organic solvent, for example xylene. This gives a product having 10% (w/w) of the active ingredient, which is applied undiluted for foliar use.

L Gel formulation (GF)

In an agitated ball mill, 20 parts by weight of active ingredient are comminuted with addition of 10 parts by weight of dispersants, 1 part by weight of a gelling agent wetters and 70 parts by weight of water or of an organic solvent to give a fine active com- pound(s) suspension. Dilution with water gives a stable suspension of the active ingredient, whereby a formulation with 20% (w/w) of the active ingredient is obtained.

For the seed treatment according to the present invention, powders, such as water- dispersible, water-soluble and dustable powders, dusts and suspensions are preferred. Further, gel formulations are preferred. Also, water-soluble concentrates and emulsions may be expediently used.

According to the present invention, the following formulations are particularly preferred: flowable concentrates (especially FS); solutions (especially LS); suspensions (espe- daily SC); powders for dry treatment (especially DS); water dispersible powders for slurry treatment (especially WS); water-soluble powders (especially SS) and emulsions (especially ES). Also preferred are gel formulations (especially GF). These formulations can be applied to the seed diluted or undiluted.

According to a particular embodiment, an SC or an FS formulation is used for seed treatment. Typically, an SC and an FS formulation may comprise 1-800 g/l of the at least one insecticide, 0-200 g/l surfactant, 0 to 200 g/l antifreeze agent, 0 to 400 g/l of binder, 0 to 200 g/l of a colorant and up to 1 litre of a solvent, preferably water.

According to a further particular embodiment, the seed treatment formulation of the present invention is a seed coating formulation.

Such seed coating formulations comprise the at least one insecticide, at least one binder (or sticker) and optionally at least one further auxiliary agent that is selected from the group consisting of fillers and plasticizers. Seed coating formulations comprising binders, fillers and/or plasticizers are well-known in the art. Seed coating formulations are disclosed, for example, in US 5,939,356, US 5,882,713, US 5,876,739, US 5,849,320, US 5,834,447, US 5,791 ,084, US 5,661 ,103, US 5,622,003, US 5,580,544, US 5,328,942, US 5,300,127, US 4,735,015, US 4,634,587, US 4,383,391 , US 4,372,080, US 4,339,456, US 4,272,417 and US 4,245,432, among others.

The amount of the at least one insecticide that is included in the coating formulation will vary depending upon the type of seed, but the coating formulation will contain an amount of the at least one insecticide that is insecticidally effective. In general, the amount of the at least one insecticide in the coating formulation will range from about 0.005 to about 75% of the total weight. A more preferred range for the at least one in- secticide is from about 0.01 to about 40%; more preferred is from about 0.05 to about 20%.

The exact amount of the at least one insecticide that is included in the coating formulation is easily determined by one skilled in the art and will vary depending upon the size and other characteristics (surface structure etc.) of the seed to be coated.

The coating formulations formed with the at least one insecticide are capable of effecting a slow rate of release of the at least one insecticide by diffusion or movement through the matrix into the seed.

The present invention also provides a grass seed different from cereal obtainable by the method described above.

Further, the present invention also provides a grass seed different from cereal seeds that has been treated with a seed treatment formulation described above, and in particular that is coated with the formulation or contains it. It also provides a seed obtainable by using the formulation described above.

Preferably, such seeds comprise an insecticidally effective amount of the at least one insecticide. Accordingly, the seeds are coated, impregnated or coated and impregnated in such a manner that the seed, when taken up by the insect to be combated exerts an insecticidal action.

The seeds treated with the at least one insecticide may also be enveloped with a film overcoating to protect the insecticide coating. Such overcoatings are known in the art and may be applied using conventional fluidized bed and drum film coating techniques.

The grass seeds comprising the at least one insecticide are as such sufficiently attractive to incite harmful social insects to eat them or at least to come into contact with them. The attractiveness can be enhanced by using feeding stimulants or sex phero- mones. Food stimulants are chosen, for example, but not exclusively, from animal and/or plant proteins (meat-, fish- or blood meal, insect parts, egg yolk) and from fats and oils of animal and/or plant origin. Mono-, oligo- or polyorganosaccharides, such as sucrose, lactose, fructose, dextrose, glucose, starch, pectin, molasses or honey, and also fresh or decaying parts of fruits are versatile attractants, too, but as they also attract useful insects, such as honeybees, they are preferentially not used. Sex phero- mones are known to be more insect specific. Specific pheromones are described in the literature and are known to those skilled in the art.

The feeding stimulants and sex pheromones can be applied to the grass seeds as part of the above-described compositions or in a separate seed treatment step.

In a specific embodiment, the grass seeds of the invention do not comprise an additional feeding stimulant. More specifically, they neither comprise additional feeding stimulants nor sex pheromones.

Unless indicated otherwise, all amounts in % by weight refer to the weight of the total composition (or formulation).

The grass seeds according to the invention comprise the at least one insecticide in a total amount of preferably from 0.0001 to 5 % by weight, more preferably from 0.0001 to 1 % by weight, even more preferably from 0.0005 to 0.5 % by weight, particularly preferably from 0.001 to 0.1 % by weight, and specifically from 0.001 to 0.05 % by weight, based on the total weight of the seeds according to the invention.

In any case, the grass seeds according to the invention preferably comprise the at least one insecticide in such an amount and are broadcast in such an amount that the application rate of the at least one insecticide per ha corresponds to the usual application rate per ha of the respective insecticide. Just by way of example, in case of fipronil being used as the at least one insecticide, the grass seeds according to the invention comprise fipronil in such an amount and are broadcast in such an amount that the ap- plication rate of fipronil is preferably from 0.1 to 100 g a.i./ha, more preferably from 1 to 50 g a.i./ha, e.g. from 3 to 40 g a.i./ha or from 5 to 40 g a.i./ha or from 10 to 40 g a.i./ha, and is specifically from 10 to 20 g a.i./ha.

The grass seeds according to the invention not only provide a long-acting insecticidal action, for example of at least 6 months or at least 10 months and under advantageous weather conditions of even at least 12 months, but also exhibit their insecticidal effect significantly faster than insecticidal bait or non-bait compositions of the prior art.

The invention is now further illustrated by the following, non-limiting examples. Examples

1. Control of fire ants

All trials were carried out as field tests in areas of reported fire ant (Solenopsis invicta) activity (i.e. with active mounds). The fields were grassland with no agricultural use (mostly bermudagrass). Plots were either a specified area (0.125 ha in example 1.1 ) or the plots were assigned so that all treatments started with almost the same number of active mounds (example 1.2).

1.1 Bermudagrass seeds

Bermudagrass seeds (Cynodon dactylon) were treated with fipronil (used as the commercial product Regent ® 4 SC from BASF; 35.2 g ai/ha) in a rotating cement mixer. Untreated seeds were used for comparison. All seeds (treated and untreated) were sown in an amount of 448 kg/ha, thus having in each case an identical ratio of seeds per hectare. As a comparison, Firestar®, a fipronil bait formulation from Bayer (contains 0.00015 % by weight of fipronil) was used (10 Ib/acre; 0.017 g ai/ha; application rate within the margins recommended by the producer).

A part of the treated seeds and the untreated seeds were overseeded with a seed spreader and left on the top of the ground to be harvested by the ants. A second part of the treated seeds were slit-seeded. Firestar® was applied by broadcasting the product to the ground.

The resulting fire ant activity was assessed 14, 28, 42 and 61 days after treatment (DAT; see table below) by slightly disturbing each fire ant mound in the plot and looking for any fire ant activity (movement or presence of fire ants). If activity was seen, the mounds were rated as being active. If ant activity was not visible, the mound was counted as being controlled by the treatment.

Table 1

number of active mounds per plot * percent control. 0% means no control (fully activated mounds) and 100% means complete control of the mounds.

⁺ no rainfall 4 days prior to application and 4 days following application

1.2 Ryegrass seeds

Perennial ryegrass seeds (Lolium perenne) were treated with fipronil (used as the commercial product Regent® FS from BASF (in some countries also called BAS 350 UCI) (500 g/l)) in a rotating cement mixer. In one treatment 1 1.2 ml of Regent ® FS were applied to 181.8 kg of seed (13.8 g ai/ha). In another treatment, 60.6 kg of seeds were treated with 1 1.2 ml of Regent ® FS while 121.2 kg of seeds were not, and then the treated and untreated seeds were thoroughly mixed, thus resulting in seeds containing the same average amount of fipronil as the first treatment ("seed blend") (13.8 g ai/ha). Untreated seeds were used for comparison. All seeds (treated, untreated and seed blend) were sown in an amount of 448 kg/ha, thus having in each case an identical ratio of seeds per hectare. Moreover, a commercial granular fipronil product (Chipco Top Choice® from Bayer; contains 0.0143% by weight of fipronil) was used for comparison (87 lbs of formulated product/acre = 97 kg of formulated product/ha - as recommended by the producer; 13.8 g ai/ha.).

The treated or untreated seeds were overseeded with a seed spreader and left on the top of the ground to be harvested by the ants. Chipco Top Choice® was broadcast with a granulator.

The resulting fire ant activity was assessed 17, 50, 255 and 353 days after treatment (DAT; see table below) by slightly disturbing each fire ant mound in the plot and looking for any fire ant activity (movement or presence of fire ants). If activity was seen, the mounds were rated as being active. If ant activity was not visible, the mound was counted as being controlled by the treatment.

Table 2

^* number of active mounds per plot * percent control. 0% means no control (fully activated mounds) and 100% means complete control of the mounds.

As the examples show, the seeds according to the invention exert their insecticidal action much faster than the prior art products and keep their activity for a comparable time period.

Claims

We claim:

1. Grass seeds different from cereal seeds, comprising at least one insecticide.

2. The grass seeds as claimed in claim 1 , where the insecticide is selected from GABA-antagonists and nicotonic receptor agonists/antagonists.

3. The grass seeds as claimed in claim 2, where the GABA-antagonists are selected from acetoprole, endosulfan, vaniliprole, pyrafluprole, pyriprole, the phenylpyrazole compound of the formula Il

or an agriculturally acceptable salt thereof.

4. The grass seeds as claimed in claim 3, where R^c is ethyl or trifluoromethyl.

5. The grass seeds as claimed in claim 4, where the compound of formula Il is fipronil.

6. The grass seeds as claimed in any of claims 1 or 2, where the nicotinic receptor agonists/antagonists are selected from acetamiprid, clothianidin, dinotefuran, imi- dacloprid, nitenpyram, thiacloprid and thiamethoxam.

7. The grass seeds as claimed in claim 6, where the nicotinic receptor agonists/antagonists are selected from acetamiprid, clothianidin, imidacloprid and thiamethoxam.

8. The grass seeds as claimed in any of the preceding claims, where the grass seeds are selected from the family of Poaceae.

9. The grass seeds as claimed in claim 8, where the grass seeds are selected from ryegrass, bermudagrass, centipedegrass, switchgrass, indiangrass, bluegrass, orchardgrass, big bluestem grass, little bluestem grass and fescue seeds.

10. The grass seeds as claimed in claim 9, where the grass seeds are bermudagrass seeds or ryegrass seeds.

1 1. The grass seeds as claimed in any of the preceding claims, where the grass seeds have been imbibed or coated with at least one insecticide as defined in any of claims 1 to 7.

12. The grass seeds as claimed in any of the preceding claims, comprising the at least one insecticide in a total amount of from 0.0001 to 5 % by weight, based on the total weight of grass seeds.

13. The use of grass seeds different from cereal seeds which have been treated with at least one insecticide as defined in any of claims 1 to 12, as baits for combating harmful social insects.

14. The use as claimed in claim 13, where the harmful social insects are selected from termites and fire ants.

15. A method for combating harmful social insects which method comprises applying to the habitat or food supply of the harmful social insects, or to the soil, area, material or environment in which the harmful social insects are staying at least tem- porarily, or to the materials, soils, surfaces or spaces to be protected from insect attack or infestation grass seeds different from cereal seeds which have been treated with at least one insecticide as defined in any of claims 1 to 12.

16. The method as claimed in claim 15, where the harmful social insects are selected from termites and fire ants.