FR2552627A1 - Oily pesticidal compositions based on entomopathogenic viruses. - Google Patents

Abstract

Oily composition in the form of a fluid suspension which comprises: a. 1 to 20 % of a viral powder based on entomopathogenic viruses; b. 5 to 40 % of an oil which is acceptable to the insects and/or mites to be destroyed; c. 0.1 to 2 % of an emulsifier; d. 1 to 40 % of a stabiliser protecting against ultraviolet; e. 5 to 30 % of a mineral pigment; and f. water to 100 %. It can be used in agriculture for controlling insects and/or mites which destroy crops and forests.

Description

 The present invention relates to novel oily pesticidal compositions based on entomopathogenic viruses and their use for insecticide and / or acaricide treatments.

 For a few years now, the aim has been to develop a new medium for the control of phytophagous insects and / or pests and forest pests, including the caterpillars of the main cotton pests, which introduce / or mites to be destroyed, entomppathogenic viruses responsible for viral diseases of these insects and / or mites.

These viruses are usually Baculoviruses that are prepared, usually in the form of viral powders, from caterpillars previously contaminated with these viruses. These caterpillars thus contaminated are then crushed and the powder thus obtained is then removed dead bodies of caterpillars by filtration according to techniques now well developed. The ingestion of these viral powders by insects and / or mites results in the destruction of the target species, in more or less significant proportions. The viruses used for this purpose are usually chosen from: - the nuclear polyhedrosis virus, also designated by the
Letters "NPV" (Nuclear polyhedrosis virus), obtained
for example from Spodoptera litto caterpillars
ralis or Mamestra brassicae; cytoplasmic polyhedrosis virus, also designed by
the letters "CPV" (Cytoplasmic polyhedrosis virus); - the granulosis virus with inclusions, also designated by
the letter "GIV" (Granulosis inclusions virus).

 These viruses are usually prepared from lepidopteran farms that are pests of crops such as moths.

 For their practical use, these viral powders are generally not used alone, but are mixed with various constituents, in order to obtain compositions for agricultural use, which can be applied to crops by means of apparatus used for agricultural treatments. .

 The preparation of these compositions for agricultural use, from the viral powders mentioned above, however, faces a number of difficulties that have up to now impede their development.

 Firstly, the viruses used in these viral powders are generally very sensitive to the action of certain ultraviolet rays, in particular those with a short wavelength (254 nm), which results in a rapid loss of virulence. these viruses and a very significant decrease in the insecticidal effect.

 Moreover, it is generally difficult to prepare from these viral powders compositions that can be used for the so-called "very low volume" treatments or "U.L.V." treatments. and at the same time stable storage and handling.

 "ULV treatments" means pesticidal agricultural treatments according to which a very small volume of "slurry" (ie dispersion or solution of the active ingredient) is applied per hectare of treated crop, generally between 1 and 5 1 / ha. These treatments U.L.V. are increasingly used in countries where water is scarce, especially in many cotton-growing countries in Africa, especially for pesticide treatments of cotton plants against their main pests.

 The present invention aims to remedy the disadvantages mentioned above.

It relates to an oily insecticide and / or acaricidal composition characterized in that - this composition is constituted by a suspension
viral powder fluid in an oil type emulsion
in water, and in that it comprises by weight
a- from 0.5 to 20% of a viral powder based on
entomopathogenic viruses,
b- from 1 to 40% of an oil acceptable by insects and / or mites to be destroyed,
c- 0.1 to 4 t of an emulsifier,
d- from 1 to 40 t of an ultraviolet anti stabitizer,
suitable for the stabilization of thin layers, and
sensing a maximum absorption between 250 nm
and 350 nm,
e- from 5 to 30% of a mineral pigment, finely crushed,
f- and water for the complement to 100 t.

 The compositions according to the invention are generally in the form of a fluid suspension of viral powder in a binary emulsion of the oil-in-water type. They may also be in the form of a fluid suspension of the viral powder in a ternary oil / ultraviolet / water absorber emulsion. These types of liquid compositions are often referred to in current agricultural practice as "fluid pastes" or "creams", or in English "concentrated flowables".

 The compositions according to the invention have good stability in storage and handling even in the case of prolonged storage. They are suitable - especially for so-called U.L.V. treatments. They can be used either in the state or after dilution with water, depending on the application technique used.

 The viral powders that can be used for the preparation of the compositions according to the invention are generally based on Baculovirus, advantageously of the "nuclear polyhedrosis virus (NPV) type or of the" inclusion granulosis virus "(GIV) type or of the" cytoplasmic virus "type. "(CPv), generally derived from various lepidopteran pests of crops.

Preferably, the compositions according to the invention contain, as active ingredient, a viral powder based on NPV type viruses. In the examples of compositions described below, this viral powder contains about
10 10 polyhedra / g, this value is however not critical.

 The oil used in the compositions according to the invention may be of various nature provided that it is acceptable by insects and / or mites to be destroyed, that is to say that it must be able to be ingested by said insects and / or mites. Its viscosity is advantageously between 20 and 30 centistokes.

 This oil is preferably a vegetable oil, preferably an industrial peanut oil. It is also possible to use other vegetable oils, preferably non-drying oils, or semi-drying oils, advantageously stabilized by an antioxidant which can be either natural, such as tocopherol, or synthetic, such as gallic acid. ethyl or propyl.

 Apart from vegetable oils, it is also possible to use mineral oils, or animal oils, of food grade.

 The emulsifier used in the compositions according to the invention is preferably nonionic. It is thus possible advantageously to use one or more fatty alcohols, linear or branched, generally containing 10 to 14 carbon atoms each, polyethoxylated with 8 to 12 moles of ethylene oxide per mole of fatty alcohol.

In addition to the polyethoxylated fatty alcohols mentioned above, other nonionic emulsifiers may be used in the context of the present invention, for example polyethoxylated alkylphenols. Preferably, from 0.5 to 2% by weight of emulsifier is used.
The anti-ultraviolet stabilizer, also called UV absorber, used in the compositions according to the invention, must be adapted to the stabilization of thin layers, such as thin strands applied to the surface of plants and cultures, during insecticidal treatments. It must also have a maximum absorption between 250 nm and 350 nm. It may itself be oily and soluble in the oil mentioned above. Suitable oily stabilizers are cyanoacrylic acid esters, such as, for example, the cyano-diphenyl acrylic acid ethylhexyl ester. The anti-ultraviolet stabilizer used in the compositions of the invention may also be in the form of a powder which is soluble in water, advantageously of the benzophenone type, such as, for example, 2-hydroxy-4-methoxybenzophenone acid. sulfonic acid. It can also be constituted by a mixture of an oil soluble stabilizer and a water soluble stabilizer.

 Preferably, an oily ultraviolet stabilizer is used, the advantage of the oily presentation being to allow an intimate mixture with the oil mentioned above and thus to improve the persistence of the film, and consequently of the viruses on the foliage treated.

 The mineral pigment, preferably white, is advantageously a titanium or zinc oxide. Titanium dioxide (TiO2), which is preferably finely ground and whose particle diameter is advantageously of the order of 1 to 5 microns, is preferably used.

 In addition to the a-b-c-d-e-f components mentioned above, the compositions according to the invention may additionally contain various suitable additives.

 Thus, when it is desired to reduce the amount of oil present in the composition, to reduce a possible phytotoxicity without impairing the biological properties, it is advantageous to add to the composition from 0.1% to 28% by weight of a substantially neutral hydrophilic silica.

For the purposes of the invention, hydrophilic silica is understood to mean a synthetic silica such as an ultrafine hydrated precipitation silica with a high specific surface area of about 250 to 300 m 2 / g, measured according to the method
BET

 Such a silica is substantially neutral, ie its pS, in aqueous solution is 7 # 0.5.

The compositions according to the invention may also contain other additives such as s - viscosity agents, or thickeners in general of 0.06 to 0.12% by weight, of the polysaccharide type, in particular heteropolysaccharides resulting from the fermentation of carbohydrates. by a microorganism of the genus
Xanthomonas, - dispersants of pigments, in aqueous medium, of the sodium polycarboxylate type (generally from 0.2 to 0.8% by weight), - antifreezing agents, preferably appetizing and / or retaining agents; water, (generally from 5 to 10% by weight, advantageously of the polyol type, acceptable for insects and mites.Glycerol (or propanetriol), or carbohydrates, is preferably used, antifoam agents (generally , 2 to 0.8% by weight), such as silicone oil emulsions.

 The compositions according to the invention advantageously contain, in addition, an effective amount of one or more suitable preservatives whose role is to prevent the proliferation of microbes and / or fungi in these compositions. Effective efficacy means a sufficient amount of ego to prevent this proliferation without having a harmful effect on viruses.

This "effective amount" may vary depending on the choice of the preservative. As preserving agents, it is advantageous to use soda derivatives of alkyl (hydroxy) benzoates, such as, for example, 4-methyl-substituted benzoate or 4-hydroxypropyl-substituted benzoate. It is also possible to advantageously use thiuram (or TMTD). . The compositions according to the invention usually contain from 0.05% to 0.5% by weight of one or other of these preservatives.

 the compositions according to the invention can be prepared in three steps. The first step is to prepare the oil-in-water emulsion in a tank which is well stirred, by pouring oil into the water.

The oily phase contains the emulsifier and the oily stabilizer and the aqueous phase the other water-soluble additives.

 In a second step, the viral powder and optionally the minera pigment, the thiuram and the hydrophilic silica are dispersed in the oily emulsion, still with stirring. The suspension obtained is then refined in a mill, for example of the super-colloid MORITZ type or ball type DYNO-MILL. In the third and last step the viscosity agent is dispersed in a small amount of water containing the soluble preservative, for example 4-hydroxy sodium benzoate. This dispersion is incorporated in the viral suspension described above. Other preservatives can be used.

 The oily compositions of viral powder according to the invention have, in addition to the advantage of a fluid formulation, easier handling than a wettable powder, the advantage of being used as such or after dilution in water, following application techniques. It is possible, for example, to adjust the viscosity of the oily composition so that it can be sprayed as such by means of an ULV treatment apparatus (required viscosity 1.5 to 2.50 Engler) or else to dilute the composition. oily composition more viscous, for example at a rate of 1 kg or 1 liter of this composition in 0.5 to 2 liters of water for the same application, or with a larger volume of water for conventional treatments. in each treatment varies from 1011 to 1013 polyhedra per hectare, their effects being appreciated by caterpillar mortality, the number of survivors at the time of pupation, and foliage damage.

 In addition to the compositions described above, the present invention relates to an insecticidal and / or acaricidal treatment method. This process is characterized in that it consists in applying to the cultures and / or forests an effective amount of a composition as described above, or prepared from such a composition by dilution with a diluent. appropriate, generally water.

 The following examples are given without limitation to illustrate the invention.

Example 1
By operating according to the method described above, an oily suspension of the following weight composition is prepared in t: - viral powder "NPV" containing about 1010
polyhedra / g - 2.5
(Spodoptera or Mamestra strain) - industrial groundnut oil 30.0 - polyethoxylated C13 fatty alcohols
9-10 moles of ethylene oxide ~ 1.0 - anti-ultraviolet stabilizer soluble in oil
(UVINUL N 539) ................................... 10.0 - titanium oxide with a diameter of particles of about
2 microns * 17.5 - 40% aqueous solution of sodium polycarboxylate, 1.0 glycerol S, O - 0.8-heteropolysaccharide silicone oil emulsion (RHODOPOL 23) .......... ....... 0,1 - thiuram. .......................................... 0,1 - 4-hydroxy benzoate Sodium methyl 0,2 - water qs, 100 g
Uvinul N 539 is the ethylhexyl ester of cyanodiphenylacrylic acid.

 RHODOPOL 23 is a heteropolysaccharide biopolymer derived from the fermentation of Xanthomonas campestris on carbohydrates.

 UVINUL MS 40 is 2-hydroxy-4-methoxy benzophenone sulfonic acid.

Example 2
According to the method of Example 1, a suspension of the following composition is prepared in% - "NPV" viral powder containing about 10
polyhedra / g .................................. 2,5
(Spodoptera or Mamestra strain) - industrial peanut oil ~ 30.0 - C13 fatty alcohols, polyethoxylated by
9-10 moles of ethylene oxide; 1.0 - anti-ultraviolet stabilizer, soluble in water
(UVINUL NS 40) ................................ 5.0 - titanium oxide with particle diameter of l order of
2 microns 22.5 - 40% aqueous solution of polycarboxylate
sodium ....................................... 1.0 - emulsion of silicone oil. ..................... 0,8 - glycerol ........................ ............... 5.0 - heteropolysaccharide (RHODOPOL 23) ............. 0,1 - thiuram ........ .............................. O, 1-hydroxy-4-methyl-sodium benzoate ......... ... 0,2 - water ........... qsp ......................... 100 g
Example 3
According to the method of Example 1, an oily suspension with the following weight composition is prepared in O :: viral powder wNPVN containing about 1010
polyhedra / g .................................... 2,5
(Spodoptera or Mamestra sugar) - industrial peanut oil, 30.0 - ethoxylated C13 fatty alcohols
9-10 moles of ethylene oxide .................. 1.0 - anti-ultraviolet stabilizer soluble in oil
(UVINUL N 539) ................................. 5.0 - anti-ultraviolet stabilizer soluble in water 'water
(UVINUL MS 40) ............................... 5.0 - Particle diameter titanium oxide of the order of
2 microns .................................... 17,5 - glycerol ....... ................................ 5.0 - aqueous polycarboxylate solution
40% sodium ................................. 1.0 - silicone oil emulsion .... .................. 0,8 - heteropolysaccharide (RHODOPL 23) ............. 0,08 - thiuram ..... ................................. 0,1 - Sodium methyl hydroxy-4-benzoate ..... ........ 0,2 - water ........... qsp ........................ 100 g
Example 4
According to the method of Example 1, an oily suspension of the following composition by weight, in-e-viral powder "NPV" containing about 1010 is prepared.
polyhedra / g ................, .................. 5,0
(Spodoptera or hiamestra strain) - industrial peanut oil ................. 20.0 - ethoxylated C13 fatty alcohols with 9-10 moles of ethylene oxide * 0.8 - anti-ultraviolet stabilizer soluble in water
(UVINUL N 539) * 12.0 - titanium oxide with particle diameter of
about 2 microns 20.0 - glycerol ........................................ 5, 0 - aqueous solution of polycarboxylate
40% sodium .................................... 1.0 - silicone oil emulsion. ........................ 0.8 - neutral hydrophilic silica + 1.0 - heteropolysaccharide (RHODOPOL 23) ......... ....... 0,12 - thiuram ...................................... .... 0.1 - methyl hydroxy-4-benzoate sode ................ 0.2 - water ........... qsq. .......................... 100 g
Example 5
According to the method of Example 1, an oily suspension with the following weight composition is prepared in% - "NPV" viral powder containing about 10
polyhedra / g; 2,5 - industrial peanut oil ................. 30,0 - ethoxylated C13 fatty alcohols by
9-10 moles of ethylene oxide ................. 1.0 - anti-ultraviolet stabilizer soluble in water
(UVINUL N 539) ............................... 10,0
- titanium oxide particle diameter of the order of
2 microns .................................... 17.5 - glucose syrupy crystal ..... ................. 10.0 - 40% aqueous sodium polycarboxylate solution; 1.0 - silicone oil emulsion; 0.8 - heteropolysaccharide (RHODOPOL 23) ............. 0.08 - thiuram ....................... ............... 0,1 - 4-hydroxy-4-methyl-sodium benzoate ............. 0.3 - water ...... ..... qsp ......................... 100 g
Example 6
Ultraviolet irradiation resistance tests
These tests were conducted in the laboratory on a synthetic nutrient medium suitable for
Spodoptera litura, parasite of cotton close to the
Spodoptera littoralis.

 The oily compositions used for these tests are those described in Examples 1 and 3. Folles were obtained by first preparing the oil emulsion in water and then incorporating therein a quantity of NPV viral powder giving 5.105 polyhedra / ml, then finally diluting with water this preparation to obtain the desired concentrations. As a control, an aqueous suspension of viral powder N.P.V.

Establishment of the test
The synthetic nutrient medium is poured into compartments of plastic material. In each box
(13 x 13 mm) are deposited 100 microliters of the virus dilution. Two boxes are prepared for each concentrate
and two for the control batch. After drying a box of each pair is placed for 1 minute-at a distance of 20 cm under a ramp of 4 MAZDA 9E TG 30 lamps giving
at the level of the boxes an ultraviolet irradiation (254
2
nm) of 0.8 mW / cm
Then 40 caterpillars are deposited in each box, one per box. The boxes are covered with a filter paper and a lid pierced with small holes, then stored upside down in an oven at 260C. After 8 days, we note the number of dead caterpillars and the number of caterpillars still alive but affected by virosis.

These results are shown in the table below:
Dose% formulations of dead caterpillars
studied thousands of viruses by (non virus (virus
irradiated caterpillar) irradiated)
2 55 5
Witness 10 45 20
2 65 45
Example 1 10 75 55 50 100 75
2 47.5 35
Example 3 77.5 60
From these results, it is observed that, in the case of the control, a simple ultraviolet irradiation leads to a considerable drop in the insecticidal activity, this drop itself resulting in a very significant destruction of the viruses in this composition. By comparison, it will be observed that, under the same conditions, the fall in insecticidal activity resulting from the ultraviolet irradiation is much lower when using the compositions according to Examples 1 and 3 of the present invention.

Claims (9)

1) Oily insecticidal and / or acaricidal composition,  characterized in that: - it is constituted by a suspension fluid ion of powder  viral in an oil - in - water emulsion, -. and she understands  a) from 1% to 20% of a viral powder containing  entomopathogenic viruses,  (b) from 1% to 40% of an acceptable oil for  insects and / or mites to be destroyed,  c) from 0.1 to 4% of an emulsifier,  d) from 1% to 40% of an anti-ultraviolet stabilizer  adapts to the stabilization of thin layers and  having an absorption maximum of between 250 nm  and 350 nm,  e) from 5% to 30% of a fine mineral pigment  milled,  f) and water, for the compliment at 100 8. 2) Composition according to claim 1, characterized in that  that it additionally contains an effective amount of one or  several preservatives preventing the proliferation  microbes and / or fungi. 3) Composition according to one of claims 1 or 2 carac  in that the viral powder is Baculo-based  virus of the type nuclear polyddrose virus (NPV), or  type cytoplasmic polyhedrosis virus (CPV) or type  Inclusion granulosis virus (GIV). 4) Composition according to one of claims 1 to 3, carac  characterized in that the emulsifier is selected from  polyethoxylated fatty alcohols and that these fatty alcohols  comprise from 10 to 14 carbon atoms and are poly  ethoxylated with 8 to 12 moles of ethylene oxide. 5) Composition according to one of claims 1 to 4, carac  in that the anti-ultraviolet stabilizer is  selected from the esters of cyanoacrylic acids and  benzophenone derivatives, alone or as mixtures between  them. 6) Composition according to one of claims 1 to 5, carac  in that the mineral pigment is carbon dioxide  titanium. 7) Composition according to one of claims 1 to 6, carac  characterized in that the preservative is selected from  methyl 4-hydroxy benzoate and thiuram. 8) Composition according to claim 7 characterized in that  that it contains, by weight, from 0.05 to 0.5 t of  Conservative. 9) insecticide treatment method and / or acaricide  terise in that it involves applying to crops  and / or forests an effective amount of a composition  according to one of claims 1 to 8.