NL8602384A - METHOD FOR DETERMINING PLANT FUNGI AND APPARATUS FOR EXPORTING THAT. - Google Patents

Description

. d l

X \ * 'Q

- i - *. · *. * ·. * '*

Method for determining plant syndromes and apparatus for carrying them out.

The invention relates to a method I.. the for determining or identifying plant fungi and on a device for carrying them out. *

It is known that cereals are affected by certain diseases, so-called foot-end diseases, namely: • ‘Trapezium fractures caused by- * - - • • Pseudocercosporella repotrichoids…

root damage. (rhizoctoniaj caused by Rhizoctonia cerealis * - fungal attack (fusariose) caused by Fusarium nivale and Fusarium roseum.

These diseases, which commonly form the parasitic foot-end complex in crops, often present difficulties in determining by simply considering the symptoms because they are very similar, often atypical, and with the pathogenic strain, in addition, these diseases often occur together in the crops.

Determining the vague cause of cereal dieback is necessary for several reasons: to investigate compounds active against these infestations, to conduct planting tests to determine whether parcels containing one or more of the these pathogens-- - * - -.

"25 have been contaminated, to assess the effect of the treatment on the crop, and for the farmer to know which pesticides are effective.

Therefore, there is a need for a practical test method for determining foot-end diseases in; Cereals.

§302334 - 2 -

The determination must be extremely, simple and as fast as possible in the test station or in the open field and with an easily manageable and reliable material.

It has been found that the diseases constituting the parasitic complex can be easily and reliably identified using a device comprising an in vitro assay kit on selective nutrient media, each of which in itself exerts a specific development of each plant fungus. uniquely cause, namely: a) a selective medium for Pseudocerco-sporella herpotrichoides, i.e. a medium on which the growth of Fusarium sp. and Rhizoctonia sp., and optionally of other pathogenic or non-pathogenic fungi, is inhibited or delayed without hindering those of Pseudocercosporella herpotrichoides (this medium is hereinafter referred to as halbromosity medium), b) a selective medium for Rhizoctonia sp. (in particular Rhizoctonia cerealis), i.e. a medium on which the mycelial growth of Fusarium sp. and Pseudocerco »20 sporella herpotrichoides, and any other pathogenic or non-pathogenic fungi is inhibited or retarded without those of Rhizoctonia sp. (this medium is hereinafter referred to as root attack medium), c) a selective medium for Fusarium, ie a medium on which the growth of Rhizoctonia sp.

and P seudocerco sporella herpotrichoides, and any other pathogenic or non-pathogenic fungi is inhibited or retarded without inhibiting or retarding those of Fusarium sp., in particular F.nivale and F.roseum (this medium is subsequently referred to as fungal 30 referred to as attack medium).

These media are suitable nutrient media for each fungus, preferably collectively, each containing the following fungicidal mixtures: a) the stent breakage medium: 160-240 ppm 0,0-diethylphthalimide phosphonothioate (ditalimphos) and 4-6 ppm 1-isopropylcarbamoyl- 3- (3,5-di-8602584 -3-chlorophenyl) hydantholine (iprodione) or an equivalent amount of 3- (3,5-dichlorophenyl) -1,2-dicarboximide of the formula 1 where R is a group of the formula 2 wherein a methoxymethyl group (myclozoline), ethoxycarbonyl group 5 (chlozolinate) or vinyl group (finlozoline) represents, or a group of formula 3 wherein R 2 represents a methyl group and and R 2 together form a methylene bridge (procymidone) or R ^ r R ^ and R ,. each represent a hydrogen atom and R 1 represents a vinyl group (dimetaclon) or methoxymethyl group (metomeclan), where iprodione or the compound of the formula 1 may be replaced by 24-36 ppm 2,6-dichloro-p-tolyl-0 , O-dimethyl thiophosphate (tolclophos-methyl), or 24-36 ppm tolclophos-methyl and 24-36 ppm pentachloomitrobenzene (PCNB), b) the rooting medium: 15 0.4-0.6 ppm methyl 2- (benzimidazole carbamate) (carbendazim ) or an equivalent amount of one of its precursors such as methyl (1-butylcazbamoyl-2-benzimidazolyl) carbamate (benomyl), methyl or ethyl 4,4-CM: enylene bis (thiallophanate) (methyl ethyl disodium and ethyl thiophenate and 2-furyl-20 benzimidazole (fuberidazole), where carbendazim or one of its precursors is combined with 0.4-2 ppm of 1 / N-propyl-N-2- (2,4,6-trichlorophenoxy) -ethylcarbamoyl-7iniidazole (prochloraz), and c) the fungal attack medium i 1.6-2.4 ppm 1- / 2- (2,4-dichlorophenyl) -n-pentyl_7-1H-1,2,4-triazole (pencona zol) or 4-6 ppm (RS) -2,4-di-fluoro (1H-1,2,4-triazol-1-ylmethyl) benzhydrol (flutriafol) and 4-6 ppm iprodione or an equivalent amount of 3- ( 3,5-dichloro-phenyl) -1,2-dicarboximide of the formula 1, or a combination of 16-24 ppm polyoxin and 56-84 ppm tetrachloroisophthalonitrile 30 (chlorothalonil).

According to a variant, the halm fracture medium may also contain 8-12 ppm carbendazim or a precursor thereof to detect strains resistant to this type of fungicide-

As the nutrient medium, any agar medium suitable for cultivation of the fungi can be used, for example Sabouraud medium or P.D.A. (potato dextrose agar).

8502384 f - 4 -

The invention further relates to a device for performing the determination method according to the invention.

Characteristic for the device according to the invention is that it comprises at least three zones (hereinafter referred to as selective zones), which respectively contain the culm fracture medium, root damage medium and fungal attack medium, and optionally at least one blank zone without fungicide but optionally with an antibiotic, and further, optionally, a selective ammonia broth with 5-50 ppm carbendazim or one of its precursor containing zone.

The zones can abut each other or be housed in separate compartments. The compartments may consist of containers with a mixture of selective medium and selective nutrients, and together form a set that is easy to handle or transport. The containers can be of glass, plastic or other inert material, and have a bottom and walls by which they are separated from each other.

Each selective zone in the device according to the invention usually contains a mixture of one of the selective media and nutrients. The culture media are prepared by carefully mixing the nutrients which may optionally contain antibiotics such as streptomycin, penicillin, aureomycin, or pimaricin with a solution in, for example, acetone or aqueous dispersion of fungicide. Each compartment is filled by hand or automatically by injection, for example under pressure and under heating to ensure good homogeneity of the mixture. This can also be checked with a dye solution.

According to another embodiment, a porous support such as paper (paper) is impregnated with the selective feed medium. To this end, the selective nutrient medium is poured onto the porous support, or an impregnated porous support is rehydrated followed by dehydration.

The device is usually provided with a lid or other closing means, and can for instance consist of a 8602384-5 divided into a Petri dish, and is then ready for use.

In carrying out the determination method according to the invention, a piece is cut off the culm of the affected cereal crop 5, which is first washed with water and then immersed in a surface disinfectant such as, for example, bleach (hypochlorite solution), potassium permanganate or ethanol. After rinsing, the stem piece is divided into three parts and each part is placed in one of the compartments 10. After the lid has been applied, it is incubated for 10 days at ambient temperature in natural or artificial light. Afterwards, fungal development is monitored for mycelium growth in each compartment and expressed as a percentage of growth in the blank compartment. The growth percentage can optionally be plotted against time on graph paper which may form part of the device according to the invention.

When using a device in which the different selective zones come into contact with each other, a single piece of blade is placed on the touch point and it is sufficient to examine whether at least one of the selective zones with which the piece of blade is in contact, growth has occurred.

In yet another embodiment, the selective nutrient media are prepared just before use by contacting a simple nutrient medium (ie, a non-selective medium without fungicide) with a porous support (paper (paper) or other material) containing identifying fungicides (and possibly water) are impregnated.

Example I

30 A set of Petri dishes, each containing a nutrient medium P.D.A. (potato dextrose agar) containing a mixture of 100ppm streptomycin, 50ppm penicillin and 50ppm aureomycin, and respectively: a) in the dish with halomobility medium 35 a mixture of 200ppm ditalimphos and 5ppm iprodione, b) in the dish with root damage medium 8802384 4 '"ς.

- 6 - a mixture of 0.5 ppm carbendazim and 0.5 ppm prochloraz, and c) in the dish with fungal attack medium 2 ppm penconazole and 5 ppm iprodione.

The three Petri dishes are used in the laboratory or taken into the open field in a larger container.

Three pieces of 0.3-0.5 cm each are cut from a wheat blade, variety Nebraska with undifferentiated traces of foot-end cereal disease, which are washed for 2 minutes after rinsing with 10 water with successively a sodium hypochlorite solution with an active chlorine content. of 2% and water, and dried on filter paper.

A piece of stem is then placed in each Petri dish and incubated for 10 days at ambient temperature and in 15 natural light.

Afterwards, the appearance of the growth (thalli) is noted and the diameter is measured. The development of mycelium in each dish is observed with the naked eye and * microscopically verified.

20 The determinations will be carried out in June and July on three wheat varieties, Nebraska, Lutin and Corin. Each culm has first been experimentally examined to see whether it shows one of the three foot-end diseases and not one or two others. The distribution of diseases indicated in the table below was then determined. The percentages are inhibition percentages.

a single complex of two miscellaneous, bac infestation, teries, yeast, none 30__. _____effecting_

H W S__H + W W + S

H 80% 8% 8% 4% W 90% 4% 3% 2% 1% S 90% 8% 2% 35 H = stickiness, W = root attack, S = fungal attack.

8602384 - 7 - "f" ►

Example II

Proceeding according to Example I, satisfactory results are obtained in the halftreatment medium of iprodione with 30 ppm of tolclophos-methyl.

Example III

Example I is repeated with the addition of 10 ppm of carbendazim to the brambling medium. Furthermore, by cultivating carbendazim resistant Pseudocercosporella herpotrichoid laboratory strains, it can be determined that this fungus develops well in the mediocrity medium.

Example IV

Example I is repeated using 20 ppm polyoxin and 70 ppm chlorothalönil as fungicides.

The examples show that the determination method according to the invention is simple and easy to perform, even by inexperienced personnel. It lends itself to use for the determination of the above diseases in all relevant cereal crops, in particular wheat, oats, barley and rye.

The method of determination lends itself particularly to the early identification of each of the diseases of the parasitic foot-end disease complex in cereals at a stage when they are very difficult or even impossible to identify by the farmer.

25 §602384

Claims (11)

Method for determining each of the diseases of the parasitic foot-end disease complex in cereal crops, characterized in that parts of affected cereal stems are contacted in vitro with each of the three media specific to each of the diseases: (a) a culmination medium selective for 'Pseudocercosporella herpotrichoides and on which the growth of The method according to claim 1, characterized in that the stiffness fracturing medium is 160-240 ppm 0,0-diethyl-N-phthalimidothiophosphonate (ditalimphos) and 4-6 ppm 3- (3,5-dichlorophenyl) -1-iso -propylcarbamoylhydantolne (iprodione) or an equivalent amount of 3- (3,5-dichlorophenyl) -1,2-dicarboximide of the formula 1 wherein R represents a group of the formula 2 wherein R 1 represents a methoxymethyl group (myclozoline ), ethoxycarbonyl group (chlozolinate) or vinyl group (finlozoline), or a group of the formula wherein R2 and Rg represent a methyl group and R3 and R4 together form a methylene bridge (procy-midon), or R3, and Rg each represent a hydrogen atom and 8602384 * i -J- represents a vinyl group (dimetaclon) or methoxymethyl group (metomeclan), where iprodione or the compound of formula 1 may be replaced by 24-36 ppm 2,6-dichloro-p- 5-toli-0,0-dimethylthiophosphate (tolclophos-methyl), or 24-36 ppm tolclophos-methyl and 24-36 ppm pentachloro contains trobenzene (PCNB). Method according to claim 1, characterized in that the root attack medium 10 0.4-0.6 ppm methyl 2-benzimidazole carbamate (2-methoxycarboxamidobenzimidazole or carbendazim) or an equivalent amount of one of the precursors of carbendazim, and 0.4 -2 ppm of 1- / N-propyl-N-2- (2,4,6-trichlorophenoxy) -ethylcarbamoyl / imidazole (prochloraz). Method according to claim 1, characterized in that the fungal attack medium is 1.6-2.4 ppm 1- (2- (2,4-dichlorophenyl) -n-pentyl-1H-1,2,4-triazole (penconazole) or 4-6 ppm (RS) -2,4-di-fluoro (1H-1,2,4-triazol-1-ylmethyl) benzhydrol (flutriafol) and 4-6 ppm iprodione or an equivalent amount of 3 - (3,5-dichlorophenyl) -1,2-dicarboxymide of the formula I, or contains 16-24 ppm polyoxin and 56-84 ppm tetrachloroisophthalonitrile (chlorothalonil). 5. A method according to claim 2, characterized in that the culm fracture medium further contains 8-12 ppm carbendazim or an equivalent amount of one of its precursors. 6. A method according to any one of claims 1-5, characterized in that the culture media contain suitable nutrients and optionally antibiotics. 7. Device for carrying out the determination method according to any one of claims 1-6, characterized in that it contains at least three selective zones containing, respectively, tragic smear medium, root attack medium and fungal attack medium, and optionally at least one blank zone without fungicide, but optionally with an antibiotic, and further 3602384 -KJ - optionally a zone with selective radial crushing medium to which is added 5-50 ppm carbendazim or one of its precursors. 8. Device according to claim 7, characterized in that the different zones are situated next to each other, the selective nutrient media being in contact with each other. 9. Device according to claim 7, characterized in that the different zones are arranged in separate compartments, each containing one of the selective nutrient media. 10. Device as claimed in claims 7-9, characterized in that it comprises a set of containers containing the selective media and has an easily manageable and transportable embodiment. 10 Fusarium sp ,, Rhizoctonia sp. and any other pathogenic or non-pathogenic fungi is inhibited or retarded without hindering that of Pseudocercosporella herpotrichoides, b) a root attack medium (rhizoctonia) selective for Rhizoctonia sp., in particular Rhizoctonia 15 cerealis, and on which the mycelium growth of Fusarium sp., Pseudo cercosporella herpotrichoides and any other pathogenic or non-pathogenic fungi are inhibited or slowed down without Rhizoctonia sp. and c) a fungal attack medium selective for Fusarium and on which the growth of Rhizoctonia sp., Pseudocercosporella herpotrichoides and any other pathogenic or non-pathogenic fungi is inhibited or retarded without that of Fusarium sp., in particular F. nivale and F.roseum, is obstructed. 11. Determination methods, devices for performing them, and media suitable for use in any of the above as described in the description and examples. 20 · 8602384