How dangerous is fusarium for humans? Diseases of spring barley at the beginning of the growing season

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This spring is generous with precipitation. The amount of precipitation in April and half of May exceeded 100 mm in the south of Ukraine. Moderately warm weather, high humidity air and soil contribute to the intensive development of grain crops. But, unfortunately, this also leads to the development of fungal diseases of the grain and ear, including fusarium ear blight. Even the slight presence of fusarium mycotoxins in a batch of grain makes it completely unsuitable for food use. And in some cases - even in feed.

Fusarium head blight (EF) remains a problem in Western Europe and North America. A limited range of fungicides (with a “suppressive” effect) and a narrow “window of application” do not allow reliable control of this disease solely by chemical means. Therefore, such an enemy must be known not only “in person”, but also from other (most vulnerable) sides.

Symptoms and damage

Never seen anything like this in my life, and here it is again!

Victor Chernomyrdin

Infection of plants with fusarium also leads to a decrease in harvested, and to a catastrophic deterioration in its quality. The relationship between the development of fusarium head blight and grain weight loss is logarithmic. Crop losses can be up to 30%, but in many cases this is not the worst thing.

Typical lesion: a pink-orange coating of mycelium appears on the glumes of the ear, followed by pale pink sporulation. Sometimes eye spots appear on the ear.

Typical signs of grain damage by fusarium

With mild damage, the mycelium is located in the grain shells, while visually the grain is practically no different from healthy ones. But with more pronounced damage, the pathogen penetrates deeper, reaching the aleurone layer and the grain germ. Diseased grains are usually lightweight. Their surface is deformed (“wrinkled”), with a depressed deep groove and pointed barrels, and may have a pinkish tint.

At the same time, it changes significantly chemical composition– protein decomposes with the release of ammonia (NH 3), starch and partially fiber are destroyed. Therefore, the endosperm of the affected seeds is loose, crumbling, and the glassiness is low. The elasticity and swelling of gluten are significantly reduced. Bread made from affected grains has a dark-colored crumb with low elasticity and large porosity.

The use of fusarium-affected barley grain for malt production causes a “hashing effect.” When you uncork a bottle of beer brewed from such malt, a sudden release of part of the contents occurs. The reason is specific proteins with foaming properties that are formed in grains damaged by fusarium and pass into beer.

Depending on the depth of penetration of the pathogen’s mycelium, the grain will either lose its germination ability altogether (if the embryo is damaged), or “give birth” to weak seedlings affected by root and basal rot. With severe damage in the groove and especially in the embryonic part of the grain, a white or pinkish cobweb-like coating of the fungal mycelium and pads of conidia accumulation are noticeable. The grain germ is not viable, dark in color on the cut. The content of more than 10% of seeds affected by fusarium in a grain batch automatically excludes the possibility of its use for seed purposes.

Fusarium infection does not always manifest itself visually, but this disease can cause the “disqualification” of a batch of full-bodied and apparently healthy seeds. The presence of literally a milligram of mycotoxins in a kilogram of grain – and that’s it! IN best case scenario such grain will be used as fodder. Neither protein content, nor IDC indicators, nor nature matter if the grain contains a microscopic amount of a deadly poison of fungal origin.

Bread with poison

We don't need to step on the same rake that we've already had

Victor Chernomyrdin

Mycotoxins (from the Greek mukos - mushroom + toxikon - poison) are specific toxic substances produced by fungi. Poisonous macromycetes are well-known “villain poisoners”. But their microscopic relatives (micromycetes) are no less poisonous and even more dangerous. After all, their toxins cannot be detected without special equipment, and they can be found not only in grain, but also in its processed products - flour and bread. Many micromycete toxins, like toadstool toxins, can withstand heat treatment (Table 1).

Table 1. Damage symptoms and specific mycotoxins
Type of mushroom	Presence of typical symptoms of fusarium		Mycotoxin produced
Type of mushroom	generative organ	corn	Mycotoxin produced
F. graminearum	++	++	DON, ZEN
F. culmorum	++	++	DON, ZEN
F. sporotrichioides	+	–	T-2
F. langsethiae	–	–	T-2
F. poae	–	–	NIV
F. tricinctum	+	–	MES
F. avenaceum	++	+	MES
F. verticillioides (on corn)	++	+	FUM

Fusarium grain poisoning (flour, bread) in humans and animals causes vomiting and damage to the central nervous system. The symptoms (excited state, convulsions, visual disturbances) resemble alcohol poisoning, which is why this grain and the disease it causes are called “drunken bread.”

In 1973, Japanese researchers T. Yoshizawa and N. Morooka isolated and identified a toxic substance, which they called vomitoxin (from English vomiting - vomiting). The modern name for this mycotoxin is deoxynivalenol (DON). Chronic DON poisoning is very dangerous due to regular consumption of food products made from contaminated grain. DON affects the central nervous system, hematopoietic and immune system, suppresses protein synthesis.

Another known disease associated with Fusarium fungi is septic tonsillitis, or nutritional toxic aleukia (ATA). Only in 1944 was it possible to establish that its cause was a fungus F. sporotrichioides. However, to determine the most toxic component produced by the fungus F. sporotrichioides, Japanese researchers were able to do this only in 1968. It was called T-2 toxin. T-2 and NT-2 toxins suppress the synthesis of RNA and DNA, cause apoptosis (programmed cell death), and suppress the immune system. The toxin is resistant to high temperatures; its destruction requires heating to a temperature of at least 250‑300°C.

DON (deoxynivalenol) and T-2 toxin are part of a large group of trichothecene mycotoxins. This is a group of toxins (more than 170 substances) that have a similar structure and have the same toxic effect at different lethal doses. Based on their chemical properties, substances can be divided into two main types: A and B, depending on the nature of their impact on animal productivity. Type A trichothecenes include, but are not limited to, T-2 toxin, HT-2 toxin, diacetoxyskirpenol (DAS), and neosolaniol (NEO). They are approximately 10 times more toxic than type B trichothecenes, which include: dioxynivalenone (DON, also known as vomitoxin) and its 3‑acetyl and 15‑acetyl derivatives (3‑AcDON and 15‑AcDON, respectively), nivalenone (NIV) and fusarenon X. Fungi of the genus Fusarium also synthesize other mycotoxins. For example, fumonisins, which have a strong phytotoxic effect on plants and damage cells in human and animal tissues. They are soluble in water and are stored for a long time. At a temperature of +125°C, only 25-30% of these toxins are destroyed, and only when heated above +175°C are more than 90% destroyed.

Fusaric acid is known primarily as a phytotoxin that causes plant wilting. It is relatively slightly toxic to warm-blooded animals, but in its presence the toxicity of DON and VW1 increases.

Why do mushrooms need such an arsenal of chemical weapons? Mushroom mutants F. graminearum with impaired DON synthesis, glumes were affected significantly less than “relatives” capable of producing mycotoxin. A pathogen with impaired DON synthesis penetrated into plant tissue, but could not grow further. The ability to produce DON is associated with the aggressiveness of pathogens. Maximum amount DON accumulates in the rachis (93 mg/kg), then in the flower glumes (50 mg/kg), in the grain (25 mg/kg) and in the peduncle (15 mg/kg).

Milligrams vs tons

Some principles that used to be principled were actually unprincipled

Victor Chernomyrdin

The concentration of mycotoxins depends on the degree of damage to the grain and the conditions for the development of the fungus. But in a batch of grain there is no clear relationship between the percentage of affected grains and the amount of mycotoxins! In some cases, in a batch of grain with 10-15% contamination, mycotoxins may be practically absent, while in another batch with 2% contamination, the concentration of mycotoxins is many times higher than the permissible level.

In EU countries, it is mandatory to analyze the content of two fusariotoxins in grain products - DON and ZEN (EC Commission regulation, 2005). For grain used in the production of baby food, it is 0.2 and 0.02 mg/kg, and for fodder it is approximately 10 times more. A more clear criterion of danger is not the content of mycotoxins per kilogram of grain or its processed products, but their permissible level of daily consumption in terms of body weight (PMTDI). For EU countries, the following maximum permissible consumption values have been established (µg/kg body weight per day): DON – 1; ZEN – 0.2; the sum of T-2 and NT-2 toxins is 0.06 (separately or jointly); NIV – 0.7 (Commission regulation EC, 2005).

You can compare the restrictions on the content of mycotoxins in feed grains of wheat and barley in Ukraine and the EU (EEC No. 1881/2006). Deoxyvalenol 1‑2 mg/kg in Ukraine and 1.25 in the EU. T-2 toxin – 0.2 mg/kg and 0.06 mg/kg, respectively. Zearalenone – 2‑3 mg/kg and 0.1 mg/kg.

Cereal grains damaged by fusarium can, at best, be used for fodder in Ukraine. And grain exports to EU countries will be closed even to grain that, according to Ukrainian standards, is “slightly” damaged by fusarium. By the way, according to the NSC-Ukraine company (E. Ageeva, 2014), in 2014, mycotoxins were found in 80% of samples in the feed of fattening pigs, of which zearalenone was found in 99% (exceeding the norm in 11% of cases) ; fumonisin – in 30% of samples (excess – in 67% of cases); DON (deoxynivalenol) – in 100% of samples (exceeding the norm in 40% of cases).

By the way, removing small grains (<2,5 мм) из урожая может снизить уровень ДОН на 80%, ЗЕН – на 85%, ДАС и Т-2 токсина – на 80‑81%. Но этот метод явно не претендует на универсальность и эффективность. Если очистка и сепарация зерна проведены непосредственно после уборки, результат может оказаться положительным. Особенно, если зерно было высушено до +13‑14°С. В случае же хранения собранного урожая до очистки и удаления мелкой фракции несколько недель, проблему фузариоза усугубят еще и сопутствующие «плесени хранения» – Penicillum And Aspergillum. Aspergillus and penicillium also produce mycotoxins (aflatoxins and ochrotoxins, respectively), which are no less dangerous than Fusarium toxins. Therefore, fusarium head blight needs to be treated. Better yet, warn!

The “bad guys” are to blame!

We have completed all points: from “A” to “B”

Victor Chernomyrdin

Plants of cereal grain crops are susceptible to fusarium in the flowering phase at high humidity and temperatures around +20‑25°C (especially F. graminearum). But for species such as Fusarium sporotrichioide and F. poae high humidity and air temperature are not mandatory conditions for infection.

Optimal time to start processing

Weather conditions are an important, but far from the only factor influencing the development of the disease. Favorable weather conditions are a kind of “catalyst” that accelerates the process of dissemination and development of FC. But in fact, a complex interaction between the cultivated plant and the pathogen occurs in the field. The less infectious origin (source of infection) there is in the field and the higher the resistance of the plants, the lower the risk of epiphytotics even with an ideal combination of temperature and air humidity, amount of precipitation, etc. for FC.

The influence of various elements of technology on the development of the disease can be obtained from Table. 2.

Table 2. The degree of influence of technology elements on the intensity of development of fusarium head blight (V. S. Shevelukha, K. V. Novozhilov and M. M. Levitin)
Degree of significance (“rank”)	Technology element	Contribution to the dynamics of the spread and manifestation of fusarium, %
1	Predecessor	20
2	Tillage system (degree of preservation of plant residues)	20
3	Agrophone (NPK imbalance)	15
4	Variety susceptibility	10
5	Excessive rates of nitrogen fertilizing	10
6	Predecessor of the predecessor	5
7	Sowing time	5
8	Seeding rate	5
9	Use of organic fertilizers	5
10	Method and organization of cleaning	3
11	Post-harvest activities	2

Thus, the development of fusarium blight in grain crops depends on a number of factors (as their importance decreases): predecessor (the worst are corn and cereal grains), precipitation and air humidity during the heading - flowering period, soil cultivation system (the worst are no-till and minimal ), variety resistance, plant condition, harvesting method, post-harvest activities.

The predecessor influences the development of fusarium head blight depending on the soil cultivation technology, variety, sowing time and seeding rate.

Late sowing of winter wheat in combination with late-ripening varieties stimulates the development of the disease. Conversely, early ripening varieties manage to “overshoot” the most dangerous time of infection. The pathogen does not have time to infect crops in the flowering phase; infection occurs late, in the grain filling phase.

An increase in plant density creates a specific microclimate with high humidity. In warm, rainy weather in thickened crops, excess nitrogen combined with lodging of the variety creates a greenhouse effect. In addition, in dense crops, the distance between spikelets is minimal, which contributes to their infection and re-infection.

When placing wheat and barley on top of corn (for grain) and applying increased rates of nitrogen mineral fertilizers, the damage to plants by fusarium head blight increases 3-7 times. Weather favorable for the pathogen with this combination of precursor and mineral nutrition may cause epiphytotic development of the disease.

Under the same environmental conditions, but with different combinations of technology elements (predecessor, soil treatment, fungicidal protection), the spread of fusarium on crops can range from 0.6 to 40%. Therefore, optimizing crop cultivation techniques can reduce the development of fusarium by 80-95%. For example, in breeding programs aimed at developing Fusarium blight resistant varieties, yield losses ranging from 6 to 74% have been observed (Snijders & Perkowski, 1990).

Resistant varieties and the “triangle”

We will not only oppose, but we will defend it in order to prevent this from happening.

Victor Chernomyrdin

Growing resistant varieties– the most economical way to reduce the likelihood of wheat and barley being affected by this disease. There are several types of physiological resistance of grain to fusarium:

I– resistance to pathogen penetration;

II– to the spread of the pathogen throughout the ear;

III– resistance of grains to pathogen infection;

IV– tolerance;

Most European varieties of soft wheat are moderately susceptible to fusarium grain blight, and almost all durum varieties are highly susceptible.

Tall, awnless, loose-eared varieties of bread wheat are considered more resistant than awned and semi-dwarf forms.

Tall varieties of barley with a loose ear also have an advantage over their low-growing “colleagues”. Moreover, unlike wheat, the awned varieties are the most resistant.

Two-row barley is much more resistant to fusarium head blight than six-row barley, and naked forms are affected much less than filmy forms. Even color matters. Chinese plant pathologists (Zhou et al., 1991) found that approximately 20% of barley varieties with black or red spikes were resistant to F. graminearum, and with a yellow ear - only 5%.

To visualize the factors influencing the development of fungal diseases, plant pathologists sometimes use a simple disease triangle diagram. Disease spread and progression require the interaction of a susceptible host, a virulent pathogen, and favorable environmental conditions. Conversely, plant disease can be prevented by eliminating any of these three components.

Integrated protection of grains from FC is based precisely on this scheme. The side of the triangle designated as “pathogen” can be significantly “shortened” using a precursor that does not accumulate the infection, or its habitat can be destroyed by accelerating the decomposition of plant debris. Tilling the soil with the incorporation of crop residues of a “bad” predecessor (corn, cereal grains), applying nitrogen fertilizers and biological products are quite effective means. Infections in seeds can (and should) be eliminated by treating the seed. Fungicidal treatments of vegetative crops are the last chance to protect the plant.

The second side of the triangle - the “host” (in our case, it is wheat or barley) - is less “elastic”, since there is a certain threshold of immunity. But this method should not be neglected either. Moreover, the use of FC-resistant varieties is the least expensive method of prevention.

Environmental impact cannot be considered a tried and true method. Precipitation, temperature and humidity are practically uncontrollable. But you can reduce the influence of other factors. For example, by forming an optimal sowing density, using retardants, and balanced application of mineral fertilizers. This is not so much a change in climate as in microclimate.

And we strangled and strangled the fusarium...

You have to think what to understand

Victor Chernomyrdin

The German historian Karl Hampe is known as the author of the expression: “Die Geschichte kennt kein Wenn,” that is, “History does not know the word “if.”

It is necessary to talk about the choice of predecessor, the method of tillage and the selection of the “right” variety before the field is cultivated and sown. If the variety is susceptible to the disease, the predecessor is a source of infection, and the soil cultivation system does not involve the destruction of plant residues, then only hope remains for chemical means of combating FC.

There are few fungicides that can effectively protect the grain in the ear from pathogen penetration. The maximum effectiveness of modern drugs allows, at best, to reduce the visible symptoms of FC disease by 60-70%. In Canada, for example, the three main fungicides registered against FC in winter wheat (Folicur, Prolineand and Bravo) are considered to be “suppressive” or “inhibitory.” The labels of these fungicides contain the definition of suppression, so the translation into Russian may be different.

PMRA (Canadian Pesticide Regulatory Agency) evaluates

suppression as fairly “reliable” disease control at a level that is “not optimal” (i.e., complete), but provides “commercial benefit” from its use. Drugs characterized by a “depressant” effect must, first of all, provide stable results. They are somewhere between a “C” student and an “excellent student”.

History of the issue with extensive geography

Today nothing, tomorrow nothing, and then we realized - and yesterday, it turns out, nothing

Victor Chernomyrdin

Interesting facts about the evolution and “natural selection” of the active ingredients of fungicides against FC were given by Roy Wilcoxson (1996). Various fungicides are mentioned (21), evaluated individually or in combinations: benzimidazoles (benomyl, carbendazim, thiophanate-methyl, thiabendazole), carboximides (prochloraz), drugs with multisite activity (mancozeb, chlorothalonil) and triazoles (triadimenol, triadimefon, bromuconazole, flusilazole, fenbuconazole, propiconazole, tebuconazole).

The first US fungicide trial against FC was published in 1977 (Barry Jacobson). Trials of benzimidazoles (benomyl) alone and mixed with mancozeb in California and Illinois showed that double treatment with benzimidazoles reduced the manifestations of FC by 70%, and a single treatment with a tank mixture of mancozeb and benomyl - by 50%. In addition, the tank mixture provided much better control of leaf diseases than benomyl alone.

But officially, drugs with this d.v. have not been registered for use during the flowering phase of wheat. In addition, double treatment of the crops was required, and benomyl-based preparations were quite expensive.

Therefore, North American farmers did not carry out specialized chemical control against FA. The result was enormous losses during the epiphytoties of fusarium head blight in the 1990s. The damage was estimated at $3 billion, which is impressive even now. And for an adequate perception at modern prices, the figure must be multiplied by at least 2.

Defeats in the fight against fusarium head blight forced us to evaluate the importance of the problem, change the control strategy and significantly update the “arsenal of chemical weapons.”

Period 1988-1996 can be called the initial stage of fungicidal “rearmament”. To determine the most effective d.v. fungicides in 1994-1997 began to conduct large-scale research. Moreover, for the first time successful attempts were made to use drugs with d.v. triazole class. But the path from experiments to commercial drugs turned out to be long.

The first triazole fungicide Tilt (propiconazole) was registered in the USA in 1988. But the regulations for use did not imply its use against ear diseases during the flowering phase. The main “targets” of the drug were leaf diseases in the period from the emergence of the tube to the appearance of the flag leaf. In 1995, an unsuccessful attempt was made to register Tilt for treatment against Fusarium head blight during the flowering phase. Fortunately, this attempt was not the last.

In Western Europe (Suty and Mauler-Machnik) in 1996 it was established that of the active substances existing and tested at that time, tebuconazole was the most effective against FC. But in the USA they were skeptical about this d.v. In 1997, they tried to “legalize” the fungicide Folicur in America, but without success, as with the drug Tilt.

The comparative effectiveness of fungicides against fusarium head blight in grain crops can be assessed by taking into account a number of indicators: reduction in the spread of the disease on ears; reduction of grain infection; reducing the level of mycotoxins in grain; increase in yield.

When conducting such an assessment, the presence of a high infectious background, strict adherence to the methodology, as well as correct analysis and interpretation of the results are also required. Many of the publications simply do not stand up to criticism. For example, in some studies the pathogenic complex of fungi was not assessed, the experiments were carried out on a low infectious background, the susceptibility or resistance of varieties was not taken into account, and the effectiveness was determined by visual assessment of symptoms in the field.

Since 1997, a national forum on the problem of fusarium head blight has been regularly held in the United States. From 1998 to the present, USWBSI has conducted uniform fungicide testing. As a result of several years of work, some active ingredients were “rejected”: due to lack of effectiveness or due to stimulation of mycotoxin synthesis (DON). And some are simply due to the discontinuation of drug production. For example, in 2001, DuPont in the USA stopped producing active fungicides. Benomyl. Accordingly, benomyl and carbendazim were out of sight of American plant pathologists from the USWBSI, although in 2000 they were included in the list of active ingredients. drugs proposed for registration against FC. The mentioned list also included drugs based on mancozeb, azoxystrobin and tebuconazole (Vern Hofman et al., 2000).

Trio of favorites: tebuconazole, prothioconazole, metconazole

If I were to name everything that I have, you would be crying here!

Victor Chernomyrdin

Tebuconazole was much luckier than strobilurins, benzimidazoles and carbamates.

Results of large-scale trials of the fungicide Folicur (tebuconazole, 38.7%) in 1998–2003. showed an average decrease in Fusarium head blight (FHB index) by 39.4% and a decrease in DON content by 27.4% (D. Hershman and G. Milus, 2003). Drugs with other active ingredients. could not even achieve such a result.

A. Mesterhazy in the chapter “Fungicides in the control of fusarium head blight of wheat” (Fusarium Head Blight of Wheat and Barley, APS Press, St. Paul, MN, 2003) formulated the situation with the range of fungicides at that time: “We can conclude that in Currently, there are no fungicides that control fusarium head blight with effectiveness that would be at the level of control of rust or powdery mildew. Testing of fungicides showed that the most effective of the tested d.v. - tebuconazole."

However, other d.v. class of triazoles turned out to be quite promising. Therefore, in 2007, the drug Proline (prothioconazole) was registered in the United States to control fusarium head blight, and in 2008, the drugs Caramba (metconazole), Folicur (tebuconazole) and Prosaro (prothioconazole + tebuconazole) were registered.

Unfortunately, the effectiveness of triazoles is very far from the cherished figure of “100% control”. According to research data from 2007-2008. (Paul et al., 2008), the use of Prosaro fungicide provided a 52% reduction in visual symptoms of the disease (FHB index) and a 42% reduction in DON (mycotoxin) compared to the untreated control. The effectiveness of the drug Proline is a decrease in FHB index by 43% and DON by 48%. For the fungicide Caramba, the reduction in FHB index was 50%, and DON – 45%.

Similar data were obtained at other times and in other places (Lipps et al.) and for other triazole drugs. In terms of effectiveness, expressed as a percentage reduction in the FHB index, prothioconazole was in the lead - 48%. Tebuconazole was slightly less effective (40%), and propiconazole took third place - 32%. In terms of the effect on the level of DON reduction, prothioconazole was also the first - 42%, tebuconazole and propiconazole lagged behind by a significant margin (23% and 12%, respectively).

Experiments to study the effectiveness of fungicides against fusarium head blight in Krasnodar (“near abroad” - geographically) from 1990 to 2000 (G.V. Grushko, L.D. Zhalieva, S.N. Lynchenko, 2004) showed significant differences in disease control when using drugs with d.v. benomyl, flutriafol, prochloraz, cyproconazole, tebuconazole, propiconazole, fenpropimorph, bromuconazole, epoxiconazole and thiophanate-methyl + epoxiconazole combinations.

The biological effectiveness of benomyl against FC did not exceed 51.5% even with double use. When drugs based on benomyl and cyproconazole were used together, the effectiveness of the mixture was significantly inferior to the drug with active ingredients. prochloraz (50.6%). The activity of benomyl was enhanced by the addition of potassium chloride (KCl) and the antibiotic fusamycin to the working solution.

The effectiveness of using drugs with d.v. cyproconazole and prochloraz against FC reached 39‑43% and 58‑56%, respectively. Tebuconazole was superior in efficacy to epoxiconazole and the combination of thiophanate-methyl and epoxiconazole.

The use of full rates of fungicide consumption and the use of adhesives (surfactants) have significantly increased the effectiveness of crop treatments against FC. The effectiveness of the full rate of consumption of the drug (based on grain contamination) with d.v. Bromuconazole vs. F. graminearum amounted to 65.8%, and reduced - 60%. When using the drug with d.v. fenpropimorph this figure was 51.3 and 40.7%, respectively.

In the mentioned study, the comparative effectiveness of d.v. fungicides were in descending order of activity as follows: tebuconazole > bromuconazole > fenpropimorph > propiconazole > cyproconazole; prochloraz > benomyl > cyproconazole.

Table 3. The effectiveness of the active ingredients of fungicides against fusarium head blight, according to the websitehttp:// www. eurowheat. org.
D.v. fungicides	Countries
D.v. fungicides	Denmark	France	Germany	Netherlands	Great Britain
Triazoles
bromuconazole					++
epoxiconazole	+	+			++
metconazole	+	+	+++	+++	+++
prochloraz			++
prothioconazole	++	++	+++	+++	+++
tebuconazole	++	++	+++		+++
Mixtures
cyproconazole + propiconazole					++
epoxiconazole + boscalid	+				++
epoxiconazole + fenpropimorph	+	+			++
epoxiconazole + kresoxim-methyl	+	+			++
epoxiconazole + pyraclostrobin					++
fluoxastrobin + prothioconazole		++	++	++	+++
fluquinconazole + prochlorazole
prochloraz + tebuconazole		++			++
prothioconazole + spiroxamine			+++		++
spiroxamine + tebuconazole		++	+++		++
tebuconazole + prothioconazole			+++	+++	+++
Note: No registration. Problem with resistance: + low; ++ average; +++ good

So, the most effective d.v. Today, triazoles are used against FC (Table 3): tebuconazole, prothioconazole and metconazole, as well as their combinations with each other and with spiroxamine. But in Japan, for example, benzimidazoles (thiophanate-methyl, in particular) are still used to control PK. And quite effectively.

What makes a king is his retinue?

All the questions that have been raised, we will collect them all in one place

Victor Chernomyrdin

When using fusarium-resistant varieties of wheat or barley sown on a good predecessor, even imperfect fungicidal protection against FC (with an effectiveness of 30 to 50%) provides a completely acceptable result.

The research of Charla R. Hollingsworth (Charla R. Hollingsworth, 2009) provides an example that on relatively resistant varieties of winter wheat, the yield increase from treatment against FA with triazoles was minimal, and in some cases it did not exceed control or was even inferior to it. But on susceptible varieties, the economic effect of using fungicides was much higher. Moreover, in this experiment, field studies were carried out on a low infectious background and in conditions moderately favorable for the development of the disease.

In conditions that are extremely favorable for the development of FC, when all factors (weather, predecessor, cultivation technology) contribute to the epiphytic development of the disease, fungicidal protection sometimes not only fails to cope with an intensively spreading infection. In the United States, for example, there were outbreaks of fusarium in both 2000 and 2011, with losses estimated at $2.7 billion and $4.4 billion, respectively. If the enormous damage caused by the epiphytoty in 2000 can be explained and justified by the lack of modern fungicides, then how can the epiphytoty of 2011 be justified?

The problem lies not in the effectiveness of the active ingredients of fungicides, but in the ability to carry out treatment in the utmost short time. A delay of 2-3 days can reduce the effectiveness of fungicides by 1.5-2 times. And if the threat is not considered serious, and the weather prevents processing (precipitation, strong wind), then it is not possible to quickly stop the spread of the infection.

The effectiveness of spraying is also influenced by weather factors (temperature, humidity, wind speed), plant resistance, the formulation and application rate of the fungicide, and the sensitivity of pathogen species and isolates.

For example, a fungicide with a.v. Tebuconazole inhibited growth more strongly in laboratory experiments F. poae, how F. graminearum. In experiments by Simpson et al. (2001) effectiveness of fungicides on the species F. avenaceum was higher than F. culmorum.

The emergence of pathogen resistance to d.v. is possible. "popular" fungicides. It is known, for example, that the sensitivity of isolates F. graminearum, F. culmorum, F. avenaceum And F. poae to carbendazim and tebuconazole decreased with regular treatments (Bateman, 1993; Xu et al., 2007). Norwegian researchers even noted that some fungicides increase the number of F. tricinctum on wheat grain (Henriksen, Elen, 2005).

Unfortunately, active agents effective against fusarium pathogens can literally be counted on the fingers of one hand. Moreover, they all belong to the class of triazoles. So all that remains is to maximize their potential. And pay attention not only to quality, but also to the timing of application.

About the quick and the dead

And I know again how it is possible. And often, and as needed.

Victor Chernomyrdin

The effectiveness of fungicides depends on the timeliness of their application. As the empirical wisdom of the "gunfighters" of the Wild West stated, "gunfighters come in two varieties - fast or dead." For someone who was late to fire, it will be little consolation that he had a very accurate revolver chambered for a very powerful cartridge. The speed and timeliness of treatment against fusarium head blight affect the result to approximately the same extent. A good fungicide applied late will not provide the desired effect. And sometimes - nothing at all. It’s too late to drink Borjomi...

The widespread presence of infection, a long period of plant susceptibility, a high rate of infection penetration into the internal tissues of the ear, a short period of effective treatment time and the difficulty of uniformly covering the ear with a working fungicide solution are far from full list reasons why differences are observed between the results of industrial application of a fungicide and the effectiveness of its tests.

Table 4. The influence of the timing of fungicidal treatment on the reduction of damage to durum wheat by fusarium head blight under conditions closed ground (N.D.S.U., McMullenet al., 2001)
A drug	Application rate, ml/ha	Stage of development byFeeks (time of processing)	Reducing the manifestation of the disease, % (FHB index)
Folicur	300	10.3-50% heading	59,1
		10.5-100% heading	75,8
		10.51% beginning of flowering	81
		10.54% – end of flowering	24,7

The optimal period for processing wheat is considered to be 2-4 days before flowering or the first 2 days after the start of flowering. For barley that flowers while the ear is still inside the wrapper, best period processing - immediately after the appearance of the ear. A few days late increases the damage from the disease and reduces the protective effect. But it is also necessary to take into account such an indicator of the effectiveness of the fungicide: the type and amount of mycotoxins in the grain.

Late or too late?

We have one course - the right one.

Victor Chernomyrdin

Under normal growing season conditions, wheat flowering occurs after heading. The properties of the variety determine the ratio of open and closed flowering, the time from opening to closing of flower scales, the daily energy of flowering, the number of flowers in an ear, etc. Flowering of one ear lasts 3-6, and the entire field lasts 6-8 days.

Dry weather shortens the flowering period, damp weather lengthens it. In hot and dry weather, when the air temperature is above +25-27°C, the ear can bloom in one or two days.

Therefore, in humid, cool conditions, FK has a much greater chance of infecting winter wheat plants than in hot and dry conditions. After all, the pathogen has a reserve of time several times longer, and high air humidity contributes to its active advancement.

Early infection, as a rule, forms a typical “fusarium” grain: puny, deformed, dull. With early infection, fusarium causes whitening of the ear due to the penetration of the fungus into the central spike shaft. The pathogen damages and clogs blood vessels (like a blood clot), which blocks the flow of nutrients to all the caryopses located above the ovary in the ear. The affected areas first become discolored, and in damp weather pink sporodochia form on the glumes.

Infection of an ear with a suspension of fungal conidia F. graminearum during the flowering period leads to massive infection of grains in the ear and a reduction in yield compared to uninfected ears by 60-80%.

Infection of an ear a week after flowering leads to a reduction in yield by 50-60%, while visible symptoms are less noticeable, despite infection of 90-95% of the seeds.

At later infection, the number of infected grains and visible symptoms of the disease decrease, and the weight of the seeds does not change. Late infection is outwardly unnoticeable, but can cause an extremely unpleasant “surprise” - contamination with mycotoxins. Moreover, stressful conditions (heat, treatment with strobilurins) do not improve the “character” of the fungus, quite the contrary. For example, in laboratory conditions strains F. sporotrichiella at a temperature of +26-28°C they are able to synthesize and accumulate mycotoxins three times faster than at a temperature of about +20°C. Therefore, you should not hope that “this will go away on its own.”

Field experiments 2011–2013 in the states of Ohio and Illinois showed the peculiarities of the “work” of fungicides with active ingredients. metconazole and with a combination of d.v. prothioconazole + tebuconazole for different dates applications. The maximum reduction in signs of damage (IND - 69%) by fusarium and the content of mycotoxins (54%) was ensured by treatment on the second day after the start of flowering of the ear. The use of drugs on the fourth and fifth days after flowering led to a decrease in the effect. Even on the sixth day, treatments were advisable, since the use of fungicides significantly reduced the accumulation of mycotoxins in the grain. But the control of disease manifestations in this case was weaker than with treatment at the beginning of flowering (D. L. D’Angelo, 2014).

Thus, when treating with fungicides at the beginning of flowering, it is possible to “kill two birds with one stone” - to reduce the spread of the disease (respectively, the amount of lightweight deformed grain) and prevent the accumulation of mycotoxins. Late treatments (end of flowering - milky ripeness) are quite effective in preventing grain contamination with mycotoxins, but have no effect on the development of the disease. Treatments between these two periods provide mediocre control of disease development, but a sufficient level of prevention of mycotoxin accumulation.

I won’t say much, otherwise I’ll say something again

Victor Chernomyrdin

Fusarium head blight is an insidious and dangerous enemy. The most justified combat tactic is prevention. If grains were sown on corn or a stubble predecessor, the likelihood of developing fusarium head blight is high. If, in addition, plant residues remain on the surface of the field after sowing (when sowing using no-till or “minimum wage”), the appearance of the disease is almost guaranteed.

However, even on crops with precursors neutral to FA (sunflower, legumes, millet), the development of the disease is quite possible. A susceptible variety and abundant nitrogen fertilizing aggravate the situation.

Therefore, you should not skimp on fungicidal ear protection. Moreover, processing costs cannot be called prohibitively high. Fungicides with a.v. tebuconazole, widely available on the market, is quite affordable and, if applied in a timely and high-quality manner, is quite effective. If you plan to control not only FC, but also other diseases of the ear (septoria) and leaf apparatus (helminthosporium, rust, powdery mildew), then it is advisable to use multicomponent drugs containing triazoles (tebuconazole, prothioconazole, flutriafol) in combination with a.v. other chemical classes with spiroxamine, for example, or with d.v. benzimidazoles group.

You should not skimp on “adhesives” (surfactants, surfactants)! In addition, you should not reduce the consumption rate of the working solution. The more uniformly the ear is processed, the more d.v. hits its surface, the better the result will be.

The effectiveness of protection depends on timeliness. Therefore, treatment should begin from the beginning of flowering. A delay of 10-12 days will not prevent grain losses, but may well prevent contamination of products with mycotoxins. Lost time means missed opportunities. But by missing some opportunities, you can take advantage of others. Therefore, if, due to the vagaries of the weather, processing can only be carried out during the milky ripeness phase, it is better to do it anyway.

Viktor Chernomyrdin said: “Forecasting is an extremely difficult thing, especially when it comes to the future.” But the future depends on the present. For example, from timely measures taken to preserve the harvest.

Alexander Goncharov, agronomy researcher at Agrosfera LLC

» Vegetable garden

This disease is found in any region, but it is most common in the foothills of the North Caucasus, in the territories of western Ukraine, Belarus, and the Baltic states. This problem also occurs in areas Russian non-black earth region

, western regions of Siberia. And if there is heavy rain on the days of grain filling, get ready to deal with this problem. This review will discuss the wheat disease called septoria, the causes of its occurrence and methods of combating this disease. The pathogen is considered to be the Septoria fungus. It most often affects tomatoes, cereals, millet, vineyards, gooseberries, currant bushes, soybean and hemp plants. Mainly the disease spreads through the remains of vegetation

through swelling of the pycnidia on rainy days. Signs of the disease are rusty or brown spots that are irregular in shape. They are surrounded by a border yellow color

. In the central parts of the spots, black dots called pycnidia can be observed. This is how the fungus multiplies.

After a certain time, the stain covers the entire leaf. When the disease fully develops, the shoots are affected, the foliage begins to dry out, the stems wrinkle and turn brown.

Often the leaves fall prematurely. Causes of the disease Favorable conditions for the development of the fungus are considered high humidity and

temperature regime

The fight against wheat disease should be carried out comprehensively, taking into account the phytosanitary conditions of the crops. They use not only agrotechnical measures, but also chemical treatments:

When harvesting, the stubble peels off, then autumn plowing in progress– these methods of soil cultivation will help to completely destroy the pathogen located on the remains of vegetation. During plowing, the pycnidia are destroyed, their spores die after two to three weeks;

It is not recommended to sow neighboring fields with crops, which may be affected by septoria fungus;
necessary maintain optimal sowing dates. The greatest development of the disease is observed on winter wheat. From these fields in the spring, the disease spreads to nearby crops. For spring wheat, it is best to adhere to early sowing dates so as not to create favorable conditions for the fungus;
seed material should be treated, after all, they can also be a source of disease. If five or more percent of the foliage is affected by the disease, then fungicidal agents come into play.

Detection of fusarium on wheat

The main source of the disease is affected seeds and soil composition. Pathogenic pathogens can persist for a long period in the ground and on vegetation debris. If the plant has sufficient immunity, the disease will not manifest itself.

The disease can develop under unfavorable conditions climatic conditions, on weakened plants damaged by insects.

The fusarium pathogen has a high level of resistance to weather conditions, which helps it remain viable for a long time. It is most active if the temperature is twenty-five degrees Celsius and the humidity level reaches ninety percent.

This disease can reduce yields and deteriorate the quality of grains.

The main signs of this disease are:

the stinginess of the affected grains, the presence of wrinkles, deep grooves, points on the sides;
grain surface loses color either turns pink and does not shine;

endosperms are loose, decrease or complete loss of glassiness;
in grain furrows and in germinal areas a plaque appears in the form of a cobweb, whitish or pink. You can also distinguish the pads in which conidia accumulate;
grain germ loses the ability to live, looks dark when cut.

Grain that appears healthy on the outside may contain microtoxins and fungal spores.

Plants affected by fusarium bloom poorly, turn yellow, and lose leaves. Root system It develops weakly; darkish vessels are visible on the cut of the stem.

Causes of appearance and methods of control

These include the following:

saturation of crop rotation grain varieties;
direct sowing, performed with minimal tillage;
susceptibility plants to disease;
hot weather, high percentage of air humidity during flowering, ripening and harvesting;
neglect protective measures.

Productivity is reduced by fifteen to twenty percent. The quality of the grain may be completely lost.

Today, advanced methods have been developed to combat this problem, which use fungicidal drugs. With their help, the disease is destroyed, and the quality of grain crops remains at the same level.

Preventing future diseases

To minimize problems with septoria, Do not take the plant out into the open air in rainy weather. It is necessary to control the level of moisture content in the room. It is recommended to ventilate the room, add nitrogen-containing preparations to the soil, and create sufficient lighting. Crops are treated with special preparations.

If the plants are sick with fusarium, then it is necessary to remove and burn the affected parts, and disinfect the soil. In case of mass lesions, it is recommended to change planting areas, use chemicals. Their effectiveness depends entirely on timely use. The speed and timeliness of processing the ears will have a proper impact on the final indicators.

Diseases of grain crops are very serious and can lead to loss in the quantity and quality of crops. Their timely identification and adoption of appropriate measures can save the situation.

Fusarium grain blight is a plant disease that causes significant losses in both yield and the quality of harvested grain. Infection of grain with Fusarium fungi leads to a decrease in germination energy and seed germination. Some fungal species produce mycotoxins such as deoxynivalenol (DON), T-2 and NT-2 toxins, zearalenone, nivalenol, etc. Mycotoxins present in grain make it unsuitable for food and feed purposes.

Fusarium grain blight is caused by various species of fungi of the genus Fusarium.

The most dangerous and widespread species in the Russian Federation are:

Fusarium graminearum
Fusarium culmorum
Fusarium sporotrichioides
Fusarium langsethiae
Fusarium avenaceum

Fusarium poae
Species of fungi of the genus Fusarium

F. graminearum

F. culmorum

F. avenaceum

F. sporotrichioides

F. langsethiae

F. poae

Symptoms of fusarium head blight

Symptoms include:

Pink-orange coating of mycelium and fungal sporulation on the glumes of the ear

Fusarium graminearum, F. culmorum, F. avenaceum

Pale pink sporulation of the fungus on the glumes

Fusarium sporotrichioides, F. poae and others

Eye spot on glumes

Fusarium tricinctum, F. sporotrichioides and others

Formation of puny, wrinkled, lightweight grains

The main signs of grain affected by fusarium

the affected grains are puny, wrinkled with a depressed deep groove and pointed barrels;
the surface of the grain is discolored or pinkish, without shine;
endosperm is loose, crumbling; low glassiness of the grain or its complete loss;
in the groove and especially in the embryonic part of the grain there is a cobweb-like coating of fungal mycelium, white or Pink colour and conidial pads;
The grain embryo is nonviable, dark in color on the cut.

However, apparently healthy grain can also be affected by fungi and contain mycotoxins!

Life cycle of fungi of the genus Fusarium

Distribution of fungi of the genus Fusarium

Fusarium fungi overwinter in the form of mycelium and spores on dying plant debris, such as straw and stubble.

Ascospores, which develop in fruiting bodies (perithecia), spread by the wind long distances. Conidiospores They infect the ear, then form again on the affected glumes and are spread by wind and raindrops to other ears during the growing season before harvesting.

Chlamydospores

Conidia

Ascospores

Perithecia

The process of plant infection by fungi

Infection of secondary spikelets

During flowering, ascospores or conidia penetrate into the inner part of the grain shell

After flowering, the hypha of the fungus penetrates the ear tissue and can infect the resulting grain at all stages of its development.

Microscopic development

Conidia develop on the surface of the plant...

They form mycelium...

penetrate the plant...

and develop in tissue...

After the incubation period, symptoms appear and new conidia are formed

Reasons for increased damage to grain by fusarium

Saturation of crop rotation with grain crops
Direct seeding and minimum tillage
Susceptible varieties
Warm weather and high humidity during flowering - ripening and harvesting of plants
Lack of protection methods!!!

Direct yield losses up to 15-20%
Loss of grain quality up to 100%

Factors influencing infection

Fusarium infection is affected by three main risk factors:

1. Weather during flowering

2. Tillage

3. Previous culture

Influence of weather conditions

Grain damage is possible at all stages of its formation.

Plants are especially susceptible to fusarium in the flowering phase under conditions of high humidity and temperatures around 20-25°C (especially F. graminearum).

However, for the development of Fusarium sporotrichioides, F. poae, such indicators as high humidity and temperature are not key!

Effect of tillage

Tillage methods have a great influence on the development of fusarium.

The presence of fungal-infected plant residues on the surface or in the surface layers of the soil after minimal processing greatly increase the likelihood of infection of growing plants.
This means that the risk of infection can be reduced by plowing in the leftovers plants into the soil, where they decompose faster.

No-Till or minimum tillage increases the risk of developing Fusarium

* DON - deoxynivalenol

Impact of crop rotations

The rotation of crops in a crop rotation has a particular impact on the potential development of infection.
Saturation of crop rotation with grain crops promotes the accumulation of inoculum.
Short crop rotation, especially including corn, increases the damage to plants by fusarium.
Beetroot is also an unfavorable predecessor.

Influence of previous culture

Corn and other grain precursors significantly increase the risk of fusarium

Influence of variety resistance

Cultivation of resistant varieties has a greater impact on reducing disease incidence and improving grain quality.
Most cultivated varieties of grain crops are susceptible to fusarium.
Bread wheat varieties vary in level of susceptibility from relatively resistant to highly susceptible.
Durum wheat and oats are highly susceptible to fusarium grain blight.

What is the effect of fusarium on grain?

Productivity
Seed quality of seeds (reduced germination energy and germination)
Nutritional value of grain-based food and feed products due to the presence of mycotoxins
Baking qualities of flour
Beer quality (hashing effect)

Fusarium and food quality

During heat treatment, the level of mycotoxins does not decrease!

Bread quality

Grains infected with fusarium have low quality, they produce dense bread with large pores

Quality of pasta

Fusarium affects the quality standard in terms of viscoelasticity and color of pasta that is made from durum varieties wheat.

Beer quality

Spontaneous and intense foam formation can lead to rapid, uncontrolled emptying of the bottle, similar to the gushing effect.

The influence of fusarium on bread quality

Uninfected grain

Grain affected by fusarium

Mycotoxins produced by various types of fungi. Fusarium have various toxicological properties.
Mycotoxins have different effects on different species, such as pigs, poultry, people, etc.
The most common mycotoxins in cereals are deoxynivalenol (DON) and T-2 toxin

DON

T-2 toxin

Zearalenone

Type of mushroom	Trichothecenes		Zearalenone	Fumonisins	Moniliformin
Type of mushroom	Type A 1	Type B 2	Zearalenone	Fumonisins	Moniliformin
		DON, NIV	+
	T-2/HT-2
		NIV, DAS
					+
				+

1 - trichothecenes type A: T-2 and HT-2 toxins, diacetoxyscirpenol (DAS)
2 - trichothecenes type B: deoxynivalenol (DON), nivalenol (NIV)

Fusarium - a threat to people in the past and present

Mitotoxin toxicity

All mycotoxins cause decreased immunity

	Toxicity
Trichothecenes type A (T-2, HT-2, DAS)	The most toxic metabolites. More toxic than type B trichothecenes Responsible for nutritional toxic aleukia (ATA) Causes epidermal necrosis and ulcerative stomatitis, serious gastrointestinal disorders that can lead to death
Trichothecenes type B (DON, NIV)	Acute toxicity characterized by vomiting (more sensitive in pigs), food refusal, weight loss, diarrhea, tissue necrosis No indication of carcinogenic, mutagenic or teratogenic effects
Zearalenone	Reduce animal productivity Estrogenic effects causing infertility, miscarriage (pigs are especially sensitive) Possible effect on cervical cancer in women
Fumonisins	Equine leukoencephalomalacia (a disease of horses), characterized by neurotoxic effects, pulmonary and cerebral edema, and liver damage Possible link to esophageal cancer in humans
Moniliformin	Changes in cardiac muscle tissue Intestinal bleeding (limited studies)

Distribution of deoxynivaleonol in fusarium wheat milling products

Fraction	Deoxynivalenol content
Fraction	mg/kg	% to original grain
Source grain	5,4	100
Flour 70% yield	2,16	40
Flour with Sh etc. and 3rd size. systems	3,6	67
Torn bran	9	167
Grinding bran	7,71	142

It has been proven that in bread made from fusarium grain the content of mycotoxins does not decrease, and sometimes even increases, especially when producing yeast dough and bread!

Effect of mycotoxins on animals

Wheat represents 50% of pig growth feed. If mycotoxins are present, feed consumption by pigs is significantly reduced. Serious symptoms include refusal to eat, weight loss and vomiting. Moreover, reproductive function may be affected

The influence of mycotoxins on feed consumption by pigs

Impact of fusariotoxins contained in feed on the health of animals and poultry

Refusal to feed
Decrease in productivity
Immunosuppression
Damage to internal organs (liver, kidneys, reproductive system organs, etc.)
Ulcerative stomatitis
Epidermal necrosis

LD 50 for some mycotoxins through the gastrointestinal tract

Mycotoxin	LD 50 for mice		LD 50 for poultry
Mycotoxin	mg/kg FA	Relates. toxicity	mg/kg FA	Relates. toxicity
T-2 toxin	5,2	1,0	5,0	1,0
HT-2 toxin	9,2	1,8	7,2	1,4
DON	70,0	13,5	140,0	28,0
Nivalenol (NIV)	4,1	0,8	—	—
Diacetoxyscirpenol (DAS)	23,0	4,4	3,8	0,7
Moniliformin	20,0	3,8	5,4	1,1

Occurrence of species of the genus Fusarium in grain samples from various regions of Russia

Type of mushroom	Region of the Russian Federation
Type of mushroom	North Caucasus	CCR + Center	Vol. Vyatsky	North West	Ural	Siberia	Far East
F. graminearum	+++	++		+			+++
F. culmorum		++	++	+		+	+
F. sporotrichioides	+++	++	+++	+++	+++	+++	+++
F. langsethiae	++	+		++
F. poae	++	+++	+++	+++	+++	+	+++
F. cerealis	++	+					++
F. avenaceum	++	++	+++	+++	++	++	++
F. tricinctum	+	++	++	++			+
F. verticillioides	++		+				++

The ability of fungi of the genus Fusarium to cause typical symptoms of fusarium and produce a mycotoxin characteristic of the species

Type of mushroom	Presence of typical symptoms of fusarium		Mycotoxin produced
Type of mushroom	generative organ	corn	Mycotoxin produced
F. graminearum	++	++	DON, ZEN
F. culmorum	++	++	DON, ZEN
F. sporotrichioides	+	-	T-2
F. langsethiae	-	-	T-2
F. poae	-	-	NIV
F. tricinctum	+	-	MES
F. avenaceum	++	+	MES
F. verticillioides (on corn)	++	+	FUM

Mass phenomenon; + possible phenomenon; - absence

The share of species of fungi of the genus Fusarium (%) in winter wheat grain from the Krasnodar Territory in 2010-2011

2010

2011

The share of species of fungi of the genus Fusarium (%) in winter wheat grain from the Stavropol Territory in 2010-2011

2010

2011

Proportion of samples (%) of wheat grain with different levels of Fusarium infection in the Krasnodar and Stavropol territories

2010

On average, federal law - 3,1% - 6,9%

2011

On average, federal law - 2,6% - 4,3%

How to identify fusarium?

Visual assessment

In areas where the species F.graminearum, F.culmorum, and F.avenaceum are distributed, visible symptoms of fusarium blight on ears can be detected in the field. However, this method is not reliable enough.

How to identify Fusarium?

Mycological analysis

In the laboratory, infected plant parts can be placed in a growing medium that encourages fungal growth.

After a few days of incubation, fungi of the genus Fusarium can be identified under a microscope based on their characteristic taxonomic features.

Molecular biological methods: the principle of polymerase chain reaction (PCR) diagnostics

PCR is based on enzymatic amplification of a DNA fragment
using an enzyme (Taq polymerase).
The chain reaction is a process that occurs in three stages (denaturation, annealing and expansion), repeated in several cycles.
At each stage of the process, the number of copies doubles from two to four, then to eight, and so on. After 20 cycles there are approximately 1 million copies, which is enough material to determine the desired DNA using the traditional method

Diagnosis of Fusarium using PCR technologies

PCR is a relatively fast and reliable method for identifying fungi.
Allows you to detect the presence of a certain type or several types of fungi in plant tissue.
Detection of the number of fungi is possible using quantitative PCR (real-time PCR). The amount of fungal DNA detected is related to the presence of mycotoxins produced by them.

Planar Waveguide Technology

Reliable and quick method, using innovative technology planar waveguide to determine from four to five toxins per measurement!!!

Simultaneous determination of several mycotoxins.
Ease of sample preparation.
Quick result (25 min).
No special laboratory training required

How to fight fusarium?

For many years, scientists around the world have been working on the problem fusarium- a disease widespread throughout the world that affects various grain crops.

Intensive research has led to a better understanding of aspects of the disease and production optimal solutions to suppress pathogenic fungi and reduce their negative impact on product quality.

Application of fungicides

Azoles are the best weapon against fusarium!

Treating crops with a fungicide during flowering is an important method of combating fusarium.

infectious disease of the ear, causing significant crop losses, making grain unsuitable for use for food and feed purposes

Specialists from the Crop Science division of Bayer, together with the laboratory of mycology and phytopathology of the All-Russian Research Institute of Plant Protection, have prepared unique information about dangerous disease- fusarium head blight; its biology; symptoms; factors that increase the risk of its occurrence; diagnostic methods, as well as control measures that allow obtaining high yields of high-quality grain

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Fusarium is a dangerous and very common disease of plants at any age, caused by fungi of the genus Fusarium

Pathogen, in different periods plant development, can infect roots, leaves and ears.

Some types of fungi form mycotoxins (from the Greek mukos - mushroom + toxikos - poison) - molecules associated with the secondary metabolism of fungi, which exhibit toxic properties and make it unsuitable for use for food and feed purposes.

Toxins cannot be detected without special equipment, and they can be found not only in grain, but also in its processed products - flour and bread.

Symptoms

Infection of plants with fusarium leads to both a decrease in yield and a catastrophic deterioration in its quality.

Symptoms of fusarium head blight:

pink-orange coating of mycelium and fungal sporulation on the glumes of the ear;
pale pink sporulation of the fungus on the glumes;
eye spot on glumes;

Symptoms of fusarium grain blight:

The affected grains are puny, wrinkled with a depressed deep groove and pointed barrels;
The surface of the grain is discolored or pinkish, without shine;
The endosperm is loose and crumbly; low glassiness of the grain or its complete loss;
In the groove and especially in the embryonic part of the grain there is a cobweb-like coating of fungal mycelium, white or pink, and accumulations of conidia, in the form of pads;
The grain germ is nonviable, dark in color on the cut.

However, apparently healthy grain can also be affected by fungi and contain mycotoxins!
This disease can cause damage to a batch of healthy and apparently healthy seeds. The presence of a milligram of mycotoxins in a kilogram of grain destroys all its beneficial properties.

Causes

Infection of leaves and ears with fusarium occurs by ascospores formed in fruiting bodies on post-harvest residues, or by conidia that appear on stubble residues or on the lower infected leaves. Infection of the ear mainly occurs during wheat flowering in conditions of sufficient humidity and at temperatures above +20°C. This subsequently leads to infection of developing grains.

The primary lesion occurs on the lower tiers of dead leaves. However, in most cases, no specific symptoms not noticeable. The resulting spores are spread by splashing rain.

The main period of infection is the flowering time of cereals. In this case, the anthers apparently serve as the entrance gate to each individual flower. Nutrient-rich pollen promotes the germination of fungal spores. Any weakening of the plant contributes to the defeat of the ears by fusarium.

Microscopic development

1. Conidia develop on the surface of the plant

2. Form mycelium

3. Penetrate the plant

4. Develop in tissues

5. After the incubation period, new conidia are formed

Factors influencing Fusarium infection

Plants of cereal crops are susceptible to fusarium in the flowering phase at high humidity and temperatures of about +20-25°C (especially F. graminearum). But for species such as Fusarium sporotrichioide and F. poae, increased humidity and air temperature are not mandatory conditions for infection. Weather conditions are an important, but far from the only factor influencing the development of the disease.

Tillage

Tillage methods have a great influence on the development of fusarium.
The presence of fungal-infected plant residues on the surface or in the surface layers of the soil after minimal tillage greatly increases the likelihood of infection of growing plants.
This means you can reduce the risk of infection by plowing plant debris into the soil, where it decomposes more quickly.

Effect of tillage on DON content in grain

3000 2000 1000 0

Crop rotations

The rotation of crops in a crop rotation has a particular impact on the potential development of infection.
Saturation of crop rotation with grain crops promotes the accumulation of inoculum.
Low-field crop rotation, especially including corn, increases the risk of plants being damaged by Fusarium.
Beetroot is also an unfavorable predecessor.

The influence of the previous crop on the DON content in grain

1500 1000 500 0 DON content, µg/kg

Variety resistance

Cultivation of resistant varieties has a greater impact on reducing disease incidence and improving grain quality.
Most cultivated varieties of grain crops are susceptible to fusarium.
Bread wheat varieties vary in level of susceptibility from relatively resistant to highly susceptible.
Durum wheat and oats are highly susceptible to fusarium grain blight.

Influence of variety susceptibility to fusarium blight on DON content in grain

These data are taken from studies on the level of deoxynivalenol DON, a minotoxin secreted by fungi of the genus Fusarium. France 2000 - 2001, number of fields 663 pcs.

Find out in 30 seconds how the Fusarium pathogen develops

The gene modified with green fluorescent protein makes it possible to monitor the development of the fungus Fusarium graminearum in the ear.

At favorable conditions, fusarium completely infects the ear in 5-6 days!

Consequences

Mycotoxins (from the Greek mukos - mushroom + toxikos - poison) are specific toxic substances produced by fungi. Poisonous macromycetes, such as toadstool and red fly agaric, are well-known “poisoning villains”. But their microscopic relatives (micromycetes) are no less poisonous and even more dangerous. After all, their toxins cannot be detected without special equipment, and they can be found not only in grain, but also in its processed products - flour and bread.

What are mycotoxins?

Mycotoxins are molecules associated with secondary metabolism mushrooms that exhibit toxic properties to humans and animals.
All major fungal species that cause Fusarium blight can produce mycotoxins.
Mycotoxins produced by various types of fungi. Fusarium have various toxicological properties.
Mycotoxins have different effects on different species, such as pigs, poultry, humans, etc.
The most common mycotoxins in cereals are deoxynivalenol (DON) and T-2 toxin

Toxic effects

Trichothecenes

type A(T-2, HT-2, DAS)

F.sporotrichioides F.langsethiae

The most toxic metabolites.
Responsible for nutritional toxic aleukia (ATA)
Causes epidermal necrosis and ulcerative stomatitis, serious gastrointestinal disorders that can lead to death

type B(DON, NIV)

F.graminearum F.poae F.culmorum F.cerealis

Acute toxicity characterized by vomiting (more sensitive in pigs), food refusal, weight loss, diarrhea, tissue necrosis
No indication of carcinogenic, mutagenic or teratogenic effects

Zearalenone

F.graminearum F.culmorum

Reduce animal productivity
Estrogenic effects causing infertility, miscarriage (pigs are especially sensitive)
Possible effect on cervical cancer in women

Fumonisins

F.verticillioides F.proliferatum

Equine leukoencephalomalacia (a disease of horses), characterized by neurotoxic effects, pulmonary and cerebral edema, and liver damage
Possible link to esophageal cancer in humans

Moniliformin

F.tricinctum F.avenaceum

Changes in cardiac muscle tissue
Intestinal bleeding (limited studies)

Distribution of deoxynivaleonol in fusarium wheat milling products

It has been proven that in bread made from fusarium grain the content of mycotoxins does not decrease, and sometimes even increases, especially when producing yeast dough and bread!

Fusarium
threat to people!

Effect of mycotoxins on animals

Impact of fusariotoxins contained in feed on the health of animals and poultry

Refusal to feed
Decrease in productivity
Immunosuppression
Ulcerative stomatitis
Epidermal necrosis
Damage to internal organs (liver, kidneys, reproductive system organs, etc.)

LD50 indicator for mycotoxins entering through the gastrointestinal tract

LD50- the average dose of a substance that causes the death of half the members of the test group. ZhM- live weight
Relative toxicity- degree of toxicity of a substance in comparison with another substance (in in this case compared to T-2 toxin). more toxic substance< 1,0 < менее токсичное вещество

	LD50 for mice		LD50 for poultry
Mycotoxin	mg/kg FA	Rel. toxicity	mg/kg FA	Rel. toxicity
T-2 toxin	5,2	1,0	5,0	1,0
HT-2 toxin	9,2	1,8	7,2	1,4
DON	70,0	13,5	140,0	28,0
Nivalenol	4,1	0,8	-	-
Diacetoxyscirpenol	23,0	4,4	3,8	0,7
Moniliformin	20,0	3,8	5,4	1,1

The ability of fungi of the genus Fusarium to cause typical symptoms and produce species-specific mycotoxin

	Presence of typical symptoms of fusarium
Type of mushroom	generative organ	corn	Mycotoxin produced
F. graminearum	++	++	DON, ZEN
F. culmorum	++	++	DON, ZEN
F. sporotrichioides	+	—	T-2
F. langsethiae	—	—	T-2
F. poae	—	—	NIV
F. tricinctum	+	—	MES
F. avenaceum	++	+	MES
F. verticillioides	++	+	FUM
absence possible phenomenon mass phenomenon

T-2 and HT-2 toxins are among the most dangerous mycotoxins produced by fungi of the genus Fusarium. At the same time, their producers - F. langsethiae and F. sporotrichioides - can develop on the ear without visible signs.

T-2 toxins
hidden threat

Occurrence of species of the genus Fusarium in grain samples from different regions Russia

	Regions of the Russian Federation
Type of mushroom	North Caucasus	Center. Part	Volgo Vyatsky	North West	Ural	Siberia	Far East
F. graminearum	+++	++		+			+++
F. culmorum		++	++	+		+	+
F. sporotrichioides	+++	++	+++	+++	+++	+++	+++
F. langsethiae	++	+		++
F. poae	++	+++	+++	+++	+++	+	+++
F. cerealis	++	+					++
F. avenaceum	++	++	+++	+++	++	++	++
F. tricinctum	+	++	++	++			+
F. verticillioides	++		+				++
rare often meets very common

Infection of winter wheat grain with fungi of the genus Fusarium depending on its predecessors

	Krasnodar region			Stavropol region
		FZ*, %			FZ*, %
Previous culture	Number of samples, pcs.	average	Min-max	Number of samples, pcs.	average	Min-max
Peas	3	2,3	1-5	2	4,5	1-8
Corn	21	3,8	1-14	5	25,8	5-53
Onion	—	—	—	1	14	—
Mn. herbs	2	1,5	0-3	1	0	—
Oz. cereals	1	1	—	9	1,7	0-4
Sunflower	24	2,7	0-8	3	6,3	2-13
Sah. beet	7	3,6	0-13	—	—	—
Steam	—	—	—	7	1,3	0-3
Soybeans	4	1,7	0-5	1	4	—
NSR		0,8	—	—	4,4	—
% FZ, on average	—	3,1	—	—	6,9	—

The least favorable predecessor in terms of the subsequent risk of developing fusarium is corn. The presence of such a precursor makes it necessary to develop a strategy for protecting winter wheat from fusarium head blight.

HOW TO DETERMINE FUSARIOSIS?

1. Visual assessment

In areas where the species F.graminearum, F.culmorum, and F.avenaceum are distributed, visible symptoms of fusarium blight on ears can be detected in the field. Infection with fusarium does not always manifest itself visually, but this disease can cause the “disqualification” of a batch of full-bodied and apparently healthy seeds. The presence of literally a milligram of mycotoxins in a kilogram of grain - and that’s it! At best, such grain will be used as fodder. Neither protein content, nor IDC indicators, nor nature matter if the grain contains a microscopic amount of a deadly poison of fungal origin.

Advantages:

Fast and inexpensive way

Flaws:

PCR is a relatively fast and reliable method for identifying fungi.
Allows you to detect the presence of a certain type or several types of fungi in plant tissue. Detection of the number of fungi is possible using quantitative PCR (real-time PCR).
The amount of fungal DNA detected is related to the presence of mycotoxins they produce.

4. Planar waveguide technology

A reliable and fast method that uses innovative planar waveguide technology to detect four to five toxins in one measurement.

Simultaneous determination of several mycotoxins.
Ease of sample preparation
Quick result (25 min)
No special laboratory training required

Need for specialized equipment

How to fight fusarium?

For more than 20 years, Bayer has worked on the problem of fusarium blight, a worldwide disease that affects a variety of grain crops.

Intensive research work has led to a better understanding of disease aspects and the development of optimal solutions to suppress pathogenic fungi and reduce their negative impact on product quality.

Application of fungicides

Treating crops with a fungicide during flowering is an important method of combating fusarium.

Azoles have fungistatic effect. They suppress the synthesis of ergosterol in the fungal cell membrane at the level of formation of dimethylergostatrienol from lanosterol by inhibiting the cytochrome P450-dependent reaction of C14-a-dimethylation

Azoles are the best weapon! against fusarium

Bayer's Crop Science division has developed a new active ingredient, prothioconazole, which provides high level protection of the ear from fusarium and, as a result, leads to the most effective reduction of the level of mycotoxins in the grain.

According to independent assessment(information from the website www.eurowheat.org) combination of various active ingredients in the fight against fusarium head blight in European countries tebuconazole with prothioconazole has maximum effectiveness against fusarium head blight!

Both active substances belong to the group of triazoles and inhibit the biosynthesis of sterols, disrupting the integrity of the cell walls of pathogens.

Among the current environmental and hygienic problems of Russia and the CIS countries, a prominent place is occupied by fungal diseases of grain crops, in particular, fusarium head blight (FB) of winter wheat. Since the 80s In the 20th century, in the Krasnodar Territory, the spread and severity of fusarium blight of winter wheat and barley, caused by the fungus Gerlachia nivalis (syn. F. nivale Ces.), is increasing. The pathogen infects plants throughout the growing season as the causative agent (sometimes along with F. culmorum Sacc.) of “snow mold.” The disease develops due to excessively early or late sowing; poor hardening of plants in autumn; high snow cover; late snow melt; cold weather with frequent frosts and high relative humidity in spring, cold and rainy summer. The damage is aggravated by the saturation of crop rotations with wheat and rye, grain predecessors, weedy crops, uneven fields, and excess doses of nitrogen fertilizers in the fall. When plants are infected with F. culmorum and F. graminearum, the affected leaf blade appears slightly darker than when infected with the typical snow mold pathogen (F. nivale Ces.). In recent years, the same pathogens have been registered as a leaf pathogen (“Fusarium leaf spot”). The source of infection is overwintered plants affected by snow mold. The ability to infect, along with leaves, ears and grains and synthesize MTs sometimes makes F. nivale and F. culmorum equal in harmfulness to F.graminearum, which causes FC. Direct damage to the yield of ears is not always great, however, the vital activity of F. nivale contributes to the accumulation of nivalenol, deoxynivalenol (DON) and other mycotoxins (MT) in the grain.

Fusarium blight of cereal crops has become widespread. It has acquired the nature of a pandemic and, under favorable weather conditions, always develops. The causative agents are fungi of the genus Fusarium Link.: F.graminearum, F.moniliforme, F.cul-morum, F.sambucinum, F.nivale, F.avenaceum. Fusarium blight of spike crops is usually represented by F.graminearum, F. cumorum, F.nivale, F.avenaceum. F.graminearum prefers warmer and milder climates, while F.culmorum and F.avenaceum tolerate dry and cool conditions more easily. The disease affects all cereals, but fusarium head and grain blight of wheat is especially widespread and harmful. The most intense infection occurs during the flowering phase of wheat. The defeat of FC (by fungi of the genus Fusarium Link.) is manifested by yellowing of the ears, a cobwebby coating of pale pink mycelium on the scales with transformation into merging pale pink or orange-red formations. A puny grain with loose endosperm causes losses of 25-30% of the yield or more, depending on the level of primary manifestation of FC and the duration of development of the disease until the phase of milky-waxy ripeness. Fusarium grain harvests amount to 3-4 million tons in some years. Fungi are capable of continuing to develop and infect grain at any stage of production - in windrows, on the floor, during harvesting, transportation, storage (at a humidity of more than 15%), processing, during the manufacturing process of products.

Purchase of grain during periods of ripening and storage poisonous properties due to the accumulation of MT in it, it is a national economic problem. The main MTs of domestic fusarium grain are DON and ZL. DON (vomitoxin) is produced mainly by various strains of F. graminearum, F. culmorum, F. nivale. The most active producer of GL is F.graminearum, but F.culmorum, F.moniliforme, F.nivale, F.tricinctum and other species also have the ability to synthesize it. MT concentrations are related to the content of fusarium grains, therefore, restrictions on the content of such grains have been introduced for grain crops.

Fusarium is a difficult to predict disease. A roughly four-year cycle has been adopted for it. Since 1985, fusarium of grain and ear has become widespread epiphytotically in the territory former USSR and the Russian Federation, the maximum outbreak occurred in 1988-1989. with unusually wet conditions during grain ripening. The main areas of fusarium are located in the southern regions of Russia, in particular, in the Krasnodar and Stavropol territories. The volume of procurement of fusarium wheat has increased many times: from the 1989 harvest, the state resources of the RSFSR received 3,980 thousand tons, including those containing fusarium grains up to 1% - 3,708 thousand tons; from 1 to 3% - 258 thousand tons and over 3% - 14.8 thousand tons.

The reasons for the spread of FC in the southern regions of the European part of the country may be not only warm, humid weather conditions during flowering, ripening and harvesting, but also the irrational use of intensive cultivation technology (minimizing tillage, surface cultivation with disc tools), substandard seeds, and a passion for late-ripening varieties. , oversaturation of crop rotations with grains, especially wheat and corn, separate prolonged harvesting. It is known that the placement of wheat after corn for grain, overestimation of mineral nutrition standards (excess nitrogen) increase the infestation of plants with FC and contribute to the growth of the harmfulness of the pathogen. The volume of treatments with plant protection products is decreasing. In the Krasnodar region from 1988 to 1994. they decreased from 365.8 to 8.9 thousand hectares. Households, citing severe financial position, refuse to treat even potentially hazardous areas. Systematic exposure to pesticides can also increase the resistance and toxin-forming properties of FC pathogens.

The difficulty of preventing the spread of fusarioses is also associated with an acute lack of fungicides that suppress FA. An important task remains the further search, development and study of these tools. In the practice of combating fusariosis of winter wheat, such fungicides as foundationazole (benlat), impact (flutriafol), sportak (prochloraz), alto (cyproconazole), folicur (tebuconazole), tilt (propiconazole), rex KS (thiophanate methyl and epoxiconazole) have become known. , corbel (fenpropimorph), granite (bromuconazole), opus (epoxiconazole), etc. Improvement chemical method within the framework of integrated plant protection, it is aimed at selecting effective but low-hazard drugs for agrocenoses. When testing new drugs and clarifying the effectiveness of recommended drugs, one should take into account their effect not only on the main pathogen, but also on accompanying microorganisms. Another side of the problem is the lack of FC-resistant wheat varieties. An effective means of combating FC is the use of agricultural techniques (crop rotation, deep plowing, incorporation of crop residues, etc.) in combination with chemical plant protection products.

Since the 1980s the spread of wheat FC in the North Caucasus acquired an epiphytotic character, the development of the disease reached 40-70%. In such years, the disease manifests itself on grain crops with an area of up to 1.0-1.5 million hectares, the amount of contaminated grain reaches 4 million tons. The proportion of affected plants of all varieties of winter wheat was in 1987-1988. 18%, and affected crops - 76%. Direct losses of commercial crops were estimated at 20-50% or more. Due to the high content of fusariotoxins, the grain was often unsuitable for use as food and fodder. In 1989, the disease was found everywhere in the Krasnodar region, but with a lesser degree of development - up to approximately 20%. The FC range covered all grain-growing areas of the region and the Republic of Adygea (RA). Crops in the Central, Northwestern, Western, Southeastern and Foothill zones were particularly affected. The maximum spread of the disease (up to 17-31%) was noted in the Starominsky, Tbilisi and Maikop regions (and in some fields - 100% with 70-80% damage to the ear). Fusarium wheat was contaminated with MT DON in 82-100% of cases. In general, in the RSFSR, 900 thousand tons of wheat (23% of the total mass of fusarium wheat) turned out to be unsuitable for use for food purposes in 1989 due to excess permissible levels MT, including 840 thousand tons - in the Krasnodar Territory.

The prevalence of fusariotoxins in grain and their danger to human health led to the introduction of regulations on their content in food raw materials in 77 countries. Russia has also established maximum permissible concentrations (MACs) for MT of fungi of the genus Fusarium. For example, the maximum permissible concentration for DON is 0.7 mg/kg in wheat, and 1.0 mg/kg in barley. For ZL this figure is 1.0 mg/kg and for T-2 toxin - 0.1 mg/kg. Each type of fusarium is capable of synthesizing a certain spectrum of MTs. Taking into account the species of the pathogenic fungus and determining the toxigenicity, it is possible to predict the contamination of Fusarium grain with specific MTs.

The species composition and properties of fusarium pathogens vary noticeably depending on the soil and climatic conditions of the zone. To characterize the phytosanitary situation, it is customary to take into account the dynamics of agrometeorological indicators that influence the state of the agrocenosis and determine its variability in the future. At each stage of plant development, information is collected on the phytosanitary state of crops, which is used both to make decisions on the tactics of agrotechnical and protective measures, and to accumulate long-term materials on the impact of plant protection systems on the state of agrocenoses. When assessing the phytosanitary situation, current information is compared with long-term observation data. These materials serve as the first and necessary step improving plant protection. The next stage is the development of an algorithm for protective measures: agrotechnical, chemical or biological in terms of timing and direction of their action, depending on the state of the agrocenosis.

Weather conditions have a fundamental influence on the development and interaction of agrocenosis. It is known that with high snow cover and slow snow melting, snow mold develops more intensively, and the damage to wheat by FC depends critically on the amount of precipitation, humidity and air temperature. FC mainly develops in those years when warm, humid, rainy weather prevails during the periods of heading, filling and ripening of grain. Conditions that develop over a certain period of time ("critical periods") may be of key importance. Therefore, taking into account the meteorological situation is required condition assessment and forecast of the phytosanitary situation. It allows you to predict the phenology and degree of development of pathogens, as well as the phenology and condition of plants, which is important for choosing tactics of preventive and protective measures. Phytosanitary diagnostics uses four forms of meteorological information: characteristics of the climatic features of the region; characteristics of the weather of the past year (season); indicators of temperature, precipitation, soil and air humidity for specific periods of time of the current season; weather forecasts for different periods of time. Climate data represents average indicators of its main characteristics over a long-term period: average annual indicators of the sum of temperatures and sum of precipitation; the average timing of the onset of the seasons of the year and deviations from them; indicators of temperature and precipitation in each season. Air temperature, precipitation, air humidity, intensity and duration are subject to recording. solar lighting and other data. For winter crops in the cold season, the soil temperature in the tillering node zone, the depth of freezing and the timing of soil thawing, snow cover, and the condition of the plants are taken into account. Quantitative relationships between indicators of condition, efficiency of plant protection and meteorological factors are established statistical methods at the next stage by analyzing the information accumulated over a number of years.

The main pathogen in the southern regions of the CIS (Krasnodar, Stavropol Territories and Ukraine) is F. graminearum, in the non-chernozem zone - F. avenaceum and F. culmorum, which are close to it in pathogenicity, symptoms and harmfulness. The dominance of F. graminearum over other species and the depletion of the species composition of the population increased in long-term foci of the disease. In the North Caucasus region and specifically in the Krasnodar Territory, F.graminearum, gradually displacing accompanying species, makes up, according to various sources, from 76-87 to 90% of the fusarium population. All 12 strains isolated from Fusarium grain in the North Caucasus produced DON and SL, although their toxigenic levels varied widely: 1.3-4820.0 mg/kg DON and 2.3-384.0 mg/kg SL. Apparently, the population of F.graminearum, which causes Fusarium grain blight in the southern regions, produces predominantly DON and ZL, just like the causative agents of FC in Canada and the USA. Representatives of another chemotype of F.graminearum, common in Southeast Asia, synthesize nivalenol along with DON, which is a more dangerous combination due to the high toxicity of the latter. This species almost does not produce other MTs (T-2 toxin, DAS).

The toxigenicity of F. graminearum depends on the geographical origin of the strains. In the Krasnodar, Stavropol Territories and North Ossetia, most isolates produced DON in quantities less than 200 mg/kg. SL was accumulated by fungi in smaller quantities than DON. In all zones, except North Ossetia, weak producers of ZL predominated, producing up to 50 mg/kg of toxin. The North Ossetian population was the most toxigenic: 48% of the strains of the population produced more than 200 mg/kg ZL. The high toxicogenicity of F. graminearum isolates from Azerbaijan was established, which synthesized up to 10,000 mg/kg of GL. It is possible that foothill agroclimatic conditions favor the acquisition by F. graminearum of the properties of synthesizing high concentrations of GL. It is obviously advisable to study this potential danger in the foothill zone of the Krasnodar Territory.

If we take as a measure of the harmfulness of Fusarium blight the DON concentrations per 1% of Fusarium grains in the grain mass, i.e. the ratio of the amount of DON to the content of fusarium grains, then in the Krasnodar region it was 1.02-1.08 and varied slightly depending on the year. In other zones southern region fusarium was less harmful, the DON/fusarium grain ratio was on average noticeably lower (0.58 and 0.71). It can be assumed that the Krasnodar fusarium population consists mainly of F.graminearum, all strains of which are capable of synthesizing DON, while the fusarium populations in the Stavropol Territory and Ukraine are more diverse and include species that are not active DON producers.

Bibliography

Donchenko L.V., Nadykta V.D. Food safety. - M.: Pishchepromizdat, 2001. - 528 p.
Zakharenko V.A., Novozhilov K.V., Goncharov N.R. Collection methodological recommendations on plant protection. - St. Petersburg, 1998. - 299 p.
Lvova L.S., Omelchenko M.D., Orlova N.Yu., Bystryakova Z.K. Fusarium wheat mycotoxins. Features of its acceptance, storage and processing // Review information. - Ser.: Elevator industry. - M.: TsNIITEM grain production, 1992. - P.1-44.
Monastyrsky O.A. Current state and problems of studying toxinogenic fungi that attack cereal crops // Current issues
biologization of plant protection. - Pushchino, 2000. - P.79-89.
Tutelyan V.A., Kravchenko L.V. Mycotoxins (medical and biological aspects). - M.: Medicine, 1985. - 320 p.
Phytosanitary examination of grain crops (Plant diseases): Recommendations / Ed. S.S. Sanina. - M.: FGNU "Rosinformagrotekh", 2002. - 140 p.

Bibliographic link

Grushko G.V., Linkenko S.N., Khan V.V. CHARACTERISTICS AND CONDITIONS OF DISTRIBUTION OF FUSARIUM HEAD BLOCK ON WINTER WHEAT CROPS IN THE SOUTHERN REGIONS OF RUSSIA // Modern problems of science and education. – 2005. – No. 2.;
URL: http://science-education.ru/ru/article/view?id=1514 (access date: 03/28/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

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