Materials used in this chapter are published in book Biostimulant Albit for increasing yields and protection of agricultures against diseases, A.K. Zlotnikov, Ed. Prof. À. Melkumova. All-Russia Institute of Plant Protection, Russia, 2006.
In this chapter, the intrinsic fungicidal properties of Albit are reviewed.
Besides stimulation of plant growth, Albit also protects plants through suppressing of development of the broad range of main crop diseases. Albit is not toxic for pathogenic organisms, but it can increase the plant immunity, natural ability of plants to resist diseases.
The effect of Albit on receptors of NADPH oxidase system of plant cells leads to synthesis of superoxide anion and peroxide (they have a direct biocidal action against plant pathogens), and also causes the synthesis of salicylic acid, active signaling compound. Spreading through plant tissues, salicylic acid immunizes plants against diseases and develops resistance to wide range of pathogens (systemic acquired resistance). Synthesis of phytoalexins (natural substance) increases in plant cells. Phytoalexins prevent pathogen development. For example, after Albit treatment, phytoalexins of stilbene nature are synthesized by 33% more in grapes. The effect of Albit is similar to effect of systemic fungicides. Systemic fungicides spread through the plant and have a direct biocidal effect on phytopathogens. However, Albit induces the spread of natural signal metabolite – salicylic acid. As a result, even plant organs untreated with Albit are immunized against diseases. Because of this mechanism of action, according to classification of well-known phytopathologist prof. Yu.T. Dyakov, Albit belongs to fungicides of the most modern fourth generation (1st and 2nd generations – contact fungicides, 3d generation – systemic fungicides, 4th generation – immunizers).
Chemical plant protection was traditionally based on use of pesticides toxic for pathogenic fungi. Historically, there was three generations of pesticides. Fungicides of the first and second generations (inorganic and organic contact poisonous preparations) are non-specific and toxic for both fungi and plants. This fungicides suppress the development of pathogenic fungi stronger than that of plants just because of plant’s more rigid and resistant cell walls protecting from penetration of undesirable substances. This features make troubles for the chemical treatments, because, at the first, the surface of treated plants must be very carefully coated with fungicide (since such fungicides acts only when contacting with parasites), and, at the second, treatments must be multiply repeated. Fungicides of the third generation are systematic organic compounds that are specific for particular groups of fungi and low-toxic for plants. They penetrate to plant, spread over tissues, and kill pathogenic fungi not only on the plant surface, but also inside of plants, that makes them considerably more convenient than the simple contact fungicides. However, their specificity to targets in metabolic pathways of parasites (for example, in chitin or steroid synthesis), leads to complete loss of toxicity in case of target modification. Thus, continuous use of systemic fungicides in general case leads to loss of their effectiveness due to rising of resistant pathogenic strains. Nowadays, the fort generation of pesticides has come. The pesticides of the forth generation does not kill pathogenic organisms, but decrease their pathogenicity and increase resistance (immunity) of plants .
Due to reinforcement of natural plant protecting mechanisms, Albit acts as a systemic broad fungicide. Owing to immunizing action, Albit have pronounced prophylactic and weak curing effect, but it can not destroy the pathogenic fauna. Therefore, treatment with Albit should be conducted in advance, before appearance of first signs of diseases. Positive effect of Albit against downy mildew was observed after seed treatment of rape seedlings (South Westphalia University of Applied Sciences, Germany) (Fig. 1). Albit decreases the infestation of plants by number of diseases: root rots, mealy dew, leaf spots, brown rust, fusarioses, anthracnose, late blight, black leg, white and grey rots, bacteriosis, etc.
Fig. 1. Influence of Albit on resistance of spring rape var. Ability against downy mildew Peronospora parasitica (South Westphalia University of Applied Sciences, Germany, 2014). Left – control, right – treatment with Albit
The basic parameter used for the characterization of fungicidal properties of pesticides is their biological efficiency which is calculated by formula:
RC — incidence (severity) of disease in the control,
Biological efficiency of 100 % means full eradication of disease, 0 % – absence of activity of a pesticide. BE is an analogue of Control Efficacy, which is more common for publications in the USA.
Biological efficiency of Albit against plant diseases is 40-80 % averagely. Albit is most effective against diseases of cereals and leguminous crops, sugar beet, sunflower, vine and flax. Against these diseases, biological efficiency of Albit can reach 90-100 % that is excellent for biostimulant.
By now we have analyzed the results of all 250 field trials with Albit and summarized the data about its efficiency against plant diseases. The results are presented in Table 9.
Table 9. Fungicidal activity of Albit (according to results of all field trials 1997–2004). (—) no data.
The main parameter for describing of fungicide activity of Albit is its average biological efficiency against this or that disease. However, depending on specific agroclimatic and phytosanitary conditions, the real efficiency of pesticide might differs from the average one, that is shown as minimal and maximal values in Table 9. Averagely, the biological efficiency of Albit against diseases can vary approximately by 30% of average value, presented in table.
For visual presentation of data from Table 9, there are diagrams of efficiency of Albit against diseases of flax, winter wheat and vine. Winter wheat is the most widespread and economically significant crop which is subjected to treatment with Albit in many regions. Flax and vine, respectively, are the most northern and southern cultures tested with Albit. Thus, presented diagram reflects general fungicidal activity of Albit.
Fig. 2. Fungicidal activity of Albit against diseases of winter wheat (field trials, 1997-2004). Green bars are the average biological efficiency of Albit, intervals are the minimal and maximal efficiency obtained in trials.
Fig. 3. Fungicidal activity of Albit against diseases of flax (blue bars) vine (green bars). Bars are the average biological efficiency of Albit, intervals are the minimal and maximal efficiency obtained in trials.
According to decision of Federal Veterinary and Phytosanitation Service (Act Nr 0470, 4 Oct. 2006, State registration Nr 09-00496-0378-1), biostimulant Albit registered as fungicide against:
Universality of immunogenic influence of Albit and new data coming reveal fungicidal activity of Albit against many other diseases.
Summarizing all data of trials, Albit exhibits the most pronounced fungicidal activity against root rots of cereal crops of different etiology - 15-100 % (Table 9). Biological efficiency of Albit against root rots of spring wheat is 59%, barley -70%, winter wheat - 81%. According to a number of trials carried out by Saratov Regional Plant Protection Station, 2001, Soil institute, 2002, Kirov Regional Plant Protection Station, 2004, etc., Albit suppressed this disease totally (BE 100%).According to All-Russia Institute of Plant Protection RAAS (2004-2005), BE of Albit against Fusarium and Helminthosporium root rots of winter wheat is 57-77 even under conditions of high artificial infectious environment (Table 10). As far as the effectiveness of majority of recommended chemical protectants against root rots is 40-70%, Albit is effective enough and competitive even among chemical analogues.
The main mechanism of action of Albit is immunization of plants through seed treatment and correction of community of root soil microorganisms through sowing of treated seeds. Consequently, amount of causative agents in rhizosphere gets lower. Chemical protectants surely defend plants against seed root rot infection, but due to stress action, they decrease plantlets resistance to secondary infection from soil. Albit provides more complex and prolonged defense, which is independent on the way of infection soil or seed).
As is well known, the subsidiary phosphoric supplement restricts development of root rots of cereals. Therefore, increase of cereal resistance by Albit can be also partially explained through its ability to increase phosphorus uptake from soil approximately by one third (Fig 24).
Table 10. Biological efficiency of different means of protection against Fusarium and Helminthosporium root rots of winter wheat var.Ofelia (All-Russia Institute of Plant Protection RAAS, All-Russia Institute of Biological Plant Protection, Krasnodar kraj, 2004-2005)
* Biological effectiveness was calculated basing on disease development (R).
The harmfulness of root rots is increasing every year. For comparison, yield losses due to smut infection and root rots make annually 5-10% and 15-30% respectively. Thus, Albit takes on special significance in agriculture. Though Albit, like the other protectants, is recommended to use only at low and moderate infestation (below 30%), its using is economically sound, since economical harmfulness threshold determined by intensity of disease development is 10-15%. Depending on etiology, Albit in laboratory and field conditions have the highest effectiveness against Fusarium and Helminthosporium root rots. The continuous immunizing activity of Albit provides pronounced plant defense not only against root rots itself, but also against late manifestations caused by the same pathogenic agents (net and spot blotch, helminthosporiose) (Tabl 9).
Albit is also effective against root rots of other cultures. The average effectiveness of Albit against root rots of: pea, soybean, rice, amaranth is 41%, 62%, 73%, 98% respectively, against black leg of sugar beet is 70%(Table 9).
Trials of All-Russia Flax Institute revealed the high effectiveness of treatment of flax seeds with Albit against the main diseases of flax. The average effectiveness of Albit against Anthracnose, ozoniozis and bacteriosis was 72–84 % that is inferior to none of the chemical protectants.
Among leaf and stem infections of eared cereals, Albit was most effective against brown rust, powdery mildew and septoria leaf spot. Biological efficiency of Albit against those diseases is 45–90 % averagely, but immunizing activity of Albit is not sufficient for total eradication of those diseases (Table 9). For full guaranteed defense one can recommend to apply Albit in mixture with half dose of chemical fungicides. The joint treatment with Albit and herbicides in stage of tillering is also high effective, especially for winter crops in spring. In this case, Albit relieves the herbicide-mediated stress which increase probability of the leaf and stem infections.
Foliar spraying with Albit is also high-effective for immunization of plants against: late blight of potatoes, downy and powdery mildew of vine, bacterial black rot of white cabbage, watery soft rot and head grey mould blight of sunflower, black leg, cercospora leaf spot and downy mildew of sugar beet. Regular and well-timed foliar sprayings with Albit allows to decrease plant infestations by 40-70 % or, in case of joint use with chemical fungicides, to eliminate pathogens completely.
Effectiveness of Albit against internal diseases is considerably less pronounced. For example, Albit is not effective against Verticillium wilt of sunflower. Plants should be immunized before infestation, therefore Albit can hardly disinfect seeds, especially mould contaminated ones (Mucor, Penicillium, Aspergillus).Tests of All-Russia Institute of Plant Protection RAAS with winter wheat var. ‘Ofelia’ demonstrated that seed treatment with Albit did not reduce the infestation of seeds with pathogens and saprophytes, but suppressed the further development of pathogens on plant germs (effectiveness against root rots approx. 67%). Albit itself is unable to disinfect seeds, but it can increase disinfection effectiveness of chemical protectants. For example, tests of All-Russia Flax Institute (2003) demonstrated that use of chemical fungicides (even reduced rates) in mixture with Albit for seed treatment considerably increased the seed disinfection effectiveness. The general contamination of seeds with bunch of infections (anthracnose, ozoniozis, bacteriosis) was 27 % in control, use of full dose of Vital and cut dose of Vital with Albit reduced contamination to 8,0 %, and 4,5 % respectively. Analogously, combination of TMTD with Albit decreased final contamination from 14,4 % (seed treatment with TMTD alone) to 6,0 %.
Albit alone as a fungicidal seed treatment agent also is not effective enough against smut infections. Albit effectiveness decreases in series loose smut --> stinking smut --> dwarf smut. Spores of dwarf smut (Tilletia controversa Kuehn.) infect plantlets of cereals generally from soil, spores of stinking smut (Tilletia caries Tul.) remain intact also on the surface of seeds. Spores of loose smut (Ustilago tritici Jens) infect plants in blossoming stage, hyphae of pathogen contaminate seed buds, that make senseless seed treatment with immunizing agents. However, foliar spray in blossoming stage (the second foliar spray) can immunize cereals and decrease loose smut contamination of seeds. Also, joint use with Albit provides dramatic increase of effectiveness of chemical seed treatment agents against smut infections, as it was demonstrated in tests performed by Agricultural Scientific Institute of South-East.
Nowadays, problem of plant diseases of bacterial etiology also become very important for agriculture. Albit effectively suppress chemical fungicide resistant bacteriosis through immunization and correction of plant-associated microbal community. In tests of All-Russia Flax Institute, average biological effectiveness of Albit against bacteriosis was 84,4 %, whereas BE of chemical seed treatment agents was less than 50 %.
In number of trials, Albit acting via immunization was not less effective than direct-acting chemical fungicides. For example, tests of Lipetsk Plant Protection Station with spring barley var. Odesskij-115 demonstrated the same effectiveness against root rots and powdery mildew (91-98 %) of Albit (30 ml/tonne of seeds+2 foliar sprays, 30 ml/hectare) and chemical (Raksil, 1,5 kg/tonne of seeds+foliar spray with Falkon, 0,6 L/hectare) treatments. Analogously, in tests of Tula Plant Protection Station with spring barley var. Zaozerskij-85, effectiveness of presowing treatment with Albit against root rots was 82–85 %, that was not inferior to treatment with standard chemical protectant (Agrosil). In tests of Agricultural Scientific Institute of South-East (2003, 2004), BE of Albit against watery soft rot and head grey mould blight of sunflower was not inferior to BE of standard chemical protectant Fundazol. In tests of North-Caucasian Institute of Horticulture and Viticulture (2004), BE of Albit against downy and powdery mildew of vine was the same (86-93 % and 94-100 % respectively) as BE of chemical pesticides (Ridomil, Falkon, Tiovit, Impakt). In tests of All-Russia Flax Institute (2002-2004), BE of Albit was 86–90 %, that is approximately the same as BE of chemical standards (Vital, TMTD, Fundazol, Fenoram-super). In tests of Leningrad Plant Protection Station with spring wheat var. Irgina, BE of Albit against septoria leaf spot was 77–100 %, whereas chemical fungicide Fundazol was ineffective. According to conclusion of All-Russia Institute of Plant Protection (2003, 2004), Albit could be used instead of TMTD for coating of sugar beet seeds, because their biological effectiveness (68-88%) are the same. Presented data reveal great plant protective potential of Albit, but it is necessary to note, that fungicidal activity of Albit in general case was 20-30% lower than that of most advanced chemical fungicides.
In summary, as shown in details further, in respect of fungicidal activity Albit was not inferior than majority of standard pesticides in field trials, but in many cases it was less efficient than specialized expensive chemical means of plant protection (protectants and fungicides). Therefore, Albit is useful for plant protection in conditions of low and moderate infestation level and for reduction of application rates of chemical means of plant protection.
According to results of tests, Albit suppresses a broad range infections (Table 11). However, as in case of other chemical and biological fungicides, the higher infestation level, the lower Albit effectiveness. Fungicidal activity of Albit was detected in experiments only when infestation was less than 30% (low and moderate infestation), and there was no internal infections. At higher infestation level, BE of Albit decreases noticeably.
For example, at disease prevalence of 3,5 %, 35%, 58% and 100% effectiveness of Albit foliar sprays against brown rust was 80 %, 57,1%, 52% and 38.3% respectively (data of Lipetsk Plant Protection Station, 2003, All-Russia Institute of Agrochemistry, 2001, All-Russia Institute of Biological Plant Protection, 2004,and Krasnodar Plant Protection Station, 2004, respectively). Analogously, according to tests of Vladimir Plant Protection Station (2004) with barley, BE of Albit for high (60-100%) and moderate helminthosporiose prevalence was 20-40% and 60,4% respectively (Table 9). BE of Albit against Bacterial black rot of white cabbage (Xanthomonas campestris Dowson) was 100 and 60% for prevalence of 4 and 13% (Vladimir Plant Protection Station, 2004, All-Russia Institute of Vegetable Selection and Seed Breeding, 2003).
Table 11. Development of Albit sensitive diseases The average data of all field trials 1997-2004.(–) no data.
Therefore, to get reproducible effect of Albit treatment under more than 30-50 % infestation (10 % infestation with internal diseases), it is necessary to combine Albit with chemical protectants. Albit increases their effectiveness, that might reduce application rates.
Albit, as growth stimulator, accelerate growth and development (see in details). Analogously, protective activity of Albit acts through retarding of disease development.
For example, in trials of All-Russia Institute of Agrochemistry and Ryazan Agricultural Academy with spring wheat var. ‘Voronezhskaya-10’ (2001), brown rust appeared in control and standard series quite fast, in stage of tubering, and infestation has reached 60-65% by stage of ear formation and wax stage of ripeness. In series with Albit treatment, the first signs of disease appeared only in stage of ear formation. Vine var. ‘Shardone’ treated with Albit exhibited the first signs of powdery mildew only by the end of vegetation. In control sets, there was 36 fold increase of number of infected bunches and 0,05-12,1% increase of disease intensity by the same time, (North-Caucasian Institute of Horticulture and Viticulture (2004). In trials of All-Russia Institute of Viticulture and Wine processing (2003) Albit treatment retarded development of vine diseases (downy mildew and phoma leaf spot) up to 1,5 month.
Similarly to yield increase, contribution of foliar spraying and seed treatment to protection from diseases is different. The most effective immunization against soil and seed infection (e.g. root rots) can be reached through seed treatment, against air infections – through foliar spraying. Immunization of vegetables and potato should be performed through foliar spray; reliable defense of apple, vine and currant takes (as shown in tests of All-Russia Institute of Plant Protection, All-Russia Institute of Horticulture, All-Russia Institute of Viticulture and Wine processing and other institutes) at least 2 sets of foliar spray in vegetation season.
In tests of All-Russia Institute of Leguminous and Groat Crops (2003), BE of presowing seed treatment of pea (var. Orlus, Truzhenik and Vega) with Albit against root rots was 35,7–59,1 % (i.e. almost the same, as BE of standard TMTD), whereas one or two foliar sprays was completely ineffective. Thus, protection of pea against root rots requires only seed treatment, whereas yield increase can be provided with both seed treatment and foliar spray. For flax (trials of All-Russia Flax Institute), presowing seed treatment with Albit demonstrated high BE (81-90%) against diseases of early growth stages (anthracnose, ozoniozis, bacteriosis), but was useless against pasmo disease in ripening stage. However, combination of Albit seed treatment and foliar spray with allowed to provide BE against pasmo of 70-77%.
According to reports of All-Russia Institute of Plant Protection (2004), effectiveness of Albit (presowing seed treatment) against blister smut of maize was 65,9 %, additional foliar spray with Albit (in stage of 4-6 leaves) increased BE by 10%, and the second treatment (in stage of blossoming) had no influence on disease development and propagation. As one can see, the earliest treatment was the most effective. The fungicidal effect of Albit against watery soft rot and head grey mould blight of sunflower was almost completely (by 94%) caused by presowing treatment; foliar spray gave only 6% of total BE (Agricultural Scientific Institute of South-East, 2003). In tests of All-Russia Institute of Plant Protection (2002) with sunflower var. Voronezhskij-638, BE of foliar spray with Albit against root and stem form of watery soft rot was approx. 3 times lower than BE of presowing seed treatment. On the other hand, twice repeated foliar spray in the same trial decreased infestation with anthodium (head) form of watery soft rot and head grey mould twice more effectively than seed treatment. The highest BE was provided by combination of seed treatment and double foliar spraying.
In most cases, the highest protective effect can be reached through combination of seed treatment and foliar spray, i.e. through accomplishment of all procedures offered in Application recommendations. Like growth promoting activity, plant protecting activity of Albit depends on stage of growth: earlier treatment provides higher activity. For proper immunization and providing of reliable protective effect, Albit should be used before appearance of first signs of diseases.
Moreover, as it was mentioned earlier, the maximal guaranteed fungicidal effect of Albit was detected at joint use with chemical fungicides.