Sergey Banadysev, Doctor of Agricultural Sciences, Head of the selection program of the SSC “Doka - Gene Technologies
The possibilities and efficiency of processing seed tubers during planting are currently increasing significantly. If earlier the main function of pickling was to control rhizoctonia, wireworm and Colorado potato beetle on seedlings, now professionals have at their disposal a whole arsenal of tools to control the most common peel diseases, soil infection of late blight, anthracnose and pitium, aphids during the first vegetation period, stem nematode, and soil improvement microbiota. In addition to the main fertilizer, it is advisable to introduce trace elements and other growth stimulants of the root system and plants during planting along with etching.
In the Russian Federation, it is officially allowed to use 18 active ingredients of fungicides, 10 active ingredients of insecticides and 15 microbial preparations with fungicidal activity for the treatment of seed. The active substances (d.v.-va) are effective against potato diseases: azoxystrobin, mefenoxam, fludioxonil, cyproconazole, benzoic acid, benomyl, pencycuron, thiabendazole, penflufen, prothioconazole, difenoconazole, thiram, imazalil, metalapyrodaxil, fluxaprodaxil. Of the 30 commercial drugs, the most analogs are Prestige (imidacloprid + pencycuron, Bayer) - 8 and Maxima (fludioxonil, Syngenta) - 5. There are several products with two dvs. fungicides: azoxystrobin + mefenoxam (Uniform, Syngenta), penflufen + prothioconazole (Emesto Silver, Bayer), in combination with an insecticide - acetamiprid + fludioxonil + cyproconazole (King Combi, Agro Expert Group + Dyentafiodeloxaminoxamol ), iprodione + imidacloprid + difenoconazole (Idicum, August). The richest composition of the fungicide Deposit (Shchelkovo-Agrokhim) is fludioxonil + imazalil + metalaxil. All other drugs are single-component or in combination with an insecticide. Azoxystrobin (Quadris, Syngenta) and in combination with mefenoxam (Uniform, Syngenta), fluxapiroxad (Sercadis, BASF) is recommended for soil cultivation in the furrow, the rest of the substances - for tubers.
The list of permitted insecticides for treating tubers during planting is also quite extensive. It is allowed to use drugs with a.v. acetamiprid, imidacloprid, bifentrin, fipronil, clothiadinine, thiamethoxam, chlorantraniliprol, oxamil. In this case, teflutrin (Force, Syngenta) and oxamyl (Vidat, Corteva) have a preparative form of granules and are introduced into the soil. The remaining drugs are best used for dressing, in the same solution with fungicides. The spectrum of action of insecticides is soil-borne pests, Colorado potato beetle and aphids on seedlings. Nematode suppression - the appointment of Vidat nematicide. A separate admission to the biting scoop is not reflected in the regulations, although the practice of recent years has shown that the effectiveness of various active substances against this dangerous pest is far from equivalent. Most commercial preparations are based on imidacloprid, clothiadinine, and thiamethoxam. There are two-component options: imidacloprid + fipronil (Tabu Super, August), imidacloprid + bifentrin (Imidalit, FM Rus), thiamethoxam + chlorantraniliprol (Voliam Flexi, Syngenta).
The assortment of biological fungicides in the Russian Federation includes living cultures and metabolites of individual bacterial strains from the genus Bacillus, Pseudomonas and carnivorous fungi from the genus Trichoderma. In total, in the list of 2020, 15 commercial preparations are registered on potatoes. The most widely used in production is Extrasol (Bisolbi-Inter), which for some reason passes in the register as a microbiological fertilizer. Us in 2017-2019 The effectiveness of all modern biofungicides on potatoes has been evaluated. Very interesting and useful experimental data were obtained that deserve separate consideration and will be published.
Seed processing should provide effective protection against diseases and pests, stimulate plant growth and development and be sufficiently technological, built into a typical production process. Efficiency is determined by the correct selection of drugs and the quality of processing. The selection of drugs should be based on an understanding of the intended use of specific fungicides and taking into account the phytopathological problems of a specific batch of planting material and a specific field. The official state catalog of pesticides of the Russian Federation contains a limited amount of information. Fungicides for dressing tubers are registered as control agents for rhizoctonia, common scab and silver scab. There is no information on the effectiveness of drugs against anthracnose, wound watery rot, late blight soil infection, which have become widespread in recent years. There are some examples of a very broad spectrum of action. Thus, the old TMTD is positioned as a remedy against late blight, rhizoctonia, scab, wet bacterial rot and fusarium. This raises reasonable doubts, since only the most modern three-component fungicide Idicum has a comparable spectrum of action - oosporosis, phomosis, anthracnose, fusarium, rhizoctonia.
Advertising of pesticide manufacturers provides certain guidelines, but objectivity in this case is not guaranteed. Advertising materials should be evaluated with restraint and prudence, taking into account the commercial interests of plant protection products manufacturers. Yes, they provide ample evidence of the advantages of specific drugs over competitors in real production conditions. There is such an iron rule: your drug always wins, the competitor always loses. In the materials of a competing company, of course, everything is exactly the opposite. An example of a proprietary comparison of the spectrum of activity of various disinfectants is shown in Table 1.
It is important to know the true purpose and effectiveness of all available plant protection products. Such information in developed potato growing countries is annually updated by independent expert institutes and brought to the attention of the professional community. Officially, free of charge and in advance. Since the state does not yet provide a similar service to agricultural producers in the Russian Federation, the information available from foreign official and open sources should be taken as a basis, adjusted for the available funds. Table 2. generalized technological methods of control of common potato diseases, indicated pesticides with proven effective suppression of specific pathogens. This is relevant information, since most of the active molecules of protective agents were synthesized for a long time. But some active molecules have been created only recently: sedaxan, penflufen, fluxopyroxade, which opened up new possibilities for the management of pathogens during planting.
Table 2. Technological methods for controlling potato diseases (according to M.Fiers et al., 2011)
Pathogen / disease | Crop rotation | Fertilizer | Soil cultivation | Landing, care, cleaning | Pesticides |
Colletotricum coccodes / Anthracnose | Rotation for more than 5 years with wheat, red clover, alfalfa, corn, herbs, steam, barley. In addition to yellow mustard, soy, rape | — | 30 cm dump plowing | Avoid water stress, Early cleaning. Short interval between topping and harvesting | Provokes oxamyl. Reduces imazalil, tolchlofos-methyl, mancozeb, thiabendazole, fenpichonil and propiconazole. |
Fusarium spp./ Fusarium dry rot | Minimum three year rotation with red clover | Humus | Minimal processing | Early cleaning. Short interval between topping and harvesting, wound healing | Chlorine dioxide, fenpichonil, and a mixture of thiabendazole, imazalil and mancozeb |
Helmintosporium solani / silver scab | Minimum three year rotation with red clover | — | Minimal processing | Low landing density, late landing and early harvesting | Mankoceb, imazalil, prochloraz, chlorine dioxide, thiabendazole, fenpichlonil, benomyl |
Phoma ssp./ Fomose dry rot | — | — | — | Early topping, digging at temperatures above 8оС | 2-aminobutane, thiabendazole |
Phytophthora erytroseptica / Pink Rot | Three year old with barley and red clover | — | — | Well-drained fields, cleaning in cold weather, minimizing injuries | Mephenoxam, metalaxyl |
Polyscytalum pustulans / Oosporosis, tuberous scab | — | — | — | Early cleaning | Imazalil, prochlorase (semen), 2-aminobutane, benomyl, thiabendazole |
Phytium ultimum / Wounded watery rot | — | Humus | — | Well-drained fields, cleaning in cold weather, minimizing injuries | Mephenoxam |
Rhizoctonia solani / Rhizoctonia, black scab | Minimum three-year rotation, except for wheat, alfalfa, ryegrass | Humus, straw | Minimal processing, autumn crest cutting | Shallow planting (5 cm), high soil temperature, low planting density. Short time between topping and digging. | It provokes 1,3 - dichloropropene, aldicarb and epoprofos. It reduces pencicuron, chlorine dioxide, thiophanate methyl, flutolanil, mancozeb, benomyl, thiabendazole |
Sclerotinia sclerotinium / White mold | 4-5 years old with cereal grains, cereal herbs | — | — | Irrigation management | Fluazinam, iprodion, thiophanate methyl, boscalide |
Spongospora subterrania / Powdery scab | Minimum 10 years, no pasture | Do not use cow dung | Do not plow in spring | Late landing on well-drained fields | Fluzulfamide, Fluazinam, Mancocheb |
Synchytrium endobioticum / Potato Cancer | Very long rotation (30 years) | Urea | — | Well-drained fields | Urea = urea |
Verticillium dahliae / Vilt, verticillez | Three-year rotation with red clover, Sudanese grass, cereals. Except steam, peas, oats, rice, mint, weeds | Ammonium lingosulfate | Minimal processing | — | Mancozeb, captan, metam, 1,3-dichloropropene, chloropicrin |
Clavibacter michiganensis ssp.sepedonicus / Ring rot | With onion | — | — | — | Flusulfamide |
Pectobacterium, Dickeya / Blackleg | Exclusion of monoculture, alternation with wheat, red clover, barley or grass | Do not overestimate nitrogen | — | Well-drained fields, Removing infected plants, preventing skin damage | Chlorine dioxide, aluminum and bisulfite salt, casugamycin, streptomycin, soda benzoate, benzoic acid, copper oxychloride + metalaxyl or cymoxanil, metiram, clorocin, |
Streptomyces scabies / Common and netted scab | With lupine, winter rye or seradella. In addition to sugar beets, carrots, pastures | Potassium, phosphorus, ammonium lingosulfate, compost, pig manure | Deep loosening | — | Provokes oxamyl. Contains boric acid, streptomycin, daminoside, DL-ethionine |
Ditylenchus destructor | — | — | — | — | Oxamyl |
Globodera rostochiensis / Cyst nematode | Long rotation with peas, flax, rye, oats and ryegrass | Phosphorus | — | Prevent the spread of infection with the technique | Dimethyl disulfide, 1,3-dichloropropene, aldicarb, foxime, A.C. 92100, 64475, carbofuran |
Meloidogine ssp./ Gall Nematode | Black steam / In addition to many crops - carrots, beets, red clover, cereals, goat | — | — | — | All soil fumigants |
In the EU countries, there is a consistent process of active, even aggressive and excessive greening of agriculture. Many groups of active substances have already been withdrawn or withdrawn from circulation by law; their use is strictly prohibited. Therefore, the range of plant protection products for the protection of seed has become very limited, as can be seen in the example of Germany (Table 3). Experts believe that if this continues, the production of intensive crops, which certainly include potatoes, will have to be stopped in Western Europe, since it is becoming more and more difficult to get high yields and product quality. At the same time, two aspects of the protection system used in the EU deserve close attention: 1) fungicides based on copper hydroxide (Funguran progress, Kuprozin progress, there are similar ones in Russia, Koside 2000, for example) are recommended to be used to control bacteriosis; 2) microbiological preparations are actively used. Against bacteria Pectobacterium and Dickeya species, approved copper preparations can be mixed with other fungicides. Copper is a trace element and when processing tubers becomes available to plants at an early stage of development. Potato plants well supplied with copper are more resistant to frost. Early absorption of copper contributes to the formation of lignin, that is, a faster formation of a strong rind.
Table 3. Assortment of seed potato protection products during planting, Germany, 2020
In 2020, German potato growers have the opportunity to use 10 preparations for applying to tubers and to the soil when planting. The biological composition of these fungicides and growth stimulants, activation and normalization of microbiota is fundamentally different from the Russian one. Commercial products appeared with other species of the genus Bacillus, not Subtilis, but Verezentis, Atrophaeus, Amyloliquefaciens. In addition to the one-component, consortia of antagonist bacteria have begun to be actively used. Thus, the SOLANOVA® product contains a balanced mixture of 5 types of microorganisms: Trichoderma, Pseudomonas, Bacillus, Streptomyceten, Mykorriza. SOLANOVA principle of action - increases soil microbial activity, plant nutrients become available, enhances root growth, removes dead organic residues in the soil, promotes the production of plant hormones and enzymes, increases stress tolerance such as salinity, heat, drought, cold, etc. effect: grows in soil and roots and competes with pathogens for root exudates as primary food, forms a microbial barrier in the root area for other microorganisms, strengthens the resistance of plants, the formation of antibiotics belonging to plants, contributes to the stable development of young plants.
The most complete set of means of protecting potato planting material in the United States (Table 4,5). Until now, there are widely used products in the form of powder (dust) for seed treatment during cutting. The calm attitude to the risks of late blight, dry rot and bacteriosis spreading during cutting and the very fact of the total traditional cutting of large material in the USA is explained by the good efficiency of commercial powder products based on mancozeb and pencycuron. By the way, until last year, 30% of all seed potatoes in England were treated with pencycuron powder (Monceren, Bayer). For liquid etching, in addition to substances known in the Russian Federation, sedaxan, hydrogen peroxide, and the bacteria Chenopodium quinoa saponins are approved for use. Sedaxan is included in the world's first four-component disinfectant by Syngenta, which in the USA is called Cruiser Maxx Vibrance Potato Ultra with a combination of d.v. fludioxonil + difenoconazole + sedaxan + thiamethoxam. The Russian Federation announced the beginning of the procedure for including a similar drug in the register for potatoes; on sugar beets, Vibrans with a similar composition has already been approved (Table 4).
Table 4. Preparations for the processing of seed potatoes (official US state regulations for 2020)
1 - dosage = amount of finished product to be applied, where oz fl (ounce) = 28,4 g, cwt (bag) = 45,4 -50,1 kg.
2 - x - product permitted for culture and disease; blank = product not intended for a specific disease.
3 - Fusarium, Rhizoctonia solani and Helminthosporium solani. These fungi cause dry rot, rhizoctonia and silvery scab.
4 - includes Erwinia, cause of mild bacterial rot and Clavibacter, cause of ring rot.
The radical difference and advantage of the American system of protection when planting potatoes is a large assortment of preparations for application to the soil. In addition to the azoxystrobin, mefenoxam, fluxapiroxade and biological preparations permitted in the Russian Federation, it is allowed to use other active substances from the group of strobirulins (pyraclostrobin, fluoxastrobin) and typically anti-phytoplastic agents (cyazofamide, fluazines, flutolanil, oxathiopipron). The purpose of soil cultivation is the control of rhizoctoniosis, late blight, pitium and anthracnose (Table 5).
Table 5. Soil preparations for planting potatoes (official US state regulations for 2020)
where ft ft, 30 cm; lb - lb, 0,4 kg; A - acre, 0,4 ha.
Analysis of independent information allows you to choose the right active substances when processing potato seed. The list of controlled pathogens in tubers is limited to rhizoctonia, common and silvery scab, fusarium and phomosis (photo 1). Furrow or soil cultivation in general makes it possible to further reduce the infectious background of rhizoctonia, anthracnose, common late blight, wound watery (pitious) and pink rot. On top of this, microbiological and copper-containing preparations are effective against bacterial diseases.
Each active substance has a very specific spectrum of action. For example, penflufen and sedaxan are effective against scab, but ineffective against fusarium, while mancozeb and difenoconazole, on the contrary, prothioconazole significantly increases the effectiveness of the suppression of silver scab by pencycuron, etc. If Sercadis is recommended to be used separately in our country, then in the USA, when processing furrows, fluxapiroxade is mixed with pyraclostrobin (Priaxor drug). And this is not because of nothing to do, but for the sake of expanding the spectrum of action, one d.v-va is not enough. There are a number of restrictions on the time of use. For example, it is better to treat dormant, unsprouted potatoes with fludioxonil. Imazalil is recommended to be used only for early etching, but at the same time it is one of the few that inhibits oosporosis. There are differences in the assessment of specific drugs in different countries. So, in Europe, it is believed that azoxystrobin and other strobirulins should be applied only to the soil, it should not get on the tubers. In the USA, there is no such restriction, the substance is used for both tubers and furrows. Noteworthy is the fact that Western Europe, the USA and Canada are not going to abandon the dusts in the future, i.e. simple dusting of tubers without technical costs.
For Russian potato growers, the practice of spreading dust on tubers in the planter bunker is a long forgotten and nowadays unacceptable method. It is even difficult to imagine that in developed countries such a method of processing is still widely practiced, and this is under the slogans about ecology (True, powders based on penflufen, flutolonil and fludioxonil have already been banned in the EU by hand, only through applicators). There are two options for wet, liquid etching: in advance at the hospital and when planting in the field. Early pickling has a number of advantages - a quieter mode, more accurate dosage of the working solution, and increased potato planting productivity. But you need to be aware that high-quality treatment at a hospital is ultra-low-volume spraying with a working fluid flow rate of no more than 3 l / t. This is possible when using disc sprayers (see photo 2,3) on any rotating surface - hopper rollers, inspection tables or special Mafex equipment. The flow rate of working fluid 10-20 l / t allowed by the standards of the Russian Federation at the hospital should be recognized as erroneous and unacceptable. In the modern phytopathological situation, the apparent moistening of tubers is a deliberate provocation of the development of bacterial diseases. After treatment in a hospital, even on the eve of planting, the potatoes must be dried. If the processing is in the process of planting, the pickled potatoes were loaded and taken to the field, but it started raining and planting stopped for at least a day - immediately pour out and dry the seeds. Otherwise, problems with germination and rotting of tubers are inevitable.
Landing handling is still preferable. There is no need to warm up, dry tubers, there is no problem of applying plant protection products in storage and there are no risks of delayed planting after processing, not only tubers, but also soil are processed. But the planting process is slowed down, the number of equipment involved is increasing, there are difficulties in observing a constant flow of fluid and processing quality control. All modern potato planters are offered tank equipment for plant protection. It is better to use special hollow-cone nozzles, which are less prone to clogging with concentrated suspension solutions (see photo 4,5,6).
Syngenta provides buyers of its treating agents with brass sprays (photo 4), which are specially designed for the application of suspension concentrates, differ by less than 40% in drift from standard sprays with a hollow torch, due to their simple design they practically do not clog and do not require filters. They are made and installed in pairs. Both nozzles are set at an angle of 45 ° to the horizontal surface and are directed towards each other: a nozzle with an angle of 20 ° (long) for processing falling tubers is installed in the first casing along the planter; a sprayer with an angle of 70 ° (short) is designed to process the bottom of the furrow, partly the tuber, as well as the soil covering the furrow, is installed in the second building.
The correct installation of the sprayers on the openers of the planter is shown in photo 7,8. Processing only tubers (photo 7) loses its relevance, since with such an arrangement of the spray nozzles, the demolition of the working solution is possible. Simultaneous application of remedies to tubers and soil is much more effective. In this case, the front angled nozzle (1) can spray 1/3 of the liquid vertically down into the open furrow directly behind the furrow. The potato tuber then falls into the liquid-treated furrow. A second, angled nozzle (2) can inject 2/3 of the sprayed liquid into the moving soil with which the disc harrow covers the tubers. It is also recommended to use the hybrid version, so that part of the working solution is directed to the tubers.
The working solution of preparations for protecting and stimulating tubers during planting may contain up to five components: fungicide, insecticide, microbiological preparation, microfertilizer or growth stimulant, adjuvant. The choice of microfertilizers with the optimal ratio of nutrients, amino acids, adjuvants for better rooting and initial growth is extensive. Modern commercial products are quite technologically advanced and well distributed, mix in an aqueous solution without precipitation. With each new combination of drugs, this must be verified by the example of a small volume. Separately, only granular insecticides and nematicides need to be applied, for which special applicators are installed on the planter (photo 9,10). With the help of the applicator, the anti-nematode biological preparation Nematofagin-Mikopro based on predatory fungi is also introduced, since, according to the manufacturer's information, it is incompatible with fungicides.
The cost of dressing and stimulating potato planting material using the most effective drugs has doubled over the past five years and reaches 8-10 thousand rubles / ha. This is the third part of the entire protection system, yes, significant, but equivalent to the cost of one ton of potatoes. The increase in income from processing is many times higher than costs, and not so much due to an increase in yields, but due to an increase in product quality. At the same time, the processing of seed material must be carried out very skillfully. Rotten and injured tubers must be removed first and very carefully, otherwise their processing will lead to a sharp increase in the development of rot, especially when planting in waterlogged or insufficiently heated soil, which will lead to a decrease in the germination of potatoes. Exceeding the optimal consumption rate, an overdose of plant protection products should not be allowed, these are tough preparations, the plants will lag behind in growth for a long time. The use of fungicides during planting cannot eliminate internal infection in tubers, i.e. dressing cannot replace high quality seeds.
In conclusion, it should be noted that the treatment with means of protection and stimulating substances of seed is a mandatory and effective stage of the protection system in large-scale potato growing. In recent years, there has been significant progress in this area and new opportunities are opening up. The study and analysis of foreign information allows us to highlight the main trends in the protection of potato planting material. This is the expansion of the number of controlled pathogens, the transition from one-two-component drugs to three-four-component drugs, the transition from tubers to soil cultivation and the creation of new active substances of chemical and biological protection. Taking into account the change in the phytopathological situation, more attention should be paid to silvery scab, pithium, anthracnose, other soil infections and bacteriosis. The range of fungicides available in the Russian Federation is quite modern and diverse. The world's leading manufacturers of plant protection products are in no hurry to offer the latest combinations of d.v-v for Russia, but Russian firms (August, Shchelkovo-Agrokhim, Agro Expert Group) with multicomponent products Idicum, Deposit and King Combi look very relevant and competitive. In terms of soil cultivation with fungicides in Europe, including the Russian Federation, there is a clear lag behind the overseas level, but there is a lot to learn and there is something to take as an example, the main reserve for increasing the effectiveness of protection when planting is here. In terms of the effectiveness of microbiological preparations, the leadership, of course, belongs to European companies. The list of biofungicides in the Russian Federation is quite large, but narrow in biological composition, the declared effectiveness against diseases needs to be confirmed in practice. The proposed methods of controlling bacterial diseases using copper-containing fungicides and biological bactericides are of particular value and relevance.