Taking care of the health of sunflowers, it is important to apply a complex of measures: growing resistant hybrids, seed treatment, crop rotation, destruction of plant residues, weeds as reservoirs of infection, protection of vegetative mass. Based on this, the development of diseases is determined and predicted, and the selection of fungicides is carried out. The main diseases of sunflowers are downy mildew, leaf spot diseases (septoria leaf spot, alternaria leaf spot, phomopsis, phomopsis) and head rots (sclerotinia, gray and dry rots).
Читай нас також у Viber та Telegram.
Downy mildew of sunflowers is not only a weed in subsequent crops, but also a significant reservoir of infection, primarily for downy mildew. Therefore, downy mildew is one of the first diseases to appear in sunflower crops, especially in hybrids with weak resistance to this disease. The spread of the fungus spores from downy mildew intensively occurs in crops at approximately the 8-leaf stage. Emphasizing the control of early downy mildew, it is recommended to use Relevant, KS (cymoxanil, 225 g/l + thiophanate-methyl, 375 g/l + fermentation product of Streptomyces spp., 5 g/l).
Relevant consists of three active substances from different chemical groups. Cymoxanil is a highly systemic active substance against downy mildew fungi. It quickly penetrates the treated plant and blocks the spread of infection. Thiophanate-methyl, due to moderate lipophilicity and solubility, not only protects the plant from fungal penetration but also exhibits long-lasting curative action. It has a preventive effect on the pathogens of sclerotinia and most leaf spot diseases. The fermentation product of Streptomyces shows pronounced bactericidal properties. This composition helps to keep the plant healthy and the leaf surface clean for active photosynthesis and maximum productivity.
In the pathogenic complex of sunflowers, fungal diseases undoubtedly dominate. However, viral and bacterial diseases also require control. If protection against viruses mainly involves controlling their vectors (leafhoppers, thrips, aphids), then in the case of bacterial diseases, more significant tools are needed – the use of bactericidal agents. Most of them are of natural origin, created based on the products of the metabolism of other microorganisms, including actinomycetes.
Under humid conditions, a simultaneous development of fungal and bacterial diseases can be observed on affected plants. For example, after the development of septoria on damaged and dead tissues, bacteria begin to colonize, especially on lower leaves closer to the soil surface. The soil, along with infected seeds, is the main source of bacterial infections. The use of typical fungicides against only fungal diseases can increase plant contamination with bacteria, as they will not feel competition for nutrients from other microorganisms or the influence of their metabolic products. The accumulation of infection on lower leaves triggers the development of bacterial diseases throughout the plant, spreading across the field. Affected leaves prematurely die, negatively affecting future yields. Therefore, it is recommended to apply the fungicide Relevant in the 2-8 leaf stage to control downy mildew and prevent leaf spot diseases, sclerotinia, and bacterial diseases. The effectiveness of Relevant can be confirmed by 190,000 hectares of sunflowers and soybeans protected from downy mildew and associated infections by this product in 2025. This represents 23% of all areas where fungicides against downy mildew were used.
Leaf spot diseases. The most common infectious leaf spot diseases on sunflowers are septoria leaf spot, alternaria leaf spot, phomopsis, and phomopsis, which can cause yield losses of up to 30-40%. In favorable years for infection, the losses can be even higher, especially if these diseases affect the upper leaf layers.
It has been repeatedly proven that neglecting the protection of lower leaves leads to the gradual spread of infection upwards to the head. This is already a very dangerous phenomenon because yield losses will be reflected not only in a smaller number of seeds in the head but also in their underdevelopment (lower weight). The quality of the product deteriorates, oil content decreases (by 5-12%), and the oil acquires a bitter taste.
It is known that blocking the growth of fungi on the plant surface is crucial for diseases like these, and in case of infection, preventing their growth in tissues is essential. In the first case, contact-systemic active substances will have an advantage, and when it comes to treatment, there are currently no triazoles that are as effective.
To address this complex challenge, Artis Plus, KS (miklobutanil, 125 g/l + tebuconazole, 125 g/l + thiophanate-methyl, 250 g/l) was developed. In the formulation of Artis Plus, scientists combined active substances with different chemical properties (solubility, lipophilicity, etc.), effective against pathogens of various fungal diseases. This provides additional advantages of the product:
– Miklobutanil, due to high water solubility, quickly enters the plant’s sap and blocks the spread of infection in tissues, distributing in new growth, protecting even the part of the plant that did not receive treatment or emerged after fungicide application.
– Tebuconazole moves somewhat slower, ensuring an extended period of curative action in sunflower leaves and stems.
– Thiophanate-methyl creates a reliable protective screen against new infections, slowly penetrating the plant.
The synergistic combination of the three active substances in Artis Plus has expanded the spectrum of curative action and provided a longer period of plant protection against leaf spot diseases.
Artis Plus has remained the number one fungicide for controlling leaf spot diseases on sunflowers for several years. For example, last year, it protected 395,000 hectares of crops, indicating high trust in the product.
Not stopping at the achieved results, in 2025, a new fungicide for sunflowers and cereals, Barrett, KE (prochloraz, 340 g/l + tebuconazole, 160 g/l + propiconazole, 100 g/l) was introduced. This powerful solution in combating leaf spot diseases is its key advantage – enhanced curative action against a wide range of infections. The recommended application rate of Barrett for sunflowers is 0.8-1.2 l/ha. Therefore, even at the average rate of 1 l/ha, 340 g/ha of prochloraz and 260 g/ha of triazoles will be applied per hectare, sufficient for reliable disease control at a moderate level of spread.
In the first year of application, we have received positive feedback from customers regarding the control of phomopsis, septoria leaf spot, alternaria leaf spot, and downy mildew with Barrett. Therefore, for the protection of hybrids with low resistance to these diseases, we recommend Barrett as the main fungicide. The curative action of the two triazoles, enhanced by prochloraz, provides protection for 3-4 weeks.
Head rot. The final and decisive stage in disease control in sunflowers is head protection. The head is a fairly massive plant organ, rich in moisture. Pollen and flower petals are good nutrient environments for microorganisms, including pathogens. It is also important to avoid damage to the head: mechanical or caused by pests.
For many farms, sclerotinia is an annual problem due to a significant infection reservoir in the soil (the pathogen’s viability can last up to 4-6 years). Soybeans, rapeseed, and most vegetables are also affected by sclerotinia. Crop rotation can somewhat improve the soil by sowing cereal crops and corn on such fields. In the absence of immune or highly resistant hybrids, the only hope is in fungicides.
If the risk of rot development on the head is low (the cultivation and protection technology correspond to the hybrid’s characteristics, and the weather conditions are without excessive moisture), then the optimal protection solution will be the fungicide Amicon, EW (pyraclostrobin, 125 g/l + miklobutanil, 125 g/l). Miklobutanil is a systemic active substance with high solubility (132 mg/l), which quickly penetrates the plant through the assimilating parts and evenly spreads through the xylem within 1-2 hours after application. This ensures rapid localization of existing infections and reliable protection of new growth. Miklobutanil’s high activity in the gas phase helps additionally protect the plant surface that did not come into contact with the fungicide solution.
On the other hand, pyraclostrobin in Amicon has low water solubility (2 mg/l), but one of the highest lipophilicity coefficients among strobilurins (4). Therefore, it reliably binds to the wax layer of the head and leaves, creating a stable supply of active substance on the plant surface resistant to washing off by precipitation. The continuous release and redistribution of pyraclostrobin during diffusion ensure prolonged protection of plants from leaf spot diseases and rots.
The emulsion oil-in-water form of the fungicide contributes to better coverage and faster penetration of active components into the plant. This is crucial under critical summer application conditions, as even after the fungicide solution dries, the oil film on the plant surface provides additional time for complete penetration of the product into the plant.
Importantly, the fungicide Amicon contributes to improving the quality and quantity indicators of yields not only by protecting the plant from infections but also by showing a pronounced healthy cell effect. This ensures the full vegetation of the crop and its use of solar insolation.
However, if enhanced protection of the head and upper leaf layers is needed, we recommend using Telamus, EW (boscalid, 133 g/l + pyraclostrobin, 167 g/l + propiconazole, 200 g/l). This premium-segment product with curative action provides prolonged protection against infection.
Agronomists in Ukraine speak positively about boscalid. It is often indispensable in controlling sclerotinia, gray rot, powdery mildew, and leaf spot diseases on sunflowers, rapeseed, vegetables, and orchards. Its advantages include affinity with the plant’s wax layer and high resistance to sunlight, rapid penetration, and uniform redistribution in tissues, resistance to washing off by precipitation, and long persistence.
After application to the plant, part of boscalid is fixed in the wax layer and cuticle, blocking the growth of fungi, the formation of infectious hyphae, and plant invasion. The rest of the active substance penetrates the tissues of treated leaves and moves trans-laminarly. Boscalid also accumulates in the cuticle and mesophyll of the leaf, gradually dissolving and locally moving through the plant. This feature ensures prolonged protective and moderate curative action against the pathogens of many diseases.
Similarly, pyraclostrobin is redistributed in the treated plant and reliably binds to the wax layer with gradual movement to the lower side of the leaf. Pyraclostrobin protects against rot, septoria, phomopsis, and alternaria infections.
Propiconazole has high solubility and pronounced curative action, so it is quickly absorbed by the plant, moves through the xylem to the site of infection, and blocks the pathogen’s further development even at the first visible signs of infection. It is effective against leaf spot diseases, rusts, and powdery mildew.
The synergy of boscalid and pyraclostrobin provides prolonged preventive action against sclerotinia, gray and white rots, leaf spot diseases, while the combination of boscalid and propiconazole offers a fast and enhanced curative effect. Depending on the plant’s condition at the time of treatment, hybrid resistance, and weather conditions, the protective period lasts up to 21-28 days.
This achieves excellent control of a wide range of phytopathogens from different genera, including rots, leaf spot diseases, rusts on the head and upper leaves. The recommended application phase for Telamus is BBCH 55-65 (mid-budding to flowering), depending on the technology and the FAO hybrid. Late-maturing hybrids are recommended to be treated closer to BBCH 65.
Therefore, the sunflower protection system must be comprehensive: resistant hybrids, seed protection, destruction of plant residues, weeds (especially from the aster family: common ragweed, common nettle, mugwort, chickweed), protection of vegetative mass. Precautionary treatment of crops against dominant diseases considering the hybrid’s resistance level, crop rotation, infection reservoir, and weather conditions is crucial. Most diseases have a long incubation period (e.g., phomopsis – up to 55 days), and after symptoms appear, they quickly spread, producing infection for re-infection of crops. Therefore, achieving fungicidal protection effectiveness at a level of 90% and above is ensured by timely application.
Five specialized fungicides – Relevant, Artis Plus, Barrett, Amicon, and Telamus – help agronomists effectively protect sunflowers from specific diseases (downy mildew), mixed infections (leaf spot diseases), and rots.
Alfa smart agro – care that bears fruit.
For orders, contact regional managers of alfa smart agro and see the effectiveness of the products in your fields.
Details at the link.
All field solutions in one application – alfa smart agro. Assistance that is always at hand.