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In 2025, Terres Inovia conducted a survey on sunflower cultivation practices. The results highlight several trends that should be considered in light of the technical recommendations.
Later planting in the Southwest
In 2025, sowing dates appear to be later in the Southwest region than in other production regions. The median sowing date is April 25 in this region, compared to April 10 in the Northeast.
This trend had already been observed in previous surveys. It raises questions because soils in the Southwest are generally expected to warm up more quickly than those in other regions. Several technical explanations can be offered, however, such as the practice of false sowing or the deliberate postponement of sowing due to the risk of bird damage.
Nevertheless, bringing forward the sowing date is a major factor in improving sunflower resilience by allowing the crop to make better use of available resources and avoid certain stresses.
Herbicide-tolerant varieties continue to gain ground
Herbicide-tolerant varieties (HTVs) continue to gain ground and will account for 50% of the surveyed acreage by 2025.
However, these varieties should be reserved for difficult weed situations, when weeds cannot be effectively controlled with pre-emergence herbicides. This is particularly the case when xanthium, wild sunflowers, ragweed, datura, thistles, or hedge bindweed are present.
The herbicides that can be used on these varieties, such as Pulsar 40, Davaï, Passat Plus, or Express SX, rely on a mode of action already widely used in French crop rotations: ALS enzyme inhibition. Repeated use of this mode of action exerts selection pressure that can promote the emergence of resistant weeds.
To limit this risk, it is essential to first consider agronomic strategies: crop diversification, staggering sowing dates, false sowing, etc. It is also important to strictly adhere to the product’s instructions for use: dose, number of applications, frequency, and sequence of treatments. Finally, alternating herbicide modes of action within the crop rotation remains essential.
VTH and lack of post-emergence control: a major concern
According to the survey, 17% of fields planted with VTH reportedly did not receive post-emergence treatment. While this situation may be explained by a lack of opportunities for application, particularly due to unfavorable weather conditions, it is nevertheless important to note that this practice poses a major risk if wild sunflowers are present in the field. In fact, beyond the risk of selecting for resistant weeds, there is a risk of transferring herbicide tolerance to wild sunflowers.
Therefore, when using a Clearfield, Clearfield Plus, or Express Sun variety, and in the presence of wild sunflowers in the field, several rules must be followed:
• Weed control must be performed using Pulsar 40, Davaï, Passat Plus, or Express SX, applying the full dose at the 4-leaf stage of the sunflower.
• Do not leave any untreated areas in the field. Follow up with cultivation if necessary.
• Destroy wild sunflowers present in untreated areas—such as field edges, areas near utility poles, or hard-to-reach zones—before flowering by pulling them up, shredding them, or using any other appropriate method.
• After weeding, if any untreated wild sunflower plants are observed, resistance development may be suspected. In this case, you must promptly notify your technician to conduct a more thorough diagnosis and ensure that the affected plants are destroyed.
Nitrogen fertilization: adjust application rates to actual needs
Mineral nitrogen was applied to 85% of the sunflower fields surveyed in 2025. When applied, the median rate was 50 units.
Given the current high prices of nitrogen fertilizers, it is important to remember that the soil is generally capable of meeting a significant portion, if not all, of the crop’s needs. To optimize nitrogen fertilization for sunflowers and determine the actual required rate, Terres Inovia recommends using the Héliotest method or a soil analysis.
Diseases: Remain Vigilant Despite a Slight Increase in the Survey
According to survey respondents, diseases do not appear to be a factor that has compromised yields. However, they are still regularly observed elsewhere, particularly in survey plots, with Verticillium being a notable example.
It is therefore important to monitor the fields throughout the growing season to assess their health status. This assessment helps guide technical decisions for the following growing season.
In sunflowers, when it comes to diseases, variety selection is a key factor, in addition to crop diversification within the rotation.
