Rapeseed, sunflowers, soybeans: successful planting and crops in good condition

Unlike the previous growing season, weather conditions between late March and late April were very favorable for early, concentrated planting of sunflower crops throughout the region. Today, more than 90% of the sunflower acreage has been planted, with sowing dates ranging from the last ten days of March—for a minority of fields—to April 27–28, before the return of rain on the weekend of May 1. Three main phases can be distinguished:

• March 23–27

The very first sowings on very marginal plots. These plots benefited from warm temperatures and residual soil moisture to germinate and emerge quickly, with limited pressure from pests (slugs) and predators (birds). These sunflowers are currently at the 4-leaf stage.

• April 4–10

Second sowing phase following light rains at the beginning of the month, just before a significant rain event between April 11 and 12. Currently at the 2- to 4-leaf stage, the crop was occasionally exposed to damage from birds (pigeons or corvids) and/or animals (badgers), with localized reseeding along plot edges in rare marginal cases. On the other hand, they benefited from rainy conditions that were favorable for the effectiveness of pre-emergence herbicide applications. Some of them were planted directly following a late, simplified mechanical removal of cover crops (a single pass with a rotary harrow) on poorly drained soils and/or soils that had become waterlogged due to excess water this winter, which can hinder the crop’s establishment.

• April 14–28

Third sowing phase, the most extensive, thanks to a long period of warm, dry weather. Growth stages ranged from germination to the two-leaf stage. While sowing quality was generally good to very good, the rapid drying of the soil and the lack of rain, particularly in the north and east of the region (Dordogne, Lot-et-Garonne, Gironde, Aude, Hérault) may have limited the effectiveness of herbicide applications following the earliest sowings, promoting weed growth, particularly grasses (bromegrasses, blood fescue, ryegrass, etc.) and/or dicotyledons (knotweed, bindweed, cocklebur, etc.). It will be important to monitor the development of weed infestation in the fields to best adjust weed control strategies based on the varieties planted (conventional varieties, varieties tolerant to herbicides containing Imazamox and/or Tribenuron) and the present flora (particular attention should be paid to difficult weeds, such as large-fruited ragweed, or Xanthium, Datura, wild sunflowers, etc.). 

For more information,

• Weed Control Strategies 2026 
• Reference articles on weed control 

The persistence of favorable conditions for spring planting over extended periods has, on the one hand, allowed for rapid progress in all “routine” planting for the season (dryland corn, sunflowers, irrigated corn, sorghum), and, on the other hand, for soybean planting to begin in earnest in areas where the soil is warmest (Gers, Lot-et-Garonne, Dordogne), with 40 to 80% of planting completed in the most advanced sectors, where the very first soybeans are at the first trifoliate leaf stage. In areas closer to the Atlantic coast and/or the Pyrenean foothills, as well as on farms where soybeans are a secondary crop, planting has also begun, but at a slower pace (between 0 and 20% of planting completed).

Over the past two weeks or so, rapeseed flowering has gradually come to a halt, giving way to the formation and filling of the siliques, on which the thousand-seed weight (TSW) now depends—an essential component of the final yield, along with the number of seeds per unit area.

While reserves are still available, with varying levels of filling depending on the cumulative rainfall recorded on April 11–12 and May 2–3, for all fields in the heart of the region (Gers, Haute-Garonne, Tarn-et-Garonne), this is no longer necessarily the case for the departments and watersheds further north (Lot-et-Garonne, Dordogne, Gironde) and to the east (Aude, Tarn, Aveyron), where rainfall has been less abundant, on soils with sometimes limited reserves, and where planting conditions may locally be average or degraded (soil structure issues, characterized by “bent or “forked” pivots, root system damage from winter waterlogging, poor growth in the fall, etc.).

Other local crop setbacks (delayed flowering and sometimes significant flower abortion in plots in the Ribérac region, exceptional pressure from the terminal bud weevil in certain plots in central Périgord and the Couronnes de Périgueux, etc.) may act as aggravating factors that will negatively impact the grain-filling phase in the event of prolonged water shortages.

As for the health status of the plots, disease pressure, with powdery mildew being the primary concern, is currently low to moderate for the majority of plots that received appropriate fungicide protection at stage G1 (fall of the first petals) or later (in some cases, treatments were delayed to better manage the powdery mildew risk and to ensure protection that is more focused toward the end of the cycle). A few symptoms of Mycosphaerella have been observed in the northern Dordogne, at levels that are not cause for alarm. As for pests, it is not uncommon to observe clusters of gray aphids along the edges of plots, particularly in the Gers, where the first colonies may have arrived earlier than elsewhere. In these situations, initial migrations to the edges of plots have occurred, at levels below the intervention thresholds.

For more information: 

• BSV Field Crops – Midi-Pyrénées and Ex-Aquitaine
• Monitoring and Control of the Ash
  Aphid 

De violents orages, accompagnés de fortes pluies voire d’importantes chutes de grêles localisées, se sont produits dans l’Ouest du Gers et au Nord des Hautes-Pyrénées et le Sud de la Haute Garonne sur ce début de mois de mai occasionnant d’importants dégâts sur les cultures présentes sur leur passage (verse et casse de siliques et d’épis sur Colza, Orge d’hiver et Blé tendre) ainsi que sur les semis en cours de levée (maïs, tournesol), avec de possibles re-semis à prévoir dans les parcelles les plus impactées. Les estimations des dégâts sont en cours.