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The 2025–26 rapeseed crop has been experiencing flowering difficulties that have been widely observed over the past 10–15 days, with plants that are weakened but often still capable of compensating. The mild, wet winter led to early and rapid regrowth and stem elongation, causing a mismatch between growth and the supply of nitrogen and assimilates.

Flea beetle larvae have been significantly more prevalent than in the past 3–4 years.
The terminal bud weevil has remained confined to its traditional areas (Centre, Champagne, Bourgogne-Franche-Comté, Auvergne), causing consistent damage to young rapeseed plants in particular. Cabbage root maggots were observed early across the entire country, with more moderate pressure in the Grand Est and Hauts-de-France regions. The western regions (Brittany, Pays de la Loire, Poitou-Charentes), however, experienced exceptional, even unprecedented, pressure.  

All these pests weakened the plants and exacerbated bud loss.

The episodes of frost and wide temperature swings in March are fairly typical for the season. Their impact remains difficult to quantify, but they likely played an aggravating role in certain situations, particularly in Burgundy, Centre, Île-de-France, Normandy, and Pays de la Loire. Sensitivity is heightened in cases of low or heterogeneous biomass (Burgundy, Champagne-Ardenne, Auvergne).

Regions with later development (Lorraine, Alsace), where rapeseed remains less advanced than elsewhere (mostly at stage E as of March 25), appear less impacted for now. However, several factors already point to converging trends and scenarios. To be continued.

As part of FiLoLég, an initiative promoting grain legumes in the Hauts-de-France region, a webinar was held on March 24 to explore potential strategies for optimizing the use of legumes, creating new value chains, and strengthening protein self-sufficiency.
 

The webinar provided an overview of emerging protein crops, examples of existing value-added initiatives, and promising innovations, with a focus on the opportunities offered by pea starch and its industrial uses, as well as insights into potential ways to utilize fava bean hulls. 

To watch the webinar replay

In Poitou-Charentes, Vendée, and Centre-Val de Loire, rapeseed crops were subjected to heavy pressure from pollen beetles in late February and early March during their early growth stages. Dropping nighttime temperatures and morning frosts locally exacerbated damage to floral parts, resulting in the loss of buds and even flowers. Other crop issues were often already present: widespread infestation of large flea beetle larvae, and locally, of terminal bud weevil larvae; poor root development and/or a taproot degraded by winter waterlogging. This is unprecedented: such an extremely early growing season with flowering beginning on March 5–10.  With much shorter daylight hours than in April, we can assume impacts on plant function, including reduced light energy capture and lower mobilization of assimilates. Added to this are the consequences of delayed fertilizer applications for a crop that is ahead in development (waiting for the soil to dry out), sometimes resulting in a significant delay between application and utilization (waiting for the return of rain). High temperatures have also accelerated the development of rapeseed, which has not always been able to feed itself properly and at the right time: climatic stress was exceptionally high in March. The explanation for plots in difficulty is often multifactorial. These abnormally stressed rapeseed plants could rebound once favorable conditions return.

Today, flowering is impaired in many situations, and the timing of fungicide application requires careful consideration. Forecasted weather conditions are dry and cold, which is generally unfavorable for the development of Mycosphaerella in affected fields. Additionally, wind will reduce application windows and limit the number of petals adhering to leaves (a route of Sclerotinia contamination).

In this context, determining stage G1 is complicated, and consequently, the decision to apply the key fungicide is as well. As a reminder, stage G1 is commonly referred to as “the first petals falling,” but petals fall from the very start of flowering! Another definition of this key stage is possible and easier to grasp: it is the formation of the first siliques on the main stem.

Stage G1 reached: Schedule fungicide application	No siliques Stage G1 NOT reached Wait
March 26, 2026, Angliers (17)