Grape Growers Battle Mildiou and Black Rot in the Gard Region

winegrowers in the Gard region of France are facing increased challenges due to persistent rainfall since mid-April, creating ideal conditions for the proliferation of grapevine diseases. Despite the adverse weather, growers have been diligently working to manage and contain the spread of these diseases, leveraging brief respites in the rain to apply treatments.

Recent reports indicate widespread outbreaks of Mildiou, also known as downy mildew, across numerous locations including Moussac, Saint Maurice-de-Cazevieille, Aspères, and several others.The Plant Health Bulletin (BSV) issued on May 6th highlighted the presence of sporing spots on both young shoots and within the vine’s core. In the Alasian basin, some households are reporting significant infestations, with early signs of the disease appearing on Grenache inflorescences in Vauvert.

Given the climatic conditions of the past and future week, the risk is strong and increasing.

Plant Health Bulletin (BSV), May 6, 2025

The BSV analysis emphasizes that even minimal rainfall or high humidity levels in affected areas are now sufficient to trigger secondary contamination. Bernard Genevet, a wine consultant for the Cooperative Wine Institute (ICV), noted the severity of the situation:

We expected that the mildiou starts this campaign strongly, this is the case. It rains all the time,diseases come out.

Bernard Genevet,Cooperative Wine Institute (ICV)

Black Rot Symptoms Emerge

Adding to the challenges,symptoms of black Rot have also been observed as late april. The BSV reports the presence of lesions on leaves, with and without pycnidia, across the department, excluding sandy and southern Costières areas. The intensity varies from a few spots per plot to multiple spots per vine, with occasional symptoms appearing on branches. The rains and morning humidity from April 27th to May 5th are considered potential sources of new infections.

Genevet confirmed the consistent rainfall pattern, stating that some areas have received considerable amounts of rain over several weekends, creating an incubation surroundings for the disease.

Growers Race Against Time

With forecasts predicting more storms, winegrowers are intensifying their efforts to protect their crops. Many are already applying their third treatment, with some on early grape varieties even proceeding with a fourth, an unusual practice for early May. fortunately, the weather has provided enough breaks for growers to access and treat their plots.

Despite the strong disease pressure, vineyards remain well-protected and accessible. Genevet reassured that while priority has been given to spraying, causing some delays in soil work and pruning, these tasks will be addressed. He also highlighted a positive aspect: the vines are currently shielded from drought, at least until early june.

The ICV is currently assessing the fertility of the vintage by counting inflorescences on 110 plots, providing valuable insights into the potential yield.