Pyralid pressure drops in Normandy maize crops

A report by the technical institute Arvalis found that pyralid pressure in Normandy's maize crops was low in 2026, with the pest present in all departments across the region. The decrease was linked to dry and warm weather, fewer larvae in 2025, and a return to sole maize cultivation after previous planting challenges.

Pyralid activity peaks in early July

Pyralids were first observed around June 16, with their numbers increasing gradually and peaking in early July. This peak was short-lived and high due to specific climatic conditions that compressed the usual flight period of the moth.

Larvae counts reveal reduced infestation

Larvae counts in stalks before harvest indicated a general decrease in infestation, with only 5% of plants affected by pyralid damage. However, early silage harvests made counting difficult, as only four plots were examined.

Shredding stalks helps reduce larvae

Shredding maize stalks was found to be 50 to 70% effective in reducing larvae populations. The Plant Health Bulletin recommends fine shredding followed by burial to destroy larvae or expose them to cold and predators, with improved effectiveness when done immediately after harvest.

Sesame moth spreads across Normandy

The sesame moth, rare in the region until recently, has now spread throughout Normandy. Eleven pheromone traps captured 40 moths between June and August, with a peak in mid-July, indicating a growing presence of the pest in the area.

Sesame moth has similar impact to pyralid

The sesame moth's damage is comparable to that of the pyralid, with no clear difference in harmfulness. Both pests require similar preventive measures, such as crop rotation, shredding, and burial of harvest residues.

Eure Valley monitors maize chrysomelid

The Eure Valley is under surveillance for the maize chrysomelid, a small beetle originally from America. It has been detected in the area since 2021, with a few sightings each year, mostly in plots that frequently return to maize cultivation.

Managing the maize chrysomelid

The beetle is no longer subject to eradication efforts, and instead requires management practices such as systematic shredding of stalks before burial and crop rotation in affected areas to prevent population growth.