Most rapeseed crops are currently at the E to F1 growth stages. Milder weather could reignite flea beetle activity, as the first flowers are now visible in nearly two-thirds of the fields.
Following an early and nearly widespread arrival of the pest in late February, threats persist in fields with slow growth or in sheltered areas (valleys, wooded edges).
This year, flea beetle larvae are weakening the crop and reducing its resilience. Weevil pressure frequently exacerbates the situation.
Many fields have already been treated against weevils, but a follow-up treatment may be warranted as long as flowering has not clearly begun. Conversely, on healthy rapeseed that has passed the E-F1 stage, the risk of damage quickly becomes negligible, making insecticide treatment unnecessary.
At this time, treatments must remain strictly targeted at plots with confirmed risk, using solutions based on tau-fluvalinate or etofenprox. Apply under favorable conditions (sufficient humidity, limited wind, avoid hot hours) with a water volume > 200 L/ha and strictly outside foraging periods, in accordance with current regulations.
Jean Lieven - j.lieven@terresinovia.fr