Parmi les arthropodes occasionnellement nuisibles aux pommiers de nos vergers, se trouvent des hyménopthères. Ce sont pour l'essentiel des tenthrèdes, dont les hoplocampes...Les traitements péri-floraux, notamment ceux appliqués à la chute des pétales ont permis de limiter les pullulations de ce ravageur qui avait pratiquement disparu de nos vergers depuis. La tendance actuele à diminuer les interventions chimiques? Apple sawfly Hoplocampa testudinea is a Tenthredo (hymenopterous), which in the past was extremely harmful. Over the last 40 years it has been rare, but recently there have been fresh outbreaks probably due to the lack of treatment. It lays its eggs in the flowers and the larvae spread over the young fruit. This fruit will then fall off or even be infested from within and is inedible. Insecticide treatment is possible but not systematic (two products are authorised) and is only needed if the insect pest exists (areas having suffered in the previous year).
The pear sawfly (Hoplocampa brevis) has a similar biology and is as harmful as the apple sawfly (lays eggs in the flowers, infests the young fruit which falls off and are inedible). Chemical control is also possible (one single product authorised).
