Beetle 1.5-2.5 mm, shiny black. Feeds on pollen. Larvae in flowers and buds, up to 4 mm, black head, three pairs of legs. Pupation in the ground. From the middle of June the young beetles hatch and ripen, from August they visit the winter storage facilities. One generation/year.
Damage is caused by the beetle feeding on the unopened buds. The earlier and more severe the infestation, the greater the possible damage. No more damage to open flowers. Damage to nymph only with mass reproduction.
Yellow trap detects inflow start and activity
Determination of infestation intensity by counting/ tapping 10 plants in a row.
Control guideline small bud: normal/strong stands: > 8 beetles/leading shoot; stressed/weak stands: >4 beetles/ leading shoot.
Control guideline large bud: normal/ vigorous stands: > 10 beetles/ leading shoot; stressed/ weak stands: > 5 beetles/ leading shoot.
In cold weather, check buds of lower side shoots!
Leave a spray window. After treatment, next morning check before the new influx.
Blossom rapeseed beetles and their larvae with many natural enemies. Ladybirds, ground beetles, rove beetles, short-winged beetles, larvae of networms, ichneumon wasps and others can decimate up to 90% of the larvae under favourable conditions.
Protect beneficial insects. Use insecticides only when damage thresholds are exceeded.
Blossom rapeseed beetle
Early infestation destroys buds
Buds eaten earlyby the blossom rapeseed beetle fall off