Ladybirds will eat Viburnum beetle larvae. Encourage Ladybirds into the garden by creating bug hotels for them to live in, near to Viburnum plants. Log piles, climbers, hanging baskets and flower patches make good refuges for natural enemies.
They're also predated by spined-solider beetles, jumping spiders, lacewing and hoverfly larvae.
Random checks beneath leaves are encouraged. Hand removal and dispose of Viburnum beetle larvae, if it is only a small number.
If a large infestation of Viburnum beetle larvae, then the plant may have to be left and after the attack, feed and water to encourage recovery and new growth. An adult Viburnum plant should survive an attack even if near total defoliation has occurred.
Check current years stems in early winter for egg-laying sites. Small round marks, flat or slightly domed 2mm to 3mm in size are capped egg sites and prune out and dispose of.
It's been proposed that using tanglefoot at the base of trees may act as a barrier, preventing larvae reaching the soil to pupate.
Horticultural oils are proposed to interrupt egg hatching, however, may scold trees in bright light.
Pyrethrin-containing organic pesticides can be used, but are only effective against the larvae. Should never be used if flowers are present.