Viburnum beetle

Viburnum beetle can cause defoliation of some Viburnum species, especially V. tinus and V. opulus.

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Viburnum beetle damage on guelder rose <EM>Viburnum opulus</EM>
Viburnum beetle damage on guelder rose Viburnum opulus

Quick facts

Common name Viburnum beetle
Scientific name Pyrrhalta viburni
Plants affected Viburnum tinus, V. opulus, V. lantana and other Viburnum spp.
Main symptoms Foliage with many holes eaten by the larvae and adult beetles
Most active Late April-June (larvae) and late July-August (adult beetles)

What is viburnum beetle?

Viburnum beetle is a leaf beetle (family Chrysomelidae). There are about 250 leaf beetle species found in Britain. They all feed on plants, most are do not have a noticeable effect on garden plants, many are colourful and many species are  local or rare. 

Viburnum beetle feeds on viburnums. Most of the damage is caused by the larvae in spring but some further defoliation is done by  the adult beetles in late summer.

Large numbers of larvae can result in most of the foliage being severely affected by late spring. Damaged leaves are often also discoloured with brown dried up edges to the holes. Affected Viburnum tinus often produces an unpleasant odour particularly when the foliage is wet.

Symptoms

  • Holes eaten in the leaves of viburnums, with the larger leaf veins remaining, giving the foliage a lace like appearance
  • Creamy yellow larvae, with black markings and up to 8mm long, are present on plants from April to June
  • Greyish brown adult beetles, 4.5-6mm long, feed on the leaves from late July to September

Management

Check susceptible plants frequently from early spring onwards so action can be taken before a damaging population has developed. When choosing control options you can minimise harm to non-target animals by using the methods in the non-pesticide section below. Pesticide treatments are likely to kill natural enemies and are only likely to be successful if the entire plant can be reached.

Control for viburnum beetle if necessary, should be targeted at the larvae in spring. Adult beetles occurring later in the season cause less damage, can fly into gardens and are more tolerant of control measures. 

Non-pesticide 

  • Where possible tolerate populations of larvae and adult beetles, viburnums usually recover from defoliation caused by this beetle
  • Remove larvae by hand where practical
  • Encourage wildlife in the garden, such as birds and predatory ground beetles who will eat the larvae and sometimes the adult beetles
  • Biological control nematodes for this beetle are available from some biological control suppliers. These are watered onto plants affected by larvae. Nematode controls have the potential to infect non-target animals. They should therefore be used with care and only when there is a specific problem to treat

Pesticides

The RHS recommends that you don't use pesticides. Most pesticides (including organic types) reduce biodiversity, including natural enemies, impact soil health and have wider adverse environmental effects.
 
Where you cannot tolerate viburnum beetle, manage them using the information above as your first course of action.
 
Pesticide treatments are likely to kill natural enemies and so reduce the likelihood of natural control and can lead to resurgence of the target animal.
 
If you do decide to use pesticides, the shorter persistence products (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife.
 
The pesticides listed are legally available in the UK. This information is provided to avoid misuse of legal products and the use of unauthorised and untested products, which potentially has more serious consequences for the environment and wildlife than when products are used legally.
 
Always follow the instructions on the products. For edible plants, make sure the food plant is listed on the label and follow instructions on maximum number of applications, spray interval and harvest interval.
 
Homemade products are not recommended as they are unregulated and usually untested.
Be aware that products such as Neem oil are not registered for use in the UK and we cannot advise on their use.
 
Plants in flower must not be sprayed due to the danger to bees and other pollinating insects.
 
  • Organic contact insecticides containing natural pyrethrum (e.g. Bug Clear Ultra 2, Neudorff Bug Free Bug and Larvae Killer) have a largely physical mode of action. These are broad spectrum so will kill a wide range of insects. Several applications of these short persistence products may be necessary to give good control. Plant oil and fatty acid products are less likely to affect larger insects
  • Further information about the use of pesticides available is on the pesticides for gardeners leaflet

Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Garden Advice. It is a list of products currently available to the home gardener
 

Downloads

Pesticides for gardeners (downloads pdf document outlining pesticides available to home gardeners)
 

Biology

Viburnum beetle overwinters as eggs that are deposited in the bark of the current years growth of viburnums in late summer. These eggs hatch in late April-early May and the larvae begin feeding on the new foliage. When fully fed in late May-June, the larvae go into the soil to pupate. Adult beetles emerge in late summer.

Most of the damage is caused by the larvae during late spring. Adult feeding damage on the foliage is much less extensive than that of the larvae.

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